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 27static int 28uvc_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 71static int 72uvc_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 89static void 90uvc_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 132static void 133uvc_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 199static void 200uvc_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 */ 237static void 238uvc_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 255static 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. */ 276static 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 */ 331static 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 369static void 370uvc_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 488static int 489uvc_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 503static int 504uvc_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 552error: 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 */ 567static 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 */ 642int 643uvcg_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 */ 722int 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 */ 763int 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} 789