drivers/usb/host/xhci-dbgcap.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /**
   3  * xhci-dbgcap.c - xHCI debug capability support
   4  *
   5  * Copyright (C) 2017 Intel Corporation
   6  *
   7  * Author: Lu Baolu <[email protected]>
   8  */
   9 #include <linux/dma-mapping.h>
  10 #include <linux/slab.h>
  11 #include <linux/nls.h>
  12
  13 #include "xhci.h"
  14 #include "xhci-trace.h"
  15 #include "xhci-dbgcap.h"
  16
  17 static inline void *
  18 dbc_dma_alloc_coherent(struct xhci_hcd *xhci, size_t size,
  19                        dma_addr_t *dma_handle, gfp_t flags)
  20 {
  21         void            *vaddr;
  22
  23         vaddr = dma_alloc_coherent(xhci_to_hcd(xhci)->self.sysdev,
  24                                    size, dma_handle, flags);
  25         memset(vaddr, 0, size);
  26         return vaddr;
  27 }
  28
  29 static inline void
  30 dbc_dma_free_coherent(struct xhci_hcd *xhci, size_t size,
  31                       void *cpu_addr, dma_addr_t dma_handle)
  32 {
  33         if (cpu_addr)
  34                 dma_free_coherent(xhci_to_hcd(xhci)->self.sysdev,
  35                                   size, cpu_addr, dma_handle);
  36 }
  37
  38 static u32 xhci_dbc_populate_strings(struct dbc_str_descs *strings)
  39 {
  40         struct usb_string_descriptor    *s_desc;
  41         u32                             string_length;
  42
  43         /* Serial string: */
  44         s_desc = (struct usb_string_descriptor *)strings->serial;
  45         utf8s_to_utf16s(DBC_STRING_SERIAL, strlen(DBC_STRING_SERIAL),
  46                         UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
  47                         DBC_MAX_STRING_LENGTH);
  48
  49         s_desc->bLength         = (strlen(DBC_STRING_SERIAL) + 1) * 2;
  50         s_desc->bDescriptorType = USB_DT_STRING;
  51         string_length           = s_desc->bLength;
  52         string_length           <<= 8;
  53
  54         /* Product string: */
  55         s_desc = (struct usb_string_descriptor *)strings->product;
  56         utf8s_to_utf16s(DBC_STRING_PRODUCT, strlen(DBC_STRING_PRODUCT),
  57                         UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
  58                         DBC_MAX_STRING_LENGTH);
  59
  60         s_desc->bLength         = (strlen(DBC_STRING_PRODUCT) + 1) * 2;
  61         s_desc->bDescriptorType = USB_DT_STRING;
  62         string_length           += s_desc->bLength;
  63         string_length           <<= 8;
  64
  65         /* Manufacture string: */
  66         s_desc = (struct usb_string_descriptor *)strings->manufacturer;
  67         utf8s_to_utf16s(DBC_STRING_MANUFACTURER,
  68                         strlen(DBC_STRING_MANUFACTURER),
  69                         UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
  70                         DBC_MAX_STRING_LENGTH);
  71
  72         s_desc->bLength         = (strlen(DBC_STRING_MANUFACTURER) + 1) * 2;
  73         s_desc->bDescriptorType = USB_DT_STRING;
  74         string_length           += s_desc->bLength;
  75         string_length           <<= 8;
  76
  77         /* String0: */
  78         strings->string0[0]     = 4;
  79         strings->string0[1]     = USB_DT_STRING;
  80         strings->string0[2]     = 0x09;
  81         strings->string0[3]     = 0x04;
  82         string_length           += 4;
  83
  84         return string_length;
  85 }
  86
  87 static void xhci_dbc_init_contexts(struct xhci_hcd *xhci, u32 string_length)
  88 {
  89         struct xhci_dbc         *dbc;
  90         struct dbc_info_context *info;
  91         struct xhci_ep_ctx      *ep_ctx;
  92         u32                     dev_info;
  93         dma_addr_t              deq, dma;
  94         unsigned int            max_burst;
  95
  96         dbc = xhci->dbc;
  97         if (!dbc)
  98                 return;
  99
 100         /* Populate info Context: */
 101         info                    = (struct dbc_info_context *)dbc->ctx->bytes;
 102         dma                     = dbc->string_dma;
 103         info->string0           = cpu_to_le64(dma);
 104         info->manufacturer      = cpu_to_le64(dma + DBC_MAX_STRING_LENGTH);
 105         info->product           = cpu_to_le64(dma + DBC_MAX_STRING_LENGTH * 2);
 106         info->serial            = cpu_to_le64(dma + DBC_MAX_STRING_LENGTH * 3);
 107         info->length            = cpu_to_le32(string_length);
 108
 109         /* Populate bulk out endpoint context: */
 110         ep_ctx                  = dbc_bulkout_ctx(dbc);
 111         max_burst               = DBC_CTRL_MAXBURST(readl(&dbc->regs->control));
 112         deq                     = dbc_bulkout_enq(dbc);
 113         ep_ctx->ep_info         = 0;
 114         ep_ctx->ep_info2        = dbc_epctx_info2(BULK_OUT_EP, 1024, max_burst);
 115         ep_ctx->deq             = cpu_to_le64(deq | dbc->ring_out->cycle_state);
 116
 117         /* Populate bulk in endpoint context: */
 118         ep_ctx                  = dbc_bulkin_ctx(dbc);
 119         deq                     = dbc_bulkin_enq(dbc);
 120         ep_ctx->ep_info         = 0;
 121         ep_ctx->ep_info2        = dbc_epctx_info2(BULK_IN_EP, 1024, max_burst);
 122         ep_ctx->deq             = cpu_to_le64(deq | dbc->ring_in->cycle_state);
 123
 124         /* Set DbC context and info registers: */
 125         xhci_write_64(xhci, dbc->ctx->dma, &dbc->regs->dccp);
 126
 127         dev_info = cpu_to_le32((DBC_VENDOR_ID << 16) | DBC_PROTOCOL);
 128         writel(dev_info, &dbc->regs->devinfo1);
 129
 130         dev_info = cpu_to_le32((DBC_DEVICE_REV << 16) | DBC_PRODUCT_ID);
 131         writel(dev_info, &dbc->regs->devinfo2);
 132 }
 133
 134 static void xhci_dbc_giveback(struct dbc_request *req, int status)
 135         __releases(&dbc->lock)
 136         __acquires(&dbc->lock)
 137 {
 138         struct dbc_ep           *dep = req->dep;
 139         struct xhci_dbc         *dbc = dep->dbc;
 140         struct xhci_hcd         *xhci = dbc->xhci;
 141         struct device           *dev = xhci_to_hcd(dbc->xhci)->self.sysdev;
 142
 143         list_del_init(&req->list_pending);
 144         req->trb_dma = 0;
 145         req->trb = NULL;
 146
 147         if (req->status == -EINPROGRESS)
 148                 req->status = status;
 149
 150         trace_xhci_dbc_giveback_request(req);
 151
 152         dma_unmap_single(dev,
 153                          req->dma,
 154                          req->length,
 155                          dbc_ep_dma_direction(dep));
 156
 157         /* Give back the transfer request: */
 158         spin_unlock(&dbc->lock);
 159         req->complete(xhci, req);
 160         spin_lock(&dbc->lock);
 161 }
 162
 163 static void xhci_dbc_flush_single_request(struct dbc_request *req)
 164 {
 165         union xhci_trb  *trb = req->trb;
 166
 167         trb->generic.field[0]   = 0;
 168         trb->generic.field[1]   = 0;
 169         trb->generic.field[2]   = 0;
 170         trb->generic.field[3]   &= cpu_to_le32(TRB_CYCLE);
 171         trb->generic.field[3]   |= cpu_to_le32(TRB_TYPE(TRB_TR_NOOP));
 172
 173         xhci_dbc_giveback(req, -ESHUTDOWN);
 174 }
 175
 176 static void xhci_dbc_flush_endpoint_requests(struct dbc_ep *dep)
 177 {
 178         struct dbc_request      *req, *tmp;
 179
 180         list_for_each_entry_safe(req, tmp, &dep->list_pending, list_pending)
 181                 xhci_dbc_flush_single_request(req);
 182 }
 183
 184 static void xhci_dbc_flush_reqests(struct xhci_dbc *dbc)
 185 {
 186         xhci_dbc_flush_endpoint_requests(&dbc->eps[BULK_OUT]);
 187         xhci_dbc_flush_endpoint_requests(&dbc->eps[BULK_IN]);
 188 }
 189
 190 struct dbc_request *
 191 dbc_alloc_request(struct dbc_ep *dep, gfp_t gfp_flags)
 192 {
 193         struct dbc_request      *req;
 194
 195         req = kzalloc(sizeof(*req), gfp_flags);
 196         if (!req)
 197                 return NULL;
 198
 199         req->dep = dep;
 200         INIT_LIST_HEAD(&req->list_pending);
 201         INIT_LIST_HEAD(&req->list_pool);
 202         req->direction = dep->direction;
 203
 204         trace_xhci_dbc_alloc_request(req);
 205
 206         return req;
 207 }
 208
 209 void
 210 dbc_free_request(struct dbc_ep *dep, struct dbc_request *req)
 211 {
 212         trace_xhci_dbc_free_request(req);
 213
 214         kfree(req);
 215 }
 216
 217 static void
 218 xhci_dbc_queue_trb(struct xhci_ring *ring, u32 field1,
 219                    u32 field2, u32 field3, u32 field4)
 220 {
 221         union xhci_trb          *trb, *next;
 222
 223         trb = ring->enqueue;
 224         trb->generic.field[0]   = cpu_to_le32(field1);
 225         trb->generic.field[1]   = cpu_to_le32(field2);
 226         trb->generic.field[2]   = cpu_to_le32(field3);
 227         trb->generic.field[3]   = cpu_to_le32(field4);
 228
 229         trace_xhci_dbc_gadget_ep_queue(ring, &trb->generic);
 230
 231         ring->num_trbs_free--;
 232         next = ++(ring->enqueue);
 233         if (TRB_TYPE_LINK_LE32(next->link.control)) {
 234                 next->link.control ^= cpu_to_le32(TRB_CYCLE);
 235                 ring->enqueue = ring->enq_seg->trbs;
 236                 ring->cycle_state ^= 1;
 237         }
 238 }
 239
 240 static int xhci_dbc_queue_bulk_tx(struct dbc_ep *dep,
 241                                   struct dbc_request *req)
 242 {
 243         u64                     addr;
 244         union xhci_trb          *trb;
 245         unsigned int            num_trbs;
 246         struct xhci_dbc         *dbc = dep->dbc;
 247         struct xhci_ring        *ring = dep->ring;
 248         u32                     length, control, cycle;
 249
 250         num_trbs = count_trbs(req->dma, req->length);
 251         WARN_ON(num_trbs != 1);
 252         if (ring->num_trbs_free < num_trbs)
 253                 return -EBUSY;
 254
 255         addr    = req->dma;
 256         trb     = ring->enqueue;
 257         cycle   = ring->cycle_state;
 258         length  = TRB_LEN(req->length);
 259         control = TRB_TYPE(TRB_NORMAL) | TRB_IOC;
 260
 261         if (cycle)
 262                 control &= cpu_to_le32(~TRB_CYCLE);
 263         else
 264                 control |= cpu_to_le32(TRB_CYCLE);
 265
 266         req->trb = ring->enqueue;
 267         req->trb_dma = xhci_trb_virt_to_dma(ring->enq_seg, ring->enqueue);
 268         xhci_dbc_queue_trb(ring,
 269                            lower_32_bits(addr),
 270                            upper_32_bits(addr),
 271                            length, control);
 272
 273         /*
 274          * Add a barrier between writes of trb fields and flipping
 275          * the cycle bit:
 276          */
 277         wmb();
 278
 279         if (cycle)
 280                 trb->generic.field[3] |= cpu_to_le32(TRB_CYCLE);
 281         else
 282                 trb->generic.field[3] &= cpu_to_le32(~TRB_CYCLE);
 283
 284         writel(DBC_DOOR_BELL_TARGET(dep->direction), &dbc->regs->doorbell);
 285
 286         return 0;
 287 }
 288
 289 static int
 290 dbc_ep_do_queue(struct dbc_ep *dep, struct dbc_request *req)
 291 {
 292         int                     ret;
 293         struct device           *dev;
 294         struct xhci_dbc         *dbc = dep->dbc;
 295         struct xhci_hcd         *xhci = dbc->xhci;
 296
 297         dev = xhci_to_hcd(xhci)->self.sysdev;
 298
 299         if (!req->length || !req->buf)
 300                 return -EINVAL;
 301
 302         req->actual             = 0;
 303         req->status             = -EINPROGRESS;
 304
 305         req->dma = dma_map_single(dev,
 306                                   req->buf,
 307                                   req->length,
 308                                   dbc_ep_dma_direction(dep));
 309         if (dma_mapping_error(dev, req->dma)) {
 310                 xhci_err(xhci, "failed to map buffer\n");
 311                 return -EFAULT;
 312         }
 313
 314         ret = xhci_dbc_queue_bulk_tx(dep, req);
 315         if (ret) {
 316                 xhci_err(xhci, "failed to queue trbs\n");
 317                 dma_unmap_single(dev,
 318                                  req->dma,
 319                                  req->length,
 320                                  dbc_ep_dma_direction(dep));
 321                 return -EFAULT;
 322         }
 323
 324         list_add_tail(&req->list_pending, &dep->list_pending);
 325
 326         return 0;
 327 }
 328
 329 int dbc_ep_queue(struct dbc_ep *dep, struct dbc_request *req,
 330                  gfp_t gfp_flags)
 331 {
 332         unsigned long           flags;
 333         struct xhci_dbc         *dbc = dep->dbc;
 334         int                     ret = -ESHUTDOWN;
 335
 336         spin_lock_irqsave(&dbc->lock, flags);
 337         if (dbc->state == DS_CONFIGURED)
 338                 ret = dbc_ep_do_queue(dep, req);
 339         spin_unlock_irqrestore(&dbc->lock, flags);
 340
 341         mod_delayed_work(system_wq, &dbc->event_work, 0);
 342
 343         trace_xhci_dbc_queue_request(req);
 344
 345         return ret;
 346 }
 347
 348 static inline void xhci_dbc_do_eps_init(struct xhci_hcd *xhci, bool direction)
 349 {
 350         struct dbc_ep           *dep;
 351         struct xhci_dbc         *dbc = xhci->dbc;
 352
 353         dep                     = &dbc->eps[direction];
 354         dep->dbc                = dbc;
 355         dep->direction          = direction;
 356         dep->ring               = direction ? dbc->ring_in : dbc->ring_out;
 357
 358         INIT_LIST_HEAD(&dep->list_pending);
 359 }
 360
 361 static void xhci_dbc_eps_init(struct xhci_hcd *xhci)
 362 {
 363         xhci_dbc_do_eps_init(xhci, BULK_OUT);
 364         xhci_dbc_do_eps_init(xhci, BULK_IN);
 365 }
 366
 367 static void xhci_dbc_eps_exit(struct xhci_hcd *xhci)
 368 {
 369         struct xhci_dbc         *dbc = xhci->dbc;
 370
 371         memset(dbc->eps, 0, sizeof(struct dbc_ep) * ARRAY_SIZE(dbc->eps));
 372 }
 373
 374 static int xhci_dbc_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 375 {
 376         int                     ret;
 377         dma_addr_t              deq;
 378         u32                     string_length;
 379         struct xhci_dbc         *dbc = xhci->dbc;
 380
 381         /* Allocate various rings for events and transfers: */
 382         dbc->ring_evt = xhci_ring_alloc(xhci, 1, 1, TYPE_EVENT, 0, flags);
 383         if (!dbc->ring_evt)
 384                 goto evt_fail;
 385
 386         dbc->ring_in = xhci_ring_alloc(xhci, 1, 1, TYPE_BULK, 0, flags);
 387         if (!dbc->ring_in)
 388                 goto in_fail;
 389
 390         dbc->ring_out = xhci_ring_alloc(xhci, 1, 1, TYPE_BULK, 0, flags);
 391         if (!dbc->ring_out)
 392                 goto out_fail;
 393
 394         /* Allocate and populate ERST: */
 395         ret = xhci_alloc_erst(xhci, dbc->ring_evt, &dbc->erst, flags);
 396         if (ret)
 397                 goto erst_fail;
 398
 399         /* Allocate context data structure: */
 400         dbc->ctx = xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_DEVICE, flags);
 401         if (!dbc->ctx)
 402                 goto ctx_fail;
 403
 404         /* Allocate the string table: */
 405         dbc->string_size = sizeof(struct dbc_str_descs);
 406         dbc->string = dbc_dma_alloc_coherent(xhci,
 407                                              dbc->string_size,
 408                                              &dbc->string_dma,
 409                                              flags);
 410         if (!dbc->string)
 411                 goto string_fail;
 412
 413         /* Setup ERST register: */
 414         writel(dbc->erst.erst_size, &dbc->regs->ersts);
 415         xhci_write_64(xhci, dbc->erst.erst_dma_addr, &dbc->regs->erstba);
 416         deq = xhci_trb_virt_to_dma(dbc->ring_evt->deq_seg,
 417                                    dbc->ring_evt->dequeue);
 418         xhci_write_64(xhci, deq, &dbc->regs->erdp);
 419
 420         /* Setup strings and contexts: */
 421         string_length = xhci_dbc_populate_strings(dbc->string);
 422         xhci_dbc_init_contexts(xhci, string_length);
 423
 424         mmiowb();
 425
 426         xhci_dbc_eps_init(xhci);
 427         dbc->state = DS_INITIALIZED;
 428
 429         return 0;
 430
 431 string_fail:
 432         xhci_free_container_ctx(xhci, dbc->ctx);
 433         dbc->ctx = NULL;
 434 ctx_fail:
 435         xhci_free_erst(xhci, &dbc->erst);
 436 erst_fail:
 437         xhci_ring_free(xhci, dbc->ring_out);
 438         dbc->ring_out = NULL;
 439 out_fail:
 440         xhci_ring_free(xhci, dbc->ring_in);
 441         dbc->ring_in = NULL;
 442 in_fail:
 443         xhci_ring_free(xhci, dbc->ring_evt);
 444         dbc->ring_evt = NULL;
 445 evt_fail:
 446         return -ENOMEM;
 447 }
 448
 449 static void xhci_dbc_mem_cleanup(struct xhci_hcd *xhci)
 450 {
 451         struct xhci_dbc         *dbc = xhci->dbc;
 452
 453         if (!dbc)
 454                 return;
 455
 456         xhci_dbc_eps_exit(xhci);
 457
 458         if (dbc->string) {
 459                 dbc_dma_free_coherent(xhci,
 460                                       dbc->string_size,
 461                                       dbc->string, dbc->string_dma);
 462                 dbc->string = NULL;
 463         }
 464
 465         xhci_free_container_ctx(xhci, dbc->ctx);
 466         dbc->ctx = NULL;
 467
 468         xhci_free_erst(xhci, &dbc->erst);
 469         xhci_ring_free(xhci, dbc->ring_out);
 470         xhci_ring_free(xhci, dbc->ring_in);
 471         xhci_ring_free(xhci, dbc->ring_evt);
 472         dbc->ring_in = NULL;
 473         dbc->ring_out = NULL;
 474         dbc->ring_evt = NULL;
 475 }
 476
 477 static int xhci_do_dbc_start(struct xhci_hcd *xhci)
 478 {
 479         int                     ret;
 480         u32                     ctrl;
 481         struct xhci_dbc         *dbc = xhci->dbc;
 482
 483         if (dbc->state != DS_DISABLED)
 484                 return -EINVAL;
 485
 486         writel(0, &dbc->regs->control);
 487         ret = xhci_handshake(&dbc->regs->control,
 488                              DBC_CTRL_DBC_ENABLE,
 489                              0, 1000);
 490         if (ret)
 491                 return ret;
 492
 493         ret = xhci_dbc_mem_init(xhci, GFP_ATOMIC);
 494         if (ret)
 495                 return ret;
 496
 497         ctrl = readl(&dbc->regs->control);
 498         writel(ctrl | DBC_CTRL_DBC_ENABLE | DBC_CTRL_PORT_ENABLE,
 499                &dbc->regs->control);
 500         ret = xhci_handshake(&dbc->regs->control,
 501                              DBC_CTRL_DBC_ENABLE,
 502                              DBC_CTRL_DBC_ENABLE, 1000);
 503         if (ret)
 504                 return ret;
 505
 506         dbc->state = DS_ENABLED;
 507
 508         return 0;
 509 }
 510
 511 static int xhci_do_dbc_stop(struct xhci_hcd *xhci)
 512 {
 513         struct xhci_dbc         *dbc = xhci->dbc;
 514
 515         if (dbc->state == DS_DISABLED)
 516                 return -1;
 517
 518         writel(0, &dbc->regs->control);
 519         xhci_dbc_mem_cleanup(xhci);
 520         dbc->state = DS_DISABLED;
 521
 522         return 0;
 523 }
 524
 525 static int xhci_dbc_start(struct xhci_hcd *xhci)
 526 {
 527         int                     ret;
 528         unsigned long           flags;
 529         struct xhci_dbc         *dbc = xhci->dbc;
 530
 531         WARN_ON(!dbc);
 532
 533         pm_runtime_get_sync(xhci_to_hcd(xhci)->self.controller);
 534
 535         spin_lock_irqsave(&dbc->lock, flags);
 536         ret = xhci_do_dbc_start(xhci);
 537         spin_unlock_irqrestore(&dbc->lock, flags);
 538
 539         if (ret) {
 540                 pm_runtime_put(xhci_to_hcd(xhci)->self.controller);
 541                 return ret;
 542         }
 543
 544         return mod_delayed_work(system_wq, &dbc->event_work, 1);
 545 }
 546
 547 static void xhci_dbc_stop(struct xhci_hcd *xhci)
 548 {
 549         int ret;
 550         unsigned long           flags;
 551         struct xhci_dbc         *dbc = xhci->dbc;
 552         struct dbc_port         *port = &dbc->port;
 553
 554         WARN_ON(!dbc);
 555
 556         cancel_delayed_work_sync(&dbc->event_work);
 557
 558         if (port->registered)
 559                 xhci_dbc_tty_unregister_device(xhci);
 560
 561         spin_lock_irqsave(&dbc->lock, flags);
 562         ret = xhci_do_dbc_stop(xhci);
 563         spin_unlock_irqrestore(&dbc->lock, flags);
 564
 565         if (!ret)
 566                 pm_runtime_put_sync(xhci_to_hcd(xhci)->self.controller);
 567 }
 568
 569 static void
 570 dbc_handle_port_status(struct xhci_hcd *xhci, union xhci_trb *event)
 571 {
 572         u32                     portsc;
 573         struct xhci_dbc         *dbc = xhci->dbc;
 574
 575         portsc = readl(&dbc->regs->portsc);
 576         if (portsc & DBC_PORTSC_CONN_CHANGE)
 577                 xhci_info(xhci, "DbC port connect change\n");
 578
 579         if (portsc & DBC_PORTSC_RESET_CHANGE)
 580                 xhci_info(xhci, "DbC port reset change\n");
 581
 582         if (portsc & DBC_PORTSC_LINK_CHANGE)
 583                 xhci_info(xhci, "DbC port link status change\n");
 584
 585         if (portsc & DBC_PORTSC_CONFIG_CHANGE)
 586                 xhci_info(xhci, "DbC config error change\n");
 587
 588         /* Port reset change bit will be cleared in other place: */
 589         writel(portsc & ~DBC_PORTSC_RESET_CHANGE, &dbc->regs->portsc);
 590 }
 591
 592 static void dbc_handle_xfer_event(struct xhci_hcd *xhci, union xhci_trb *event)
 593 {
 594         struct dbc_ep           *dep;
 595         struct xhci_ring        *ring;
 596         int                     ep_id;
 597         int                     status;
 598         u32                     comp_code;
 599         size_t                  remain_length;
 600         struct dbc_request      *req = NULL, *r;
 601
 602         comp_code       = GET_COMP_CODE(le32_to_cpu(event->generic.field[2]));
 603         remain_length   = EVENT_TRB_LEN(le32_to_cpu(event->generic.field[2]));
 604         ep_id           = TRB_TO_EP_ID(le32_to_cpu(event->generic.field[3]));
 605         dep             = (ep_id == EPID_OUT) ?
 606                                 get_out_ep(xhci) : get_in_ep(xhci);
 607         ring            = dep->ring;
 608
 609         switch (comp_code) {
 610         case COMP_SUCCESS:
 611                 remain_length = 0;
 612         /* FALLTHROUGH */
 613         case COMP_SHORT_PACKET:
 614                 status = 0;
 615                 break;
 616         case COMP_TRB_ERROR:
 617         case COMP_BABBLE_DETECTED_ERROR:
 618         case COMP_USB_TRANSACTION_ERROR:
 619         case COMP_STALL_ERROR:
 620                 xhci_warn(xhci, "tx error %d detected\n", comp_code);
 621                 status = -comp_code;
 622                 break;
 623         default:
 624                 xhci_err(xhci, "unknown tx error %d\n", comp_code);
 625                 status = -comp_code;
 626                 break;
 627         }
 628
 629         /* Match the pending request: */
 630         list_for_each_entry(r, &dep->list_pending, list_pending) {
 631                 if (r->trb_dma == event->trans_event.buffer) {
 632                         req = r;
 633                         break;
 634                 }
 635         }
 636
 637         if (!req) {
 638                 xhci_warn(xhci, "no matched request\n");
 639                 return;
 640         }
 641
 642         trace_xhci_dbc_handle_transfer(ring, &req->trb->generic);
 643
 644         ring->num_trbs_free++;
 645         req->actual = req->length - remain_length;
 646         xhci_dbc_giveback(req, status);
 647 }
 648
 649 static enum evtreturn xhci_dbc_do_handle_events(struct xhci_dbc *dbc)
 650 {
 651         dma_addr_t              deq;
 652         struct dbc_ep           *dep;
 653         union xhci_trb          *evt;
 654         u32                     ctrl, portsc;
 655         struct xhci_hcd         *xhci = dbc->xhci;
 656         bool                    update_erdp = false;
 657
 658         /* DbC state machine: */
 659         switch (dbc->state) {
 660         case DS_DISABLED:
 661         case DS_INITIALIZED:
 662
 663                 return EVT_ERR;
 664         case DS_ENABLED:
 665                 portsc = readl(&dbc->regs->portsc);
 666                 if (portsc & DBC_PORTSC_CONN_STATUS) {
 667                         dbc->state = DS_CONNECTED;
 668                         xhci_info(xhci, "DbC connected\n");
 669                 }
 670
 671                 return EVT_DONE;
 672         case DS_CONNECTED:
 673                 ctrl = readl(&dbc->regs->control);
 674                 if (ctrl & DBC_CTRL_DBC_RUN) {
 675                         dbc->state = DS_CONFIGURED;
 676                         xhci_info(xhci, "DbC configured\n");
 677                         portsc = readl(&dbc->regs->portsc);
 678                         writel(portsc, &dbc->regs->portsc);
 679                         return EVT_GSER;
 680                 }
 681
 682                 return EVT_DONE;
 683         case DS_CONFIGURED:
 684                 /* Handle cable unplug event: */
 685                 portsc = readl(&dbc->regs->portsc);
 686                 if (!(portsc & DBC_PORTSC_PORT_ENABLED) &&
 687                     !(portsc & DBC_PORTSC_CONN_STATUS)) {
 688                         xhci_info(xhci, "DbC cable unplugged\n");
 689                         dbc->state = DS_ENABLED;
 690                         xhci_dbc_flush_reqests(dbc);
 691
 692                         return EVT_DISC;
 693                 }
 694
 695                 /* Handle debug port reset event: */
 696                 if (portsc & DBC_PORTSC_RESET_CHANGE) {
 697                         xhci_info(xhci, "DbC port reset\n");
 698                         writel(portsc, &dbc->regs->portsc);
 699                         dbc->state = DS_ENABLED;
 700                         xhci_dbc_flush_reqests(dbc);
 701
 702                         return EVT_DISC;
 703                 }
 704
 705                 /* Handle endpoint stall event: */
 706                 ctrl = readl(&dbc->regs->control);
 707                 if ((ctrl & DBC_CTRL_HALT_IN_TR) ||
 708                     (ctrl & DBC_CTRL_HALT_OUT_TR)) {
 709                         xhci_info(xhci, "DbC Endpoint stall\n");
 710                         dbc->state = DS_STALLED;
 711
 712                         if (ctrl & DBC_CTRL_HALT_IN_TR) {
 713                                 dep = get_in_ep(xhci);
 714                                 xhci_dbc_flush_endpoint_requests(dep);
 715                         }
 716
 717                         if (ctrl & DBC_CTRL_HALT_OUT_TR) {
 718                                 dep = get_out_ep(xhci);
 719                                 xhci_dbc_flush_endpoint_requests(dep);
 720                         }
 721
 722                         return EVT_DONE;
 723                 }
 724
 725                 /* Clear DbC run change bit: */
 726                 if (ctrl & DBC_CTRL_DBC_RUN_CHANGE) {
 727                         writel(ctrl, &dbc->regs->control);
 728                         ctrl = readl(&dbc->regs->control);
 729                 }
 730
 731                 break;
 732         case DS_STALLED:
 733                 ctrl = readl(&dbc->regs->control);
 734                 if (!(ctrl & DBC_CTRL_HALT_IN_TR) &&
 735                     !(ctrl & DBC_CTRL_HALT_OUT_TR) &&
 736                     (ctrl & DBC_CTRL_DBC_RUN)) {
 737                         dbc->state = DS_CONFIGURED;
 738                         break;
 739                 }
 740
 741                 return EVT_DONE;
 742         default:
 743                 xhci_err(xhci, "Unknown DbC state %d\n", dbc->state);
 744                 break;
 745         }
 746
 747         /* Handle the events in the event ring: */
 748         evt = dbc->ring_evt->dequeue;
 749         while ((le32_to_cpu(evt->event_cmd.flags) & TRB_CYCLE) ==
 750                         dbc->ring_evt->cycle_state) {
 751                 /*
 752                  * Add a barrier between reading the cycle flag and any
 753                  * reads of the event's flags/data below:
 754                  */
 755                 rmb();
 756
 757                 trace_xhci_dbc_handle_event(dbc->ring_evt, &evt->generic);
 758
 759                 switch (le32_to_cpu(evt->event_cmd.flags) & TRB_TYPE_BITMASK) {
 760                 case TRB_TYPE(TRB_PORT_STATUS):
 761                         dbc_handle_port_status(xhci, evt);
 762                         break;
 763                 case TRB_TYPE(TRB_TRANSFER):
 764                         dbc_handle_xfer_event(xhci, evt);
 765                         break;
 766                 default:
 767                         break;
 768                 }
 769
 770                 inc_deq(xhci, dbc->ring_evt);
 771                 evt = dbc->ring_evt->dequeue;
 772                 update_erdp = true;
 773         }
 774
 775         /* Update event ring dequeue pointer: */
 776         if (update_erdp) {
 777                 deq = xhci_trb_virt_to_dma(dbc->ring_evt->deq_seg,
 778                                            dbc->ring_evt->dequeue);
 779                 xhci_write_64(xhci, deq, &dbc->regs->erdp);
 780         }
 781
 782         return EVT_DONE;
 783 }
 784
 785 static void xhci_dbc_handle_events(struct work_struct *work)
 786 {
 787         int                     ret;
 788         enum evtreturn          evtr;
 789         struct xhci_dbc         *dbc;
 790         unsigned long           flags;
 791         struct xhci_hcd         *xhci;
 792
 793         dbc = container_of(to_delayed_work(work), struct xhci_dbc, event_work);
 794         xhci = dbc->xhci;
 795
 796         spin_lock_irqsave(&dbc->lock, flags);
 797         evtr = xhci_dbc_do_handle_events(dbc);
 798         spin_unlock_irqrestore(&dbc->lock, flags);
 799
 800         switch (evtr) {
 801         case EVT_GSER:
 802                 ret = xhci_dbc_tty_register_device(xhci);
 803                 if (ret) {
 804                         xhci_err(xhci, "failed to alloc tty device\n");
 805                         break;
 806                 }
 807
 808                 xhci_info(xhci, "DbC now attached to /dev/ttyDBC0\n");
 809                 break;
 810         case EVT_DISC:
 811                 xhci_dbc_tty_unregister_device(xhci);
 812                 break;
 813         case EVT_DONE:
 814                 break;
 815         default:
 816                 xhci_info(xhci, "stop handling dbc events\n");
 817                 return;
 818         }
 819
 820         mod_delayed_work(system_wq, &dbc->event_work, 1);
 821 }
 822
 823 static void xhci_do_dbc_exit(struct xhci_hcd *xhci)
 824 {
 825         unsigned long           flags;
 826
 827         spin_lock_irqsave(&xhci->lock, flags);
 828         kfree(xhci->dbc);
 829         xhci->dbc = NULL;
 830         spin_unlock_irqrestore(&xhci->lock, flags);
 831 }
 832
 833 static int xhci_do_dbc_init(struct xhci_hcd *xhci)
 834 {
 835         u32                     reg;
 836         struct xhci_dbc         *dbc;
 837         unsigned long           flags;
 838         void __iomem            *base;
 839         int                     dbc_cap_offs;
 840
 841         base = &xhci->cap_regs->hc_capbase;
 842         dbc_cap_offs = xhci_find_next_ext_cap(base, 0, XHCI_EXT_CAPS_DEBUG);
 843         if (!dbc_cap_offs)
 844                 return -ENODEV;
 845
 846         dbc = kzalloc(sizeof(*dbc), GFP_KERNEL);
 847         if (!dbc)
 848                 return -ENOMEM;
 849
 850         dbc->regs = base + dbc_cap_offs;
 851
 852         /* We will avoid using DbC in xhci driver if it's in use. */
 853         reg = readl(&dbc->regs->control);
 854         if (reg & DBC_CTRL_DBC_ENABLE) {
 855                 kfree(dbc);
 856                 return -EBUSY;
 857         }
 858
 859         spin_lock_irqsave(&xhci->lock, flags);
 860         if (xhci->dbc) {
 861                 spin_unlock_irqrestore(&xhci->lock, flags);
 862                 kfree(dbc);
 863                 return -EBUSY;
 864         }
 865         xhci->dbc = dbc;
 866         spin_unlock_irqrestore(&xhci->lock, flags);
 867
 868         dbc->xhci = xhci;
 869         INIT_DELAYED_WORK(&dbc->event_work, xhci_dbc_handle_events);
 870         spin_lock_init(&dbc->lock);
 871
 872         return 0;
 873 }
 874
 875 static ssize_t dbc_show(struct device *dev,
 876                         struct device_attribute *attr,
 877                         char *buf)
 878 {
 879         const char              *p;
 880         struct xhci_dbc         *dbc;
 881         struct xhci_hcd         *xhci;
 882
 883         xhci = hcd_to_xhci(dev_get_drvdata(dev));
 884         dbc = xhci->dbc;
 885
 886         switch (dbc->state) {
 887         case DS_DISABLED:
 888                 p = "disabled";
 889                 break;
 890         case DS_INITIALIZED:
 891                 p = "initialized";
 892                 break;
 893         case DS_ENABLED:
 894                 p = "enabled";
 895                 break;
 896         case DS_CONNECTED:
 897                 p = "connected";
 898                 break;
 899         case DS_CONFIGURED:
 900                 p = "configured";
 901                 break;
 902         case DS_STALLED:
 903                 p = "stalled";
 904                 break;
 905         default:
 906                 p = "unknown";
 907         }
 908
 909         return sprintf(buf, "%s\n", p);
 910 }
 911
 912 static ssize_t dbc_store(struct device *dev,
 913                          struct device_attribute *attr,
 914                          const char *buf, size_t count)
 915 {
 916         struct xhci_hcd         *xhci;
 917
 918         xhci = hcd_to_xhci(dev_get_drvdata(dev));
 919
 920         if (!strncmp(buf, "enable", 6))
 921                 xhci_dbc_start(xhci);
 922         else if (!strncmp(buf, "disable", 7))
 923                 xhci_dbc_stop(xhci);
 924         else
 925                 return -EINVAL;
 926
 927         return count;
 928 }
 929
 930 static DEVICE_ATTR_RW(dbc);
 931
 932 int xhci_dbc_init(struct xhci_hcd *xhci)
 933 {
 934         int                     ret;
 935         struct device           *dev = xhci_to_hcd(xhci)->self.controller;
 936
 937         ret = xhci_do_dbc_init(xhci);
 938         if (ret)
 939                 goto init_err3;
 940
 941         ret = xhci_dbc_tty_register_driver(xhci);
 942         if (ret)
 943                 goto init_err2;
 944
 945         ret = device_create_file(dev, &dev_attr_dbc);
 946         if (ret)
 947                 goto init_err1;
 948
 949         return 0;
 950
 951 init_err1:
 952         xhci_dbc_tty_unregister_driver();
 953 init_err2:
 954         xhci_do_dbc_exit(xhci);
 955 init_err3:
 956         return ret;
 957 }
 958
 959 void xhci_dbc_exit(struct xhci_hcd *xhci)
 960 {
 961         struct device           *dev = xhci_to_hcd(xhci)->self.controller;
 962
 963         if (!xhci->dbc)
 964                 return;
 965
 966         device_remove_file(dev, &dev_attr_dbc);
 967         xhci_dbc_tty_unregister_driver();
 968         xhci_dbc_stop(xhci);
 969         xhci_do_dbc_exit(xhci);
 970 }
 971
 972 #ifdef CONFIG_PM
 973 int xhci_dbc_suspend(struct xhci_hcd *xhci)
 974 {
 975         struct xhci_dbc         *dbc = xhci->dbc;
 976
 977         if (!dbc)
 978                 return 0;
 979
 980         if (dbc->state == DS_CONFIGURED)
 981                 dbc->resume_required = 1;
 982
 983         xhci_dbc_stop(xhci);
 984
 985         return 0;
 986 }
 987
 988 int xhci_dbc_resume(struct xhci_hcd *xhci)
 989 {
 990         int                     ret = 0;
 991         struct xhci_dbc         *dbc = xhci->dbc;
 992
 993         if (!dbc)
 994                 return 0;
 995
 996         if (dbc->resume_required) {
 997                 dbc->resume_required = 0;
 998                 xhci_dbc_start(xhci);
 999         }
1000
1001         return ret;
1002 }
1003 #endif /* CONFIG_PM */