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