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 ([email protected])
   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 <linux/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 #include "uvc_trace.h"
  23
  24 /* --------------------------------------------------------------------------
  25  * Video codecs
  26  */
  27
  28 static int
  29 uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf,
  30                 u8 *data, int len)
  31 {
  32         struct uvc_device *uvc = container_of(video, struct uvc_device, video);
  33         struct usb_composite_dev *cdev = uvc->func.config->cdev;
  34         struct timespec64 ts = ns_to_timespec64(buf->buf.vb2_buf.timestamp);
  35         int pos = 2;
  36
  37         data[1] = UVC_STREAM_EOH | video->fid;
  38
  39         if (video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE)
  40                 data[1] |= UVC_STREAM_ERR;
  41
  42         if (video->queue.buf_used == 0 && ts.tv_sec) {
  43                 /* dwClockFrequency is 48 MHz */
  44                 u32 pts = ((u64)ts.tv_sec * USEC_PER_SEC + ts.tv_nsec / NSEC_PER_USEC) * 48;
  45
  46                 data[1] |= UVC_STREAM_PTS;
  47                 put_unaligned_le32(pts, &data[pos]);
  48                 pos += 4;
  49         }
  50
  51         if (cdev->gadget->ops->get_frame) {
  52                 u32 sof, stc;
  53
  54                 sof = usb_gadget_frame_number(cdev->gadget);
  55                 ktime_get_ts64(&ts);
  56                 stc = ((u64)ts.tv_sec * USEC_PER_SEC + ts.tv_nsec / NSEC_PER_USEC) * 48;
  57
  58                 data[1] |= UVC_STREAM_SCR;
  59                 put_unaligned_le32(stc, &data[pos]);
  60                 put_unaligned_le16(sof, &data[pos+4]);
  61                 pos += 6;
  62         }
  63
  64         data[0] = pos;
  65
  66         if (buf->bytesused - video->queue.buf_used <= len - pos)
  67                 data[1] |= UVC_STREAM_EOF;
  68
  69         return pos;
  70 }
  71
  72 static int
  73 uvc_video_encode_data(struct uvc_video *video, struct uvc_buffer *buf,
  74                 u8 *data, int len)
  75 {
  76         struct uvc_video_queue *queue = &video->queue;
  77         unsigned int nbytes;
  78         void *mem;
  79
  80         /* Copy video data to the USB buffer. */
  81         mem = buf->mem + queue->buf_used;
  82         nbytes = min_t(unsigned int, len, buf->bytesused - queue->buf_used);
  83
  84         memcpy(data, mem, nbytes);
  85         queue->buf_used += nbytes;
  86
  87         return nbytes;
  88 }
  89
  90 static void
  91 uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video,
  92                 struct uvc_buffer *buf)
  93 {
  94         void *mem = req->buf;
  95         struct uvc_request *ureq = req->context;
  96         int len = video->req_size;
  97         int ret;
  98
  99         /* Add a header at the beginning of the payload. */
 100         if (video->payload_size == 0) {
 101                 ret = uvc_video_encode_header(video, buf, mem, len);
 102                 video->payload_size += ret;
 103                 mem += ret;
 104                 len -= ret;
 105         }
 106
 107         /* Process video data. */
 108         len = min_t(int, video->max_payload_size - video->payload_size, len);
 109         ret = uvc_video_encode_data(video, buf, mem, len);
 110
 111         video->payload_size += ret;
 112         len -= ret;
 113
 114         req->length = video->req_size - len;
 115         req->zero = video->payload_size == video->max_payload_size;
 116
 117         if (buf->bytesused == video->queue.buf_used) {
 118                 video->queue.buf_used = 0;
 119                 buf->state = UVC_BUF_STATE_DONE;
 120                 list_del(&buf->queue);
 121                 video->fid ^= UVC_STREAM_FID;
 122                 ureq->last_buf = buf;
 123
 124                 video->payload_size = 0;
 125         }
 126
 127         if (video->payload_size == video->max_payload_size ||
 128             video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE ||
 129             buf->bytesused == video->queue.buf_used)
 130                 video->payload_size = 0;
 131 }
 132
 133 static void
 134 uvc_video_encode_isoc_sg(struct usb_request *req, struct uvc_video *video,
 135                 struct uvc_buffer *buf)
 136 {
 137         unsigned int pending = buf->bytesused - video->queue.buf_used;
 138         struct uvc_request *ureq = req->context;
 139         struct scatterlist *sg, *iter;
 140         unsigned int len = buf->req_payload_size;
 141         unsigned int sg_left, part = 0;
 142         unsigned int i;
 143         int header_len;
 144
 145         sg = ureq->sgt.sgl;
 146         sg_init_table(sg, ureq->sgt.nents);
 147
 148         /* Init the header. */
 149         header_len = uvc_video_encode_header(video, buf, ureq->header,
 150                                              buf->req_payload_size);
 151         sg_set_buf(sg, ureq->header, header_len);
 152         len -= header_len;
 153
 154         if (pending <= len)
 155                 len = pending;
 156
 157         req->length = (len == pending) ? len + header_len :
 158                 buf->req_payload_size;
 159
 160         /* Init the pending sgs with payload */
 161         sg = sg_next(sg);
 162
 163         for_each_sg(sg, iter, ureq->sgt.nents - 1, i) {
 164                 if (!len || !buf->sg || !buf->sg->length)
 165                         break;
 166
 167                 sg_left = buf->sg->length - buf->offset;
 168                 part = min_t(unsigned int, len, sg_left);
 169
 170                 sg_set_page(iter, sg_page(buf->sg), part, buf->offset);
 171
 172                 if (part == sg_left) {
 173                         buf->offset = 0;
 174                         buf->sg = sg_next(buf->sg);
 175                 } else {
 176                         buf->offset += part;
 177                 }
 178                 len -= part;
 179         }
 180
 181         /* Assign the video data with header. */
 182         req->buf = NULL;
 183         req->sg = ureq->sgt.sgl;
 184         req->num_sgs = i + 1;
 185
 186         req->length -= len;
 187         video->queue.buf_used += req->length - header_len;
 188
 189         if (buf->bytesused == video->queue.buf_used || !buf->sg ||
 190                         video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE) {
 191                 video->queue.buf_used = 0;
 192                 buf->state = UVC_BUF_STATE_DONE;
 193                 buf->offset = 0;
 194                 list_del(&buf->queue);
 195                 video->fid ^= UVC_STREAM_FID;
 196                 ureq->last_buf = buf;
 197         }
 198 }
 199
 200 static void
 201 uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video,
 202                 struct uvc_buffer *buf)
 203 {
 204         void *mem = req->buf;
 205         struct uvc_request *ureq = req->context;
 206         int len = buf->req_payload_size;
 207         int ret;
 208
 209         /* Add the header. */
 210         ret = uvc_video_encode_header(video, buf, mem, len);
 211         mem += ret;
 212         len -= ret;
 213
 214         /* Process video data. */
 215         ret = uvc_video_encode_data(video, buf, mem, len);
 216         len -= ret;
 217
 218         req->length = buf->req_payload_size - len;
 219
 220         if (buf->bytesused == video->queue.buf_used ||
 221                         video->queue.flags & UVC_QUEUE_DROP_INCOMPLETE) {
 222                 video->queue.buf_used = 0;
 223                 buf->state = UVC_BUF_STATE_DONE;
 224                 list_del(&buf->queue);
 225                 video->fid ^= UVC_STREAM_FID;
 226                 ureq->last_buf = buf;
 227         }
 228 }
 229
 230 /* --------------------------------------------------------------------------
 231  * Request handling
 232  */
 233
 234 /*
 235  * Callers must take care to hold req_lock when this function may be called
 236  * from multiple threads. For example, when frames are streaming to the host.
 237  */
 238 static void
 239 uvc_video_free_request(struct uvc_request *ureq, struct usb_ep *ep)
 240 {
 241         sg_free_table(&ureq->sgt);
 242         if (ureq->req && ep) {
 243                 usb_ep_free_request(ep, ureq->req);
 244                 ureq->req = NULL;
 245         }
 246
 247         kfree(ureq->req_buffer);
 248         ureq->req_buffer = NULL;
 249
 250         if (!list_empty(&ureq->list))
 251                 list_del_init(&ureq->list);
 252
 253         kfree(ureq);
 254 }
 255
 256 static int uvcg_video_ep_queue(struct uvc_video *video, struct usb_request *req)
 257 {
 258         int ret;
 259
 260         ret = usb_ep_queue(video->ep, req, GFP_ATOMIC);
 261         if (ret < 0) {
 262                 uvcg_err(&video->uvc->func, "Failed to queue request (%d).\n",
 263                          ret);
 264
 265                 /* If the endpoint is disabled the descriptor may be NULL. */
 266                 if (video->ep->desc) {
 267                         /* Isochronous endpoints can't be halted. */
 268                         if (usb_endpoint_xfer_bulk(video->ep->desc))
 269                                 usb_ep_set_halt(video->ep);
 270                 }
 271         }
 272
 273         atomic_inc(&video->queued);
 274
 275         trace_uvcg_video_queue(req, atomic_read(&video->queued));
 276
 277         return ret;
 278 }
 279
 280 /* This function must be called with video->req_lock held. */
 281 static int uvcg_video_usb_req_queue(struct uvc_video *video,
 282         struct usb_request *req, bool queue_to_ep)
 283 {
 284         bool is_bulk = video->max_payload_size;
 285         struct list_head *list = NULL;
 286
 287         if (!video->is_enabled)
 288                 return -ENODEV;
 289
 290         if (queue_to_ep) {
 291                 struct uvc_request *ureq = req->context;
 292                 /*
 293                  * With USB3 handling more requests at a higher speed, we can't
 294                  * afford to generate an interrupt for every request. Decide to
 295                  * interrupt:
 296                  *
 297                  * - When no more requests are available in the free queue, as
 298                  *   this may be our last chance to refill the endpoint's
 299                  *   request queue.
 300                  *
 301                  * - When this is request is the last request for the video
 302                  *   buffer, as we want to start sending the next video buffer
 303                  *   ASAP in case it doesn't get started already in the next
 304                  *   iteration of this loop.
 305                  *
 306                  * - Four times over the length of the requests queue (as
 307                  *   indicated by video->uvc_num_requests), as a trade-off
 308                  *   between latency and interrupt load.
 309                  */
 310                 if (list_empty(&video->req_free) || ureq->last_buf ||
 311                         !(video->req_int_count %
 312                         min(DIV_ROUND_UP(video->uvc_num_requests, 4), UVCG_REQ_MAX_INT_COUNT))) {
 313                         video->req_int_count = 0;
 314                         req->no_interrupt = 0;
 315                 } else {
 316                         req->no_interrupt = 1;
 317                 }
 318                 video->req_int_count++;
 319                 return uvcg_video_ep_queue(video, req);
 320         }
 321         /*
 322          * If we're not queuing to the ep, for isoc we're queuing
 323          * to the req_ready list, otherwise req_free.
 324          */
 325         list = is_bulk ? &video->req_free : &video->req_ready;
 326         list_add_tail(&req->list, list);
 327         return 0;
 328 }
 329
 330 static void
 331 uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
 332 {
 333         struct uvc_request *ureq = req->context;
 334         struct uvc_video *video = ureq->video;
 335         struct uvc_video_queue *queue = &video->queue;
 336         struct uvc_buffer *last_buf;
 337         unsigned long flags;
 338
 339         spin_lock_irqsave(&video->req_lock, flags);
 340         atomic_dec(&video->queued);
 341         if (!video->is_enabled) {
 342                 /*
 343                  * When is_enabled is false, uvcg_video_disable() ensures
 344                  * that in-flight uvc_buffers are returned, so we can
 345                  * safely call free_request without worrying about
 346                  * last_buf.
 347                  */
 348                 uvc_video_free_request(ureq, ep);
 349                 spin_unlock_irqrestore(&video->req_lock, flags);
 350                 return;
 351         }
 352
 353         last_buf = ureq->last_buf;
 354         ureq->last_buf = NULL;
 355         spin_unlock_irqrestore(&video->req_lock, flags);
 356
 357         switch (req->status) {
 358         case 0:
 359                 break;
 360
 361         case -EXDEV:
 362                 uvcg_dbg(&video->uvc->func, "VS request missed xfer.\n");
 363                 if (req->length != 0)
 364                         queue->flags |= UVC_QUEUE_DROP_INCOMPLETE;
 365                 break;
 366
 367         case -ESHUTDOWN:        /* disconnect from host. */
 368                 uvcg_dbg(&video->uvc->func, "VS request cancelled.\n");
 369                 uvcg_queue_cancel(queue, 1);
 370                 break;
 371
 372         default:
 373                 uvcg_warn(&video->uvc->func,
 374                           "VS request completed with status %d.\n",
 375                           req->status);
 376                 uvcg_queue_cancel(queue, 0);
 377         }
 378
 379         if (last_buf) {
 380                 spin_lock_irqsave(&queue->irqlock, flags);
 381                 uvcg_complete_buffer(queue, last_buf);
 382                 spin_unlock_irqrestore(&queue->irqlock, flags);
 383         }
 384
 385         spin_lock_irqsave(&video->req_lock, flags);
 386         /*
 387          * Video stream might have been disabled while we were
 388          * processing the current usb_request. So make sure
 389          * we're still streaming before queueing the usb_request
 390          * back to req_free
 391          */
 392         if (!video->is_enabled) {
 393                 uvc_video_free_request(ureq, ep);
 394                 spin_unlock_irqrestore(&video->req_lock, flags);
 395                 uvcg_queue_cancel(queue, 0);
 396
 397                 return;
 398         }
 399
 400         list_add_tail(&req->list, &video->req_free);
 401         /*
 402          * Queue work to the wq as well since it is possible that a
 403          * buffer may not have been completely encoded with the set of
 404          * in-flight usb requests for whih the complete callbacks are
 405          * firing.
 406          * In that case, if we do not queue work to the worker thread,
 407          * the buffer will never be marked as complete - and therefore
 408          * not be returned to userpsace. As a result,
 409          * dequeue -> queue -> dequeue flow of uvc buffers will not
 410          * happen. Since there are is a new free request wake up the pump.
 411          */
 412         queue_work(video->async_wq, &video->pump);
 413
 414         trace_uvcg_video_complete(req, atomic_read(&video->queued));
 415
 416         spin_unlock_irqrestore(&video->req_lock, flags);
 417
 418         kthread_queue_work(video->kworker, &video->hw_submit);
 419 }
 420
 421 static void uvcg_video_hw_submit(struct kthread_work *work)
 422 {
 423         struct uvc_video *video = container_of(work, struct uvc_video, hw_submit);
 424         bool is_bulk = video->max_payload_size;
 425         unsigned long flags;
 426         struct usb_request *req;
 427         int ret = 0;
 428
 429         while (true) {
 430                 if (!video->ep->enabled)
 431                         return;
 432                 spin_lock_irqsave(&video->req_lock, flags);
 433                 /*
 434                  * Here we check whether any request is available in the ready
 435                  * list. If it is, queue it to the ep and add the current
 436                  * usb_request to the req_free list - for video_pump to fill in.
 437                  * Otherwise, just use the current usb_request to queue a 0
 438                  * length request to the ep. Since we always add to the req_free
 439                  * list if we dequeue from the ready list, there will never
 440                  * be a situation where the req_free list is completely out of
 441                  * requests and cannot recover.
 442                  */
 443                 if (!list_empty(&video->req_ready)) {
 444                         req = list_first_entry(&video->req_ready,
 445                                                struct usb_request, list);
 446                 } else {
 447                         if (list_empty(&video->req_free) ||
 448                             (atomic_read(&video->queued) > UVCG_REQ_MAX_ZERO_COUNT)) {
 449                                 spin_unlock_irqrestore(&video->req_lock, flags);
 450
 451                                 return;
 452                         }
 453                         req = list_first_entry(&video->req_free, struct usb_request,
 454                                                list);
 455                         req->length = 0;
 456                 }
 457                 list_del(&req->list);
 458
 459                 /*
 460                  * Queue to the endpoint. The actual queueing to ep will
 461                  * only happen on one thread - the async_wq for bulk endpoints
 462                  * and this thread for isoc endpoints.
 463                  */
 464                 ret = uvcg_video_usb_req_queue(video, req, !is_bulk);
 465                 if (ret < 0) {
 466                         /*
 467                          * Endpoint error, but the stream is still enabled.
 468                          * Put request back in req_free for it to be cleaned
 469                          * up later.
 470                          */
 471                         list_add_tail(&req->list, &video->req_free);
 472                         /*
 473                          * There is a new free request - wake up the pump.
 474                          */
 475                         queue_work(video->async_wq, &video->pump);
 476
 477                 }
 478
 479                 spin_unlock_irqrestore(&video->req_lock, flags);
 480         }
 481 }
 482
 483 static int
 484 uvc_video_free_requests(struct uvc_video *video)
 485 {
 486         struct uvc_request *ureq, *temp;
 487
 488         list_for_each_entry_safe(ureq, temp, &video->ureqs, list)
 489                 uvc_video_free_request(ureq, video->ep);
 490
 491         INIT_LIST_HEAD(&video->ureqs);
 492         INIT_LIST_HEAD(&video->req_free);
 493         INIT_LIST_HEAD(&video->req_ready);
 494         return 0;
 495 }
 496
 497 static void
 498 uvc_video_prep_requests(struct uvc_video *video)
 499 {
 500         struct uvc_device *uvc = container_of(video, struct uvc_device, video);
 501         struct usb_composite_dev *cdev = uvc->func.config->cdev;
 502         unsigned int interval_duration = video->ep->desc->bInterval * 1250;
 503         unsigned int max_req_size, req_size, header_size;
 504         unsigned int nreq;
 505
 506         max_req_size = video->ep->maxpacket
 507                  * max_t(unsigned int, video->ep->maxburst, 1)
 508                  * (video->ep->mult);
 509
 510         if (!usb_endpoint_xfer_isoc(video->ep->desc)) {
 511                 video->req_size = max_req_size;
 512                 video->reqs_per_frame = video->uvc_num_requests =
 513                         DIV_ROUND_UP(video->imagesize, max_req_size);
 514
 515                 return;
 516         }
 517
 518         if (cdev->gadget->speed < USB_SPEED_HIGH)
 519                 interval_duration = video->ep->desc->bInterval * 10000;
 520
 521         nreq = DIV_ROUND_UP(video->interval, interval_duration);
 522
 523         header_size = nreq * UVCG_REQUEST_HEADER_LEN;
 524
 525         req_size = DIV_ROUND_UP(video->imagesize + header_size, nreq);
 526
 527         if (req_size > max_req_size) {
 528                 /* The prepared interval length and expected buffer size
 529                  * is not possible to stream with the currently configured
 530                  * isoc bandwidth. Fallback to the maximum.
 531                  */
 532                 req_size = max_req_size;
 533         }
 534         video->req_size = req_size;
 535
 536         /* We need to compensate the amount of requests to be
 537          * allocated with the maximum amount of zero length requests.
 538          * Since it is possible that hw_submit will initially
 539          * enqueue some zero length requests and we then will not be
 540          * able to fully encode one frame.
 541          */
 542         video->uvc_num_requests = nreq + UVCG_REQ_MAX_ZERO_COUNT;
 543         video->reqs_per_frame = nreq;
 544 }
 545
 546 static int
 547 uvc_video_alloc_requests(struct uvc_video *video)
 548 {
 549         struct uvc_request *ureq;
 550         unsigned int i;
 551         int ret = -ENOMEM;
 552
 553         /*
 554          * calculate in uvc_video_prep_requests
 555          * - video->uvc_num_requests
 556          * - video->req_size
 557          */
 558         uvc_video_prep_requests(video);
 559
 560         for (i = 0; i < video->uvc_num_requests; i++) {
 561                 ureq = kzalloc(sizeof(struct uvc_request), GFP_KERNEL);
 562                 if (ureq == NULL)
 563                         goto error;
 564
 565                 INIT_LIST_HEAD(&ureq->list);
 566
 567                 list_add_tail(&ureq->list, &video->ureqs);
 568
 569                 ureq->req_buffer = kmalloc(video->req_size, GFP_KERNEL);
 570                 if (ureq->req_buffer == NULL)
 571                         goto error;
 572
 573                 ureq->req = usb_ep_alloc_request(video->ep, GFP_KERNEL);
 574                 if (ureq->req == NULL)
 575                         goto error;
 576
 577                 ureq->req->buf = ureq->req_buffer;
 578                 ureq->req->length = 0;
 579                 ureq->req->complete = uvc_video_complete;
 580                 ureq->req->context = ureq;
 581                 ureq->video = video;
 582                 ureq->last_buf = NULL;
 583
 584                 list_add_tail(&ureq->req->list, &video->req_free);
 585                 /* req_size/PAGE_SIZE + 1 for overruns and + 1 for header */
 586                 sg_alloc_table(&ureq->sgt,
 587                                DIV_ROUND_UP(video->req_size - UVCG_REQUEST_HEADER_LEN,
 588                                             PAGE_SIZE) + 2, GFP_KERNEL);
 589         }
 590
 591         return 0;
 592
 593 error:
 594         uvc_video_free_requests(video);
 595         return ret;
 596 }
 597
 598 /* --------------------------------------------------------------------------
 599  * Video streaming
 600  */
 601
 602 /*
 603  * uvcg_video_pump - Pump video data into the USB requests
 604  *
 605  * This function fills the available USB requests (listed in req_free) with
 606  * video data from the queued buffers.
 607  */
 608 static void uvcg_video_pump(struct work_struct *work)
 609 {
 610         struct uvc_video *video = container_of(work, struct uvc_video, pump);
 611         struct uvc_video_queue *queue = &video->queue;
 612         /* video->max_payload_size is only set when using bulk transfer */
 613         bool is_bulk = video->max_payload_size;
 614         struct usb_request *req = NULL;
 615         struct uvc_buffer *buf;
 616         unsigned long flags;
 617         int ret = 0;
 618
 619         while (true) {
 620                 if (!video->ep->enabled)
 621                         return;
 622
 623                 /*
 624                  * Check is_enabled and retrieve the first available USB
 625                  * request, protected by the request lock.
 626                  */
 627                 spin_lock_irqsave(&video->req_lock, flags);
 628                 if (!video->is_enabled || list_empty(&video->req_free)) {
 629                         spin_unlock_irqrestore(&video->req_lock, flags);
 630                         return;
 631                 }
 632                 req = list_first_entry(&video->req_free, struct usb_request,
 633                                         list);
 634                 list_del(&req->list);
 635                 spin_unlock_irqrestore(&video->req_lock, flags);
 636
 637                 /*
 638                  * Retrieve the first available video buffer and fill the
 639                  * request, protected by the video queue irqlock.
 640                  */
 641                 spin_lock_irqsave(&queue->irqlock, flags);
 642                 buf = uvcg_queue_head(queue);
 643                 if (!buf) {
 644                         /*
 645                          * Either the queue has been disconnected or no video buffer
 646                          * available for bulk transfer. Either way, stop processing
 647                          * further.
 648                          */
 649                         spin_unlock_irqrestore(&queue->irqlock, flags);
 650                         break;
 651                 }
 652
 653                 video->encode(req, video, buf);
 654
 655                 spin_unlock_irqrestore(&queue->irqlock, flags);
 656
 657                 spin_lock_irqsave(&video->req_lock, flags);
 658                 /* For bulk end points we queue from the worker thread
 659                  * since we would preferably not want to wait on requests
 660                  * to be ready, in the uvcg_video_complete() handler.
 661                  * For isoc endpoints we add the request to the ready list
 662                  * and only queue it to the endpoint from the complete handler.
 663                  */
 664                 ret = uvcg_video_usb_req_queue(video, req, is_bulk);
 665                 spin_unlock_irqrestore(&video->req_lock, flags);
 666
 667                 if (ret < 0) {
 668                         uvcg_queue_cancel(queue, 0);
 669                         break;
 670                 }
 671         }
 672         spin_lock_irqsave(&video->req_lock, flags);
 673         if (video->is_enabled)
 674                 list_add_tail(&req->list, &video->req_free);
 675         else
 676                 uvc_video_free_request(req->context, video->ep);
 677         spin_unlock_irqrestore(&video->req_lock, flags);
 678 }
 679
 680 /*
 681  * Disable the video stream
 682  */
 683 int
 684 uvcg_video_disable(struct uvc_video *video)
 685 {
 686         unsigned long flags;
 687         struct list_head inflight_bufs;
 688         struct usb_request *req, *temp;
 689         struct uvc_buffer *buf, *btemp;
 690         struct uvc_request *ureq, *utemp;
 691
 692         if (video->ep == NULL) {
 693                 uvcg_info(&video->uvc->func,
 694                           "Video disable failed, device is uninitialized.\n");
 695                 return -ENODEV;
 696         }
 697
 698         INIT_LIST_HEAD(&inflight_bufs);
 699         spin_lock_irqsave(&video->req_lock, flags);
 700         video->is_enabled = false;
 701
 702         /*
 703          * Remove any in-flight buffers from the uvc_requests
 704          * because we want to return them before cancelling the
 705          * queue. This ensures that we aren't stuck waiting for
 706          * all complete callbacks to come through before disabling
 707          * vb2 queue.
 708          */
 709         list_for_each_entry(ureq, &video->ureqs, list) {
 710                 if (ureq->last_buf) {
 711                         list_add_tail(&ureq->last_buf->queue, &inflight_bufs);
 712                         ureq->last_buf = NULL;
 713                 }
 714         }
 715         spin_unlock_irqrestore(&video->req_lock, flags);
 716
 717         cancel_work_sync(&video->pump);
 718         uvcg_queue_cancel(&video->queue, 0);
 719
 720         spin_lock_irqsave(&video->req_lock, flags);
 721         /*
 722          * Remove all uvc_requests from ureqs with list_del_init
 723          * This lets uvc_video_free_request correctly identify
 724          * if the uvc_request is attached to a list or not when freeing
 725          * memory.
 726          */
 727         list_for_each_entry_safe(ureq, utemp, &video->ureqs, list)
 728                 list_del_init(&ureq->list);
 729
 730         list_for_each_entry_safe(req, temp, &video->req_free, list) {
 731                 list_del(&req->list);
 732                 uvc_video_free_request(req->context, video->ep);
 733         }
 734
 735         list_for_each_entry_safe(req, temp, &video->req_ready, list) {
 736                 list_del(&req->list);
 737                 uvc_video_free_request(req->context, video->ep);
 738         }
 739
 740         INIT_LIST_HEAD(&video->ureqs);
 741         INIT_LIST_HEAD(&video->req_free);
 742         INIT_LIST_HEAD(&video->req_ready);
 743         spin_unlock_irqrestore(&video->req_lock, flags);
 744
 745         /*
 746          * Return all the video buffers before disabling the queue.
 747          */
 748         spin_lock_irqsave(&video->queue.irqlock, flags);
 749         list_for_each_entry_safe(buf, btemp, &inflight_bufs, queue) {
 750                 list_del(&buf->queue);
 751                 uvcg_complete_buffer(&video->queue, buf);
 752         }
 753         spin_unlock_irqrestore(&video->queue.irqlock, flags);
 754
 755         uvcg_queue_enable(&video->queue, 0);
 756         return 0;
 757 }
 758
 759 /*
 760  * Enable the video stream.
 761  */
 762 int uvcg_video_enable(struct uvc_video *video)
 763 {
 764         int ret;
 765
 766         if (video->ep == NULL) {
 767                 uvcg_info(&video->uvc->func,
 768                           "Video enable failed, device is uninitialized.\n");
 769                 return -ENODEV;
 770         }
 771
 772         /*
 773          * Safe to access request related fields without req_lock because
 774          * this is the only thread currently active, and no other
 775          * request handling thread will become active until this function
 776          * returns.
 777          */
 778         video->is_enabled = true;
 779
 780         if ((ret = uvcg_queue_enable(&video->queue, 1)) < 0)
 781                 return ret;
 782
 783         if ((ret = uvc_video_alloc_requests(video)) < 0)
 784                 return ret;
 785
 786         if (video->max_payload_size) {
 787                 video->encode = uvc_video_encode_bulk;
 788                 video->payload_size = 0;
 789         } else
 790                 video->encode = video->queue.use_sg ?
 791                         uvc_video_encode_isoc_sg : uvc_video_encode_isoc;
 792
 793         video->req_int_count = 0;
 794
 795         atomic_set(&video->queued, 0);
 796
 797         kthread_queue_work(video->kworker, &video->hw_submit);
 798         queue_work(video->async_wq, &video->pump);
 799
 800         return ret;
 801 }
 802
 803 /*
 804  * Initialize the UVC video stream.
 805  */
 806 int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc)
 807 {
 808         video->is_enabled = false;
 809         INIT_LIST_HEAD(&video->ureqs);
 810         INIT_LIST_HEAD(&video->req_free);
 811         INIT_LIST_HEAD(&video->req_ready);
 812         spin_lock_init(&video->req_lock);
 813         INIT_WORK(&video->pump, uvcg_video_pump);
 814
 815         /* Allocate a work queue for asynchronous video pump handler. */
 816         video->async_wq = alloc_workqueue("uvcgadget", WQ_UNBOUND | WQ_HIGHPRI, 0);
 817         if (!video->async_wq)
 818                 return -EINVAL;
 819
 820         /* Allocate a kthread for asynchronous hw submit handler. */
 821         video->kworker = kthread_create_worker(0, "UVCG");
 822         if (IS_ERR(video->kworker)) {
 823                 uvcg_err(&video->uvc->func, "failed to create UVCG kworker\n");
 824                 return PTR_ERR(video->kworker);
 825         }
 826
 827         kthread_init_work(&video->hw_submit, uvcg_video_hw_submit);
 828
 829         sched_set_fifo(video->kworker->task);
 830
 831         video->uvc = uvc;
 832         video->fcc = V4L2_PIX_FMT_YUYV;
 833         video->bpp = 16;
 834         video->width = 320;
 835         video->height = 240;
 836         video->imagesize = 320 * 240 * 2;
 837         video->interval = 666666;
 838
 839         /* Initialize the video buffers queue. */
 840         uvcg_queue_init(&video->queue, uvc->v4l2_dev.dev->parent,
 841                         V4L2_BUF_TYPE_VIDEO_OUTPUT, &video->mutex);
 842         return 0;
 843 }