drivers/usb/gadget/function/uvc_video.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *      uvc_video.c  --  USB Video Class Gadget driver
   4  *
   5  *      Copyright (C) 2009-2010
   6  *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/device.h>
  11 #include <linux/errno.h>
  12 #include <linux/usb/ch9.h>
  13 #include <linux/usb/gadget.h>
  14 #include <linux/usb/video.h>
  15 #include <asm/unaligned.h>
  16
  17 #include <media/v4l2-dev.h>
  18
  19 #include "uvc.h"
  20 #include "uvc_queue.h"
  21 #include "uvc_video.h"
  22
  23 /* --------------------------------------------------------------------------
  24  * Video codecs
  25  */
  26
  27 static int
  28 uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf,
  29                 u8 *data, int len)
  30 {
  31         struct uvc_device *uvc = container_of(video, struct uvc_device, video);
  32         struct usb_composite_dev *cdev = uvc->func.config->cdev;
  33         struct timespec64 ts = ns_to_timespec64(buf->buf.vb2_buf.timestamp);
  34         int pos = 2;
  35
  36         data[1] = UVC_STREAM_EOH | video->fid;
  37
  38         if (video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE)
  39                 data[1] |= UVC_STREAM_ERR;
  40
  41         if (video->queue.buf_used == 0 && ts.tv_sec) {
  42                 /* dwClockFrequency is 48 MHz */
  43                 u32 pts = ((u64)ts.tv_sec * USEC_PER_SEC + ts.tv_nsec / NSEC_PER_USEC) * 48;
  44
  45                 data[1] |= UVC_STREAM_PTS;
  46                 put_unaligned_le32(pts, &data[pos]);
  47                 pos += 4;
  48         }
  49
  50         if (cdev->gadget->ops->get_frame) {
  51                 u32 sof, stc;
  52
  53                 sof = usb_gadget_frame_number(cdev->gadget);
  54                 ktime_get_ts64(&ts);
  55                 stc = ((u64)ts.tv_sec * USEC_PER_SEC + ts.tv_nsec / NSEC_PER_USEC) * 48;
  56
  57                 data[1] |= UVC_STREAM_SCR;
  58                 put_unaligned_le32(stc, &data[pos]);
  59                 put_unaligned_le16(sof, &data[pos+4]);
  60                 pos += 6;
  61         }
  62
  63         data[0] = pos;
  64
  65         if (buf->bytesused - video->queue.buf_used <= len - pos)
  66                 data[1] |= UVC_STREAM_EOF;
  67
  68         return pos;
  69 }
  70
  71 static int
  72 uvc_video_encode_data(struct uvc_video *video, struct uvc_buffer *buf,
  73                 u8 *data, int len)
  74 {
  75         struct uvc_video_queue *queue = &video->queue;
  76         unsigned int nbytes;
  77         void *mem;
  78
  79         /* Copy video data to the USB buffer. */
  80         mem = buf->mem + queue->buf_used;
  81         nbytes = min((unsigned int)len, buf->bytesused - queue->buf_used);
  82
  83         memcpy(data, mem, nbytes);
  84         queue->buf_used += nbytes;
  85
  86         return nbytes;
  87 }
  88
  89 static void
  90 uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video,
  91                 struct uvc_buffer *buf)
  92 {
  93         void *mem = req->buf;
  94         struct uvc_request *ureq = req->context;
  95         int len = video->req_size;
  96         int ret;
  97
  98         /* Add a header at the beginning of the payload. */
  99         if (video->payload_size == 0) {
 100                 ret = uvc_video_encode_header(video, buf, mem, len);
 101                 video->payload_size += ret;
 102                 mem += ret;
 103                 len -= ret;
 104         }
 105
 106         /* Process video data. */
 107         len = min((int)(video->max_payload_size - video->payload_size), len);
 108         ret = uvc_video_encode_data(video, buf, mem, len);
 109
 110         video->payload_size += ret;
 111         len -= ret;
 112
 113         req->length = video->req_size - len;
 114         req->zero = video->payload_size == video->max_payload_size;
 115
 116         if (buf->bytesused == video->queue.buf_used) {
 117                 video->queue.buf_used = 0;
 118                 buf->state = UVC_BUF_STATE_DONE;
 119                 list_del(&buf->queue);
 120                 video->fid ^= UVC_STREAM_FID;
 121                 ureq->last_buf = buf;
 122
 123                 video->payload_size = 0;
 124         }
 125
 126         if (video->payload_size == video->max_payload_size ||
 127             video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE ||
 128             buf->bytesused == video->queue.buf_used)
 129                 video->payload_size = 0;
 130 }
 131
 132 static void
 133 uvc_video_encode_isoc_sg(struct usb_request *req, struct uvc_video *video,
 134                 struct uvc_buffer *buf)
 135 {
 136         unsigned int pending = buf->bytesused - video->queue.buf_used;
 137         struct uvc_request *ureq = req->context;
 138         struct scatterlist *sg, *iter;
 139         unsigned int len = video->req_size;
 140         unsigned int sg_left, part = 0;
 141         unsigned int i;
 142         int header_len;
 143
 144         sg = ureq->sgt.sgl;
 145         sg_init_table(sg, ureq->sgt.nents);
 146
 147         /* Init the header. */
 148         header_len = uvc_video_encode_header(video, buf, ureq->header,
 149                                       video->req_size);
 150         sg_set_buf(sg, ureq->header, header_len);
 151         len -= header_len;
 152
 153         if (pending <= len)
 154                 len = pending;
 155
 156         req->length = (len == pending) ?
 157                 len + header_len : video->req_size;
 158
 159         /* Init the pending sgs with payload */
 160         sg = sg_next(sg);
 161
 162         for_each_sg(sg, iter, ureq->sgt.nents - 1, i) {
 163                 if (!len || !buf->sg || !buf->sg->length)
 164                         break;
 165
 166                 sg_left = buf->sg->length - buf->offset;
 167                 part = min_t(unsigned int, len, sg_left);
 168
 169                 sg_set_page(iter, sg_page(buf->sg), part, buf->offset);
 170
 171                 if (part == sg_left) {
 172                         buf->offset = 0;
 173                         buf->sg = sg_next(buf->sg);
 174                 } else {
 175                         buf->offset += part;
 176                 }
 177                 len -= part;
 178         }
 179
 180         /* Assign the video data with header. */
 181         req->buf = NULL;
 182         req->sg = ureq->sgt.sgl;
 183         req->num_sgs = i + 1;
 184
 185         req->length -= len;
 186         video->queue.buf_used += req->length - header_len;
 187
 188         if (buf->bytesused == video->queue.buf_used || !buf->sg ||
 189                         video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE) {
 190                 video->queue.buf_used = 0;
 191                 buf->state = UVC_BUF_STATE_DONE;
 192                 buf->offset = 0;
 193                 list_del(&buf->queue);
 194                 video->fid ^= UVC_STREAM_FID;
 195                 ureq->last_buf = buf;
 196         }
 197 }
 198
 199 static void
 200 uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video,
 201                 struct uvc_buffer *buf)
 202 {
 203         void *mem = req->buf;
 204         struct uvc_request *ureq = req->context;
 205         int len = video->req_size;
 206         int ret;
 207
 208         /* Add the header. */
 209         ret = uvc_video_encode_header(video, buf, mem, len);
 210         mem += ret;
 211         len -= ret;
 212
 213         /* Process video data. */
 214         ret = uvc_video_encode_data(video, buf, mem, len);
 215         len -= ret;
 216
 217         req->length = video->req_size - len;
 218
 219         if (buf->bytesused == video->queue.buf_used ||
 220                         video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE) {
 221                 video->queue.buf_used = 0;
 222                 buf->state = UVC_BUF_STATE_DONE;
 223                 list_del(&buf->queue);
 224                 video->fid ^= UVC_STREAM_FID;
 225                 ureq->last_buf = buf;
 226         }
 227 }
 228
 229 /* --------------------------------------------------------------------------
 230  * Request handling
 231  */
 232
 233 /*
 234  * Callers must take care to hold req_lock when this function may be called
 235  * from multiple threads. For example, when frames are streaming to the host.
 236  */
 237 static void
 238 uvc_video_free_request(struct uvc_request *ureq, struct usb_ep *ep)
 239 {
 240         sg_free_table(&ureq->sgt);
 241         if (ureq->req && ep) {
 242                 usb_ep_free_request(ep, ureq->req);
 243                 ureq->req = NULL;
 244         }
 245
 246         kfree(ureq->req_buffer);
 247         ureq->req_buffer = NULL;
 248
 249         if (!list_empty(&ureq->list))
 250                 list_del_init(&ureq->list);
 251
 252         kfree(ureq);
 253 }
 254
 255 static int uvcg_video_ep_queue(struct uvc_video *video, struct usb_request *req)
 256 {
 257         int ret;
 258
 259         ret = usb_ep_queue(video->ep, req, GFP_ATOMIC);
 260         if (ret < 0) {
 261                 uvcg_err(&video->uvc->func, "Failed to queue request (%d).\n",
 262                          ret);
 263
 264                 /* If the endpoint is disabled the descriptor may be NULL. */
 265                 if (video->ep->desc) {
 266                         /* Isochronous endpoints can't be halted. */
 267                         if (usb_endpoint_xfer_bulk(video->ep->desc))
 268                                 usb_ep_set_halt(video->ep);
 269                 }
 270         }
 271
 272         return ret;
 273 }
 274
 275 /* This function must be called with video->req_lock held. */
 276 static int uvcg_video_usb_req_queue(struct uvc_video *video,
 277         struct usb_request *req, bool queue_to_ep)
 278 {
 279         bool is_bulk = video->max_payload_size;
 280         struct list_head *list = NULL;
 281
 282         if (!video->is_enabled)
 283                 return -ENODEV;
 284
 285         if (queue_to_ep) {
 286                 struct uvc_request *ureq = req->context;
 287                 /*
 288                  * With USB3 handling more requests at a higher speed, we can't
 289                  * afford to generate an interrupt for every request. Decide to
 290                  * interrupt:
 291                  *
 292                  * - When no more requests are available in the free queue, as
 293                  *   this may be our last chance to refill the endpoint's
 294                  *   request queue.
 295                  *
 296                  * - When this is request is the last request for the video
 297                  *   buffer, as we want to start sending the next video buffer
 298                  *   ASAP in case it doesn't get started already in the next
 299                  *   iteration of this loop.
 300                  *
 301                  * - Four times over the length of the requests queue (as
 302                  *   indicated by video->uvc_num_requests), as a trade-off
 303                  *   between latency and interrupt load.
 304                  */
 305                 if (list_empty(&video->req_free) || ureq->last_buf ||
 306                         !(video->req_int_count %
 307                         DIV_ROUND_UP(video->uvc_num_requests, 4))) {
 308                         video->req_int_count = 0;
 309                         req->no_interrupt = 0;
 310                 } else {
 311                         req->no_interrupt = 1;
 312                 }
 313                 video->req_int_count++;
 314                 return uvcg_video_ep_queue(video, req);
 315         }
 316         /*
 317          * If we're not queuing to the ep, for isoc we're queuing
 318          * to the req_ready list, otherwise req_free.
 319          */
 320         list = is_bulk ? &video->req_free : &video->req_ready;
 321         list_add_tail(&req->list, list);
 322         return 0;
 323 }
 324
 325 /*
 326  * Must only be called from uvcg_video_enable - since after that we only want to
 327  * queue requests to the endpoint from the uvc_video_complete complete handler.
 328  * This function is needed in order to 'kick start' the flow of requests from
 329  * gadget driver to the usb controller.
 330  */
 331 static void uvc_video_ep_queue_initial_requests(struct uvc_video *video)
 332 {
 333         struct usb_request *req = NULL;
 334         unsigned long flags = 0;
 335         unsigned int count = 0;
 336         int ret = 0;
 337
 338         /*
 339          * We only queue half of the free list since we still want to have
 340          * some free usb_requests in the free list for the video_pump async_wq
 341          * thread to encode uvc buffers into. Otherwise we could get into a
 342          * situation where the free list does not have any usb requests to
 343          * encode into - we always end up queueing 0 length requests to the
 344          * end point.
 345          */
 346         unsigned int half_list_size = video->uvc_num_requests / 2;
 347
 348         spin_lock_irqsave(&video->req_lock, flags);
 349         /*
 350          * Take these requests off the free list and queue them all to the
 351          * endpoint. Since we queue 0 length requests with the req_lock held,
 352          * there isn't any 'data' race involved here with the complete handler.
 353          */
 354         while (count < half_list_size) {
 355                 req = list_first_entry(&video->req_free, struct usb_request,
 356                                         list);
 357                 list_del(&req->list);
 358                 req->length = 0;
 359                 ret = uvcg_video_ep_queue(video, req);
 360                 if (ret < 0) {
 361                         uvcg_queue_cancel(&video->queue, 0);
 362                         break;
 363                 }
 364                 count++;
 365         }
 366         spin_unlock_irqrestore(&video->req_lock, flags);
 367 }
 368
 369 static void
 370 uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
 371 {
 372         struct uvc_request *ureq = req->context;
 373         struct uvc_video *video = ureq->video;
 374         struct uvc_video_queue *queue = &video->queue;
 375         struct uvc_buffer *last_buf;
 376         struct usb_request *to_queue = req;
 377         unsigned long flags;
 378         bool is_bulk = video->max_payload_size;
 379         int ret = 0;
 380
 381         spin_lock_irqsave(&video->req_lock, flags);
 382         if (!video->is_enabled) {
 383                 /*
 384                  * When is_enabled is false, uvcg_video_disable() ensures
 385                  * that in-flight uvc_buffers are returned, so we can
 386                  * safely call free_request without worrying about
 387                  * last_buf.
 388                  */
 389                 uvc_video_free_request(ureq, ep);
 390                 spin_unlock_irqrestore(&video->req_lock, flags);
 391                 return;
 392         }
 393
 394         last_buf = ureq->last_buf;
 395         ureq->last_buf = NULL;
 396         spin_unlock_irqrestore(&video->req_lock, flags);
 397
 398         switch (req->status) {
 399         case 0:
 400                 break;
 401
 402         case -EXDEV:
 403                 uvcg_dbg(&video->uvc->func, "VS request missed xfer.\n");
 404                 if (req->length != 0)
 405                         queue->flags |= UVC_QUEUE_DROP_INCOMPLETE;
 406                 break;
 407
 408         case -ESHUTDOWN:        /* disconnect from host. */
 409                 uvcg_dbg(&video->uvc->func, "VS request cancelled.\n");
 410                 uvcg_queue_cancel(queue, 1);
 411                 break;
 412
 413         default:
 414                 uvcg_warn(&video->uvc->func,
 415                           "VS request completed with status %d.\n",
 416                           req->status);
 417                 uvcg_queue_cancel(queue, 0);
 418         }
 419
 420         if (last_buf) {
 421                 spin_lock_irqsave(&queue->irqlock, flags);
 422                 uvcg_complete_buffer(queue, last_buf);
 423                 spin_unlock_irqrestore(&queue->irqlock, flags);
 424         }
 425
 426         spin_lock_irqsave(&video->req_lock, flags);
 427         /*
 428          * Video stream might have been disabled while we were
 429          * processing the current usb_request. So make sure
 430          * we're still streaming before queueing the usb_request
 431          * back to req_free
 432          */
 433         if (!video->is_enabled) {
 434                 uvc_video_free_request(ureq, ep);
 435                 spin_unlock_irqrestore(&video->req_lock, flags);
 436                 uvcg_queue_cancel(queue, 0);
 437
 438                 return;
 439         }
 440
 441         /*
 442          * Here we check whether any request is available in the ready
 443          * list. If it is, queue it to the ep and add the current
 444          * usb_request to the req_free list - for video_pump to fill in.
 445          * Otherwise, just use the current usb_request to queue a 0
 446          * length request to the ep. Since we always add to the req_free
 447          * list if we dequeue from the ready list, there will never
 448          * be a situation where the req_free list is completely out of
 449          * requests and cannot recover.
 450          */
 451         to_queue->length = 0;
 452         if (!list_empty(&video->req_ready)) {
 453                 to_queue = list_first_entry(&video->req_ready,
 454                         struct usb_request, list);
 455                 list_del(&to_queue->list);
 456                 list_add_tail(&req->list, &video->req_free);
 457                 /*
 458                  * Queue work to the wq as well since it is possible that a
 459                  * buffer may not have been completely encoded with the set of
 460                  * in-flight usb requests for whih the complete callbacks are
 461                  * firing.
 462                  * In that case, if we do not queue work to the worker thread,
 463                  * the buffer will never be marked as complete - and therefore
 464                  * not be returned to userpsace. As a result,
 465                  * dequeue -> queue -> dequeue flow of uvc buffers will not
 466                  * happen.
 467                  */
 468                 queue_work(video->async_wq, &video->pump);
 469         }
 470         /*
 471          * Queue to the endpoint. The actual queueing to ep will
 472          * only happen on one thread - the async_wq for bulk endpoints
 473          * and this thread for isoc endpoints.
 474          */
 475         ret = uvcg_video_usb_req_queue(video, to_queue, !is_bulk);
 476         if (ret < 0) {
 477                 /*
 478                  * Endpoint error, but the stream is still enabled.
 479                  * Put request back in req_free for it to be cleaned
 480                  * up later.
 481                  */
 482                 list_add_tail(&to_queue->list, &video->req_free);
 483         }
 484
 485         spin_unlock_irqrestore(&video->req_lock, flags);
 486 }
 487
 488 static int
 489 uvc_video_free_requests(struct uvc_video *video)
 490 {
 491         struct uvc_request *ureq, *temp;
 492
 493         list_for_each_entry_safe(ureq, temp, &video->ureqs, list)
 494                 uvc_video_free_request(ureq, video->ep);
 495
 496         INIT_LIST_HEAD(&video->ureqs);
 497         INIT_LIST_HEAD(&video->req_free);
 498         INIT_LIST_HEAD(&video->req_ready);
 499         video->req_size = 0;
 500         return 0;
 501 }
 502
 503 static int
 504 uvc_video_alloc_requests(struct uvc_video *video)
 505 {
 506         struct uvc_request *ureq;
 507         unsigned int req_size;
 508         unsigned int i;
 509         int ret = -ENOMEM;
 510
 511         BUG_ON(video->req_size);
 512
 513         req_size = video->ep->maxpacket
 514                  * max_t(unsigned int, video->ep->maxburst, 1)
 515                  * (video->ep->mult);
 516
 517         for (i = 0; i < video->uvc_num_requests; i++) {
 518                 ureq = kzalloc(sizeof(struct uvc_request), GFP_KERNEL);
 519                 if (ureq == NULL)
 520                         goto error;
 521
 522                 INIT_LIST_HEAD(&ureq->list);
 523
 524                 list_add_tail(&ureq->list, &video->ureqs);
 525
 526                 ureq->req_buffer = kmalloc(req_size, GFP_KERNEL);
 527                 if (ureq->req_buffer == NULL)
 528                         goto error;
 529
 530                 ureq->req = usb_ep_alloc_request(video->ep, GFP_KERNEL);
 531                 if (ureq->req == NULL)
 532                         goto error;
 533
 534                 ureq->req->buf = ureq->req_buffer;
 535                 ureq->req->length = 0;
 536                 ureq->req->complete = uvc_video_complete;
 537                 ureq->req->context = ureq;
 538                 ureq->video = video;
 539                 ureq->last_buf = NULL;
 540
 541                 list_add_tail(&ureq->req->list, &video->req_free);
 542                 /* req_size/PAGE_SIZE + 1 for overruns and + 1 for header */
 543                 sg_alloc_table(&ureq->sgt,
 544                                DIV_ROUND_UP(req_size - UVCG_REQUEST_HEADER_LEN,
 545                                             PAGE_SIZE) + 2, GFP_KERNEL);
 546         }
 547
 548         video->req_size = req_size;
 549
 550         return 0;
 551
 552 error:
 553         uvc_video_free_requests(video);
 554         return ret;
 555 }
 556
 557 /* --------------------------------------------------------------------------
 558  * Video streaming
 559  */
 560
 561 /*
 562  * uvcg_video_pump - Pump video data into the USB requests
 563  *
 564  * This function fills the available USB requests (listed in req_free) with
 565  * video data from the queued buffers.
 566  */
 567 static void uvcg_video_pump(struct work_struct *work)
 568 {
 569         struct uvc_video *video = container_of(work, struct uvc_video, pump);
 570         struct uvc_video_queue *queue = &video->queue;
 571         /* video->max_payload_size is only set when using bulk transfer */
 572         bool is_bulk = video->max_payload_size;
 573         struct usb_request *req = NULL;
 574         struct uvc_buffer *buf;
 575         unsigned long flags;
 576         int ret = 0;
 577
 578         while (true) {
 579                 if (!video->ep->enabled)
 580                         return;
 581
 582                 /*
 583                  * Check is_enabled and retrieve the first available USB
 584                  * request, protected by the request lock.
 585                  */
 586                 spin_lock_irqsave(&video->req_lock, flags);
 587                 if (!video->is_enabled || list_empty(&video->req_free)) {
 588                         spin_unlock_irqrestore(&video->req_lock, flags);
 589                         return;
 590                 }
 591                 req = list_first_entry(&video->req_free, struct usb_request,
 592                                         list);
 593                 list_del(&req->list);
 594                 spin_unlock_irqrestore(&video->req_lock, flags);
 595
 596                 /*
 597                  * Retrieve the first available video buffer and fill the
 598                  * request, protected by the video queue irqlock.
 599                  */
 600                 spin_lock_irqsave(&queue->irqlock, flags);
 601                 buf = uvcg_queue_head(queue);
 602                 if (!buf) {
 603                         /*
 604                          * Either the queue has been disconnected or no video buffer
 605                          * available for bulk transfer. Either way, stop processing
 606                          * further.
 607                          */
 608                         spin_unlock_irqrestore(&queue->irqlock, flags);
 609                         break;
 610                 }
 611
 612                 video->encode(req, video, buf);
 613
 614                 spin_unlock_irqrestore(&queue->irqlock, flags);
 615
 616                 spin_lock_irqsave(&video->req_lock, flags);
 617                 /* For bulk end points we queue from the worker thread
 618                  * since we would preferably not want to wait on requests
 619                  * to be ready, in the uvcg_video_complete() handler.
 620                  * For isoc endpoints we add the request to the ready list
 621                  * and only queue it to the endpoint from the complete handler.
 622                  */
 623                 ret = uvcg_video_usb_req_queue(video, req, is_bulk);
 624                 spin_unlock_irqrestore(&video->req_lock, flags);
 625
 626                 if (ret < 0) {
 627                         uvcg_queue_cancel(queue, 0);
 628                         break;
 629                 }
 630         }
 631         spin_lock_irqsave(&video->req_lock, flags);
 632         if (video->is_enabled)
 633                 list_add_tail(&req->list, &video->req_free);
 634         else
 635                 uvc_video_free_request(req->context, video->ep);
 636         spin_unlock_irqrestore(&video->req_lock, flags);
 637 }
 638
 639 /*
 640  * Disable the video stream
 641  */
 642 int
 643 uvcg_video_disable(struct uvc_video *video)
 644 {
 645         unsigned long flags;
 646         struct list_head inflight_bufs;
 647         struct usb_request *req, *temp;
 648         struct uvc_buffer *buf, *btemp;
 649         struct uvc_request *ureq, *utemp;
 650
 651         if (video->ep == NULL) {
 652                 uvcg_info(&video->uvc->func,
 653                           "Video disable failed, device is uninitialized.\n");
 654                 return -ENODEV;
 655         }
 656
 657         INIT_LIST_HEAD(&inflight_bufs);
 658         spin_lock_irqsave(&video->req_lock, flags);
 659         video->is_enabled = false;
 660
 661         /*
 662          * Remove any in-flight buffers from the uvc_requests
 663          * because we want to return them before cancelling the
 664          * queue. This ensures that we aren't stuck waiting for
 665          * all complete callbacks to come through before disabling
 666          * vb2 queue.
 667          */
 668         list_for_each_entry(ureq, &video->ureqs, list) {
 669                 if (ureq->last_buf) {
 670                         list_add_tail(&ureq->last_buf->queue, &inflight_bufs);
 671                         ureq->last_buf = NULL;
 672                 }
 673         }
 674         spin_unlock_irqrestore(&video->req_lock, flags);
 675
 676         cancel_work_sync(&video->pump);
 677         uvcg_queue_cancel(&video->queue, 0);
 678
 679         spin_lock_irqsave(&video->req_lock, flags);
 680         /*
 681          * Remove all uvc_requests from ureqs with list_del_init
 682          * This lets uvc_video_free_request correctly identify
 683          * if the uvc_request is attached to a list or not when freeing
 684          * memory.
 685          */
 686         list_for_each_entry_safe(ureq, utemp, &video->ureqs, list)
 687                 list_del_init(&ureq->list);
 688
 689         list_for_each_entry_safe(req, temp, &video->req_free, list) {
 690                 list_del(&req->list);
 691                 uvc_video_free_request(req->context, video->ep);
 692         }
 693
 694         list_for_each_entry_safe(req, temp, &video->req_ready, list) {
 695                 list_del(&req->list);
 696                 uvc_video_free_request(req->context, video->ep);
 697         }
 698
 699         INIT_LIST_HEAD(&video->ureqs);
 700         INIT_LIST_HEAD(&video->req_free);
 701         INIT_LIST_HEAD(&video->req_ready);
 702         video->req_size = 0;
 703         spin_unlock_irqrestore(&video->req_lock, flags);
 704
 705         /*
 706          * Return all the video buffers before disabling the queue.
 707          */
 708         spin_lock_irqsave(&video->queue.irqlock, flags);
 709         list_for_each_entry_safe(buf, btemp, &inflight_bufs, queue) {
 710                 list_del(&buf->queue);
 711                 uvcg_complete_buffer(&video->queue, buf);
 712         }
 713         spin_unlock_irqrestore(&video->queue.irqlock, flags);
 714
 715         uvcg_queue_enable(&video->queue, 0);
 716         return 0;
 717 }
 718
 719 /*
 720  * Enable the video stream.
 721  */
 722 int uvcg_video_enable(struct uvc_video *video)
 723 {
 724         int ret;
 725
 726         if (video->ep == NULL) {
 727                 uvcg_info(&video->uvc->func,
 728                           "Video enable failed, device is uninitialized.\n");
 729                 return -ENODEV;
 730         }
 731
 732         /*
 733          * Safe to access request related fields without req_lock because
 734          * this is the only thread currently active, and no other
 735          * request handling thread will become active until this function
 736          * returns.
 737          */
 738         video->is_enabled = true;
 739
 740         if ((ret = uvcg_queue_enable(&video->queue, 1)) < 0)
 741                 return ret;
 742
 743         if ((ret = uvc_video_alloc_requests(video)) < 0)
 744                 return ret;
 745
 746         if (video->max_payload_size) {
 747                 video->encode = uvc_video_encode_bulk;
 748                 video->payload_size = 0;
 749         } else
 750                 video->encode = video->queue.use_sg ?
 751                         uvc_video_encode_isoc_sg : uvc_video_encode_isoc;
 752
 753         video->req_int_count = 0;
 754
 755         uvc_video_ep_queue_initial_requests(video);
 756
 757         return ret;
 758 }
 759
 760 /*
 761  * Initialize the UVC video stream.
 762  */
 763 int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc)
 764 {
 765         video->is_enabled = false;
 766         INIT_LIST_HEAD(&video->ureqs);
 767         INIT_LIST_HEAD(&video->req_free);
 768         INIT_LIST_HEAD(&video->req_ready);
 769         spin_lock_init(&video->req_lock);
 770         INIT_WORK(&video->pump, uvcg_video_pump);
 771
 772         /* Allocate a work queue for asynchronous video pump handler. */
 773         video->async_wq = alloc_workqueue("uvcgadget", WQ_UNBOUND | WQ_HIGHPRI, 0);
 774         if (!video->async_wq)
 775                 return -EINVAL;
 776
 777         video->uvc = uvc;
 778         video->fcc = V4L2_PIX_FMT_YUYV;
 779         video->bpp = 16;
 780         video->width = 320;
 781         video->height = 240;
 782         video->imagesize = 320 * 240 * 2;
 783
 784         /* Initialize the video buffers queue. */
 785         uvcg_queue_init(&video->queue, uvc->v4l2_dev.dev->parent,
 786                         V4L2_BUF_TYPE_VIDEO_OUTPUT, &video->mutex);
 787         return 0;
 788 }