drivers/gpu/drm/drm_dp_mst_topology.c

   1 /*
   2  * Copyright © 2014 Red Hat
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and its
   5  * documentation for any purpose is hereby granted without fee, provided that
   6  * the above copyright notice appear in all copies and that both that copyright
   7  * notice and this permission notice appear in supporting documentation, and
   8  * that the name of the copyright holders not be used in advertising or
   9  * publicity pertaining to distribution of the software without specific,
  10  * written prior permission.  The copyright holders make no representations
  11  * about the suitability of this software for any purpose.  It is provided "as
  12  * is" without express or implied warranty.
  13  *
  14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  20  * OF THIS SOFTWARE.
  21  */
  22
  23 #include <linux/bitfield.h>
  24 #include <linux/delay.h>
  25 #include <linux/errno.h>
  26 #include <linux/i2c.h>
  27 #include <linux/init.h>
  28 #include <linux/kernel.h>
  29 #include <linux/random.h>
  30 #include <linux/sched.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/iopoll.h>
  33
  34 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
  35 #include <linux/stacktrace.h>
  36 #include <linux/sort.h>
  37 #include <linux/timekeeping.h>
  38 #include <linux/math64.h>
  39 #endif
  40
  41 #include <drm/drm_atomic.h>
  42 #include <drm/drm_atomic_helper.h>
  43 #include <drm/drm_dp_mst_helper.h>
  44 #include <drm/drm_drv.h>
  45 #include <drm/drm_print.h>
  46 #include <drm/drm_probe_helper.h>
  47
  48 #include "drm_crtc_helper_internal.h"
  49 #include "drm_dp_mst_topology_internal.h"
  50
  51 /**
  52  * DOC: dp mst helper
  53  *
  54  * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
  55  * protocol. The helpers contain a topology manager and bandwidth manager.
  56  * The helpers encapsulate the sending and received of sideband msgs.
  57  */
  58 struct drm_dp_pending_up_req {
  59         struct drm_dp_sideband_msg_hdr hdr;
  60         struct drm_dp_sideband_msg_req_body msg;
  61         struct list_head next;
  62 };
  63
  64 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
  65                                   char *buf);
  66
  67 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
  68
  69 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
  70                                      int id,
  71                                      struct drm_dp_payload *payload);
  72
  73 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
  74                                  struct drm_dp_mst_port *port,
  75                                  int offset, int size, u8 *bytes);
  76 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
  77                                   struct drm_dp_mst_port *port,
  78                                   int offset, int size, u8 *bytes);
  79
  80 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
  81                                     struct drm_dp_mst_branch *mstb);
  82
  83 static void
  84 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
  85                                    struct drm_dp_mst_branch *mstb);
  86
  87 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
  88                                            struct drm_dp_mst_branch *mstb,
  89                                            struct drm_dp_mst_port *port);
  90 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
  91                                  u8 *guid);
  92
  93 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
  94 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
  95 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
  96
  97 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
  98                                                  struct drm_dp_mst_branch *branch);
  99
 100 #define DBG_PREFIX "[dp_mst]"
 101
 102 #define DP_STR(x) [DP_ ## x] = #x
 103
 104 static const char *drm_dp_mst_req_type_str(u8 req_type)
 105 {
 106         static const char * const req_type_str[] = {
 107                 DP_STR(GET_MSG_TRANSACTION_VERSION),
 108                 DP_STR(LINK_ADDRESS),
 109                 DP_STR(CONNECTION_STATUS_NOTIFY),
 110                 DP_STR(ENUM_PATH_RESOURCES),
 111                 DP_STR(ALLOCATE_PAYLOAD),
 112                 DP_STR(QUERY_PAYLOAD),
 113                 DP_STR(RESOURCE_STATUS_NOTIFY),
 114                 DP_STR(CLEAR_PAYLOAD_ID_TABLE),
 115                 DP_STR(REMOTE_DPCD_READ),
 116                 DP_STR(REMOTE_DPCD_WRITE),
 117                 DP_STR(REMOTE_I2C_READ),
 118                 DP_STR(REMOTE_I2C_WRITE),
 119                 DP_STR(POWER_UP_PHY),
 120                 DP_STR(POWER_DOWN_PHY),
 121                 DP_STR(SINK_EVENT_NOTIFY),
 122                 DP_STR(QUERY_STREAM_ENC_STATUS),
 123         };
 124
 125         if (req_type >= ARRAY_SIZE(req_type_str) ||
 126             !req_type_str[req_type])
 127                 return "unknown";
 128
 129         return req_type_str[req_type];
 130 }
 131
 132 #undef DP_STR
 133 #define DP_STR(x) [DP_NAK_ ## x] = #x
 134
 135 static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
 136 {
 137         static const char * const nak_reason_str[] = {
 138                 DP_STR(WRITE_FAILURE),
 139                 DP_STR(INVALID_READ),
 140                 DP_STR(CRC_FAILURE),
 141                 DP_STR(BAD_PARAM),
 142                 DP_STR(DEFER),
 143                 DP_STR(LINK_FAILURE),
 144                 DP_STR(NO_RESOURCES),
 145                 DP_STR(DPCD_FAIL),
 146                 DP_STR(I2C_NAK),
 147                 DP_STR(ALLOCATE_FAIL),
 148         };
 149
 150         if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
 151             !nak_reason_str[nak_reason])
 152                 return "unknown";
 153
 154         return nak_reason_str[nak_reason];
 155 }
 156
 157 #undef DP_STR
 158 #define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
 159
 160 static const char *drm_dp_mst_sideband_tx_state_str(int state)
 161 {
 162         static const char * const sideband_reason_str[] = {
 163                 DP_STR(QUEUED),
 164                 DP_STR(START_SEND),
 165                 DP_STR(SENT),
 166                 DP_STR(RX),
 167                 DP_STR(TIMEOUT),
 168         };
 169
 170         if (state >= ARRAY_SIZE(sideband_reason_str) ||
 171             !sideband_reason_str[state])
 172                 return "unknown";
 173
 174         return sideband_reason_str[state];
 175 }
 176
 177 static int
 178 drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
 179 {
 180         int i;
 181         u8 unpacked_rad[16];
 182
 183         for (i = 0; i < lct; i++) {
 184                 if (i % 2)
 185                         unpacked_rad[i] = rad[i / 2] >> 4;
 186                 else
 187                         unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
 188         }
 189
 190         /* TODO: Eventually add something to printk so we can format the rad
 191          * like this: 1.2.3
 192          */
 193         return snprintf(out, len, "%*phC", lct, unpacked_rad);
 194 }
 195
 196 /* sideband msg handling */
 197 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
 198 {
 199         u8 bitmask = 0x80;
 200         u8 bitshift = 7;
 201         u8 array_index = 0;
 202         int number_of_bits = num_nibbles * 4;
 203         u8 remainder = 0;
 204
 205         while (number_of_bits != 0) {
 206                 number_of_bits--;
 207                 remainder <<= 1;
 208                 remainder |= (data[array_index] & bitmask) >> bitshift;
 209                 bitmask >>= 1;
 210                 bitshift--;
 211                 if (bitmask == 0) {
 212                         bitmask = 0x80;
 213                         bitshift = 7;
 214                         array_index++;
 215                 }
 216                 if ((remainder & 0x10) == 0x10)
 217                         remainder ^= 0x13;
 218         }
 219
 220         number_of_bits = 4;
 221         while (number_of_bits != 0) {
 222                 number_of_bits--;
 223                 remainder <<= 1;
 224                 if ((remainder & 0x10) != 0)
 225                         remainder ^= 0x13;
 226         }
 227
 228         return remainder;
 229 }
 230
 231 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
 232 {
 233         u8 bitmask = 0x80;
 234         u8 bitshift = 7;
 235         u8 array_index = 0;
 236         int number_of_bits = number_of_bytes * 8;
 237         u16 remainder = 0;
 238
 239         while (number_of_bits != 0) {
 240                 number_of_bits--;
 241                 remainder <<= 1;
 242                 remainder |= (data[array_index] & bitmask) >> bitshift;
 243                 bitmask >>= 1;
 244                 bitshift--;
 245                 if (bitmask == 0) {
 246                         bitmask = 0x80;
 247                         bitshift = 7;
 248                         array_index++;
 249                 }
 250                 if ((remainder & 0x100) == 0x100)
 251                         remainder ^= 0xd5;
 252         }
 253
 254         number_of_bits = 8;
 255         while (number_of_bits != 0) {
 256                 number_of_bits--;
 257                 remainder <<= 1;
 258                 if ((remainder & 0x100) != 0)
 259                         remainder ^= 0xd5;
 260         }
 261
 262         return remainder & 0xff;
 263 }
 264 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
 265 {
 266         u8 size = 3;
 267
 268         size += (hdr->lct / 2);
 269         return size;
 270 }
 271
 272 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 273                                            u8 *buf, int *len)
 274 {
 275         int idx = 0;
 276         int i;
 277         u8 crc4;
 278
 279         buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
 280         for (i = 0; i < (hdr->lct / 2); i++)
 281                 buf[idx++] = hdr->rad[i];
 282         buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
 283                 (hdr->msg_len & 0x3f);
 284         buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
 285
 286         crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
 287         buf[idx - 1] |= (crc4 & 0xf);
 288
 289         *len = idx;
 290 }
 291
 292 static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr *mgr,
 293                                            struct drm_dp_sideband_msg_hdr *hdr,
 294                                            u8 *buf, int buflen, u8 *hdrlen)
 295 {
 296         u8 crc4;
 297         u8 len;
 298         int i;
 299         u8 idx;
 300
 301         if (buf[0] == 0)
 302                 return false;
 303         len = 3;
 304         len += ((buf[0] & 0xf0) >> 4) / 2;
 305         if (len > buflen)
 306                 return false;
 307         crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
 308
 309         if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
 310                 drm_dbg_kms(mgr->dev, "crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
 311                 return false;
 312         }
 313
 314         hdr->lct = (buf[0] & 0xf0) >> 4;
 315         hdr->lcr = (buf[0] & 0xf);
 316         idx = 1;
 317         for (i = 0; i < (hdr->lct / 2); i++)
 318                 hdr->rad[i] = buf[idx++];
 319         hdr->broadcast = (buf[idx] >> 7) & 0x1;
 320         hdr->path_msg = (buf[idx] >> 6) & 0x1;
 321         hdr->msg_len = buf[idx] & 0x3f;
 322         idx++;
 323         hdr->somt = (buf[idx] >> 7) & 0x1;
 324         hdr->eomt = (buf[idx] >> 6) & 0x1;
 325         hdr->seqno = (buf[idx] >> 4) & 0x1;
 326         idx++;
 327         *hdrlen = idx;
 328         return true;
 329 }
 330
 331 void
 332 drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
 333                            struct drm_dp_sideband_msg_tx *raw)
 334 {
 335         int idx = 0;
 336         int i;
 337         u8 *buf = raw->msg;
 338
 339         buf[idx++] = req->req_type & 0x7f;
 340
 341         switch (req->req_type) {
 342         case DP_ENUM_PATH_RESOURCES:
 343         case DP_POWER_DOWN_PHY:
 344         case DP_POWER_UP_PHY:
 345                 buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
 346                 idx++;
 347                 break;
 348         case DP_ALLOCATE_PAYLOAD:
 349                 buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
 350                         (req->u.allocate_payload.number_sdp_streams & 0xf);
 351                 idx++;
 352                 buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
 353                 idx++;
 354                 buf[idx] = (req->u.allocate_payload.pbn >> 8);
 355                 idx++;
 356                 buf[idx] = (req->u.allocate_payload.pbn & 0xff);
 357                 idx++;
 358                 for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
 359                         buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
 360                                 (req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
 361                         idx++;
 362                 }
 363                 if (req->u.allocate_payload.number_sdp_streams & 1) {
 364                         i = req->u.allocate_payload.number_sdp_streams - 1;
 365                         buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
 366                         idx++;
 367                 }
 368                 break;
 369         case DP_QUERY_PAYLOAD:
 370                 buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
 371                 idx++;
 372                 buf[idx] = (req->u.query_payload.vcpi & 0x7f);
 373                 idx++;
 374                 break;
 375         case DP_REMOTE_DPCD_READ:
 376                 buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
 377                 buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
 378                 idx++;
 379                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
 380                 idx++;
 381                 buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
 382                 idx++;
 383                 buf[idx] = (req->u.dpcd_read.num_bytes);
 384                 idx++;
 385                 break;
 386
 387         case DP_REMOTE_DPCD_WRITE:
 388                 buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
 389                 buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
 390                 idx++;
 391                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
 392                 idx++;
 393                 buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
 394                 idx++;
 395                 buf[idx] = (req->u.dpcd_write.num_bytes);
 396                 idx++;
 397                 memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
 398                 idx += req->u.dpcd_write.num_bytes;
 399                 break;
 400         case DP_REMOTE_I2C_READ:
 401                 buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
 402                 buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
 403                 idx++;
 404                 for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
 405                         buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
 406                         idx++;
 407                         buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
 408                         idx++;
 409                         memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
 410                         idx += req->u.i2c_read.transactions[i].num_bytes;
 411
 412                         buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
 413                         buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
 414                         idx++;
 415                 }
 416                 buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
 417                 idx++;
 418                 buf[idx] = (req->u.i2c_read.num_bytes_read);
 419                 idx++;
 420                 break;
 421
 422         case DP_REMOTE_I2C_WRITE:
 423                 buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
 424                 idx++;
 425                 buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
 426                 idx++;
 427                 buf[idx] = (req->u.i2c_write.num_bytes);
 428                 idx++;
 429                 memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
 430                 idx += req->u.i2c_write.num_bytes;
 431                 break;
 432         case DP_QUERY_STREAM_ENC_STATUS: {
 433                 const struct drm_dp_query_stream_enc_status *msg;
 434
 435                 msg = &req->u.enc_status;
 436                 buf[idx] = msg->stream_id;
 437                 idx++;
 438                 memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
 439                 idx += sizeof(msg->client_id);
 440                 buf[idx] = 0;
 441                 buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
 442                 buf[idx] |= msg->valid_stream_event ? BIT(2) : 0;
 443                 buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
 444                 buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0;
 445                 idx++;
 446                 }
 447                 break;
 448         }
 449         raw->cur_len = idx;
 450 }
 451 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
 452
 453 /* Decode a sideband request we've encoded, mainly used for debugging */
 454 int
 455 drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
 456                            struct drm_dp_sideband_msg_req_body *req)
 457 {
 458         const u8 *buf = raw->msg;
 459         int i, idx = 0;
 460
 461         req->req_type = buf[idx++] & 0x7f;
 462         switch (req->req_type) {
 463         case DP_ENUM_PATH_RESOURCES:
 464         case DP_POWER_DOWN_PHY:
 465         case DP_POWER_UP_PHY:
 466                 req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
 467                 break;
 468         case DP_ALLOCATE_PAYLOAD:
 469                 {
 470                         struct drm_dp_allocate_payload *a =
 471                                 &req->u.allocate_payload;
 472
 473                         a->number_sdp_streams = buf[idx] & 0xf;
 474                         a->port_number = (buf[idx] >> 4) & 0xf;
 475
 476                         WARN_ON(buf[++idx] & 0x80);
 477                         a->vcpi = buf[idx] & 0x7f;
 478
 479                         a->pbn = buf[++idx] << 8;
 480                         a->pbn |= buf[++idx];
 481
 482                         idx++;
 483                         for (i = 0; i < a->number_sdp_streams; i++) {
 484                                 a->sdp_stream_sink[i] =
 485                                         (buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
 486                         }
 487                 }
 488                 break;
 489         case DP_QUERY_PAYLOAD:
 490                 req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
 491                 WARN_ON(buf[++idx] & 0x80);
 492                 req->u.query_payload.vcpi = buf[idx] & 0x7f;
 493                 break;
 494         case DP_REMOTE_DPCD_READ:
 495                 {
 496                         struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
 497
 498                         r->port_number = (buf[idx] >> 4) & 0xf;
 499
 500                         r->dpcd_address = (buf[idx] << 16) & 0xf0000;
 501                         r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 502                         r->dpcd_address |= buf[++idx] & 0xff;
 503
 504                         r->num_bytes = buf[++idx];
 505                 }
 506                 break;
 507         case DP_REMOTE_DPCD_WRITE:
 508                 {
 509                         struct drm_dp_remote_dpcd_write *w =
 510                                 &req->u.dpcd_write;
 511
 512                         w->port_number = (buf[idx] >> 4) & 0xf;
 513
 514                         w->dpcd_address = (buf[idx] << 16) & 0xf0000;
 515                         w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 516                         w->dpcd_address |= buf[++idx] & 0xff;
 517
 518                         w->num_bytes = buf[++idx];
 519
 520                         w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 521                                            GFP_KERNEL);
 522                         if (!w->bytes)
 523                                 return -ENOMEM;
 524                 }
 525                 break;
 526         case DP_REMOTE_I2C_READ:
 527                 {
 528                         struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
 529                         struct drm_dp_remote_i2c_read_tx *tx;
 530                         bool failed = false;
 531
 532                         r->num_transactions = buf[idx] & 0x3;
 533                         r->port_number = (buf[idx] >> 4) & 0xf;
 534                         for (i = 0; i < r->num_transactions; i++) {
 535                                 tx = &r->transactions[i];
 536
 537                                 tx->i2c_dev_id = buf[++idx] & 0x7f;
 538                                 tx->num_bytes = buf[++idx];
 539                                 tx->bytes = kmemdup(&buf[++idx],
 540                                                     tx->num_bytes,
 541                                                     GFP_KERNEL);
 542                                 if (!tx->bytes) {
 543                                         failed = true;
 544                                         break;
 545                                 }
 546                                 idx += tx->num_bytes;
 547                                 tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
 548                                 tx->i2c_transaction_delay = buf[idx] & 0xf;
 549                         }
 550
 551                         if (failed) {
 552                                 for (i = 0; i < r->num_transactions; i++) {
 553                                         tx = &r->transactions[i];
 554                                         kfree(tx->bytes);
 555                                 }
 556                                 return -ENOMEM;
 557                         }
 558
 559                         r->read_i2c_device_id = buf[++idx] & 0x7f;
 560                         r->num_bytes_read = buf[++idx];
 561                 }
 562                 break;
 563         case DP_REMOTE_I2C_WRITE:
 564                 {
 565                         struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
 566
 567                         w->port_number = (buf[idx] >> 4) & 0xf;
 568                         w->write_i2c_device_id = buf[++idx] & 0x7f;
 569                         w->num_bytes = buf[++idx];
 570                         w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 571                                            GFP_KERNEL);
 572                         if (!w->bytes)
 573                                 return -ENOMEM;
 574                 }
 575                 break;
 576         case DP_QUERY_STREAM_ENC_STATUS:
 577                 req->u.enc_status.stream_id = buf[idx++];
 578                 for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
 579                         req->u.enc_status.client_id[i] = buf[idx++];
 580
 581                 req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
 582                                                            buf[idx]);
 583                 req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
 584                                                                  buf[idx]);
 585                 req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
 586                                                               buf[idx]);
 587                 req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
 588                                                                     buf[idx]);
 589                 break;
 590         }
 591
 592         return 0;
 593 }
 594 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
 595
 596 void
 597 drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
 598                                   int indent, struct drm_printer *printer)
 599 {
 600         int i;
 601
 602 #define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
 603         if (req->req_type == DP_LINK_ADDRESS) {
 604                 /* No contents to print */
 605                 P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
 606                 return;
 607         }
 608
 609         P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
 610         indent++;
 611
 612         switch (req->req_type) {
 613         case DP_ENUM_PATH_RESOURCES:
 614         case DP_POWER_DOWN_PHY:
 615         case DP_POWER_UP_PHY:
 616                 P("port=%d\n", req->u.port_num.port_number);
 617                 break;
 618         case DP_ALLOCATE_PAYLOAD:
 619                 P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
 620                   req->u.allocate_payload.port_number,
 621                   req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
 622                   req->u.allocate_payload.number_sdp_streams,
 623                   req->u.allocate_payload.number_sdp_streams,
 624                   req->u.allocate_payload.sdp_stream_sink);
 625                 break;
 626         case DP_QUERY_PAYLOAD:
 627                 P("port=%d vcpi=%d\n",
 628                   req->u.query_payload.port_number,
 629                   req->u.query_payload.vcpi);
 630                 break;
 631         case DP_REMOTE_DPCD_READ:
 632                 P("port=%d dpcd_addr=%05x len=%d\n",
 633                   req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
 634                   req->u.dpcd_read.num_bytes);
 635                 break;
 636         case DP_REMOTE_DPCD_WRITE:
 637                 P("port=%d addr=%05x len=%d: %*ph\n",
 638                   req->u.dpcd_write.port_number,
 639                   req->u.dpcd_write.dpcd_address,
 640                   req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
 641                   req->u.dpcd_write.bytes);
 642                 break;
 643         case DP_REMOTE_I2C_READ:
 644                 P("port=%d num_tx=%d id=%d size=%d:\n",
 645                   req->u.i2c_read.port_number,
 646                   req->u.i2c_read.num_transactions,
 647                   req->u.i2c_read.read_i2c_device_id,
 648                   req->u.i2c_read.num_bytes_read);
 649
 650                 indent++;
 651                 for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
 652                         const struct drm_dp_remote_i2c_read_tx *rtx =
 653                                 &req->u.i2c_read.transactions[i];
 654
 655                         P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
 656                           i, rtx->i2c_dev_id, rtx->num_bytes,
 657                           rtx->no_stop_bit, rtx->i2c_transaction_delay,
 658                           rtx->num_bytes, rtx->bytes);
 659                 }
 660                 break;
 661         case DP_REMOTE_I2C_WRITE:
 662                 P("port=%d id=%d size=%d: %*ph\n",
 663                   req->u.i2c_write.port_number,
 664                   req->u.i2c_write.write_i2c_device_id,
 665                   req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
 666                   req->u.i2c_write.bytes);
 667                 break;
 668         case DP_QUERY_STREAM_ENC_STATUS:
 669                 P("stream_id=%u client_id=%*ph stream_event=%x "
 670                   "valid_event=%d stream_behavior=%x valid_behavior=%d",
 671                   req->u.enc_status.stream_id,
 672                   (int)ARRAY_SIZE(req->u.enc_status.client_id),
 673                   req->u.enc_status.client_id, req->u.enc_status.stream_event,
 674                   req->u.enc_status.valid_stream_event,
 675                   req->u.enc_status.stream_behavior,
 676                   req->u.enc_status.valid_stream_behavior);
 677                 break;
 678         default:
 679                 P("???\n");
 680                 break;
 681         }
 682 #undef P
 683 }
 684 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
 685
 686 static inline void
 687 drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
 688                                 const struct drm_dp_sideband_msg_tx *txmsg)
 689 {
 690         struct drm_dp_sideband_msg_req_body req;
 691         char buf[64];
 692         int ret;
 693         int i;
 694
 695         drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
 696                               sizeof(buf));
 697         drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
 698                    txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
 699                    drm_dp_mst_sideband_tx_state_str(txmsg->state),
 700                    txmsg->path_msg, buf);
 701
 702         ret = drm_dp_decode_sideband_req(txmsg, &req);
 703         if (ret) {
 704                 drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
 705                 return;
 706         }
 707         drm_dp_dump_sideband_msg_req_body(&req, 1, p);
 708
 709         switch (req.req_type) {
 710         case DP_REMOTE_DPCD_WRITE:
 711                 kfree(req.u.dpcd_write.bytes);
 712                 break;
 713         case DP_REMOTE_I2C_READ:
 714                 for (i = 0; i < req.u.i2c_read.num_transactions; i++)
 715                         kfree(req.u.i2c_read.transactions[i].bytes);
 716                 break;
 717         case DP_REMOTE_I2C_WRITE:
 718                 kfree(req.u.i2c_write.bytes);
 719                 break;
 720         }
 721 }
 722
 723 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
 724 {
 725         u8 crc4;
 726
 727         crc4 = drm_dp_msg_data_crc4(msg, len);
 728         msg[len] = crc4;
 729 }
 730
 731 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
 732                                          struct drm_dp_sideband_msg_tx *raw)
 733 {
 734         int idx = 0;
 735         u8 *buf = raw->msg;
 736
 737         buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
 738
 739         raw->cur_len = idx;
 740 }
 741
 742 static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
 743                                           struct drm_dp_sideband_msg_hdr *hdr,
 744                                           u8 hdrlen)
 745 {
 746         /*
 747          * ignore out-of-order messages or messages that are part of a
 748          * failed transaction
 749          */
 750         if (!hdr->somt && !msg->have_somt)
 751                 return false;
 752
 753         /* get length contained in this portion */
 754         msg->curchunk_idx = 0;
 755         msg->curchunk_len = hdr->msg_len;
 756         msg->curchunk_hdrlen = hdrlen;
 757
 758         /* we have already gotten an somt - don't bother parsing */
 759         if (hdr->somt && msg->have_somt)
 760                 return false;
 761
 762         if (hdr->somt) {
 763                 memcpy(&msg->initial_hdr, hdr,
 764                        sizeof(struct drm_dp_sideband_msg_hdr));
 765                 msg->have_somt = true;
 766         }
 767         if (hdr->eomt)
 768                 msg->have_eomt = true;
 769
 770         return true;
 771 }
 772
 773 /* this adds a chunk of msg to the builder to get the final msg */
 774 static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
 775                                            u8 *replybuf, u8 replybuflen)
 776 {
 777         u8 crc4;
 778
 779         memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
 780         msg->curchunk_idx += replybuflen;
 781
 782         if (msg->curchunk_idx >= msg->curchunk_len) {
 783                 /* do CRC */
 784                 crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
 785                 if (crc4 != msg->chunk[msg->curchunk_len - 1])
 786                         print_hex_dump(KERN_DEBUG, "wrong crc",
 787                                        DUMP_PREFIX_NONE, 16, 1,
 788                                        msg->chunk,  msg->curchunk_len, false);
 789                 /* copy chunk into bigger msg */
 790                 memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
 791                 msg->curlen += msg->curchunk_len - 1;
 792         }
 793         return true;
 794 }
 795
 796 static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr *mgr,
 797                                                struct drm_dp_sideband_msg_rx *raw,
 798                                                struct drm_dp_sideband_msg_reply_body *repmsg)
 799 {
 800         int idx = 1;
 801         int i;
 802
 803         memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
 804         idx += 16;
 805         repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
 806         idx++;
 807         if (idx > raw->curlen)
 808                 goto fail_len;
 809         for (i = 0; i < repmsg->u.link_addr.nports; i++) {
 810                 if (raw->msg[idx] & 0x80)
 811                         repmsg->u.link_addr.ports[i].input_port = 1;
 812
 813                 repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
 814                 repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
 815
 816                 idx++;
 817                 if (idx > raw->curlen)
 818                         goto fail_len;
 819                 repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
 820                 repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
 821                 if (repmsg->u.link_addr.ports[i].input_port == 0)
 822                         repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 823                 idx++;
 824                 if (idx > raw->curlen)
 825                         goto fail_len;
 826                 if (repmsg->u.link_addr.ports[i].input_port == 0) {
 827                         repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
 828                         idx++;
 829                         if (idx > raw->curlen)
 830                                 goto fail_len;
 831                         memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
 832                         idx += 16;
 833                         if (idx > raw->curlen)
 834                                 goto fail_len;
 835                         repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
 836                         repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
 837                         idx++;
 838
 839                 }
 840                 if (idx > raw->curlen)
 841                         goto fail_len;
 842         }
 843
 844         return true;
 845 fail_len:
 846         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 847         return false;
 848 }
 849
 850 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
 851                                                    struct drm_dp_sideband_msg_reply_body *repmsg)
 852 {
 853         int idx = 1;
 854
 855         repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
 856         idx++;
 857         if (idx > raw->curlen)
 858                 goto fail_len;
 859         repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
 860         idx++;
 861         if (idx > raw->curlen)
 862                 goto fail_len;
 863
 864         memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
 865         return true;
 866 fail_len:
 867         DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 868         return false;
 869 }
 870
 871 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
 872                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 873 {
 874         int idx = 1;
 875
 876         repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
 877         idx++;
 878         if (idx > raw->curlen)
 879                 goto fail_len;
 880         return true;
 881 fail_len:
 882         DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
 883         return false;
 884 }
 885
 886 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
 887                                                       struct drm_dp_sideband_msg_reply_body *repmsg)
 888 {
 889         int idx = 1;
 890
 891         repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
 892         idx++;
 893         if (idx > raw->curlen)
 894                 goto fail_len;
 895         repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
 896         idx++;
 897         /* TODO check */
 898         memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
 899         return true;
 900 fail_len:
 901         DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
 902         return false;
 903 }
 904
 905 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
 906                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 907 {
 908         int idx = 1;
 909
 910         repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
 911         repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
 912         idx++;
 913         if (idx > raw->curlen)
 914                 goto fail_len;
 915         repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 916         idx += 2;
 917         if (idx > raw->curlen)
 918                 goto fail_len;
 919         repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 920         idx += 2;
 921         if (idx > raw->curlen)
 922                 goto fail_len;
 923         return true;
 924 fail_len:
 925         DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
 926         return false;
 927 }
 928
 929 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 930                                                           struct drm_dp_sideband_msg_reply_body *repmsg)
 931 {
 932         int idx = 1;
 933
 934         repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 935         idx++;
 936         if (idx > raw->curlen)
 937                 goto fail_len;
 938         repmsg->u.allocate_payload.vcpi = raw->msg[idx];
 939         idx++;
 940         if (idx > raw->curlen)
 941                 goto fail_len;
 942         repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 943         idx += 2;
 944         if (idx > raw->curlen)
 945                 goto fail_len;
 946         return true;
 947 fail_len:
 948         DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
 949         return false;
 950 }
 951
 952 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 953                                                     struct drm_dp_sideband_msg_reply_body *repmsg)
 954 {
 955         int idx = 1;
 956
 957         repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 958         idx++;
 959         if (idx > raw->curlen)
 960                 goto fail_len;
 961         repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 962         idx += 2;
 963         if (idx > raw->curlen)
 964                 goto fail_len;
 965         return true;
 966 fail_len:
 967         DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
 968         return false;
 969 }
 970
 971 static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
 972                                                        struct drm_dp_sideband_msg_reply_body *repmsg)
 973 {
 974         int idx = 1;
 975
 976         repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
 977         idx++;
 978         if (idx > raw->curlen) {
 979                 DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
 980                               idx, raw->curlen);
 981                 return false;
 982         }
 983         return true;
 984 }
 985
 986 static bool
 987 drm_dp_sideband_parse_query_stream_enc_status(
 988                                 struct drm_dp_sideband_msg_rx *raw,
 989                                 struct drm_dp_sideband_msg_reply_body *repmsg)
 990 {
 991         struct drm_dp_query_stream_enc_status_ack_reply *reply;
 992
 993         reply = &repmsg->u.enc_status;
 994
 995         reply->stream_id = raw->msg[3];
 996
 997         reply->reply_signed = raw->msg[2] & BIT(0);
 998
 999         /*
1000          * NOTE: It's my impression from reading the spec that the below parsing
1001          * is correct. However I noticed while testing with an HDCP 1.4 display
1002          * through an HDCP 2.2 hub that only bit 3 was set. In that case, I
1003          * would expect both bits to be set. So keep the parsing following the
1004          * spec, but beware reality might not match the spec (at least for some
1005          * configurations).
1006          */
1007         reply->hdcp_1x_device_present = raw->msg[2] & BIT(4);
1008         reply->hdcp_2x_device_present = raw->msg[2] & BIT(3);
1009
1010         reply->query_capable_device_present = raw->msg[2] & BIT(5);
1011         reply->legacy_device_present = raw->msg[2] & BIT(6);
1012         reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
1013
1014         reply->auth_completed = !!(raw->msg[1] & BIT(3));
1015         reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
1016         reply->repeater_present = !!(raw->msg[1] & BIT(5));
1017         reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
1018
1019         return true;
1020 }
1021
1022 static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr *mgr,
1023                                         struct drm_dp_sideband_msg_rx *raw,
1024                                         struct drm_dp_sideband_msg_reply_body *msg)
1025 {
1026         memset(msg, 0, sizeof(*msg));
1027         msg->reply_type = (raw->msg[0] & 0x80) >> 7;
1028         msg->req_type = (raw->msg[0] & 0x7f);
1029
1030         if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
1031                 memcpy(msg->u.nak.guid, &raw->msg[1], 16);
1032                 msg->u.nak.reason = raw->msg[17];
1033                 msg->u.nak.nak_data = raw->msg[18];
1034                 return false;
1035         }
1036
1037         switch (msg->req_type) {
1038         case DP_LINK_ADDRESS:
1039                 return drm_dp_sideband_parse_link_address(mgr, raw, msg);
1040         case DP_QUERY_PAYLOAD:
1041                 return drm_dp_sideband_parse_query_payload_ack(raw, msg);
1042         case DP_REMOTE_DPCD_READ:
1043                 return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
1044         case DP_REMOTE_DPCD_WRITE:
1045                 return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
1046         case DP_REMOTE_I2C_READ:
1047                 return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
1048         case DP_REMOTE_I2C_WRITE:
1049                 return true; /* since there's nothing to parse */
1050         case DP_ENUM_PATH_RESOURCES:
1051                 return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
1052         case DP_ALLOCATE_PAYLOAD:
1053                 return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
1054         case DP_POWER_DOWN_PHY:
1055         case DP_POWER_UP_PHY:
1056                 return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
1057         case DP_CLEAR_PAYLOAD_ID_TABLE:
1058                 return true; /* since there's nothing to parse */
1059         case DP_QUERY_STREAM_ENC_STATUS:
1060                 return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
1061         default:
1062                 drm_err(mgr->dev, "Got unknown reply 0x%02x (%s)\n",
1063                         msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1064                 return false;
1065         }
1066 }
1067
1068 static bool
1069 drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1070                                                struct drm_dp_sideband_msg_rx *raw,
1071                                                struct drm_dp_sideband_msg_req_body *msg)
1072 {
1073         int idx = 1;
1074
1075         msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1076         idx++;
1077         if (idx > raw->curlen)
1078                 goto fail_len;
1079
1080         memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
1081         idx += 16;
1082         if (idx > raw->curlen)
1083                 goto fail_len;
1084
1085         msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
1086         msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
1087         msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
1088         msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
1089         msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
1090         idx++;
1091         return true;
1092 fail_len:
1093         drm_dbg_kms(mgr->dev, "connection status reply parse length fail %d %d\n",
1094                     idx, raw->curlen);
1095         return false;
1096 }
1097
1098 static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1099                                                          struct drm_dp_sideband_msg_rx *raw,
1100                                                          struct drm_dp_sideband_msg_req_body *msg)
1101 {
1102         int idx = 1;
1103
1104         msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1105         idx++;
1106         if (idx > raw->curlen)
1107                 goto fail_len;
1108
1109         memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1110         idx += 16;
1111         if (idx > raw->curlen)
1112                 goto fail_len;
1113
1114         msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1115         idx++;
1116         return true;
1117 fail_len:
1118         drm_dbg_kms(mgr->dev, "resource status reply parse length fail %d %d\n", idx, raw->curlen);
1119         return false;
1120 }
1121
1122 static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
1123                                       struct drm_dp_sideband_msg_rx *raw,
1124                                       struct drm_dp_sideband_msg_req_body *msg)
1125 {
1126         memset(msg, 0, sizeof(*msg));
1127         msg->req_type = (raw->msg[0] & 0x7f);
1128
1129         switch (msg->req_type) {
1130         case DP_CONNECTION_STATUS_NOTIFY:
1131                 return drm_dp_sideband_parse_connection_status_notify(mgr, raw, msg);
1132         case DP_RESOURCE_STATUS_NOTIFY:
1133                 return drm_dp_sideband_parse_resource_status_notify(mgr, raw, msg);
1134         default:
1135                 drm_err(mgr->dev, "Got unknown request 0x%02x (%s)\n",
1136                         msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1137                 return false;
1138         }
1139 }
1140
1141 static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1142                              u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1143 {
1144         struct drm_dp_sideband_msg_req_body req;
1145
1146         req.req_type = DP_REMOTE_DPCD_WRITE;
1147         req.u.dpcd_write.port_number = port_num;
1148         req.u.dpcd_write.dpcd_address = offset;
1149         req.u.dpcd_write.num_bytes = num_bytes;
1150         req.u.dpcd_write.bytes = bytes;
1151         drm_dp_encode_sideband_req(&req, msg);
1152 }
1153
1154 static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1155 {
1156         struct drm_dp_sideband_msg_req_body req;
1157
1158         req.req_type = DP_LINK_ADDRESS;
1159         drm_dp_encode_sideband_req(&req, msg);
1160 }
1161
1162 static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1163 {
1164         struct drm_dp_sideband_msg_req_body req;
1165
1166         req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1167         drm_dp_encode_sideband_req(&req, msg);
1168         msg->path_msg = true;
1169 }
1170
1171 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1172                                      int port_num)
1173 {
1174         struct drm_dp_sideband_msg_req_body req;
1175
1176         req.req_type = DP_ENUM_PATH_RESOURCES;
1177         req.u.port_num.port_number = port_num;
1178         drm_dp_encode_sideband_req(&req, msg);
1179         msg->path_msg = true;
1180         return 0;
1181 }
1182
1183 static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1184                                    int port_num,
1185                                    u8 vcpi, uint16_t pbn,
1186                                    u8 number_sdp_streams,
1187                                    u8 *sdp_stream_sink)
1188 {
1189         struct drm_dp_sideband_msg_req_body req;
1190
1191         memset(&req, 0, sizeof(req));
1192         req.req_type = DP_ALLOCATE_PAYLOAD;
1193         req.u.allocate_payload.port_number = port_num;
1194         req.u.allocate_payload.vcpi = vcpi;
1195         req.u.allocate_payload.pbn = pbn;
1196         req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1197         memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1198                    number_sdp_streams);
1199         drm_dp_encode_sideband_req(&req, msg);
1200         msg->path_msg = true;
1201 }
1202
1203 static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1204                                    int port_num, bool power_up)
1205 {
1206         struct drm_dp_sideband_msg_req_body req;
1207
1208         if (power_up)
1209                 req.req_type = DP_POWER_UP_PHY;
1210         else
1211                 req.req_type = DP_POWER_DOWN_PHY;
1212
1213         req.u.port_num.port_number = port_num;
1214         drm_dp_encode_sideband_req(&req, msg);
1215         msg->path_msg = true;
1216 }
1217
1218 static int
1219 build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
1220                               u8 *q_id)
1221 {
1222         struct drm_dp_sideband_msg_req_body req;
1223
1224         req.req_type = DP_QUERY_STREAM_ENC_STATUS;
1225         req.u.enc_status.stream_id = stream_id;
1226         memcpy(req.u.enc_status.client_id, q_id,
1227                sizeof(req.u.enc_status.client_id));
1228         req.u.enc_status.stream_event = 0;
1229         req.u.enc_status.valid_stream_event = false;
1230         req.u.enc_status.stream_behavior = 0;
1231         req.u.enc_status.valid_stream_behavior = false;
1232
1233         drm_dp_encode_sideband_req(&req, msg);
1234         return 0;
1235 }
1236
1237 static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1238                                         struct drm_dp_vcpi *vcpi)
1239 {
1240         int ret, vcpi_ret;
1241
1242         mutex_lock(&mgr->payload_lock);
1243         ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
1244         if (ret > mgr->max_payloads) {
1245                 ret = -EINVAL;
1246                 drm_dbg_kms(mgr->dev, "out of payload ids %d\n", ret);
1247                 goto out_unlock;
1248         }
1249
1250         vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
1251         if (vcpi_ret > mgr->max_payloads) {
1252                 ret = -EINVAL;
1253                 drm_dbg_kms(mgr->dev, "out of vcpi ids %d\n", ret);
1254                 goto out_unlock;
1255         }
1256
1257         set_bit(ret, &mgr->payload_mask);
1258         set_bit(vcpi_ret, &mgr->vcpi_mask);
1259         vcpi->vcpi = vcpi_ret + 1;
1260         mgr->proposed_vcpis[ret - 1] = vcpi;
1261 out_unlock:
1262         mutex_unlock(&mgr->payload_lock);
1263         return ret;
1264 }
1265
1266 static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1267                                       int vcpi)
1268 {
1269         int i;
1270
1271         if (vcpi == 0)
1272                 return;
1273
1274         mutex_lock(&mgr->payload_lock);
1275         drm_dbg_kms(mgr->dev, "putting payload %d\n", vcpi);
1276         clear_bit(vcpi - 1, &mgr->vcpi_mask);
1277
1278         for (i = 0; i < mgr->max_payloads; i++) {
1279                 if (mgr->proposed_vcpis[i] &&
1280                     mgr->proposed_vcpis[i]->vcpi == vcpi) {
1281                         mgr->proposed_vcpis[i] = NULL;
1282                         clear_bit(i + 1, &mgr->payload_mask);
1283                 }
1284         }
1285         mutex_unlock(&mgr->payload_lock);
1286 }
1287
1288 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1289                               struct drm_dp_sideband_msg_tx *txmsg)
1290 {
1291         unsigned int state;
1292
1293         /*
1294          * All updates to txmsg->state are protected by mgr->qlock, and the two
1295          * cases we check here are terminal states. For those the barriers
1296          * provided by the wake_up/wait_event pair are enough.
1297          */
1298         state = READ_ONCE(txmsg->state);
1299         return (state == DRM_DP_SIDEBAND_TX_RX ||
1300                 state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1301 }
1302
1303 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1304                                     struct drm_dp_sideband_msg_tx *txmsg)
1305 {
1306         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1307         unsigned long wait_timeout = msecs_to_jiffies(4000);
1308         unsigned long wait_expires = jiffies + wait_timeout;
1309         int ret;
1310
1311         for (;;) {
1312                 /*
1313                  * If the driver provides a way for this, change to
1314                  * poll-waiting for the MST reply interrupt if we didn't receive
1315                  * it for 50 msec. This would cater for cases where the HPD
1316                  * pulse signal got lost somewhere, even though the sink raised
1317                  * the corresponding MST interrupt correctly. One example is the
1318                  * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1319                  * filters out short pulses with a duration less than ~540 usec.
1320                  *
1321                  * The poll period is 50 msec to avoid missing an interrupt
1322                  * after the sink has cleared it (after a 110msec timeout
1323                  * since it raised the interrupt).
1324                  */
1325                 ret = wait_event_timeout(mgr->tx_waitq,
1326                                          check_txmsg_state(mgr, txmsg),
1327                                          mgr->cbs->poll_hpd_irq ?
1328                                                 msecs_to_jiffies(50) :
1329                                                 wait_timeout);
1330
1331                 if (ret || !mgr->cbs->poll_hpd_irq ||
1332                     time_after(jiffies, wait_expires))
1333                         break;
1334
1335                 mgr->cbs->poll_hpd_irq(mgr);
1336         }
1337
1338         mutex_lock(&mgr->qlock);
1339         if (ret > 0) {
1340                 if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1341                         ret = -EIO;
1342                         goto out;
1343                 }
1344         } else {
1345                 drm_dbg_kms(mgr->dev, "timedout msg send %p %d %d\n",
1346                             txmsg, txmsg->state, txmsg->seqno);
1347
1348                 /* dump some state */
1349                 ret = -EIO;
1350
1351                 /* remove from q */
1352                 if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1353                     txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1354                     txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1355                         list_del(&txmsg->next);
1356         }
1357 out:
1358         if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1359                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1360
1361                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1362         }
1363         mutex_unlock(&mgr->qlock);
1364
1365         drm_dp_mst_kick_tx(mgr);
1366         return ret;
1367 }
1368
1369 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1370 {
1371         struct drm_dp_mst_branch *mstb;
1372
1373         mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1374         if (!mstb)
1375                 return NULL;
1376
1377         mstb->lct = lct;
1378         if (lct > 1)
1379                 memcpy(mstb->rad, rad, lct / 2);
1380         INIT_LIST_HEAD(&mstb->ports);
1381         kref_init(&mstb->topology_kref);
1382         kref_init(&mstb->malloc_kref);
1383         return mstb;
1384 }
1385
1386 static void drm_dp_free_mst_branch_device(struct kref *kref)
1387 {
1388         struct drm_dp_mst_branch *mstb =
1389                 container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1390
1391         if (mstb->port_parent)
1392                 drm_dp_mst_put_port_malloc(mstb->port_parent);
1393
1394         kfree(mstb);
1395 }
1396
1397 /**
1398  * DOC: Branch device and port refcounting
1399  *
1400  * Topology refcount overview
1401  * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1402  *
1403  * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1404  * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1405  * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1406  *
1407  * Topology refcounts are not exposed to drivers, and are handled internally
1408  * by the DP MST helpers. The helpers use them in order to prevent the
1409  * in-memory topology state from being changed in the middle of critical
1410  * operations like changing the internal state of payload allocations. This
1411  * means each branch and port will be considered to be connected to the rest
1412  * of the topology until its topology refcount reaches zero. Additionally,
1413  * for ports this means that their associated &struct drm_connector will stay
1414  * registered with userspace until the port's refcount reaches 0.
1415  *
1416  * Malloc refcount overview
1417  * ~~~~~~~~~~~~~~~~~~~~~~~~
1418  *
1419  * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1420  * drm_dp_mst_branch allocated even after all of its topology references have
1421  * been dropped, so that the driver or MST helpers can safely access each
1422  * branch's last known state before it was disconnected from the topology.
1423  * When the malloc refcount of a port or branch reaches 0, the memory
1424  * allocation containing the &struct drm_dp_mst_branch or &struct
1425  * drm_dp_mst_port respectively will be freed.
1426  *
1427  * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1428  * to drivers. As of writing this documentation, there are no drivers that
1429  * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1430  * helpers. Exposing this API to drivers in a race-free manner would take more
1431  * tweaking of the refcounting scheme, however patches are welcome provided
1432  * there is a legitimate driver usecase for this.
1433  *
1434  * Refcount relationships in a topology
1435  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1436  *
1437  * Let's take a look at why the relationship between topology and malloc
1438  * refcounts is designed the way it is.
1439  *
1440  * .. kernel-figure:: dp-mst/topology-figure-1.dot
1441  *
1442  *    An example of topology and malloc refs in a DP MST topology with two
1443  *    active payloads. Topology refcount increments are indicated by solid
1444  *    lines, and malloc refcount increments are indicated by dashed lines.
1445  *    Each starts from the branch which incremented the refcount, and ends at
1446  *    the branch to which the refcount belongs to, i.e. the arrow points the
1447  *    same way as the C pointers used to reference a structure.
1448  *
1449  * As you can see in the above figure, every branch increments the topology
1450  * refcount of its children, and increments the malloc refcount of its
1451  * parent. Additionally, every payload increments the malloc refcount of its
1452  * assigned port by 1.
1453  *
1454  * So, what would happen if MSTB #3 from the above figure was unplugged from
1455  * the system, but the driver hadn't yet removed payload #2 from port #3? The
1456  * topology would start to look like the figure below.
1457  *
1458  * .. kernel-figure:: dp-mst/topology-figure-2.dot
1459  *
1460  *    Ports and branch devices which have been released from memory are
1461  *    colored grey, and references which have been removed are colored red.
1462  *
1463  * Whenever a port or branch device's topology refcount reaches zero, it will
1464  * decrement the topology refcounts of all its children, the malloc refcount
1465  * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1466  * #4, this means they both have been disconnected from the topology and freed
1467  * from memory. But, because payload #2 is still holding a reference to port
1468  * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1469  * is still accessible from memory. This also means port #3 has not yet
1470  * decremented the malloc refcount of MSTB #3, so its &struct
1471  * drm_dp_mst_branch will also stay allocated in memory until port #3's
1472  * malloc refcount reaches 0.
1473  *
1474  * This relationship is necessary because in order to release payload #2, we
1475  * need to be able to figure out the last relative of port #3 that's still
1476  * connected to the topology. In this case, we would travel up the topology as
1477  * shown below.
1478  *
1479  * .. kernel-figure:: dp-mst/topology-figure-3.dot
1480  *
1481  * And finally, remove payload #2 by communicating with port #2 through
1482  * sideband transactions.
1483  */
1484
1485 /**
1486  * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1487  * device
1488  * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1489  *
1490  * Increments &drm_dp_mst_branch.malloc_kref. When
1491  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1492  * will be released and @mstb may no longer be used.
1493  *
1494  * See also: drm_dp_mst_put_mstb_malloc()
1495  */
1496 static void
1497 drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1498 {
1499         kref_get(&mstb->malloc_kref);
1500         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1501 }
1502
1503 /**
1504  * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1505  * device
1506  * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1507  *
1508  * Decrements &drm_dp_mst_branch.malloc_kref. When
1509  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1510  * will be released and @mstb may no longer be used.
1511  *
1512  * See also: drm_dp_mst_get_mstb_malloc()
1513  */
1514 static void
1515 drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1516 {
1517         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1518         kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1519 }
1520
1521 static void drm_dp_free_mst_port(struct kref *kref)
1522 {
1523         struct drm_dp_mst_port *port =
1524                 container_of(kref, struct drm_dp_mst_port, malloc_kref);
1525
1526         drm_dp_mst_put_mstb_malloc(port->parent);
1527         kfree(port);
1528 }
1529
1530 /**
1531  * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1532  * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1533  *
1534  * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1535  * reaches 0, the memory allocation for @port will be released and @port may
1536  * no longer be used.
1537  *
1538  * Because @port could potentially be freed at any time by the DP MST helpers
1539  * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1540  * function, drivers that which to make use of &struct drm_dp_mst_port should
1541  * ensure that they grab at least one main malloc reference to their MST ports
1542  * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1543  * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1544  *
1545  * See also: drm_dp_mst_put_port_malloc()
1546  */
1547 void
1548 drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1549 {
1550         kref_get(&port->malloc_kref);
1551         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref));
1552 }
1553 EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1554
1555 /**
1556  * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1557  * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1558  *
1559  * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1560  * reaches 0, the memory allocation for @port will be released and @port may
1561  * no longer be used.
1562  *
1563  * See also: drm_dp_mst_get_port_malloc()
1564  */
1565 void
1566 drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1567 {
1568         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1569         kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1570 }
1571 EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1572
1573 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1574
1575 #define STACK_DEPTH 8
1576
1577 static noinline void
1578 __topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1579                     struct drm_dp_mst_topology_ref_history *history,
1580                     enum drm_dp_mst_topology_ref_type type)
1581 {
1582         struct drm_dp_mst_topology_ref_entry *entry = NULL;
1583         depot_stack_handle_t backtrace;
1584         ulong stack_entries[STACK_DEPTH];
1585         uint n;
1586         int i;
1587
1588         n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1589         backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1590         if (!backtrace)
1591                 return;
1592
1593         /* Try to find an existing entry for this backtrace */
1594         for (i = 0; i < history->len; i++) {
1595                 if (history->entries[i].backtrace == backtrace) {
1596                         entry = &history->entries[i];
1597                         break;
1598                 }
1599         }
1600
1601         /* Otherwise add one */
1602         if (!entry) {
1603                 struct drm_dp_mst_topology_ref_entry *new;
1604                 int new_len = history->len + 1;
1605
1606                 new = krealloc(history->entries, sizeof(*new) * new_len,
1607                                GFP_KERNEL);
1608                 if (!new)
1609                         return;
1610
1611                 entry = &new[history->len];
1612                 history->len = new_len;
1613                 history->entries = new;
1614
1615                 entry->backtrace = backtrace;
1616                 entry->type = type;
1617                 entry->count = 0;
1618         }
1619         entry->count++;
1620         entry->ts_nsec = ktime_get_ns();
1621 }
1622
1623 static int
1624 topology_ref_history_cmp(const void *a, const void *b)
1625 {
1626         const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1627
1628         if (entry_a->ts_nsec > entry_b->ts_nsec)
1629                 return 1;
1630         else if (entry_a->ts_nsec < entry_b->ts_nsec)
1631                 return -1;
1632         else
1633                 return 0;
1634 }
1635
1636 static inline const char *
1637 topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1638 {
1639         if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1640                 return "get";
1641         else
1642                 return "put";
1643 }
1644
1645 static void
1646 __dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
1647                             void *ptr, const char *type_str)
1648 {
1649         struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1650         char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1651         int i;
1652
1653         if (!buf)
1654                 return;
1655
1656         if (!history->len)
1657                 goto out;
1658
1659         /* First, sort the list so that it goes from oldest to newest
1660          * reference entry
1661          */
1662         sort(history->entries, history->len, sizeof(*history->entries),
1663              topology_ref_history_cmp, NULL);
1664
1665         drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1666                    type_str, ptr);
1667
1668         for (i = 0; i < history->len; i++) {
1669                 const struct drm_dp_mst_topology_ref_entry *entry =
1670                         &history->entries[i];
1671                 ulong *entries;
1672                 uint nr_entries;
1673                 u64 ts_nsec = entry->ts_nsec;
1674                 u32 rem_nsec = do_div(ts_nsec, 1000000000);
1675
1676                 nr_entries = stack_depot_fetch(entry->backtrace, &entries);
1677                 stack_trace_snprint(buf, PAGE_SIZE, entries, nr_entries, 4);
1678
1679                 drm_printf(&p, "  %d %ss (last at %5llu.%06u):\n%s",
1680                            entry->count,
1681                            topology_ref_type_to_str(entry->type),
1682                            ts_nsec, rem_nsec / 1000, buf);
1683         }
1684
1685         /* Now free the history, since this is the only time we expose it */
1686         kfree(history->entries);
1687 out:
1688         kfree(buf);
1689 }
1690
1691 static __always_inline void
1692 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1693 {
1694         __dump_topology_ref_history(&mstb->topology_ref_history, mstb,
1695                                     "MSTB");
1696 }
1697
1698 static __always_inline void
1699 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1700 {
1701         __dump_topology_ref_history(&port->topology_ref_history, port,
1702                                     "Port");
1703 }
1704
1705 static __always_inline void
1706 save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1707                        enum drm_dp_mst_topology_ref_type type)
1708 {
1709         __topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1710 }
1711
1712 static __always_inline void
1713 save_port_topology_ref(struct drm_dp_mst_port *port,
1714                        enum drm_dp_mst_topology_ref_type type)
1715 {
1716         __topology_ref_save(port->mgr, &port->topology_ref_history, type);
1717 }
1718
1719 static inline void
1720 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1721 {
1722         mutex_lock(&mgr->topology_ref_history_lock);
1723 }
1724
1725 static inline void
1726 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1727 {
1728         mutex_unlock(&mgr->topology_ref_history_lock);
1729 }
1730 #else
1731 static inline void
1732 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1733 static inline void
1734 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1735 static inline void
1736 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1737 static inline void
1738 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1739 #define save_mstb_topology_ref(mstb, type)
1740 #define save_port_topology_ref(port, type)
1741 #endif
1742
1743 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1744 {
1745         struct drm_dp_mst_branch *mstb =
1746                 container_of(kref, struct drm_dp_mst_branch, topology_kref);
1747         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1748
1749         drm_dp_mst_dump_mstb_topology_history(mstb);
1750
1751         INIT_LIST_HEAD(&mstb->destroy_next);
1752
1753         /*
1754          * This can get called under mgr->mutex, so we need to perform the
1755          * actual destruction of the mstb in another worker
1756          */
1757         mutex_lock(&mgr->delayed_destroy_lock);
1758         list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1759         mutex_unlock(&mgr->delayed_destroy_lock);
1760         queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1761 }
1762
1763 /**
1764  * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1765  * branch device unless it's zero
1766  * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1767  *
1768  * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1769  * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1770  * reached 0). Holding a topology reference implies that a malloc reference
1771  * will be held to @mstb as long as the user holds the topology reference.
1772  *
1773  * Care should be taken to ensure that the user has at least one malloc
1774  * reference to @mstb. If you already have a topology reference to @mstb, you
1775  * should use drm_dp_mst_topology_get_mstb() instead.
1776  *
1777  * See also:
1778  * drm_dp_mst_topology_get_mstb()
1779  * drm_dp_mst_topology_put_mstb()
1780  *
1781  * Returns:
1782  * * 1: A topology reference was grabbed successfully
1783  * * 0: @port is no longer in the topology, no reference was grabbed
1784  */
1785 static int __must_check
1786 drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1787 {
1788         int ret;
1789
1790         topology_ref_history_lock(mstb->mgr);
1791         ret = kref_get_unless_zero(&mstb->topology_kref);
1792         if (ret) {
1793                 drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1794                 save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1795         }
1796
1797         topology_ref_history_unlock(mstb->mgr);
1798
1799         return ret;
1800 }
1801
1802 /**
1803  * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1804  * branch device
1805  * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1806  *
1807  * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1808  * not it's already reached 0. This is only valid to use in scenarios where
1809  * you are already guaranteed to have at least one active topology reference
1810  * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1811  *
1812  * See also:
1813  * drm_dp_mst_topology_try_get_mstb()
1814  * drm_dp_mst_topology_put_mstb()
1815  */
1816 static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1817 {
1818         topology_ref_history_lock(mstb->mgr);
1819
1820         save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1821         WARN_ON(kref_read(&mstb->topology_kref) == 0);
1822         kref_get(&mstb->topology_kref);
1823         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1824
1825         topology_ref_history_unlock(mstb->mgr);
1826 }
1827
1828 /**
1829  * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1830  * device
1831  * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1832  *
1833  * Releases a topology reference from @mstb by decrementing
1834  * &drm_dp_mst_branch.topology_kref.
1835  *
1836  * See also:
1837  * drm_dp_mst_topology_try_get_mstb()
1838  * drm_dp_mst_topology_get_mstb()
1839  */
1840 static void
1841 drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1842 {
1843         topology_ref_history_lock(mstb->mgr);
1844
1845         drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref) - 1);
1846         save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1847
1848         topology_ref_history_unlock(mstb->mgr);
1849         kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1850 }
1851
1852 static void drm_dp_destroy_port(struct kref *kref)
1853 {
1854         struct drm_dp_mst_port *port =
1855                 container_of(kref, struct drm_dp_mst_port, topology_kref);
1856         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1857
1858         drm_dp_mst_dump_port_topology_history(port);
1859
1860         /* There's nothing that needs locking to destroy an input port yet */
1861         if (port->input) {
1862                 drm_dp_mst_put_port_malloc(port);
1863                 return;
1864         }
1865
1866         kfree(port->cached_edid);
1867
1868         /*
1869          * we can't destroy the connector here, as we might be holding the
1870          * mode_config.mutex from an EDID retrieval
1871          */
1872         mutex_lock(&mgr->delayed_destroy_lock);
1873         list_add(&port->next, &mgr->destroy_port_list);
1874         mutex_unlock(&mgr->delayed_destroy_lock);
1875         queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1876 }
1877
1878 /**
1879  * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1880  * port unless it's zero
1881  * @port: &struct drm_dp_mst_port to increment the topology refcount of
1882  *
1883  * Attempts to grab a topology reference to @port, if it hasn't yet been
1884  * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1885  * 0). Holding a topology reference implies that a malloc reference will be
1886  * held to @port as long as the user holds the topology reference.
1887  *
1888  * Care should be taken to ensure that the user has at least one malloc
1889  * reference to @port. If you already have a topology reference to @port, you
1890  * should use drm_dp_mst_topology_get_port() instead.
1891  *
1892  * See also:
1893  * drm_dp_mst_topology_get_port()
1894  * drm_dp_mst_topology_put_port()
1895  *
1896  * Returns:
1897  * * 1: A topology reference was grabbed successfully
1898  * * 0: @port is no longer in the topology, no reference was grabbed
1899  */
1900 static int __must_check
1901 drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1902 {
1903         int ret;
1904
1905         topology_ref_history_lock(port->mgr);
1906         ret = kref_get_unless_zero(&port->topology_kref);
1907         if (ret) {
1908                 drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1909                 save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1910         }
1911
1912         topology_ref_history_unlock(port->mgr);
1913         return ret;
1914 }
1915
1916 /**
1917  * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1918  * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1919  *
1920  * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1921  * not it's already reached 0. This is only valid to use in scenarios where
1922  * you are already guaranteed to have at least one active topology reference
1923  * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1924  *
1925  * See also:
1926  * drm_dp_mst_topology_try_get_port()
1927  * drm_dp_mst_topology_put_port()
1928  */
1929 static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1930 {
1931         topology_ref_history_lock(port->mgr);
1932
1933         WARN_ON(kref_read(&port->topology_kref) == 0);
1934         kref_get(&port->topology_kref);
1935         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1936         save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1937
1938         topology_ref_history_unlock(port->mgr);
1939 }
1940
1941 /**
1942  * drm_dp_mst_topology_put_port() - release a topology reference to a port
1943  * @port: The &struct drm_dp_mst_port to release the topology reference from
1944  *
1945  * Releases a topology reference from @port by decrementing
1946  * &drm_dp_mst_port.topology_kref.
1947  *
1948  * See also:
1949  * drm_dp_mst_topology_try_get_port()
1950  * drm_dp_mst_topology_get_port()
1951  */
1952 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1953 {
1954         topology_ref_history_lock(port->mgr);
1955
1956         drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref) - 1);
1957         save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1958
1959         topology_ref_history_unlock(port->mgr);
1960         kref_put(&port->topology_kref, drm_dp_destroy_port);
1961 }
1962
1963 static struct drm_dp_mst_branch *
1964 drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1965                                               struct drm_dp_mst_branch *to_find)
1966 {
1967         struct drm_dp_mst_port *port;
1968         struct drm_dp_mst_branch *rmstb;
1969
1970         if (to_find == mstb)
1971                 return mstb;
1972
1973         list_for_each_entry(port, &mstb->ports, next) {
1974                 if (port->mstb) {
1975                         rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1976                             port->mstb, to_find);
1977                         if (rmstb)
1978                                 return rmstb;
1979                 }
1980         }
1981         return NULL;
1982 }
1983
1984 static struct drm_dp_mst_branch *
1985 drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1986                                        struct drm_dp_mst_branch *mstb)
1987 {
1988         struct drm_dp_mst_branch *rmstb = NULL;
1989
1990         mutex_lock(&mgr->lock);
1991         if (mgr->mst_primary) {
1992                 rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1993                     mgr->mst_primary, mstb);
1994
1995                 if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1996                         rmstb = NULL;
1997         }
1998         mutex_unlock(&mgr->lock);
1999         return rmstb;
2000 }
2001
2002 static struct drm_dp_mst_port *
2003 drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
2004                                               struct drm_dp_mst_port *to_find)
2005 {
2006         struct drm_dp_mst_port *port, *mport;
2007
2008         list_for_each_entry(port, &mstb->ports, next) {
2009                 if (port == to_find)
2010                         return port;
2011
2012                 if (port->mstb) {
2013                         mport = drm_dp_mst_topology_get_port_validated_locked(
2014                             port->mstb, to_find);
2015                         if (mport)
2016                                 return mport;
2017                 }
2018         }
2019         return NULL;
2020 }
2021
2022 static struct drm_dp_mst_port *
2023 drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
2024                                        struct drm_dp_mst_port *port)
2025 {
2026         struct drm_dp_mst_port *rport = NULL;
2027
2028         mutex_lock(&mgr->lock);
2029         if (mgr->mst_primary) {
2030                 rport = drm_dp_mst_topology_get_port_validated_locked(
2031                     mgr->mst_primary, port);
2032
2033                 if (rport && !drm_dp_mst_topology_try_get_port(rport))
2034                         rport = NULL;
2035         }
2036         mutex_unlock(&mgr->lock);
2037         return rport;
2038 }
2039
2040 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
2041 {
2042         struct drm_dp_mst_port *port;
2043         int ret;
2044
2045         list_for_each_entry(port, &mstb->ports, next) {
2046                 if (port->port_num == port_num) {
2047                         ret = drm_dp_mst_topology_try_get_port(port);
2048                         return ret ? port : NULL;
2049                 }
2050         }
2051
2052         return NULL;
2053 }
2054
2055 /*
2056  * calculate a new RAD for this MST branch device
2057  * if parent has an LCT of 2 then it has 1 nibble of RAD,
2058  * if parent has an LCT of 3 then it has 2 nibbles of RAD,
2059  */
2060 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
2061                                  u8 *rad)
2062 {
2063         int parent_lct = port->parent->lct;
2064         int shift = 4;
2065         int idx = (parent_lct - 1) / 2;
2066
2067         if (parent_lct > 1) {
2068                 memcpy(rad, port->parent->rad, idx + 1);
2069                 shift = (parent_lct % 2) ? 4 : 0;
2070         } else
2071                 rad[0] = 0;
2072
2073         rad[idx] |= port->port_num << shift;
2074         return parent_lct + 1;
2075 }
2076
2077 static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
2078 {
2079         switch (pdt) {
2080         case DP_PEER_DEVICE_DP_LEGACY_CONV:
2081         case DP_PEER_DEVICE_SST_SINK:
2082                 return true;
2083         case DP_PEER_DEVICE_MST_BRANCHING:
2084                 /* For sst branch device */
2085                 if (!mcs)
2086                         return true;
2087
2088                 return false;
2089         }
2090         return true;
2091 }
2092
2093 static int
2094 drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
2095                     bool new_mcs)
2096 {
2097         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2098         struct drm_dp_mst_branch *mstb;
2099         u8 rad[8], lct;
2100         int ret = 0;
2101
2102         if (port->pdt == new_pdt && port->mcs == new_mcs)
2103                 return 0;
2104
2105         /* Teardown the old pdt, if there is one */
2106         if (port->pdt != DP_PEER_DEVICE_NONE) {
2107                 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2108                         /*
2109                          * If the new PDT would also have an i2c bus,
2110                          * don't bother with reregistering it
2111                          */
2112                         if (new_pdt != DP_PEER_DEVICE_NONE &&
2113                             drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
2114                                 port->pdt = new_pdt;
2115                                 port->mcs = new_mcs;
2116                                 return 0;
2117                         }
2118
2119                         /* remove i2c over sideband */
2120                         drm_dp_mst_unregister_i2c_bus(port);
2121                 } else {
2122                         mutex_lock(&mgr->lock);
2123                         drm_dp_mst_topology_put_mstb(port->mstb);
2124                         port->mstb = NULL;
2125                         mutex_unlock(&mgr->lock);
2126                 }
2127         }
2128
2129         port->pdt = new_pdt;
2130         port->mcs = new_mcs;
2131
2132         if (port->pdt != DP_PEER_DEVICE_NONE) {
2133                 if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2134                         /* add i2c over sideband */
2135                         ret = drm_dp_mst_register_i2c_bus(port);
2136                 } else {
2137                         lct = drm_dp_calculate_rad(port, rad);
2138                         mstb = drm_dp_add_mst_branch_device(lct, rad);
2139                         if (!mstb) {
2140                                 ret = -ENOMEM;
2141                                 drm_err(mgr->dev, "Failed to create MSTB for port %p", port);
2142                                 goto out;
2143                         }
2144
2145                         mutex_lock(&mgr->lock);
2146                         port->mstb = mstb;
2147                         mstb->mgr = port->mgr;
2148                         mstb->port_parent = port;
2149
2150                         /*
2151                          * Make sure this port's memory allocation stays
2152                          * around until its child MSTB releases it
2153                          */
2154                         drm_dp_mst_get_port_malloc(port);
2155                         mutex_unlock(&mgr->lock);
2156
2157                         /* And make sure we send a link address for this */
2158                         ret = 1;
2159                 }
2160         }
2161
2162 out:
2163         if (ret < 0)
2164                 port->pdt = DP_PEER_DEVICE_NONE;
2165         return ret;
2166 }
2167
2168 /**
2169  * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2170  * @aux: Fake sideband AUX CH
2171  * @offset: address of the (first) register to read
2172  * @buffer: buffer to store the register values
2173  * @size: number of bytes in @buffer
2174  *
2175  * Performs the same functionality for remote devices via
2176  * sideband messaging as drm_dp_dpcd_read() does for local
2177  * devices via actual AUX CH.
2178  *
2179  * Return: Number of bytes read, or negative error code on failure.
2180  */
2181 ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2182                              unsigned int offset, void *buffer, size_t size)
2183 {
2184         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2185                                                     aux);
2186
2187         return drm_dp_send_dpcd_read(port->mgr, port,
2188                                      offset, size, buffer);
2189 }
2190
2191 /**
2192  * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2193  * @aux: Fake sideband AUX CH
2194  * @offset: address of the (first) register to write
2195  * @buffer: buffer containing the values to write
2196  * @size: number of bytes in @buffer
2197  *
2198  * Performs the same functionality for remote devices via
2199  * sideband messaging as drm_dp_dpcd_write() does for local
2200  * devices via actual AUX CH.
2201  *
2202  * Return: number of bytes written on success, negative error code on failure.
2203  */
2204 ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2205                               unsigned int offset, void *buffer, size_t size)
2206 {
2207         struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2208                                                     aux);
2209
2210         return drm_dp_send_dpcd_write(port->mgr, port,
2211                                       offset, size, buffer);
2212 }
2213
2214 static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2215 {
2216         int ret = 0;
2217
2218         memcpy(mstb->guid, guid, 16);
2219
2220         if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2221                 if (mstb->port_parent) {
2222                         ret = drm_dp_send_dpcd_write(mstb->mgr,
2223                                                      mstb->port_parent,
2224                                                      DP_GUID, 16, mstb->guid);
2225                 } else {
2226                         ret = drm_dp_dpcd_write(mstb->mgr->aux,
2227                                                 DP_GUID, mstb->guid, 16);
2228                 }
2229         }
2230
2231         if (ret < 16 && ret > 0)
2232                 return -EPROTO;
2233
2234         return ret == 16 ? 0 : ret;
2235 }
2236
2237 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2238                                 int pnum,
2239                                 char *proppath,
2240                                 size_t proppath_size)
2241 {
2242         int i;
2243         char temp[8];
2244
2245         snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2246         for (i = 0; i < (mstb->lct - 1); i++) {
2247                 int shift = (i % 2) ? 0 : 4;
2248                 int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2249
2250                 snprintf(temp, sizeof(temp), "-%d", port_num);
2251                 strlcat(proppath, temp, proppath_size);
2252         }
2253         snprintf(temp, sizeof(temp), "-%d", pnum);
2254         strlcat(proppath, temp, proppath_size);
2255 }
2256
2257 /**
2258  * drm_dp_mst_connector_late_register() - Late MST connector registration
2259  * @connector: The MST connector
2260  * @port: The MST port for this connector
2261  *
2262  * Helper to register the remote aux device for this MST port. Drivers should
2263  * call this from their mst connector's late_register hook to enable MST aux
2264  * devices.
2265  *
2266  * Return: 0 on success, negative error code on failure.
2267  */
2268 int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2269                                        struct drm_dp_mst_port *port)
2270 {
2271         drm_dbg_kms(port->mgr->dev, "registering %s remote bus for %s\n",
2272                     port->aux.name, connector->kdev->kobj.name);
2273
2274         port->aux.dev = connector->kdev;
2275         return drm_dp_aux_register_devnode(&port->aux);
2276 }
2277 EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2278
2279 /**
2280  * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2281  * @connector: The MST connector
2282  * @port: The MST port for this connector
2283  *
2284  * Helper to unregister the remote aux device for this MST port, registered by
2285  * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2286  * connector's early_unregister hook.
2287  */
2288 void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2289                                            struct drm_dp_mst_port *port)
2290 {
2291         drm_dbg_kms(port->mgr->dev, "unregistering %s remote bus for %s\n",
2292                     port->aux.name, connector->kdev->kobj.name);
2293         drm_dp_aux_unregister_devnode(&port->aux);
2294 }
2295 EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2296
2297 static void
2298 drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2299                               struct drm_dp_mst_port *port)
2300 {
2301         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2302         char proppath[255];
2303         int ret;
2304
2305         build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2306         port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2307         if (!port->connector) {
2308                 ret = -ENOMEM;
2309                 goto error;
2310         }
2311
2312         if (port->pdt != DP_PEER_DEVICE_NONE &&
2313             drm_dp_mst_is_end_device(port->pdt, port->mcs) &&
2314             port->port_num >= DP_MST_LOGICAL_PORT_0)
2315                 port->cached_edid = drm_get_edid(port->connector,
2316                                                  &port->aux.ddc);
2317
2318         drm_connector_register(port->connector);
2319         return;
2320
2321 error:
2322         drm_err(mgr->dev, "Failed to create connector for port %p: %d\n", port, ret);
2323 }
2324
2325 /*
2326  * Drop a topology reference, and unlink the port from the in-memory topology
2327  * layout
2328  */
2329 static void
2330 drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2331                                 struct drm_dp_mst_port *port)
2332 {
2333         mutex_lock(&mgr->lock);
2334         port->parent->num_ports--;
2335         list_del(&port->next);
2336         mutex_unlock(&mgr->lock);
2337         drm_dp_mst_topology_put_port(port);
2338 }
2339
2340 static struct drm_dp_mst_port *
2341 drm_dp_mst_add_port(struct drm_device *dev,
2342                     struct drm_dp_mst_topology_mgr *mgr,
2343                     struct drm_dp_mst_branch *mstb, u8 port_number)
2344 {
2345         struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2346
2347         if (!port)
2348                 return NULL;
2349
2350         kref_init(&port->topology_kref);
2351         kref_init(&port->malloc_kref);
2352         port->parent = mstb;
2353         port->port_num = port_number;
2354         port->mgr = mgr;
2355         port->aux.name = "DPMST";
2356         port->aux.dev = dev->dev;
2357         port->aux.is_remote = true;
2358
2359         /* initialize the MST downstream port's AUX crc work queue */
2360         port->aux.drm_dev = dev;
2361         drm_dp_remote_aux_init(&port->aux);
2362
2363         /*
2364          * Make sure the memory allocation for our parent branch stays
2365          * around until our own memory allocation is released
2366          */
2367         drm_dp_mst_get_mstb_malloc(mstb);
2368
2369         return port;
2370 }
2371
2372 static int
2373 drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2374                                     struct drm_device *dev,
2375                                     struct drm_dp_link_addr_reply_port *port_msg)
2376 {
2377         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2378         struct drm_dp_mst_port *port;
2379         int old_ddps = 0, ret;
2380         u8 new_pdt = DP_PEER_DEVICE_NONE;
2381         bool new_mcs = 0;
2382         bool created = false, send_link_addr = false, changed = false;
2383
2384         port = drm_dp_get_port(mstb, port_msg->port_number);
2385         if (!port) {
2386                 port = drm_dp_mst_add_port(dev, mgr, mstb,
2387                                            port_msg->port_number);
2388                 if (!port)
2389                         return -ENOMEM;
2390                 created = true;
2391                 changed = true;
2392         } else if (!port->input && port_msg->input_port && port->connector) {
2393                 /* Since port->connector can't be changed here, we create a
2394                  * new port if input_port changes from 0 to 1
2395                  */
2396                 drm_dp_mst_topology_unlink_port(mgr, port);
2397                 drm_dp_mst_topology_put_port(port);
2398                 port = drm_dp_mst_add_port(dev, mgr, mstb,
2399                                            port_msg->port_number);
2400                 if (!port)
2401                         return -ENOMEM;
2402                 changed = true;
2403                 created = true;
2404         } else if (port->input && !port_msg->input_port) {
2405                 changed = true;
2406         } else if (port->connector) {
2407                 /* We're updating a port that's exposed to userspace, so do it
2408                  * under lock
2409                  */
2410                 drm_modeset_lock(&mgr->base.lock, NULL);
2411
2412                 old_ddps = port->ddps;
2413                 changed = port->ddps != port_msg->ddps ||
2414                         (port->ddps &&
2415                          (port->ldps != port_msg->legacy_device_plug_status ||
2416                           port->dpcd_rev != port_msg->dpcd_revision ||
2417                           port->mcs != port_msg->mcs ||
2418                           port->pdt != port_msg->peer_device_type ||
2419                           port->num_sdp_stream_sinks !=
2420                           port_msg->num_sdp_stream_sinks));
2421         }
2422
2423         port->input = port_msg->input_port;
2424         if (!port->input)
2425                 new_pdt = port_msg->peer_device_type;
2426         new_mcs = port_msg->mcs;
2427         port->ddps = port_msg->ddps;
2428         port->ldps = port_msg->legacy_device_plug_status;
2429         port->dpcd_rev = port_msg->dpcd_revision;
2430         port->num_sdp_streams = port_msg->num_sdp_streams;
2431         port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2432
2433         /* manage mstb port lists with mgr lock - take a reference
2434            for this list */
2435         if (created) {
2436                 mutex_lock(&mgr->lock);
2437                 drm_dp_mst_topology_get_port(port);
2438                 list_add(&port->next, &mstb->ports);
2439                 mstb->num_ports++;
2440                 mutex_unlock(&mgr->lock);
2441         }
2442
2443         /*
2444          * Reprobe PBN caps on both hotplug, and when re-probing the link
2445          * for our parent mstb
2446          */
2447         if (old_ddps != port->ddps || !created) {
2448                 if (port->ddps && !port->input) {
2449                         ret = drm_dp_send_enum_path_resources(mgr, mstb,
2450                                                               port);
2451                         if (ret == 1)
2452                                 changed = true;
2453                 } else {
2454                         port->full_pbn = 0;
2455                 }
2456         }
2457
2458         ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2459         if (ret == 1) {
2460                 send_link_addr = true;
2461         } else if (ret < 0) {
2462                 drm_err(dev, "Failed to change PDT on port %p: %d\n", port, ret);
2463                 goto fail;
2464         }
2465
2466         /*
2467          * If this port wasn't just created, then we're reprobing because
2468          * we're coming out of suspend. In this case, always resend the link
2469          * address if there's an MSTB on this port
2470          */
2471         if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2472             port->mcs)
2473                 send_link_addr = true;
2474
2475         if (port->connector)
2476                 drm_modeset_unlock(&mgr->base.lock);
2477         else if (!port->input)
2478                 drm_dp_mst_port_add_connector(mstb, port);
2479
2480         if (send_link_addr && port->mstb) {
2481                 ret = drm_dp_send_link_address(mgr, port->mstb);
2482                 if (ret == 1) /* MSTB below us changed */
2483                         changed = true;
2484                 else if (ret < 0)
2485                         goto fail_put;
2486         }
2487
2488         /* put reference to this port */
2489         drm_dp_mst_topology_put_port(port);
2490         return changed;
2491
2492 fail:
2493         drm_dp_mst_topology_unlink_port(mgr, port);
2494         if (port->connector)
2495                 drm_modeset_unlock(&mgr->base.lock);
2496 fail_put:
2497         drm_dp_mst_topology_put_port(port);
2498         return ret;
2499 }
2500
2501 static void
2502 drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2503                             struct drm_dp_connection_status_notify *conn_stat)
2504 {
2505         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2506         struct drm_dp_mst_port *port;
2507         int old_ddps, ret;
2508         u8 new_pdt;
2509         bool new_mcs;
2510         bool dowork = false, create_connector = false;
2511
2512         port = drm_dp_get_port(mstb, conn_stat->port_number);
2513         if (!port)
2514                 return;
2515
2516         if (port->connector) {
2517                 if (!port->input && conn_stat->input_port) {
2518                         /*
2519                          * We can't remove a connector from an already exposed
2520                          * port, so just throw the port out and make sure we
2521                          * reprobe the link address of it's parent MSTB
2522                          */
2523                         drm_dp_mst_topology_unlink_port(mgr, port);
2524                         mstb->link_address_sent = false;
2525                         dowork = true;
2526                         goto out;
2527                 }
2528
2529                 /* Locking is only needed if the port's exposed to userspace */
2530                 drm_modeset_lock(&mgr->base.lock, NULL);
2531         } else if (port->input && !conn_stat->input_port) {
2532                 create_connector = true;
2533                 /* Reprobe link address so we get num_sdp_streams */
2534                 mstb->link_address_sent = false;
2535                 dowork = true;
2536         }
2537
2538         old_ddps = port->ddps;
2539         port->input = conn_stat->input_port;
2540         port->ldps = conn_stat->legacy_device_plug_status;
2541         port->ddps = conn_stat->displayport_device_plug_status;
2542
2543         if (old_ddps != port->ddps) {
2544                 if (port->ddps && !port->input)
2545                         drm_dp_send_enum_path_resources(mgr, mstb, port);
2546                 else
2547                         port->full_pbn = 0;
2548         }
2549
2550         new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2551         new_mcs = conn_stat->message_capability_status;
2552         ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2553         if (ret == 1) {
2554                 dowork = true;
2555         } else if (ret < 0) {
2556                 drm_err(mgr->dev, "Failed to change PDT for port %p: %d\n", port, ret);
2557                 dowork = false;
2558         }
2559
2560         if (port->connector)
2561                 drm_modeset_unlock(&mgr->base.lock);
2562         else if (create_connector)
2563                 drm_dp_mst_port_add_connector(mstb, port);
2564
2565 out:
2566         drm_dp_mst_topology_put_port(port);
2567         if (dowork)
2568                 queue_work(system_long_wq, &mstb->mgr->work);
2569 }
2570
2571 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2572                                                                u8 lct, u8 *rad)
2573 {
2574         struct drm_dp_mst_branch *mstb;
2575         struct drm_dp_mst_port *port;
2576         int i, ret;
2577         /* find the port by iterating down */
2578
2579         mutex_lock(&mgr->lock);
2580         mstb = mgr->mst_primary;
2581
2582         if (!mstb)
2583                 goto out;
2584
2585         for (i = 0; i < lct - 1; i++) {
2586                 int shift = (i % 2) ? 0 : 4;
2587                 int port_num = (rad[i / 2] >> shift) & 0xf;
2588
2589                 list_for_each_entry(port, &mstb->ports, next) {
2590                         if (port->port_num == port_num) {
2591                                 mstb = port->mstb;
2592                                 if (!mstb) {
2593                                         drm_err(mgr->dev,
2594                                                 "failed to lookup MSTB with lct %d, rad %02x\n",
2595                                                 lct, rad[0]);
2596                                         goto out;
2597                                 }
2598
2599                                 break;
2600                         }
2601                 }
2602         }
2603         ret = drm_dp_mst_topology_try_get_mstb(mstb);
2604         if (!ret)
2605                 mstb = NULL;
2606 out:
2607         mutex_unlock(&mgr->lock);
2608         return mstb;
2609 }
2610
2611 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2612         struct drm_dp_mst_branch *mstb,
2613         const uint8_t *guid)
2614 {
2615         struct drm_dp_mst_branch *found_mstb;
2616         struct drm_dp_mst_port *port;
2617
2618         if (memcmp(mstb->guid, guid, 16) == 0)
2619                 return mstb;
2620
2621
2622         list_for_each_entry(port, &mstb->ports, next) {
2623                 if (!port->mstb)
2624                         continue;
2625
2626                 found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2627
2628                 if (found_mstb)
2629                         return found_mstb;
2630         }
2631
2632         return NULL;
2633 }
2634
2635 static struct drm_dp_mst_branch *
2636 drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2637                                      const uint8_t *guid)
2638 {
2639         struct drm_dp_mst_branch *mstb;
2640         int ret;
2641
2642         /* find the port by iterating down */
2643         mutex_lock(&mgr->lock);
2644
2645         mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2646         if (mstb) {
2647                 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2648                 if (!ret)
2649                         mstb = NULL;
2650         }
2651
2652         mutex_unlock(&mgr->lock);
2653         return mstb;
2654 }
2655
2656 static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2657                                                struct drm_dp_mst_branch *mstb)
2658 {
2659         struct drm_dp_mst_port *port;
2660         int ret;
2661         bool changed = false;
2662
2663         if (!mstb->link_address_sent) {
2664                 ret = drm_dp_send_link_address(mgr, mstb);
2665                 if (ret == 1)
2666                         changed = true;
2667                 else if (ret < 0)
2668                         return ret;
2669         }
2670
2671         list_for_each_entry(port, &mstb->ports, next) {
2672                 struct drm_dp_mst_branch *mstb_child = NULL;
2673
2674                 if (port->input || !port->ddps)
2675                         continue;
2676
2677                 if (port->mstb)
2678                         mstb_child = drm_dp_mst_topology_get_mstb_validated(
2679                             mgr, port->mstb);
2680
2681                 if (mstb_child) {
2682                         ret = drm_dp_check_and_send_link_address(mgr,
2683                                                                  mstb_child);
2684                         drm_dp_mst_topology_put_mstb(mstb_child);
2685                         if (ret == 1)
2686                                 changed = true;
2687                         else if (ret < 0)
2688                                 return ret;
2689                 }
2690         }
2691
2692         return changed;
2693 }
2694
2695 static void drm_dp_mst_link_probe_work(struct work_struct *work)
2696 {
2697         struct drm_dp_mst_topology_mgr *mgr =
2698                 container_of(work, struct drm_dp_mst_topology_mgr, work);
2699         struct drm_device *dev = mgr->dev;
2700         struct drm_dp_mst_branch *mstb;
2701         int ret;
2702         bool clear_payload_id_table;
2703
2704         mutex_lock(&mgr->probe_lock);
2705
2706         mutex_lock(&mgr->lock);
2707         clear_payload_id_table = !mgr->payload_id_table_cleared;
2708         mgr->payload_id_table_cleared = true;
2709
2710         mstb = mgr->mst_primary;
2711         if (mstb) {
2712                 ret = drm_dp_mst_topology_try_get_mstb(mstb);
2713                 if (!ret)
2714                         mstb = NULL;
2715         }
2716         mutex_unlock(&mgr->lock);
2717         if (!mstb) {
2718                 mutex_unlock(&mgr->probe_lock);
2719                 return;
2720         }
2721
2722         /*
2723          * Certain branch devices seem to incorrectly report an available_pbn
2724          * of 0 on downstream sinks, even after clearing the
2725          * DP_PAYLOAD_ALLOCATE_* registers in
2726          * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2727          * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2728          * things work again.
2729          */
2730         if (clear_payload_id_table) {
2731                 drm_dbg_kms(dev, "Clearing payload ID table\n");
2732                 drm_dp_send_clear_payload_id_table(mgr, mstb);
2733         }
2734
2735         ret = drm_dp_check_and_send_link_address(mgr, mstb);
2736         drm_dp_mst_topology_put_mstb(mstb);
2737
2738         mutex_unlock(&mgr->probe_lock);
2739         if (ret > 0)
2740                 drm_kms_helper_hotplug_event(dev);
2741 }
2742
2743 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2744                                  u8 *guid)
2745 {
2746         u64 salt;
2747
2748         if (memchr_inv(guid, 0, 16))
2749                 return true;
2750
2751         salt = get_jiffies_64();
2752
2753         memcpy(&guid[0], &salt, sizeof(u64));
2754         memcpy(&guid[8], &salt, sizeof(u64));
2755
2756         return false;
2757 }
2758
2759 static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2760                             u8 port_num, u32 offset, u8 num_bytes)
2761 {
2762         struct drm_dp_sideband_msg_req_body req;
2763
2764         req.req_type = DP_REMOTE_DPCD_READ;
2765         req.u.dpcd_read.port_number = port_num;
2766         req.u.dpcd_read.dpcd_address = offset;
2767         req.u.dpcd_read.num_bytes = num_bytes;
2768         drm_dp_encode_sideband_req(&req, msg);
2769 }
2770
2771 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2772                                     bool up, u8 *msg, int len)
2773 {
2774         int ret;
2775         int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2776         int tosend, total, offset;
2777         int retries = 0;
2778
2779 retry:
2780         total = len;
2781         offset = 0;
2782         do {
2783                 tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2784
2785                 ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2786                                         &msg[offset],
2787                                         tosend);
2788                 if (ret != tosend) {
2789                         if (ret == -EIO && retries < 5) {
2790                                 retries++;
2791                                 goto retry;
2792                         }
2793                         drm_dbg_kms(mgr->dev, "failed to dpcd write %d %d\n", tosend, ret);
2794
2795                         return -EIO;
2796                 }
2797                 offset += tosend;
2798                 total -= tosend;
2799         } while (total > 0);
2800         return 0;
2801 }
2802
2803 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2804                                   struct drm_dp_sideband_msg_tx *txmsg)
2805 {
2806         struct drm_dp_mst_branch *mstb = txmsg->dst;
2807         u8 req_type;
2808
2809         req_type = txmsg->msg[0] & 0x7f;
2810         if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2811                 req_type == DP_RESOURCE_STATUS_NOTIFY ||
2812                 req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
2813                 hdr->broadcast = 1;
2814         else
2815                 hdr->broadcast = 0;
2816         hdr->path_msg = txmsg->path_msg;
2817         if (hdr->broadcast) {
2818                 hdr->lct = 1;
2819                 hdr->lcr = 6;
2820         } else {
2821                 hdr->lct = mstb->lct;
2822                 hdr->lcr = mstb->lct - 1;
2823         }
2824
2825         memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
2826
2827         return 0;
2828 }
2829 /*
2830  * process a single block of the next message in the sideband queue
2831  */
2832 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2833                                    struct drm_dp_sideband_msg_tx *txmsg,
2834                                    bool up)
2835 {
2836         u8 chunk[48];
2837         struct drm_dp_sideband_msg_hdr hdr;
2838         int len, space, idx, tosend;
2839         int ret;
2840
2841         if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2842                 return 0;
2843
2844         memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2845
2846         if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2847                 txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2848
2849         /* make hdr from dst mst */
2850         ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2851         if (ret < 0)
2852                 return ret;
2853
2854         /* amount left to send in this message */
2855         len = txmsg->cur_len - txmsg->cur_offset;
2856
2857         /* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2858         space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2859
2860         tosend = min(len, space);
2861         if (len == txmsg->cur_len)
2862                 hdr.somt = 1;
2863         if (space >= len)
2864                 hdr.eomt = 1;
2865
2866
2867         hdr.msg_len = tosend + 1;
2868         drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2869         memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2870         /* add crc at end */
2871         drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2872         idx += tosend + 1;
2873
2874         ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2875         if (ret) {
2876                 if (drm_debug_enabled(DRM_UT_DP)) {
2877                         struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2878
2879                         drm_printf(&p, "sideband msg failed to send\n");
2880                         drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2881                 }
2882                 return ret;
2883         }
2884
2885         txmsg->cur_offset += tosend;
2886         if (txmsg->cur_offset == txmsg->cur_len) {
2887                 txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2888                 return 1;
2889         }
2890         return 0;
2891 }
2892
2893 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2894 {
2895         struct drm_dp_sideband_msg_tx *txmsg;
2896         int ret;
2897
2898         WARN_ON(!mutex_is_locked(&mgr->qlock));
2899
2900         /* construct a chunk from the first msg in the tx_msg queue */
2901         if (list_empty(&mgr->tx_msg_downq))
2902                 return;
2903
2904         txmsg = list_first_entry(&mgr->tx_msg_downq,
2905                                  struct drm_dp_sideband_msg_tx, next);
2906         ret = process_single_tx_qlock(mgr, txmsg, false);
2907         if (ret < 0) {
2908                 drm_dbg_kms(mgr->dev, "failed to send msg in q %d\n", ret);
2909                 list_del(&txmsg->next);
2910                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2911                 wake_up_all(&mgr->tx_waitq);
2912         }
2913 }
2914
2915 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2916                                  struct drm_dp_sideband_msg_tx *txmsg)
2917 {
2918         mutex_lock(&mgr->qlock);
2919         list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2920
2921         if (drm_debug_enabled(DRM_UT_DP)) {
2922                 struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2923
2924                 drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2925         }
2926
2927         if (list_is_singular(&mgr->tx_msg_downq))
2928                 process_single_down_tx_qlock(mgr);
2929         mutex_unlock(&mgr->qlock);
2930 }
2931
2932 static void
2933 drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr *mgr,
2934                          struct drm_dp_link_address_ack_reply *reply)
2935 {
2936         struct drm_dp_link_addr_reply_port *port_reply;
2937         int i;
2938
2939         for (i = 0; i < reply->nports; i++) {
2940                 port_reply = &reply->ports[i];
2941                 drm_dbg_kms(mgr->dev,
2942                             "port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2943                             i,
2944                             port_reply->input_port,
2945                             port_reply->peer_device_type,
2946                             port_reply->port_number,
2947                             port_reply->dpcd_revision,
2948                             port_reply->mcs,
2949                             port_reply->ddps,
2950                             port_reply->legacy_device_plug_status,
2951                             port_reply->num_sdp_streams,
2952                             port_reply->num_sdp_stream_sinks);
2953         }
2954 }
2955
2956 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2957                                      struct drm_dp_mst_branch *mstb)
2958 {
2959         struct drm_dp_sideband_msg_tx *txmsg;
2960         struct drm_dp_link_address_ack_reply *reply;
2961         struct drm_dp_mst_port *port, *tmp;
2962         int i, ret, port_mask = 0;
2963         bool changed = false;
2964
2965         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2966         if (!txmsg)
2967                 return -ENOMEM;
2968
2969         txmsg->dst = mstb;
2970         build_link_address(txmsg);
2971
2972         mstb->link_address_sent = true;
2973         drm_dp_queue_down_tx(mgr, txmsg);
2974
2975         /* FIXME: Actually do some real error handling here */
2976         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2977         if (ret <= 0) {
2978                 drm_err(mgr->dev, "Sending link address failed with %d\n", ret);
2979                 goto out;
2980         }
2981         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2982                 drm_err(mgr->dev, "link address NAK received\n");
2983                 ret = -EIO;
2984                 goto out;
2985         }
2986
2987         reply = &txmsg->reply.u.link_addr;
2988         drm_dbg_kms(mgr->dev, "link address reply: %d\n", reply->nports);
2989         drm_dp_dump_link_address(mgr, reply);
2990
2991         ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2992         if (ret) {
2993                 char buf[64];
2994
2995                 drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
2996                 drm_err(mgr->dev, "GUID check on %s failed: %d\n", buf, ret);
2997                 goto out;
2998         }
2999
3000         for (i = 0; i < reply->nports; i++) {
3001                 port_mask |= BIT(reply->ports[i].port_number);
3002                 ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
3003                                                           &reply->ports[i]);
3004                 if (ret == 1)
3005                         changed = true;
3006                 else if (ret < 0)
3007                         goto out;
3008         }
3009
3010         /* Prune any ports that are currently a part of mstb in our in-memory
3011          * topology, but were not seen in this link address. Usually this
3012          * means that they were removed while the topology was out of sync,
3013          * e.g. during suspend/resume
3014          */
3015         mutex_lock(&mgr->lock);
3016         list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
3017                 if (port_mask & BIT(port->port_num))
3018                         continue;
3019
3020                 drm_dbg_kms(mgr->dev, "port %d was not in link address, removing\n",
3021                             port->port_num);
3022                 list_del(&port->next);
3023                 drm_dp_mst_topology_put_port(port);
3024                 changed = true;
3025         }
3026         mutex_unlock(&mgr->lock);
3027
3028 out:
3029         if (ret <= 0)
3030                 mstb->link_address_sent = false;
3031         kfree(txmsg);
3032         return ret < 0 ? ret : changed;
3033 }
3034
3035 static void
3036 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
3037                                    struct drm_dp_mst_branch *mstb)
3038 {
3039         struct drm_dp_sideband_msg_tx *txmsg;
3040         int ret;
3041
3042         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3043         if (!txmsg)
3044                 return;
3045
3046         txmsg->dst = mstb;
3047         build_clear_payload_id_table(txmsg);
3048
3049         drm_dp_queue_down_tx(mgr, txmsg);
3050
3051         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3052         if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3053                 drm_dbg_kms(mgr->dev, "clear payload table id nak received\n");
3054
3055         kfree(txmsg);
3056 }
3057
3058 static int
3059 drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
3060                                 struct drm_dp_mst_branch *mstb,
3061                                 struct drm_dp_mst_port *port)
3062 {
3063         struct drm_dp_enum_path_resources_ack_reply *path_res;
3064         struct drm_dp_sideband_msg_tx *txmsg;
3065         int ret;
3066
3067         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3068         if (!txmsg)
3069                 return -ENOMEM;
3070
3071         txmsg->dst = mstb;
3072         build_enum_path_resources(txmsg, port->port_num);
3073
3074         drm_dp_queue_down_tx(mgr, txmsg);
3075
3076         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3077         if (ret > 0) {
3078                 ret = 0;
3079                 path_res = &txmsg->reply.u.path_resources;
3080
3081                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3082                         drm_dbg_kms(mgr->dev, "enum path resources nak received\n");
3083                 } else {
3084                         if (port->port_num != path_res->port_number)
3085                                 DRM_ERROR("got incorrect port in response\n");
3086
3087                         drm_dbg_kms(mgr->dev, "enum path resources %d: %d %d\n",
3088                                     path_res->port_number,
3089                                     path_res->full_payload_bw_number,
3090                                     path_res->avail_payload_bw_number);
3091
3092                         /*
3093                          * If something changed, make sure we send a
3094                          * hotplug
3095                          */
3096                         if (port->full_pbn != path_res->full_payload_bw_number ||
3097                             port->fec_capable != path_res->fec_capable)
3098                                 ret = 1;
3099
3100                         port->full_pbn = path_res->full_payload_bw_number;
3101                         port->fec_capable = path_res->fec_capable;
3102                 }
3103         }
3104
3105         kfree(txmsg);
3106         return ret;
3107 }
3108
3109 static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
3110 {
3111         if (!mstb->port_parent)
3112                 return NULL;
3113
3114         if (mstb->port_parent->mstb != mstb)
3115                 return mstb->port_parent;
3116
3117         return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
3118 }
3119
3120 /*
3121  * Searches upwards in the topology starting from mstb to try to find the
3122  * closest available parent of mstb that's still connected to the rest of the
3123  * topology. This can be used in order to perform operations like releasing
3124  * payloads, where the branch device which owned the payload may no longer be
3125  * around and thus would require that the payload on the last living relative
3126  * be freed instead.
3127  */
3128 static struct drm_dp_mst_branch *
3129 drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
3130                                         struct drm_dp_mst_branch *mstb,
3131                                         int *port_num)
3132 {
3133         struct drm_dp_mst_branch *rmstb = NULL;
3134         struct drm_dp_mst_port *found_port;
3135
3136         mutex_lock(&mgr->lock);
3137         if (!mgr->mst_primary)
3138                 goto out;
3139
3140         do {
3141                 found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
3142                 if (!found_port)
3143                         break;
3144
3145                 if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
3146                         rmstb = found_port->parent;
3147                         *port_num = found_port->port_num;
3148                 } else {
3149                         /* Search again, starting from this parent */
3150                         mstb = found_port->parent;
3151                 }
3152         } while (!rmstb);
3153 out:
3154         mutex_unlock(&mgr->lock);
3155         return rmstb;
3156 }
3157
3158 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
3159                                    struct drm_dp_mst_port *port,
3160                                    int id,
3161                                    int pbn)
3162 {
3163         struct drm_dp_sideband_msg_tx *txmsg;
3164         struct drm_dp_mst_branch *mstb;
3165         int ret, port_num;
3166         u8 sinks[DRM_DP_MAX_SDP_STREAMS];
3167         int i;
3168
3169         port_num = port->port_num;
3170         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3171         if (!mstb) {
3172                 mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
3173                                                                port->parent,
3174                                                                &port_num);
3175
3176                 if (!mstb)
3177                         return -EINVAL;
3178         }
3179
3180         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3181         if (!txmsg) {
3182                 ret = -ENOMEM;
3183                 goto fail_put;
3184         }
3185
3186         for (i = 0; i < port->num_sdp_streams; i++)
3187                 sinks[i] = i;
3188
3189         txmsg->dst = mstb;
3190         build_allocate_payload(txmsg, port_num,
3191                                id,
3192                                pbn, port->num_sdp_streams, sinks);
3193
3194         drm_dp_queue_down_tx(mgr, txmsg);
3195
3196         /*
3197          * FIXME: there is a small chance that between getting the last
3198          * connected mstb and sending the payload message, the last connected
3199          * mstb could also be removed from the topology. In the future, this
3200          * needs to be fixed by restarting the
3201          * drm_dp_get_last_connected_port_and_mstb() search in the event of a
3202          * timeout if the topology is still connected to the system.
3203          */
3204         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3205         if (ret > 0) {
3206                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3207                         ret = -EINVAL;
3208                 else
3209                         ret = 0;
3210         }
3211         kfree(txmsg);
3212 fail_put:
3213         drm_dp_mst_topology_put_mstb(mstb);
3214         return ret;
3215 }
3216
3217 int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
3218                                  struct drm_dp_mst_port *port, bool power_up)
3219 {
3220         struct drm_dp_sideband_msg_tx *txmsg;
3221         int ret;
3222
3223         port = drm_dp_mst_topology_get_port_validated(mgr, port);
3224         if (!port)
3225                 return -EINVAL;
3226
3227         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3228         if (!txmsg) {
3229                 drm_dp_mst_topology_put_port(port);
3230                 return -ENOMEM;
3231         }
3232
3233         txmsg->dst = port->parent;
3234         build_power_updown_phy(txmsg, port->port_num, power_up);
3235         drm_dp_queue_down_tx(mgr, txmsg);
3236
3237         ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
3238         if (ret > 0) {
3239                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3240                         ret = -EINVAL;
3241                 else
3242                         ret = 0;
3243         }
3244         kfree(txmsg);
3245         drm_dp_mst_topology_put_port(port);
3246
3247         return ret;
3248 }
3249 EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
3250
3251 int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
3252                 struct drm_dp_mst_port *port,
3253                 struct drm_dp_query_stream_enc_status_ack_reply *status)
3254 {
3255         struct drm_dp_sideband_msg_tx *txmsg;
3256         u8 nonce[7];
3257         int ret;
3258
3259         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3260         if (!txmsg)
3261                 return -ENOMEM;
3262
3263         port = drm_dp_mst_topology_get_port_validated(mgr, port);
3264         if (!port) {
3265                 ret = -EINVAL;
3266                 goto out_get_port;
3267         }
3268
3269         get_random_bytes(nonce, sizeof(nonce));
3270
3271         /*
3272          * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
3273          *  transaction at the MST Branch device directly connected to the
3274          *  Source"
3275          */
3276         txmsg->dst = mgr->mst_primary;
3277
3278         build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
3279
3280         drm_dp_queue_down_tx(mgr, txmsg);
3281
3282         ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
3283         if (ret < 0) {
3284                 goto out;
3285         } else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3286                 drm_dbg_kms(mgr->dev, "query encryption status nak received\n");
3287                 ret = -ENXIO;
3288                 goto out;
3289         }
3290
3291         ret = 0;
3292         memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
3293
3294 out:
3295         drm_dp_mst_topology_put_port(port);
3296 out_get_port:
3297         kfree(txmsg);
3298         return ret;
3299 }
3300 EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
3301
3302 static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3303                                        int id,
3304                                        struct drm_dp_payload *payload)
3305 {
3306         int ret;
3307
3308         ret = drm_dp_dpcd_write_payload(mgr, id, payload);
3309         if (ret < 0) {
3310                 payload->payload_state = 0;
3311                 return ret;
3312         }
3313         payload->payload_state = DP_PAYLOAD_LOCAL;
3314         return 0;
3315 }
3316
3317 static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3318                                        struct drm_dp_mst_port *port,
3319                                        int id,
3320                                        struct drm_dp_payload *payload)
3321 {
3322         int ret;
3323
3324         ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
3325         if (ret < 0)
3326                 return ret;
3327         payload->payload_state = DP_PAYLOAD_REMOTE;
3328         return ret;
3329 }
3330
3331 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3332                                         struct drm_dp_mst_port *port,
3333                                         int id,
3334                                         struct drm_dp_payload *payload)
3335 {
3336         drm_dbg_kms(mgr->dev, "\n");
3337         /* it's okay for these to fail */
3338         if (port) {
3339                 drm_dp_payload_send_msg(mgr, port, id, 0);
3340         }
3341
3342         drm_dp_dpcd_write_payload(mgr, id, payload);
3343         payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
3344         return 0;
3345 }
3346
3347 static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3348                                         int id,
3349                                         struct drm_dp_payload *payload)
3350 {
3351         payload->payload_state = 0;
3352         return 0;
3353 }
3354
3355 /**
3356  * drm_dp_update_payload_part1() - Execute payload update part 1
3357  * @mgr: manager to use.
3358  *
3359  * This iterates over all proposed virtual channels, and tries to
3360  * allocate space in the link for them. For 0->slots transitions,
3361  * this step just writes the VCPI to the MST device. For slots->0
3362  * transitions, this writes the updated VCPIs and removes the
3363  * remote VC payloads.
3364  *
3365  * after calling this the driver should generate ACT and payload
3366  * packets.
3367  */
3368 int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
3369 {
3370         struct drm_dp_payload req_payload;
3371         struct drm_dp_mst_port *port;
3372         int i, j;
3373         int cur_slots = 1;
3374         bool skip;
3375
3376         mutex_lock(&mgr->payload_lock);
3377         for (i = 0; i < mgr->max_payloads; i++) {
3378                 struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
3379                 struct drm_dp_payload *payload = &mgr->payloads[i];
3380                 bool put_port = false;
3381
3382                 /* solve the current payloads - compare to the hw ones
3383                    - update the hw view */
3384                 req_payload.start_slot = cur_slots;
3385                 if (vcpi) {
3386                         port = container_of(vcpi, struct drm_dp_mst_port,
3387                                             vcpi);
3388
3389                         mutex_lock(&mgr->lock);
3390                         skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
3391                         mutex_unlock(&mgr->lock);
3392
3393                         if (skip) {
3394                                 drm_dbg_kms(mgr->dev,
3395                                             "Virtual channel %d is not in current topology\n",
3396                                             i);
3397                                 continue;
3398                         }
3399                         /* Validated ports don't matter if we're releasing
3400                          * VCPI
3401                          */
3402                         if (vcpi->num_slots) {
3403                                 port = drm_dp_mst_topology_get_port_validated(
3404                                     mgr, port);
3405                                 if (!port) {
3406                                         if (vcpi->num_slots == payload->num_slots) {
3407                                                 cur_slots += vcpi->num_slots;
3408                                                 payload->start_slot = req_payload.start_slot;
3409                                                 continue;
3410                                         } else {
3411                                                 drm_dbg_kms(mgr->dev,
3412                                                             "Fail:set payload to invalid sink");
3413                                                 mutex_unlock(&mgr->payload_lock);
3414                                                 return -EINVAL;
3415                                         }
3416                                 }
3417                                 put_port = true;
3418                         }
3419
3420                         req_payload.num_slots = vcpi->num_slots;
3421                         req_payload.vcpi = vcpi->vcpi;
3422                 } else {
3423                         port = NULL;
3424                         req_payload.num_slots = 0;
3425                 }
3426
3427                 payload->start_slot = req_payload.start_slot;
3428                 /* work out what is required to happen with this payload */
3429                 if (payload->num_slots != req_payload.num_slots) {
3430
3431                         /* need to push an update for this payload */
3432                         if (req_payload.num_slots) {
3433                                 drm_dp_create_payload_step1(mgr, vcpi->vcpi,
3434                                                             &req_payload);
3435                                 payload->num_slots = req_payload.num_slots;
3436                                 payload->vcpi = req_payload.vcpi;
3437
3438                         } else if (payload->num_slots) {
3439                                 payload->num_slots = 0;
3440                                 drm_dp_destroy_payload_step1(mgr, port,
3441                                                              payload->vcpi,
3442                                                              payload);
3443                                 req_payload.payload_state =
3444                                         payload->payload_state;
3445                                 payload->start_slot = 0;
3446                         }
3447                         payload->payload_state = req_payload.payload_state;
3448                 }
3449                 cur_slots += req_payload.num_slots;
3450
3451                 if (put_port)
3452                         drm_dp_mst_topology_put_port(port);
3453         }
3454
3455         for (i = 0; i < mgr->max_payloads; /* do nothing */) {
3456                 if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
3457                         i++;
3458                         continue;
3459                 }
3460
3461                 drm_dbg_kms(mgr->dev, "removing payload %d\n", i);
3462                 for (j = i; j < mgr->max_payloads - 1; j++) {
3463                         mgr->payloads[j] = mgr->payloads[j + 1];
3464                         mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
3465
3466                         if (mgr->proposed_vcpis[j] &&
3467                             mgr->proposed_vcpis[j]->num_slots) {
3468                                 set_bit(j + 1, &mgr->payload_mask);
3469                         } else {
3470                                 clear_bit(j + 1, &mgr->payload_mask);
3471                         }
3472                 }
3473
3474                 memset(&mgr->payloads[mgr->max_payloads - 1], 0,
3475                        sizeof(struct drm_dp_payload));
3476                 mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
3477                 clear_bit(mgr->max_payloads, &mgr->payload_mask);
3478         }
3479         mutex_unlock(&mgr->payload_lock);
3480
3481         return 0;
3482 }
3483 EXPORT_SYMBOL(drm_dp_update_payload_part1);
3484
3485 /**
3486  * drm_dp_update_payload_part2() - Execute payload update part 2
3487  * @mgr: manager to use.
3488  *
3489  * This iterates over all proposed virtual channels, and tries to
3490  * allocate space in the link for them. For 0->slots transitions,
3491  * this step writes the remote VC payload commands. For slots->0
3492  * this just resets some internal state.
3493  */
3494 int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
3495 {
3496         struct drm_dp_mst_port *port;
3497         int i;
3498         int ret = 0;
3499         bool skip;
3500
3501         mutex_lock(&mgr->payload_lock);
3502         for (i = 0; i < mgr->max_payloads; i++) {
3503
3504                 if (!mgr->proposed_vcpis[i])
3505                         continue;
3506
3507                 port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
3508
3509                 mutex_lock(&mgr->lock);
3510                 skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
3511                 mutex_unlock(&mgr->lock);
3512
3513                 if (skip)
3514                         continue;
3515
3516                 drm_dbg_kms(mgr->dev, "payload %d %d\n", i, mgr->payloads[i].payload_state);
3517                 if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
3518                         ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3519                 } else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
3520                         ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3521                 }
3522                 if (ret) {
3523                         mutex_unlock(&mgr->payload_lock);
3524                         return ret;
3525                 }
3526         }
3527         mutex_unlock(&mgr->payload_lock);
3528         return 0;
3529 }
3530 EXPORT_SYMBOL(drm_dp_update_payload_part2);
3531
3532 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3533                                  struct drm_dp_mst_port *port,
3534                                  int offset, int size, u8 *bytes)
3535 {
3536         int ret = 0;
3537         struct drm_dp_sideband_msg_tx *txmsg;
3538         struct drm_dp_mst_branch *mstb;
3539
3540         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3541         if (!mstb)
3542                 return -EINVAL;
3543
3544         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3545         if (!txmsg) {
3546                 ret = -ENOMEM;
3547                 goto fail_put;
3548         }
3549
3550         build_dpcd_read(txmsg, port->port_num, offset, size);
3551         txmsg->dst = port->parent;
3552
3553         drm_dp_queue_down_tx(mgr, txmsg);
3554
3555         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3556         if (ret < 0)
3557                 goto fail_free;
3558
3559         /* DPCD read should never be NACKed */
3560         if (txmsg->reply.reply_type == 1) {
3561                 drm_err(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3562                         mstb, port->port_num, offset, size);
3563                 ret = -EIO;
3564                 goto fail_free;
3565         }
3566
3567         if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3568                 ret = -EPROTO;
3569                 goto fail_free;
3570         }
3571
3572         ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3573                     size);
3574         memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3575
3576 fail_free:
3577         kfree(txmsg);
3578 fail_put:
3579         drm_dp_mst_topology_put_mstb(mstb);
3580
3581         return ret;
3582 }
3583
3584 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3585                                   struct drm_dp_mst_port *port,
3586                                   int offset, int size, u8 *bytes)
3587 {
3588         int ret;
3589         struct drm_dp_sideband_msg_tx *txmsg;
3590         struct drm_dp_mst_branch *mstb;
3591
3592         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3593         if (!mstb)
3594                 return -EINVAL;
3595
3596         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3597         if (!txmsg) {
3598                 ret = -ENOMEM;
3599                 goto fail_put;
3600         }
3601
3602         build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3603         txmsg->dst = mstb;
3604
3605         drm_dp_queue_down_tx(mgr, txmsg);
3606
3607         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3608         if (ret > 0) {
3609                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3610                         ret = -EIO;
3611                 else
3612                         ret = size;
3613         }
3614
3615         kfree(txmsg);
3616 fail_put:
3617         drm_dp_mst_topology_put_mstb(mstb);
3618         return ret;
3619 }
3620
3621 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3622 {
3623         struct drm_dp_sideband_msg_reply_body reply;
3624
3625         reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3626         reply.req_type = req_type;
3627         drm_dp_encode_sideband_reply(&reply, msg);
3628         return 0;
3629 }
3630
3631 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3632                                     struct drm_dp_mst_branch *mstb,
3633                                     int req_type, bool broadcast)
3634 {
3635         struct drm_dp_sideband_msg_tx *txmsg;
3636
3637         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3638         if (!txmsg)
3639                 return -ENOMEM;
3640
3641         txmsg->dst = mstb;
3642         drm_dp_encode_up_ack_reply(txmsg, req_type);
3643
3644         mutex_lock(&mgr->qlock);
3645         /* construct a chunk from the first msg in the tx_msg queue */
3646         process_single_tx_qlock(mgr, txmsg, true);
3647         mutex_unlock(&mgr->qlock);
3648
3649         kfree(txmsg);
3650         return 0;
3651 }
3652
3653 /**
3654  * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
3655  * @mgr: The &drm_dp_mst_topology_mgr to use
3656  * @link_rate: link rate in 10kbits/s units
3657  * @link_lane_count: lane count
3658  *
3659  * Calculate the total bandwidth of a MultiStream Transport link. The returned
3660  * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
3661  * convert the number of PBNs required for a given stream to the number of
3662  * timeslots this stream requires in each MTP.
3663  */
3664 int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
3665                              int link_rate, int link_lane_count)
3666 {
3667         if (link_rate == 0 || link_lane_count == 0)
3668                 drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n",
3669                             link_rate, link_lane_count);
3670
3671         /* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
3672         return link_rate * link_lane_count / 54000;
3673 }
3674 EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
3675
3676 /**
3677  * drm_dp_read_mst_cap() - check whether or not a sink supports MST
3678  * @aux: The DP AUX channel to use
3679  * @dpcd: A cached copy of the DPCD capabilities for this sink
3680  *
3681  * Returns: %True if the sink supports MST, %false otherwise
3682  */
3683 bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
3684                          const u8 dpcd[DP_RECEIVER_CAP_SIZE])
3685 {
3686         u8 mstm_cap;
3687
3688         if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
3689                 return false;
3690
3691         if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
3692                 return false;
3693
3694         return mstm_cap & DP_MST_CAP;
3695 }
3696 EXPORT_SYMBOL(drm_dp_read_mst_cap);
3697
3698 /**
3699  * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3700  * @mgr: manager to set state for
3701  * @mst_state: true to enable MST on this connector - false to disable.
3702  *
3703  * This is called by the driver when it detects an MST capable device plugged
3704  * into a DP MST capable port, or when a DP MST capable device is unplugged.
3705  */
3706 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3707 {
3708         int ret = 0;
3709         struct drm_dp_mst_branch *mstb = NULL;
3710
3711         mutex_lock(&mgr->payload_lock);
3712         mutex_lock(&mgr->lock);
3713         if (mst_state == mgr->mst_state)
3714                 goto out_unlock;
3715
3716         mgr->mst_state = mst_state;
3717         /* set the device into MST mode */
3718         if (mst_state) {
3719                 struct drm_dp_payload reset_pay;
3720                 int lane_count;
3721                 int link_rate;
3722
3723                 WARN_ON(mgr->mst_primary);
3724
3725                 /* get dpcd info */
3726                 ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
3727                 if (ret < 0) {
3728                         drm_dbg_kms(mgr->dev, "%s: failed to read DPCD, ret %d\n",
3729                                     mgr->aux->name, ret);
3730                         goto out_unlock;
3731                 }
3732
3733                 lane_count = min_t(int, mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK, mgr->max_lane_count);
3734                 link_rate = min_t(int, drm_dp_bw_code_to_link_rate(mgr->dpcd[1]), mgr->max_link_rate);
3735                 mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr,
3736                                                         link_rate,
3737                                                         lane_count);
3738                 if (mgr->pbn_div == 0) {
3739                         ret = -EINVAL;
3740                         goto out_unlock;
3741                 }
3742
3743                 /* add initial branch device at LCT 1 */
3744                 mstb = drm_dp_add_mst_branch_device(1, NULL);
3745                 if (mstb == NULL) {
3746                         ret = -ENOMEM;
3747                         goto out_unlock;
3748                 }
3749                 mstb->mgr = mgr;
3750
3751                 /* give this the main reference */
3752                 mgr->mst_primary = mstb;
3753                 drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3754
3755                 ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3756                                          DP_MST_EN |
3757                                          DP_UP_REQ_EN |
3758                                          DP_UPSTREAM_IS_SRC);
3759                 if (ret < 0)
3760                         goto out_unlock;
3761
3762                 reset_pay.start_slot = 0;
3763                 reset_pay.num_slots = 0x3f;
3764                 drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
3765
3766                 queue_work(system_long_wq, &mgr->work);
3767
3768                 ret = 0;
3769         } else {
3770                 /* disable MST on the device */
3771                 mstb = mgr->mst_primary;
3772                 mgr->mst_primary = NULL;
3773                 /* this can fail if the device is gone */
3774                 drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3775                 ret = 0;
3776                 memset(mgr->payloads, 0,
3777                        mgr->max_payloads * sizeof(mgr->payloads[0]));
3778                 memset(mgr->proposed_vcpis, 0,
3779                        mgr->max_payloads * sizeof(mgr->proposed_vcpis[0]));
3780                 mgr->payload_mask = 0;
3781                 set_bit(0, &mgr->payload_mask);
3782                 mgr->vcpi_mask = 0;
3783                 mgr->payload_id_table_cleared = false;
3784         }
3785
3786 out_unlock:
3787         mutex_unlock(&mgr->lock);
3788         mutex_unlock(&mgr->payload_lock);
3789         if (mstb)
3790                 drm_dp_mst_topology_put_mstb(mstb);
3791         return ret;
3792
3793 }
3794 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3795
3796 static void
3797 drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3798 {
3799         struct drm_dp_mst_port *port;
3800
3801         /* The link address will need to be re-sent on resume */
3802         mstb->link_address_sent = false;
3803
3804         list_for_each_entry(port, &mstb->ports, next)
3805                 if (port->mstb)
3806                         drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3807 }
3808
3809 /**
3810  * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3811  * @mgr: manager to suspend
3812  *
3813  * This function tells the MST device that we can't handle UP messages
3814  * anymore. This should stop it from sending any since we are suspended.
3815  */
3816 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3817 {
3818         mutex_lock(&mgr->lock);
3819         drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3820                            DP_MST_EN | DP_UPSTREAM_IS_SRC);
3821         mutex_unlock(&mgr->lock);
3822         flush_work(&mgr->up_req_work);
3823         flush_work(&mgr->work);
3824         flush_work(&mgr->delayed_destroy_work);
3825
3826         mutex_lock(&mgr->lock);
3827         if (mgr->mst_state && mgr->mst_primary)
3828                 drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3829         mutex_unlock(&mgr->lock);
3830 }
3831 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3832
3833 /**
3834  * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3835  * @mgr: manager to resume
3836  * @sync: whether or not to perform topology reprobing synchronously
3837  *
3838  * This will fetch DPCD and see if the device is still there,
3839  * if it is, it will rewrite the MSTM control bits, and return.
3840  *
3841  * If the device fails this returns -1, and the driver should do
3842  * a full MST reprobe, in case we were undocked.
3843  *
3844  * During system resume (where it is assumed that the driver will be calling
3845  * drm_atomic_helper_resume()) this function should be called beforehand with
3846  * @sync set to true. In contexts like runtime resume where the driver is not
3847  * expected to be calling drm_atomic_helper_resume(), this function should be
3848  * called with @sync set to false in order to avoid deadlocking.
3849  *
3850  * Returns: -1 if the MST topology was removed while we were suspended, 0
3851  * otherwise.
3852  */
3853 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3854                                    bool sync)
3855 {
3856         int ret;
3857         u8 guid[16];
3858
3859         mutex_lock(&mgr->lock);
3860         if (!mgr->mst_primary)
3861                 goto out_fail;
3862
3863         ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd,
3864                                DP_RECEIVER_CAP_SIZE);
3865         if (ret != DP_RECEIVER_CAP_SIZE) {
3866                 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3867                 goto out_fail;
3868         }
3869
3870         ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3871                                  DP_MST_EN |
3872                                  DP_UP_REQ_EN |
3873                                  DP_UPSTREAM_IS_SRC);
3874         if (ret < 0) {
3875                 drm_dbg_kms(mgr->dev, "mst write failed - undocked during suspend?\n");
3876                 goto out_fail;
3877         }
3878
3879         /* Some hubs forget their guids after they resume */
3880         ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3881         if (ret != 16) {
3882                 drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3883                 goto out_fail;
3884         }
3885
3886         ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3887         if (ret) {
3888                 drm_dbg_kms(mgr->dev, "check mstb failed - undocked during suspend?\n");
3889                 goto out_fail;
3890         }
3891
3892         /*
3893          * For the final step of resuming the topology, we need to bring the
3894          * state of our in-memory topology back into sync with reality. So,
3895          * restart the probing process as if we're probing a new hub
3896          */
3897         queue_work(system_long_wq, &mgr->work);
3898         mutex_unlock(&mgr->lock);
3899
3900         if (sync) {
3901                 drm_dbg_kms(mgr->dev,
3902                             "Waiting for link probe work to finish re-syncing topology...\n");
3903                 flush_work(&mgr->work);
3904         }
3905
3906         return 0;
3907
3908 out_fail:
3909         mutex_unlock(&mgr->lock);
3910         return -1;
3911 }
3912 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3913
3914 static bool
3915 drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3916                       struct drm_dp_mst_branch **mstb)
3917 {
3918         int len;
3919         u8 replyblock[32];
3920         int replylen, curreply;
3921         int ret;
3922         u8 hdrlen;
3923         struct drm_dp_sideband_msg_hdr hdr;
3924         struct drm_dp_sideband_msg_rx *msg =
3925                 up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3926         int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3927                            DP_SIDEBAND_MSG_DOWN_REP_BASE;
3928
3929         if (!up)
3930                 *mstb = NULL;
3931
3932         len = min(mgr->max_dpcd_transaction_bytes, 16);
3933         ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3934         if (ret != len) {
3935                 drm_dbg_kms(mgr->dev, "failed to read DPCD down rep %d %d\n", len, ret);
3936                 return false;
3937         }
3938
3939         ret = drm_dp_decode_sideband_msg_hdr(mgr, &hdr, replyblock, len, &hdrlen);
3940         if (ret == false) {
3941                 print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3942                                1, replyblock, len, false);
3943                 drm_dbg_kms(mgr->dev, "ERROR: failed header\n");
3944                 return false;
3945         }
3946
3947         if (!up) {
3948                 /* Caller is responsible for giving back this reference */
3949                 *mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3950                 if (!*mstb) {
3951                         drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr.lct);
3952                         return false;
3953                 }
3954         }
3955
3956         if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
3957                 drm_dbg_kms(mgr->dev, "sideband msg set header failed %d\n", replyblock[0]);
3958                 return false;
3959         }
3960
3961         replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
3962         ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
3963         if (!ret) {
3964                 drm_dbg_kms(mgr->dev, "sideband msg build failed %d\n", replyblock[0]);
3965                 return false;
3966         }
3967
3968         replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
3969         curreply = len;
3970         while (replylen > 0) {
3971                 len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
3972                 ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
3973                                     replyblock, len);
3974                 if (ret != len) {
3975                         drm_dbg_kms(mgr->dev, "failed to read a chunk (len %d, ret %d)\n",
3976                                     len, ret);
3977                         return false;
3978                 }
3979
3980                 ret = drm_dp_sideband_append_payload(msg, replyblock, len);
3981                 if (!ret) {
3982                         drm_dbg_kms(mgr->dev, "failed to build sideband msg\n");
3983                         return false;
3984                 }
3985
3986                 curreply += len;
3987                 replylen -= len;
3988         }
3989         return true;
3990 }
3991
3992 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
3993 {
3994         struct drm_dp_sideband_msg_tx *txmsg;
3995         struct drm_dp_mst_branch *mstb = NULL;
3996         struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
3997
3998         if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3999                 goto out;
4000
4001         /* Multi-packet message transmission, don't clear the reply */
4002         if (!msg->have_eomt)
4003                 goto out;
4004
4005         /* find the message */
4006         mutex_lock(&mgr->qlock);
4007         txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
4008                                          struct drm_dp_sideband_msg_tx, next);
4009         mutex_unlock(&mgr->qlock);
4010
4011         /* Were we actually expecting a response, and from this mstb? */
4012         if (!txmsg || txmsg->dst != mstb) {
4013                 struct drm_dp_sideband_msg_hdr *hdr;
4014
4015                 hdr = &msg->initial_hdr;
4016                 drm_dbg_kms(mgr->dev, "Got MST reply with no msg %p %d %d %02x %02x\n",
4017                             mstb, hdr->seqno, hdr->lct, hdr->rad[0], msg->msg[0]);
4018                 goto out_clear_reply;
4019         }
4020
4021         drm_dp_sideband_parse_reply(mgr, msg, &txmsg->reply);
4022
4023         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
4024                 drm_dbg_kms(mgr->dev,
4025                             "Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
4026                             txmsg->reply.req_type,
4027                             drm_dp_mst_req_type_str(txmsg->reply.req_type),
4028                             txmsg->reply.u.nak.reason,
4029                             drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
4030                             txmsg->reply.u.nak.nak_data);
4031         }
4032
4033         memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
4034         drm_dp_mst_topology_put_mstb(mstb);
4035
4036         mutex_lock(&mgr->qlock);
4037         txmsg->state = DRM_DP_SIDEBAND_TX_RX;
4038         list_del(&txmsg->next);
4039         mutex_unlock(&mgr->qlock);
4040
4041         wake_up_all(&mgr->tx_waitq);
4042
4043         return 0;
4044
4045 out_clear_reply:
4046         memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
4047 out:
4048         if (mstb)
4049                 drm_dp_mst_topology_put_mstb(mstb);
4050
4051         return 0;
4052 }
4053
4054 static inline bool
4055 drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
4056                           struct drm_dp_pending_up_req *up_req)
4057 {
4058         struct drm_dp_mst_branch *mstb = NULL;
4059         struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
4060         struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
4061         bool hotplug = false;
4062
4063         if (hdr->broadcast) {
4064                 const u8 *guid = NULL;
4065
4066                 if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
4067                         guid = msg->u.conn_stat.guid;
4068                 else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
4069                         guid = msg->u.resource_stat.guid;
4070
4071                 if (guid)
4072                         mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
4073         } else {
4074                 mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
4075         }
4076
4077         if (!mstb) {
4078                 drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr->lct);
4079                 return false;
4080         }
4081
4082         /* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
4083         if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
4084                 drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
4085                 hotplug = true;
4086         }
4087
4088         drm_dp_mst_topology_put_mstb(mstb);
4089         return hotplug;
4090 }
4091
4092 static void drm_dp_mst_up_req_work(struct work_struct *work)
4093 {
4094         struct drm_dp_mst_topology_mgr *mgr =
4095                 container_of(work, struct drm_dp_mst_topology_mgr,
4096                              up_req_work);
4097         struct drm_dp_pending_up_req *up_req;
4098         bool send_hotplug = false;
4099
4100         mutex_lock(&mgr->probe_lock);
4101         while (true) {
4102                 mutex_lock(&mgr->up_req_lock);
4103                 up_req = list_first_entry_or_null(&mgr->up_req_list,
4104                                                   struct drm_dp_pending_up_req,
4105                                                   next);
4106                 if (up_req)
4107                         list_del(&up_req->next);
4108                 mutex_unlock(&mgr->up_req_lock);
4109
4110                 if (!up_req)
4111                         break;
4112
4113                 send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
4114                 kfree(up_req);
4115         }
4116         mutex_unlock(&mgr->probe_lock);
4117
4118         if (send_hotplug)
4119                 drm_kms_helper_hotplug_event(mgr->dev);
4120 }
4121
4122 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
4123 {
4124         struct drm_dp_pending_up_req *up_req;
4125
4126         if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
4127                 goto out;
4128
4129         if (!mgr->up_req_recv.have_eomt)
4130                 return 0;
4131
4132         up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
4133         if (!up_req)
4134                 return -ENOMEM;
4135
4136         INIT_LIST_HEAD(&up_req->next);
4137
4138         drm_dp_sideband_parse_req(mgr, &mgr->up_req_recv, &up_req->msg);
4139
4140         if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
4141             up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
4142                 drm_dbg_kms(mgr->dev, "Received unknown up req type, ignoring: %x\n",
4143                             up_req->msg.req_type);
4144                 kfree(up_req);
4145                 goto out;
4146         }
4147
4148         drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
4149                                  false);
4150
4151         if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
4152                 const struct drm_dp_connection_status_notify *conn_stat =
4153                         &up_req->msg.u.conn_stat;
4154
4155                 drm_dbg_kms(mgr->dev, "Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
4156                             conn_stat->port_number,
4157                             conn_stat->legacy_device_plug_status,
4158                             conn_stat->displayport_device_plug_status,
4159                             conn_stat->message_capability_status,
4160                             conn_stat->input_port,
4161                             conn_stat->peer_device_type);
4162         } else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
4163                 const struct drm_dp_resource_status_notify *res_stat =
4164                         &up_req->msg.u.resource_stat;
4165
4166                 drm_dbg_kms(mgr->dev, "Got RSN: pn: %d avail_pbn %d\n",
4167                             res_stat->port_number,
4168                             res_stat->available_pbn);
4169         }
4170
4171         up_req->hdr = mgr->up_req_recv.initial_hdr;
4172         mutex_lock(&mgr->up_req_lock);
4173         list_add_tail(&up_req->next, &mgr->up_req_list);
4174         mutex_unlock(&mgr->up_req_lock);
4175         queue_work(system_long_wq, &mgr->up_req_work);
4176
4177 out:
4178         memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
4179         return 0;
4180 }
4181
4182 /**
4183  * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
4184  * @mgr: manager to notify irq for.
4185  * @esi: 4 bytes from SINK_COUNT_ESI
4186  * @handled: whether the hpd interrupt was consumed or not
4187  *
4188  * This should be called from the driver when it detects a short IRQ,
4189  * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
4190  * topology manager will process the sideband messages received as a result
4191  * of this.
4192  */
4193 int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
4194 {
4195         int ret = 0;
4196         int sc;
4197         *handled = false;
4198         sc = esi[0] & 0x3f;
4199
4200         if (sc != mgr->sink_count) {
4201                 mgr->sink_count = sc;
4202                 *handled = true;
4203         }
4204
4205         if (esi[1] & DP_DOWN_REP_MSG_RDY) {
4206                 ret = drm_dp_mst_handle_down_rep(mgr);
4207                 *handled = true;
4208         }
4209
4210         if (esi[1] & DP_UP_REQ_MSG_RDY) {
4211                 ret |= drm_dp_mst_handle_up_req(mgr);
4212                 *handled = true;
4213         }
4214
4215         drm_dp_mst_kick_tx(mgr);
4216         return ret;
4217 }
4218 EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
4219
4220 /**
4221  * drm_dp_mst_detect_port() - get connection status for an MST port
4222  * @connector: DRM connector for this port
4223  * @ctx: The acquisition context to use for grabbing locks
4224  * @mgr: manager for this port
4225  * @port: pointer to a port
4226  *
4227  * This returns the current connection state for a port.
4228  */
4229 int
4230 drm_dp_mst_detect_port(struct drm_connector *connector,
4231                        struct drm_modeset_acquire_ctx *ctx,
4232                        struct drm_dp_mst_topology_mgr *mgr,
4233                        struct drm_dp_mst_port *port)
4234 {
4235         int ret;
4236
4237         /* we need to search for the port in the mgr in case it's gone */
4238         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4239         if (!port)
4240                 return connector_status_disconnected;
4241
4242         ret = drm_modeset_lock(&mgr->base.lock, ctx);
4243         if (ret)
4244                 goto out;
4245
4246         ret = connector_status_disconnected;
4247
4248         if (!port->ddps)
4249                 goto out;
4250
4251         switch (port->pdt) {
4252         case DP_PEER_DEVICE_NONE:
4253                 break;
4254         case DP_PEER_DEVICE_MST_BRANCHING:
4255                 if (!port->mcs)
4256                         ret = connector_status_connected;
4257                 break;
4258
4259         case DP_PEER_DEVICE_SST_SINK:
4260                 ret = connector_status_connected;
4261                 /* for logical ports - cache the EDID */
4262                 if (port->port_num >= DP_MST_LOGICAL_PORT_0 && !port->cached_edid)
4263                         port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
4264                 break;
4265         case DP_PEER_DEVICE_DP_LEGACY_CONV:
4266                 if (port->ldps)
4267                         ret = connector_status_connected;
4268                 break;
4269         }
4270 out:
4271         drm_dp_mst_topology_put_port(port);
4272         return ret;
4273 }
4274 EXPORT_SYMBOL(drm_dp_mst_detect_port);
4275
4276 /**
4277  * drm_dp_mst_get_edid() - get EDID for an MST port
4278  * @connector: toplevel connector to get EDID for
4279  * @mgr: manager for this port
4280  * @port: unverified pointer to a port.
4281  *
4282  * This returns an EDID for the port connected to a connector,
4283  * It validates the pointer still exists so the caller doesn't require a
4284  * reference.
4285  */
4286 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4287 {
4288         struct edid *edid = NULL;
4289
4290         /* we need to search for the port in the mgr in case it's gone */
4291         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4292         if (!port)
4293                 return NULL;
4294
4295         if (port->cached_edid)
4296                 edid = drm_edid_duplicate(port->cached_edid);
4297         else {
4298                 edid = drm_get_edid(connector, &port->aux.ddc);
4299         }
4300         port->has_audio = drm_detect_monitor_audio(edid);
4301         drm_dp_mst_topology_put_port(port);
4302         return edid;
4303 }
4304 EXPORT_SYMBOL(drm_dp_mst_get_edid);
4305
4306 /**
4307  * drm_dp_find_vcpi_slots() - Find VCPI slots for this PBN value
4308  * @mgr: manager to use
4309  * @pbn: payload bandwidth to convert into slots.
4310  *
4311  * Calculate the number of VCPI slots that will be required for the given PBN
4312  * value. This function is deprecated, and should not be used in atomic
4313  * drivers.
4314  *
4315  * RETURNS:
4316  * The total slots required for this port, or error.
4317  */
4318 int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
4319                            int pbn)
4320 {
4321         int num_slots;
4322
4323         num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
4324
4325         /* max. time slots - one slot for MTP header */
4326         if (num_slots > 63)
4327                 return -ENOSPC;
4328         return num_slots;
4329 }
4330 EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
4331
4332 static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4333                             struct drm_dp_vcpi *vcpi, int pbn, int slots)
4334 {
4335         int ret;
4336
4337         vcpi->pbn = pbn;
4338         vcpi->aligned_pbn = slots * mgr->pbn_div;
4339         vcpi->num_slots = slots;
4340
4341         ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
4342         if (ret < 0)
4343                 return ret;
4344         return 0;
4345 }
4346
4347 /**
4348  * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
4349  * @state: global atomic state
4350  * @mgr: MST topology manager for the port
4351  * @port: port to find vcpi slots for
4352  * @pbn: bandwidth required for the mode in PBN
4353  * @pbn_div: divider for DSC mode that takes FEC into account
4354  *
4355  * Allocates VCPI slots to @port, replacing any previous VCPI allocations it
4356  * may have had. Any atomic drivers which support MST must call this function
4357  * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
4358  * current VCPI allocation for the new state, but only when
4359  * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
4360  * to ensure compatibility with userspace applications that still use the
4361  * legacy modesetting UAPI.
4362  *
4363  * Allocations set by this function are not checked against the bandwidth
4364  * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4365  *
4366  * Additionally, it is OK to call this function multiple times on the same
4367  * @port as needed. It is not OK however, to call this function and
4368  * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
4369  *
4370  * See also:
4371  * drm_dp_atomic_release_vcpi_slots()
4372  * drm_dp_mst_atomic_check()
4373  *
4374  * Returns:
4375  * Total slots in the atomic state assigned for this port, or a negative error
4376  * code if the port no longer exists
4377  */
4378 int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
4379                                   struct drm_dp_mst_topology_mgr *mgr,
4380                                   struct drm_dp_mst_port *port, int pbn,
4381                                   int pbn_div)
4382 {
4383         struct drm_dp_mst_topology_state *topology_state;
4384         struct drm_dp_vcpi_allocation *pos, *vcpi = NULL;
4385         int prev_slots, prev_bw, req_slots;
4386
4387         topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4388         if (IS_ERR(topology_state))
4389                 return PTR_ERR(topology_state);
4390
4391         /* Find the current allocation for this port, if any */
4392         list_for_each_entry(pos, &topology_state->vcpis, next) {
4393                 if (pos->port == port) {
4394                         vcpi = pos;
4395                         prev_slots = vcpi->vcpi;
4396                         prev_bw = vcpi->pbn;
4397
4398                         /*
4399                          * This should never happen, unless the driver tries
4400                          * releasing and allocating the same VCPI allocation,
4401                          * which is an error
4402                          */
4403                         if (WARN_ON(!prev_slots)) {
4404                                 drm_err(mgr->dev,
4405                                         "cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
4406                                         port);
4407                                 return -EINVAL;
4408                         }
4409
4410                         break;
4411                 }
4412         }
4413         if (!vcpi) {
4414                 prev_slots = 0;
4415                 prev_bw = 0;
4416         }
4417
4418         if (pbn_div <= 0)
4419                 pbn_div = mgr->pbn_div;
4420
4421         req_slots = DIV_ROUND_UP(pbn, pbn_div);
4422
4423         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n",
4424                        port->connector->base.id, port->connector->name,
4425                        port, prev_slots, req_slots);
4426         drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4427                        port->connector->base.id, port->connector->name,
4428                        port, prev_bw, pbn);
4429
4430         /* Add the new allocation to the state */
4431         if (!vcpi) {
4432                 vcpi = kzalloc(sizeof(*vcpi), GFP_KERNEL);
4433                 if (!vcpi)
4434                         return -ENOMEM;
4435
4436                 drm_dp_mst_get_port_malloc(port);
4437                 vcpi->port = port;
4438                 list_add(&vcpi->next, &topology_state->vcpis);
4439         }
4440         vcpi->vcpi = req_slots;
4441         vcpi->pbn = pbn;
4442
4443         return req_slots;
4444 }
4445 EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
4446
4447 /**
4448  * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
4449  * @state: global atomic state
4450  * @mgr: MST topology manager for the port
4451  * @port: The port to release the VCPI slots from
4452  *
4453  * Releases any VCPI slots that have been allocated to a port in the atomic
4454  * state. Any atomic drivers which support MST must call this function in
4455  * their &drm_connector_helper_funcs.atomic_check() callback when the
4456  * connector will no longer have VCPI allocated (e.g. because its CRTC was
4457  * removed) when it had VCPI allocated in the previous atomic state.
4458  *
4459  * It is OK to call this even if @port has been removed from the system.
4460  * Additionally, it is OK to call this function multiple times on the same
4461  * @port as needed. It is not OK however, to call this function and
4462  * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic check
4463  * phase.
4464  *
4465  * See also:
4466  * drm_dp_atomic_find_vcpi_slots()
4467  * drm_dp_mst_atomic_check()
4468  *
4469  * Returns:
4470  * 0 if all slots for this port were added back to
4471  * &drm_dp_mst_topology_state.avail_slots or negative error code
4472  */
4473 int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
4474                                      struct drm_dp_mst_topology_mgr *mgr,
4475                                      struct drm_dp_mst_port *port)
4476 {
4477         struct drm_dp_mst_topology_state *topology_state;
4478         struct drm_dp_vcpi_allocation *pos;
4479         bool found = false;
4480
4481         topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4482         if (IS_ERR(topology_state))
4483                 return PTR_ERR(topology_state);
4484
4485         list_for_each_entry(pos, &topology_state->vcpis, next) {
4486                 if (pos->port == port) {
4487                         found = true;
4488                         break;
4489                 }
4490         }
4491         if (WARN_ON(!found)) {
4492                 drm_err(mgr->dev, "no VCPI for [MST PORT:%p] found in mst state %p\n",
4493                         port, &topology_state->base);
4494                 return -EINVAL;
4495         }
4496
4497         drm_dbg_atomic(mgr->dev, "[MST PORT:%p] VCPI %d -> 0\n", port, pos->vcpi);
4498         if (pos->vcpi) {
4499                 drm_dp_mst_put_port_malloc(port);
4500                 pos->vcpi = 0;
4501                 pos->pbn = 0;
4502         }
4503
4504         return 0;
4505 }
4506 EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
4507
4508 /**
4509  * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
4510  * @mgr: manager for this port
4511  * @port: port to allocate a virtual channel for.
4512  * @pbn: payload bandwidth number to request
4513  * @slots: returned number of slots for this PBN.
4514  */
4515 bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4516                               struct drm_dp_mst_port *port, int pbn, int slots)
4517 {
4518         int ret;
4519
4520         if (slots < 0)
4521                 return false;
4522
4523         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4524         if (!port)
4525                 return false;
4526
4527         if (port->vcpi.vcpi > 0) {
4528                 drm_dbg_kms(mgr->dev,
4529                             "payload: vcpi %d already allocated for pbn %d - requested pbn %d\n",
4530                             port->vcpi.vcpi, port->vcpi.pbn, pbn);
4531                 if (pbn == port->vcpi.pbn) {
4532                         drm_dp_mst_topology_put_port(port);
4533                         return true;
4534                 }
4535         }
4536
4537         ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
4538         if (ret) {
4539                 drm_dbg_kms(mgr->dev, "failed to init vcpi slots=%d ret=%d\n",
4540                             DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
4541                 drm_dp_mst_topology_put_port(port);
4542                 goto out;
4543         }
4544         drm_dbg_kms(mgr->dev, "initing vcpi for pbn=%d slots=%d\n", pbn, port->vcpi.num_slots);
4545
4546         /* Keep port allocated until its payload has been removed */
4547         drm_dp_mst_get_port_malloc(port);
4548         drm_dp_mst_topology_put_port(port);
4549         return true;
4550 out:
4551         return false;
4552 }
4553 EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
4554
4555 int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4556 {
4557         int slots = 0;
4558
4559         port = drm_dp_mst_topology_get_port_validated(mgr, port);
4560         if (!port)
4561                 return slots;
4562
4563         slots = port->vcpi.num_slots;
4564         drm_dp_mst_topology_put_port(port);
4565         return slots;
4566 }
4567 EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
4568
4569 /**
4570  * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
4571  * @mgr: manager for this port
4572  * @port: unverified pointer to a port.
4573  *
4574  * This just resets the number of slots for the ports VCPI for later programming.
4575  */
4576 void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4577 {
4578         /*
4579          * A port with VCPI will remain allocated until its VCPI is
4580          * released, no verified ref needed
4581          */
4582
4583         port->vcpi.num_slots = 0;
4584 }
4585 EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
4586
4587 /**
4588  * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
4589  * @mgr: manager for this port
4590  * @port: port to deallocate vcpi for
4591  *
4592  * This can be called unconditionally, regardless of whether
4593  * drm_dp_mst_allocate_vcpi() succeeded or not.
4594  */
4595 void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4596                                 struct drm_dp_mst_port *port)
4597 {
4598         bool skip;
4599
4600         if (!port->vcpi.vcpi)
4601                 return;
4602
4603         mutex_lock(&mgr->lock);
4604         skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
4605         mutex_unlock(&mgr->lock);
4606
4607         if (skip)
4608                 return;
4609
4610         drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
4611         port->vcpi.num_slots = 0;
4612         port->vcpi.pbn = 0;
4613         port->vcpi.aligned_pbn = 0;
4614         port->vcpi.vcpi = 0;
4615         drm_dp_mst_put_port_malloc(port);
4616 }
4617 EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
4618
4619 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
4620                                      int id, struct drm_dp_payload *payload)
4621 {
4622         u8 payload_alloc[3], status;
4623         int ret;
4624         int retries = 0;
4625
4626         drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
4627                            DP_PAYLOAD_TABLE_UPDATED);
4628
4629         payload_alloc[0] = id;
4630         payload_alloc[1] = payload->start_slot;
4631         payload_alloc[2] = payload->num_slots;
4632
4633         ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
4634         if (ret != 3) {
4635                 drm_dbg_kms(mgr->dev, "failed to write payload allocation %d\n", ret);
4636                 goto fail;
4637         }
4638
4639 retry:
4640         ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4641         if (ret < 0) {
4642                 drm_dbg_kms(mgr->dev, "failed to read payload table status %d\n", ret);
4643                 goto fail;
4644         }
4645
4646         if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
4647                 retries++;
4648                 if (retries < 20) {
4649                         usleep_range(10000, 20000);
4650                         goto retry;
4651                 }
4652                 drm_dbg_kms(mgr->dev, "status not set after read payload table status %d\n",
4653                             status);
4654                 ret = -EINVAL;
4655                 goto fail;
4656         }
4657         ret = 0;
4658 fail:
4659         return ret;
4660 }
4661
4662 static int do_get_act_status(struct drm_dp_aux *aux)
4663 {
4664         int ret;
4665         u8 status;
4666
4667         ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4668         if (ret < 0)
4669                 return ret;
4670
4671         return status;
4672 }
4673
4674 /**
4675  * drm_dp_check_act_status() - Polls for ACT handled status.
4676  * @mgr: manager to use
4677  *
4678  * Tries waiting for the MST hub to finish updating it's payload table by
4679  * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
4680  * take that long).
4681  *
4682  * Returns:
4683  * 0 if the ACT was handled in time, negative error code on failure.
4684  */
4685 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
4686 {
4687         /*
4688          * There doesn't seem to be any recommended retry count or timeout in
4689          * the MST specification. Since some hubs have been observed to take
4690          * over 1 second to update their payload allocations under certain
4691          * conditions, we use a rather large timeout value.
4692          */
4693         const int timeout_ms = 3000;
4694         int ret, status;
4695
4696         ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
4697                                  status & DP_PAYLOAD_ACT_HANDLED || status < 0,
4698                                  200, timeout_ms * USEC_PER_MSEC);
4699         if (ret < 0 && status >= 0) {
4700                 drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
4701                         timeout_ms, status);
4702                 return -EINVAL;
4703         } else if (status < 0) {
4704                 /*
4705                  * Failure here isn't unexpected - the hub may have
4706                  * just been unplugged
4707                  */
4708                 drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
4709                 return status;
4710         }
4711
4712         return 0;
4713 }
4714 EXPORT_SYMBOL(drm_dp_check_act_status);
4715
4716 /**
4717  * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
4718  * @clock: dot clock for the mode
4719  * @bpp: bpp for the mode.
4720  * @dsc: DSC mode. If true, bpp has units of 1/16 of a bit per pixel
4721  *
4722  * This uses the formula in the spec to calculate the PBN value for a mode.
4723  */
4724 int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc)
4725 {
4726         /*
4727          * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
4728          * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
4729          * common multiplier to render an integer PBN for all link rate/lane
4730          * counts combinations
4731          * calculate
4732          * peak_kbps *= (1006/1000)
4733          * peak_kbps *= (64/54)
4734          * peak_kbps *= 8    convert to bytes
4735          *
4736          * If the bpp is in units of 1/16, further divide by 16. Put this
4737          * factor in the numerator rather than the denominator to avoid
4738          * integer overflow
4739          */
4740
4741         if (dsc)
4742                 return DIV_ROUND_UP_ULL(mul_u32_u32(clock * (bpp / 16), 64 * 1006),
4743                                         8 * 54 * 1000 * 1000);
4744
4745         return DIV_ROUND_UP_ULL(mul_u32_u32(clock * bpp, 64 * 1006),
4746                                 8 * 54 * 1000 * 1000);
4747 }
4748 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
4749
4750 /* we want to kick the TX after we've ack the up/down IRQs. */
4751 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
4752 {
4753         queue_work(system_long_wq, &mgr->tx_work);
4754 }
4755
4756 /*
4757  * Helper function for parsing DP device types into convenient strings
4758  * for use with dp_mst_topology
4759  */
4760 static const char *pdt_to_string(u8 pdt)
4761 {
4762         switch (pdt) {
4763         case DP_PEER_DEVICE_NONE:
4764                 return "NONE";
4765         case DP_PEER_DEVICE_SOURCE_OR_SST:
4766                 return "SOURCE OR SST";
4767         case DP_PEER_DEVICE_MST_BRANCHING:
4768                 return "MST BRANCHING";
4769         case DP_PEER_DEVICE_SST_SINK:
4770                 return "SST SINK";
4771         case DP_PEER_DEVICE_DP_LEGACY_CONV:
4772                 return "DP LEGACY CONV";
4773         default:
4774                 return "ERR";
4775         }
4776 }
4777
4778 static void drm_dp_mst_dump_mstb(struct seq_file *m,
4779                                  struct drm_dp_mst_branch *mstb)
4780 {
4781         struct drm_dp_mst_port *port;
4782         int tabs = mstb->lct;
4783         char prefix[10];
4784         int i;
4785
4786         for (i = 0; i < tabs; i++)
4787                 prefix[i] = '\t';
4788         prefix[i] = '\0';
4789
4790         seq_printf(m, "%smstb - [%p]: num_ports: %d\n", prefix, mstb, mstb->num_ports);
4791         list_for_each_entry(port, &mstb->ports, next) {
4792                 seq_printf(m, "%sport %d - [%p] (%s - %s): ddps: %d, ldps: %d, sdp: %d/%d, fec: %s, conn: %p\n",
4793                            prefix,
4794                            port->port_num,
4795                            port,
4796                            port->input ? "input" : "output",
4797                            pdt_to_string(port->pdt),
4798                            port->ddps,
4799                            port->ldps,
4800                            port->num_sdp_streams,
4801                            port->num_sdp_stream_sinks,
4802                            port->fec_capable ? "true" : "false",
4803                            port->connector);
4804                 if (port->mstb)
4805                         drm_dp_mst_dump_mstb(m, port->mstb);
4806         }
4807 }
4808
4809 #define DP_PAYLOAD_TABLE_SIZE           64
4810
4811 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
4812                                   char *buf)
4813 {
4814         int i;
4815
4816         for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
4817                 if (drm_dp_dpcd_read(mgr->aux,
4818                                      DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
4819                                      &buf[i], 16) != 16)
4820                         return false;
4821         }
4822         return true;
4823 }
4824
4825 static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
4826                                struct drm_dp_mst_port *port, char *name,
4827                                int namelen)
4828 {
4829         struct edid *mst_edid;
4830
4831         mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
4832         drm_edid_get_monitor_name(mst_edid, name, namelen);
4833 }
4834
4835 /**
4836  * drm_dp_mst_dump_topology(): dump topology to seq file.
4837  * @m: seq_file to dump output to
4838  * @mgr: manager to dump current topology for.
4839  *
4840  * helper to dump MST topology to a seq file for debugfs.
4841  */
4842 void drm_dp_mst_dump_topology(struct seq_file *m,
4843                               struct drm_dp_mst_topology_mgr *mgr)
4844 {
4845         int i;
4846         struct drm_dp_mst_port *port;
4847
4848         mutex_lock(&mgr->lock);
4849         if (mgr->mst_primary)
4850                 drm_dp_mst_dump_mstb(m, mgr->mst_primary);
4851
4852         /* dump VCPIs */
4853         mutex_unlock(&mgr->lock);
4854
4855         mutex_lock(&mgr->payload_lock);
4856         seq_printf(m, "\n*** VCPI Info ***\n");
4857         seq_printf(m, "payload_mask: %lx, vcpi_mask: %lx, max_payloads: %d\n", mgr->payload_mask, mgr->vcpi_mask, mgr->max_payloads);
4858
4859         seq_printf(m, "\n|   idx   |  port # |  vcp_id | # slots |     sink name     |\n");
4860         for (i = 0; i < mgr->max_payloads; i++) {
4861                 if (mgr->proposed_vcpis[i]) {
4862                         char name[14];
4863
4864                         port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
4865                         fetch_monitor_name(mgr, port, name, sizeof(name));
4866                         seq_printf(m, "%10d%10d%10d%10d%20s\n",
4867                                    i,
4868                                    port->port_num,
4869                                    port->vcpi.vcpi,
4870                                    port->vcpi.num_slots,
4871                                    (*name != 0) ? name : "Unknown");
4872                 } else
4873                         seq_printf(m, "%6d - Unused\n", i);
4874         }
4875         seq_printf(m, "\n*** Payload Info ***\n");
4876         seq_printf(m, "|   idx   |  state  |  start slot  | # slots |\n");
4877         for (i = 0; i < mgr->max_payloads; i++) {
4878                 seq_printf(m, "%10d%10d%15d%10d\n",
4879                            i,
4880                            mgr->payloads[i].payload_state,
4881                            mgr->payloads[i].start_slot,
4882                            mgr->payloads[i].num_slots);
4883         }
4884         mutex_unlock(&mgr->payload_lock);
4885
4886         seq_printf(m, "\n*** DPCD Info ***\n");
4887         mutex_lock(&mgr->lock);
4888         if (mgr->mst_primary) {
4889                 u8 buf[DP_PAYLOAD_TABLE_SIZE];
4890                 int ret;
4891
4892                 ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
4893                 if (ret) {
4894                         seq_printf(m, "dpcd read failed\n");
4895                         goto out;
4896                 }
4897                 seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
4898
4899                 ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
4900                 if (ret) {
4901                         seq_printf(m, "faux/mst read failed\n");
4902                         goto out;
4903                 }
4904                 seq_printf(m, "faux/mst: %*ph\n", 2, buf);
4905
4906                 ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
4907                 if (ret) {
4908                         seq_printf(m, "mst ctrl read failed\n");
4909                         goto out;
4910                 }
4911                 seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
4912
4913                 /* dump the standard OUI branch header */
4914                 ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
4915                 if (ret) {
4916                         seq_printf(m, "branch oui read failed\n");
4917                         goto out;
4918                 }
4919                 seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
4920
4921                 for (i = 0x3; i < 0x8 && buf[i]; i++)
4922                         seq_printf(m, "%c", buf[i]);
4923                 seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
4924                            buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
4925                 if (dump_dp_payload_table(mgr, buf))
4926                         seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
4927         }
4928
4929 out:
4930         mutex_unlock(&mgr->lock);
4931
4932 }
4933 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
4934
4935 static void drm_dp_tx_work(struct work_struct *work)
4936 {
4937         struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
4938
4939         mutex_lock(&mgr->qlock);
4940         if (!list_empty(&mgr->tx_msg_downq))
4941                 process_single_down_tx_qlock(mgr);
4942         mutex_unlock(&mgr->qlock);
4943 }
4944
4945 static inline void
4946 drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
4947 {
4948         drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4949
4950         if (port->connector) {
4951                 drm_connector_unregister(port->connector);
4952                 drm_connector_put(port->connector);
4953         }
4954
4955         drm_dp_mst_put_port_malloc(port);
4956 }
4957
4958 static inline void
4959 drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4960 {
4961         struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4962         struct drm_dp_mst_port *port, *port_tmp;
4963         struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4964         bool wake_tx = false;
4965
4966         mutex_lock(&mgr->lock);
4967         list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
4968                 list_del(&port->next);
4969                 drm_dp_mst_topology_put_port(port);
4970         }
4971         mutex_unlock(&mgr->lock);
4972
4973         /* drop any tx slot msg */
4974         mutex_lock(&mstb->mgr->qlock);
4975         list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
4976                 if (txmsg->dst != mstb)
4977                         continue;
4978
4979                 txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
4980                 list_del(&txmsg->next);
4981                 wake_tx = true;
4982         }
4983         mutex_unlock(&mstb->mgr->qlock);
4984
4985         if (wake_tx)
4986                 wake_up_all(&mstb->mgr->tx_waitq);
4987
4988         drm_dp_mst_put_mstb_malloc(mstb);
4989 }
4990
4991 static void drm_dp_delayed_destroy_work(struct work_struct *work)
4992 {
4993         struct drm_dp_mst_topology_mgr *mgr =
4994                 container_of(work, struct drm_dp_mst_topology_mgr,
4995                              delayed_destroy_work);
4996         bool send_hotplug = false, go_again;
4997
4998         /*
4999          * Not a regular list traverse as we have to drop the destroy
5000          * connector lock before destroying the mstb/port, to avoid AB->BA
5001          * ordering between this lock and the config mutex.
5002          */
5003         do {
5004                 go_again = false;
5005
5006                 for (;;) {
5007                         struct drm_dp_mst_branch *mstb;
5008
5009                         mutex_lock(&mgr->delayed_destroy_lock);
5010                         mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
5011                                                         struct drm_dp_mst_branch,
5012                                                         destroy_next);
5013                         if (mstb)
5014                                 list_del(&mstb->destroy_next);
5015                         mutex_unlock(&mgr->delayed_destroy_lock);
5016
5017                         if (!mstb)
5018                                 break;
5019
5020                         drm_dp_delayed_destroy_mstb(mstb);
5021                         go_again = true;
5022                 }
5023
5024                 for (;;) {
5025                         struct drm_dp_mst_port *port;
5026
5027                         mutex_lock(&mgr->delayed_destroy_lock);
5028                         port = list_first_entry_or_null(&mgr->destroy_port_list,
5029                                                         struct drm_dp_mst_port,
5030                                                         next);
5031                         if (port)
5032                                 list_del(&port->next);
5033                         mutex_unlock(&mgr->delayed_destroy_lock);
5034
5035                         if (!port)
5036                                 break;
5037
5038                         drm_dp_delayed_destroy_port(port);
5039                         send_hotplug = true;
5040                         go_again = true;
5041                 }
5042         } while (go_again);
5043
5044         if (send_hotplug)
5045                 drm_kms_helper_hotplug_event(mgr->dev);
5046 }
5047
5048 static struct drm_private_state *
5049 drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
5050 {
5051         struct drm_dp_mst_topology_state *state, *old_state =
5052                 to_dp_mst_topology_state(obj->state);
5053         struct drm_dp_vcpi_allocation *pos, *vcpi;
5054
5055         state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
5056         if (!state)
5057                 return NULL;
5058
5059         __drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
5060
5061         INIT_LIST_HEAD(&state->vcpis);
5062
5063         list_for_each_entry(pos, &old_state->vcpis, next) {
5064                 /* Prune leftover freed VCPI allocations */
5065                 if (!pos->vcpi)
5066                         continue;
5067
5068                 vcpi = kmemdup(pos, sizeof(*vcpi), GFP_KERNEL);
5069                 if (!vcpi)
5070                         goto fail;
5071
5072                 drm_dp_mst_get_port_malloc(vcpi->port);
5073                 list_add(&vcpi->next, &state->vcpis);
5074         }
5075
5076         return &state->base;
5077
5078 fail:
5079         list_for_each_entry_safe(pos, vcpi, &state->vcpis, next) {
5080                 drm_dp_mst_put_port_malloc(pos->port);
5081                 kfree(pos);
5082         }
5083         kfree(state);
5084
5085         return NULL;
5086 }
5087
5088 static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
5089                                      struct drm_private_state *state)
5090 {
5091         struct drm_dp_mst_topology_state *mst_state =
5092                 to_dp_mst_topology_state(state);
5093         struct drm_dp_vcpi_allocation *pos, *tmp;
5094
5095         list_for_each_entry_safe(pos, tmp, &mst_state->vcpis, next) {
5096                 /* We only keep references to ports with non-zero VCPIs */
5097                 if (pos->vcpi)
5098                         drm_dp_mst_put_port_malloc(pos->port);
5099                 kfree(pos);
5100         }
5101
5102         kfree(mst_state);
5103 }
5104
5105 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
5106                                                  struct drm_dp_mst_branch *branch)
5107 {
5108         while (port->parent) {
5109                 if (port->parent == branch)
5110                         return true;
5111
5112                 if (port->parent->port_parent)
5113                         port = port->parent->port_parent;
5114                 else
5115                         break;
5116         }
5117         return false;
5118 }
5119
5120 static int
5121 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5122                                       struct drm_dp_mst_topology_state *state);
5123
5124 static int
5125 drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
5126                                       struct drm_dp_mst_topology_state *state)
5127 {
5128         struct drm_dp_vcpi_allocation *vcpi;
5129         struct drm_dp_mst_port *port;
5130         int pbn_used = 0, ret;
5131         bool found = false;
5132
5133         /* Check that we have at least one port in our state that's downstream
5134          * of this branch, otherwise we can skip this branch
5135          */
5136         list_for_each_entry(vcpi, &state->vcpis, next) {
5137                 if (!vcpi->pbn ||
5138                     !drm_dp_mst_port_downstream_of_branch(vcpi->port, mstb))
5139                         continue;
5140
5141                 found = true;
5142                 break;
5143         }
5144         if (!found)
5145                 return 0;
5146
5147         if (mstb->port_parent)
5148                 drm_dbg_atomic(mstb->mgr->dev,
5149                                "[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
5150                                mstb->port_parent->parent, mstb->port_parent, mstb);
5151         else
5152                 drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb);
5153
5154         list_for_each_entry(port, &mstb->ports, next) {
5155                 ret = drm_dp_mst_atomic_check_port_bw_limit(port, state);
5156                 if (ret < 0)
5157                         return ret;
5158
5159                 pbn_used += ret;
5160         }
5161
5162         return pbn_used;
5163 }
5164
5165 static int
5166 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5167                                       struct drm_dp_mst_topology_state *state)
5168 {
5169         struct drm_dp_vcpi_allocation *vcpi;
5170         int pbn_used = 0;
5171
5172         if (port->pdt == DP_PEER_DEVICE_NONE)
5173                 return 0;
5174
5175         if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
5176                 bool found = false;
5177
5178                 list_for_each_entry(vcpi, &state->vcpis, next) {
5179                         if (vcpi->port != port)
5180                                 continue;
5181                         if (!vcpi->pbn)
5182                                 return 0;
5183
5184                         found = true;
5185                         break;
5186                 }
5187                 if (!found)
5188                         return 0;
5189
5190                 /*
5191                  * This could happen if the sink deasserted its HPD line, but
5192                  * the branch device still reports it as attached (PDT != NONE).
5193                  */
5194                 if (!port->full_pbn) {
5195                         drm_dbg_atomic(port->mgr->dev,
5196                                        "[MSTB:%p] [MST PORT:%p] no BW available for the port\n",
5197                                        port->parent, port);
5198                         return -EINVAL;
5199                 }
5200
5201                 pbn_used = vcpi->pbn;
5202         } else {
5203                 pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
5204                                                                  state);
5205                 if (pbn_used <= 0)
5206                         return pbn_used;
5207         }
5208
5209         if (pbn_used > port->full_pbn) {
5210                 drm_dbg_atomic(port->mgr->dev,
5211                                "[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
5212                                port->parent, port, pbn_used, port->full_pbn);
5213                 return -ENOSPC;
5214         }
5215
5216         drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
5217                        port->parent, port, pbn_used, port->full_pbn);
5218
5219         return pbn_used;
5220 }
5221
5222 static inline int
5223 drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr,
5224                                          struct drm_dp_mst_topology_state *mst_state)
5225 {
5226         struct drm_dp_vcpi_allocation *vcpi;
5227         int avail_slots = 63, payload_count = 0;
5228
5229         list_for_each_entry(vcpi, &mst_state->vcpis, next) {
5230                 /* Releasing VCPI is always OK-even if the port is gone */
5231                 if (!vcpi->vcpi) {
5232                         drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all VCPI slots\n",
5233                                        vcpi->port);
5234                         continue;
5235                 }
5236
5237                 drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d vcpi slots\n",
5238                                vcpi->port, vcpi->vcpi);
5239
5240                 avail_slots -= vcpi->vcpi;
5241                 if (avail_slots < 0) {
5242                         drm_dbg_atomic(mgr->dev,
5243                                        "[MST PORT:%p] not enough VCPI slots in mst state %p (avail=%d)\n",
5244                                        vcpi->port, mst_state, avail_slots + vcpi->vcpi);
5245                         return -ENOSPC;
5246                 }
5247
5248                 if (++payload_count > mgr->max_payloads) {
5249                         drm_dbg_atomic(mgr->dev,
5250                                        "[MST MGR:%p] state %p has too many payloads (max=%d)\n",
5251                                        mgr, mst_state, mgr->max_payloads);
5252                         return -EINVAL;
5253                 }
5254         }
5255         drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
5256                        mgr, mst_state, avail_slots, 63 - avail_slots);
5257
5258         return 0;
5259 }
5260
5261 /**
5262  * drm_dp_mst_add_affected_dsc_crtcs
5263  * @state: Pointer to the new struct drm_dp_mst_topology_state
5264  * @mgr: MST topology manager
5265  *
5266  * Whenever there is a change in mst topology
5267  * DSC configuration would have to be recalculated
5268  * therefore we need to trigger modeset on all affected
5269  * CRTCs in that topology
5270  *
5271  * See also:
5272  * drm_dp_mst_atomic_enable_dsc()
5273  */
5274 int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
5275 {
5276         struct drm_dp_mst_topology_state *mst_state;
5277         struct drm_dp_vcpi_allocation *pos;
5278         struct drm_connector *connector;
5279         struct drm_connector_state *conn_state;
5280         struct drm_crtc *crtc;
5281         struct drm_crtc_state *crtc_state;
5282
5283         mst_state = drm_atomic_get_mst_topology_state(state, mgr);
5284
5285         if (IS_ERR(mst_state))
5286                 return -EINVAL;
5287
5288         list_for_each_entry(pos, &mst_state->vcpis, next) {
5289
5290                 connector = pos->port->connector;
5291
5292                 if (!connector)
5293                         return -EINVAL;
5294
5295                 conn_state = drm_atomic_get_connector_state(state, connector);
5296
5297                 if (IS_ERR(conn_state))
5298                         return PTR_ERR(conn_state);
5299
5300                 crtc = conn_state->crtc;
5301
5302                 if (!crtc)
5303                         continue;
5304
5305                 if (!drm_dp_mst_dsc_aux_for_port(pos->port))
5306                         continue;
5307
5308                 crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
5309
5310                 if (IS_ERR(crtc_state))
5311                         return PTR_ERR(crtc_state);
5312
5313                 drm_dbg_atomic(mgr->dev, "[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
5314                                mgr, crtc);
5315
5316                 crtc_state->mode_changed = true;
5317         }
5318         return 0;
5319 }
5320 EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
5321
5322 /**
5323  * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
5324  * @state: Pointer to the new drm_atomic_state
5325  * @port: Pointer to the affected MST Port
5326  * @pbn: Newly recalculated bw required for link with DSC enabled
5327  * @pbn_div: Divider to calculate correct number of pbn per slot
5328  * @enable: Boolean flag to enable or disable DSC on the port
5329  *
5330  * This function enables DSC on the given Port
5331  * by recalculating its vcpi from pbn provided
5332  * and sets dsc_enable flag to keep track of which
5333  * ports have DSC enabled
5334  *
5335  */
5336 int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
5337                                  struct drm_dp_mst_port *port,
5338                                  int pbn, int pbn_div,
5339                                  bool enable)
5340 {
5341         struct drm_dp_mst_topology_state *mst_state;
5342         struct drm_dp_vcpi_allocation *pos;
5343         bool found = false;
5344         int vcpi = 0;
5345
5346         mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
5347
5348         if (IS_ERR(mst_state))
5349                 return PTR_ERR(mst_state);
5350
5351         list_for_each_entry(pos, &mst_state->vcpis, next) {
5352                 if (pos->port == port) {
5353                         found = true;
5354                         break;
5355                 }
5356         }
5357
5358         if (!found) {
5359                 drm_dbg_atomic(state->dev,
5360                                "[MST PORT:%p] Couldn't find VCPI allocation in mst state %p\n",
5361                                port, mst_state);
5362                 return -EINVAL;
5363         }
5364
5365         if (pos->dsc_enabled == enable) {
5366                 drm_dbg_atomic(state->dev,
5367                                "[MST PORT:%p] DSC flag is already set to %d, returning %d VCPI slots\n",
5368                                port, enable, pos->vcpi);
5369                 vcpi = pos->vcpi;
5370         }
5371
5372         if (enable) {
5373                 vcpi = drm_dp_atomic_find_vcpi_slots(state, port->mgr, port, pbn, pbn_div);
5374                 drm_dbg_atomic(state->dev,
5375                                "[MST PORT:%p] Enabling DSC flag, reallocating %d VCPI slots on the port\n",
5376                                port, vcpi);
5377                 if (vcpi < 0)
5378                         return -EINVAL;
5379         }
5380
5381         pos->dsc_enabled = enable;
5382
5383         return vcpi;
5384 }
5385 EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
5386 /**
5387  * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
5388  * atomic update is valid
5389  * @state: Pointer to the new &struct drm_dp_mst_topology_state
5390  *
5391  * Checks the given topology state for an atomic update to ensure that it's
5392  * valid. This includes checking whether there's enough bandwidth to support
5393  * the new VCPI allocations in the atomic update.
5394  *
5395  * Any atomic drivers supporting DP MST must make sure to call this after
5396  * checking the rest of their state in their
5397  * &drm_mode_config_funcs.atomic_check() callback.
5398  *
5399  * See also:
5400  * drm_dp_atomic_find_vcpi_slots()
5401  * drm_dp_atomic_release_vcpi_slots()
5402  *
5403  * Returns:
5404  *
5405  * 0 if the new state is valid, negative error code otherwise.
5406  */
5407 int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
5408 {
5409         struct drm_dp_mst_topology_mgr *mgr;
5410         struct drm_dp_mst_topology_state *mst_state;
5411         int i, ret = 0;
5412
5413         for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
5414                 if (!mgr->mst_state)
5415                         continue;
5416
5417                 ret = drm_dp_mst_atomic_check_vcpi_alloc_limit(mgr, mst_state);
5418                 if (ret)
5419                         break;
5420
5421                 mutex_lock(&mgr->lock);
5422                 ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
5423                                                             mst_state);
5424                 mutex_unlock(&mgr->lock);
5425                 if (ret < 0)
5426                         break;
5427                 else
5428                         ret = 0;
5429         }
5430
5431         return ret;
5432 }
5433 EXPORT_SYMBOL(drm_dp_mst_atomic_check);
5434
5435 const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
5436         .atomic_duplicate_state = drm_dp_mst_duplicate_state,
5437         .atomic_destroy_state = drm_dp_mst_destroy_state,
5438 };
5439 EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
5440
5441 /**
5442  * drm_atomic_get_mst_topology_state: get MST topology state
5443  *
5444  * @state: global atomic state
5445  * @mgr: MST topology manager, also the private object in this case
5446  *
5447  * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5448  * state vtable so that the private object state returned is that of a MST
5449  * topology object. Also, drm_atomic_get_private_obj_state() expects the caller
5450  * to care of the locking, so warn if don't hold the connection_mutex.
5451  *
5452  * RETURNS:
5453  *
5454  * The MST topology state or error pointer.
5455  */
5456 struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
5457                                                                     struct drm_dp_mst_topology_mgr *mgr)
5458 {
5459         return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
5460 }
5461 EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
5462
5463 /**
5464  * drm_dp_mst_topology_mgr_init - initialise a topology manager
5465  * @mgr: manager struct to initialise
5466  * @dev: device providing this structure - for i2c addition.
5467  * @aux: DP helper aux channel to talk to this device
5468  * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
5469  * @max_payloads: maximum number of payloads this GPU can source
5470  * @max_lane_count: maximum number of lanes this GPU supports
5471  * @max_link_rate: maximum link rate per lane this GPU supports in kHz
5472  * @conn_base_id: the connector object ID the MST device is connected to.
5473  *
5474  * Return 0 for success, or negative error code on failure
5475  */
5476 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
5477                                  struct drm_device *dev, struct drm_dp_aux *aux,
5478                                  int max_dpcd_transaction_bytes, int max_payloads,
5479                                  int max_lane_count, int max_link_rate,
5480                                  int conn_base_id)
5481 {
5482         struct drm_dp_mst_topology_state *mst_state;
5483
5484         mutex_init(&mgr->lock);
5485         mutex_init(&mgr->qlock);
5486         mutex_init(&mgr->payload_lock);
5487         mutex_init(&mgr->delayed_destroy_lock);
5488         mutex_init(&mgr->up_req_lock);
5489         mutex_init(&mgr->probe_lock);
5490 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5491         mutex_init(&mgr->topology_ref_history_lock);
5492 #endif
5493         INIT_LIST_HEAD(&mgr->tx_msg_downq);
5494         INIT_LIST_HEAD(&mgr->destroy_port_list);
5495         INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
5496         INIT_LIST_HEAD(&mgr->up_req_list);
5497
5498         /*
5499          * delayed_destroy_work will be queued on a dedicated WQ, so that any
5500          * requeuing will be also flushed when deiniting the topology manager.
5501          */
5502         mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5503         if (mgr->delayed_destroy_wq == NULL)
5504                 return -ENOMEM;
5505
5506         INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5507         INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5508         INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5509         INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5510         init_waitqueue_head(&mgr->tx_waitq);
5511         mgr->dev = dev;
5512         mgr->aux = aux;
5513         mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5514         mgr->max_payloads = max_payloads;
5515         mgr->max_lane_count = max_lane_count;
5516         mgr->max_link_rate = max_link_rate;
5517         mgr->conn_base_id = conn_base_id;
5518         if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
5519             max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
5520                 return -EINVAL;
5521         mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
5522         if (!mgr->payloads)
5523                 return -ENOMEM;
5524         mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
5525         if (!mgr->proposed_vcpis)
5526                 return -ENOMEM;
5527         set_bit(0, &mgr->payload_mask);
5528
5529         mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5530         if (mst_state == NULL)
5531                 return -ENOMEM;
5532
5533         mst_state->mgr = mgr;
5534         INIT_LIST_HEAD(&mst_state->vcpis);
5535
5536         drm_atomic_private_obj_init(dev, &mgr->base,
5537                                     &mst_state->base,
5538                                     &drm_dp_mst_topology_state_funcs);
5539
5540         return 0;
5541 }
5542 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5543
5544 /**
5545  * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5546  * @mgr: manager to destroy
5547  */
5548 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
5549 {
5550         drm_dp_mst_topology_mgr_set_mst(mgr, false);
5551         flush_work(&mgr->work);
5552         /* The following will also drain any requeued work on the WQ. */
5553         if (mgr->delayed_destroy_wq) {
5554                 destroy_workqueue(mgr->delayed_destroy_wq);
5555                 mgr->delayed_destroy_wq = NULL;
5556         }
5557         mutex_lock(&mgr->payload_lock);
5558         kfree(mgr->payloads);
5559         mgr->payloads = NULL;
5560         kfree(mgr->proposed_vcpis);
5561         mgr->proposed_vcpis = NULL;
5562         mutex_unlock(&mgr->payload_lock);
5563         mgr->dev = NULL;
5564         mgr->aux = NULL;
5565         drm_atomic_private_obj_fini(&mgr->base);
5566         mgr->funcs = NULL;
5567
5568         mutex_destroy(&mgr->delayed_destroy_lock);
5569         mutex_destroy(&mgr->payload_lock);
5570         mutex_destroy(&mgr->qlock);
5571         mutex_destroy(&mgr->lock);
5572         mutex_destroy(&mgr->up_req_lock);
5573         mutex_destroy(&mgr->probe_lock);
5574 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5575         mutex_destroy(&mgr->topology_ref_history_lock);
5576 #endif
5577 }
5578 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5579
5580 static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5581 {
5582         int i;
5583
5584         if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5585                 return false;
5586
5587         for (i = 0; i < num - 1; i++) {
5588                 if (msgs[i].flags & I2C_M_RD ||
5589                     msgs[i].len > 0xff)
5590                         return false;
5591         }
5592
5593         return msgs[num - 1].flags & I2C_M_RD &&
5594                 msgs[num - 1].len <= 0xff;
5595 }
5596
5597 static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num)
5598 {
5599         int i;
5600
5601         for (i = 0; i < num - 1; i++) {
5602                 if (msgs[i].flags & I2C_M_RD || !(msgs[i].flags & I2C_M_STOP) ||
5603                     msgs[i].len > 0xff)
5604                         return false;
5605         }
5606
5607         return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff;
5608 }
5609
5610 static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb,
5611                                struct drm_dp_mst_port *port,
5612                                struct i2c_msg *msgs, int num)
5613 {
5614         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5615         unsigned int i;
5616         struct drm_dp_sideband_msg_req_body msg;
5617         struct drm_dp_sideband_msg_tx *txmsg = NULL;
5618         int ret;
5619
5620         memset(&msg, 0, sizeof(msg));
5621         msg.req_type = DP_REMOTE_I2C_READ;
5622         msg.u.i2c_read.num_transactions = num - 1;
5623         msg.u.i2c_read.port_number = port->port_num;
5624         for (i = 0; i < num - 1; i++) {
5625                 msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5626                 msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5627                 msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5628                 msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5629         }
5630         msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5631         msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5632
5633         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5634         if (!txmsg) {
5635                 ret = -ENOMEM;
5636                 goto out;
5637         }
5638
5639         txmsg->dst = mstb;
5640         drm_dp_encode_sideband_req(&msg, txmsg);
5641
5642         drm_dp_queue_down_tx(mgr, txmsg);
5643
5644         ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5645         if (ret > 0) {
5646
5647                 if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5648                         ret = -EREMOTEIO;
5649                         goto out;
5650                 }
5651                 if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5652                         ret = -EIO;
5653                         goto out;
5654                 }
5655                 memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5656                 ret = num;
5657         }
5658 out:
5659         kfree(txmsg);
5660         return ret;
5661 }
5662
5663 static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb,
5664                                 struct drm_dp_mst_port *port,
5665                                 struct i2c_msg *msgs, int num)
5666 {
5667         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5668         unsigned int i;
5669         struct drm_dp_sideband_msg_req_body msg;
5670         struct drm_dp_sideband_msg_tx *txmsg = NULL;
5671         int ret;
5672
5673         txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5674         if (!txmsg) {
5675                 ret = -ENOMEM;
5676                 goto out;
5677         }
5678         for (i = 0; i < num; i++) {
5679                 memset(&msg, 0, sizeof(msg));
5680                 msg.req_type = DP_REMOTE_I2C_WRITE;
5681                 msg.u.i2c_write.port_number = port->port_num;
5682                 msg.u.i2c_write.write_i2c_device_id = msgs[i].addr;
5683                 msg.u.i2c_write.num_bytes = msgs[i].len;
5684                 msg.u.i2c_write.bytes = msgs[i].buf;
5685
5686                 memset(txmsg, 0, sizeof(*txmsg));
5687                 txmsg->dst = mstb;
5688
5689                 drm_dp_encode_sideband_req(&msg, txmsg);
5690                 drm_dp_queue_down_tx(mgr, txmsg);
5691
5692                 ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5693                 if (ret > 0) {
5694                         if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5695                                 ret = -EREMOTEIO;
5696                                 goto out;
5697                         }
5698                 } else {
5699                         goto out;
5700                 }
5701         }
5702         ret = num;
5703 out:
5704         kfree(txmsg);
5705         return ret;
5706 }
5707
5708 /* I2C device */
5709 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
5710                                struct i2c_msg *msgs, int num)
5711 {
5712         struct drm_dp_aux *aux = adapter->algo_data;
5713         struct drm_dp_mst_port *port =
5714                 container_of(aux, struct drm_dp_mst_port, aux);
5715         struct drm_dp_mst_branch *mstb;
5716         struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5717         int ret;
5718
5719         mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5720         if (!mstb)
5721                 return -EREMOTEIO;
5722
5723         if (remote_i2c_read_ok(msgs, num)) {
5724                 ret = drm_dp_mst_i2c_read(mstb, port, msgs, num);
5725         } else if (remote_i2c_write_ok(msgs, num)) {
5726                 ret = drm_dp_mst_i2c_write(mstb, port, msgs, num);
5727         } else {
5728                 drm_dbg_kms(mgr->dev, "Unsupported I2C transaction for MST device\n");
5729                 ret = -EIO;
5730         }
5731
5732         drm_dp_mst_topology_put_mstb(mstb);
5733         return ret;
5734 }
5735
5736 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5737 {
5738         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5739                I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5740                I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5741                I2C_FUNC_10BIT_ADDR;
5742 }
5743
5744 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5745         .functionality = drm_dp_mst_i2c_functionality,
5746         .master_xfer = drm_dp_mst_i2c_xfer,
5747 };
5748
5749 /**
5750  * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5751  * @port: The port to add the I2C bus on
5752  *
5753  * Returns 0 on success or a negative error code on failure.
5754  */
5755 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5756 {
5757         struct drm_dp_aux *aux = &port->aux;
5758         struct device *parent_dev = port->mgr->dev->dev;
5759
5760         aux->ddc.algo = &drm_dp_mst_i2c_algo;
5761         aux->ddc.algo_data = aux;
5762         aux->ddc.retries = 3;
5763
5764         aux->ddc.class = I2C_CLASS_DDC;
5765         aux->ddc.owner = THIS_MODULE;
5766         /* FIXME: set the kdev of the port's connector as parent */
5767         aux->ddc.dev.parent = parent_dev;
5768         aux->ddc.dev.of_node = parent_dev->of_node;
5769
5770         strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5771                 sizeof(aux->ddc.name));
5772
5773         return i2c_add_adapter(&aux->ddc);
5774 }
5775
5776 /**
5777  * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5778  * @port: The port to remove the I2C bus from
5779  */
5780 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5781 {
5782         i2c_del_adapter(&port->aux.ddc);
5783 }
5784
5785 /**
5786  * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5787  * @port: The port to check
5788  *
5789  * A single physical MST hub object can be represented in the topology
5790  * by multiple branches, with virtual ports between those branches.
5791  *
5792  * As of DP1.4, An MST hub with internal (virtual) ports must expose
5793  * certain DPCD registers over those ports. See sections 2.6.1.1.1
5794  * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5795  *
5796  * May acquire mgr->lock
5797  *
5798  * Returns:
5799  * true if the port is a virtual DP peer device, false otherwise
5800  */
5801 static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5802 {
5803         struct drm_dp_mst_port *downstream_port;
5804
5805         if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5806                 return false;
5807
5808         /* Virtual DP Sink (Internal Display Panel) */
5809         if (port->port_num >= 8)
5810                 return true;
5811
5812         /* DP-to-HDMI Protocol Converter */
5813         if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5814             !port->mcs &&
5815             port->ldps)
5816                 return true;
5817
5818         /* DP-to-DP */
5819         mutex_lock(&port->mgr->lock);
5820         if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5821             port->mstb &&
5822             port->mstb->num_ports == 2) {
5823                 list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5824                         if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
5825                             !downstream_port->input) {
5826                                 mutex_unlock(&port->mgr->lock);
5827                                 return true;
5828                         }
5829                 }
5830         }
5831         mutex_unlock(&port->mgr->lock);
5832
5833         return false;
5834 }
5835
5836 /**
5837  * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
5838  * @port: The port to check. A leaf of the MST tree with an attached display.
5839  *
5840  * Depending on the situation, DSC may be enabled via the endpoint aux,
5841  * the immediately upstream aux, or the connector's physical aux.
5842  *
5843  * This is both the correct aux to read DSC_CAPABILITY and the
5844  * correct aux to write DSC_ENABLED.
5845  *
5846  * This operation can be expensive (up to four aux reads), so
5847  * the caller should cache the return.
5848  *
5849  * Returns:
5850  * NULL if DSC cannot be enabled on this port, otherwise the aux device
5851  */
5852 struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
5853 {
5854         struct drm_dp_mst_port *immediate_upstream_port;
5855         struct drm_dp_mst_port *fec_port;
5856         struct drm_dp_desc desc = {};
5857         u8 endpoint_fec;
5858         u8 endpoint_dsc;
5859
5860         if (!port)
5861                 return NULL;
5862
5863         if (port->parent->port_parent)
5864                 immediate_upstream_port = port->parent->port_parent;
5865         else
5866                 immediate_upstream_port = NULL;
5867
5868         fec_port = immediate_upstream_port;
5869         while (fec_port) {
5870                 /*
5871                  * Each physical link (i.e. not a virtual port) between the
5872                  * output and the primary device must support FEC
5873                  */
5874                 if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
5875                     !fec_port->fec_capable)
5876                         return NULL;
5877
5878                 fec_port = fec_port->parent->port_parent;
5879         }
5880
5881         /* DP-to-DP peer device */
5882         if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
5883                 u8 upstream_dsc;
5884
5885                 if (drm_dp_dpcd_read(&port->aux,
5886                                      DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5887                         return NULL;
5888                 if (drm_dp_dpcd_read(&port->aux,
5889                                      DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5890                         return NULL;
5891                 if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
5892                                      DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
5893                         return NULL;
5894
5895                 /* Enpoint decompression with DP-to-DP peer device */
5896                 if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5897                     (endpoint_fec & DP_FEC_CAPABLE) &&
5898                     (upstream_dsc & 0x2) /* DSC passthrough */)
5899                         return &port->aux;
5900
5901                 /* Virtual DPCD decompression with DP-to-DP peer device */
5902                 return &immediate_upstream_port->aux;
5903         }
5904
5905         /* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
5906         if (drm_dp_mst_is_virtual_dpcd(port))
5907                 return &port->aux;
5908
5909         /*
5910          * Synaptics quirk
5911          * Applies to ports for which:
5912          * - Physical aux has Synaptics OUI
5913          * - DPv1.4 or higher
5914          * - Port is on primary branch device
5915          * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
5916          */
5917         if (drm_dp_read_desc(port->mgr->aux, &desc, true))
5918                 return NULL;
5919
5920         if (drm_dp_has_quirk(&desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
5921             port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
5922             port->parent == port->mgr->mst_primary) {
5923                 u8 dpcd_ext[DP_RECEIVER_CAP_SIZE];
5924
5925                 if (drm_dp_read_dpcd_caps(port->mgr->aux, dpcd_ext) < 0)
5926                         return NULL;
5927
5928                 if ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT) &&
5929                     ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK)
5930                      != DP_DWN_STRM_PORT_TYPE_ANALOG))
5931                         return port->mgr->aux;
5932         }
5933
5934         /*
5935          * The check below verifies if the MST sink
5936          * connected to the GPU is capable of DSC -
5937          * therefore the endpoint needs to be
5938          * both DSC and FEC capable.
5939          */
5940         if (drm_dp_dpcd_read(&port->aux,
5941            DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5942                 return NULL;
5943         if (drm_dp_dpcd_read(&port->aux,
5944            DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5945                 return NULL;
5946         if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5947            (endpoint_fec & DP_FEC_CAPABLE))
5948                 return &port->aux;
5949
5950         return NULL;
5951 }
5952 EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);