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Commit | Line | Data |
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c0efd232 LP |
1 | /* |
2 | * uvc_queue.c -- USB Video Class driver - Buffers management | |
3 | * | |
11fc5baf LP |
4 | * Copyright (C) 2005-2010 |
5 | * Laurent Pinchart (laurent.pinchart@ideasonboard.com) | |
c0efd232 LP |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | */ | |
13 | ||
14 | #include <linux/kernel.h> | |
27ac792c | 15 | #include <linux/mm.h> |
c0efd232 LP |
16 | #include <linux/list.h> |
17 | #include <linux/module.h> | |
18 | #include <linux/usb.h> | |
19 | #include <linux/videodev2.h> | |
20 | #include <linux/vmalloc.h> | |
21 | #include <linux/wait.h> | |
60063497 | 22 | #include <linux/atomic.h> |
c0efd232 LP |
23 | |
24 | #include "uvcvideo.h" | |
25 | ||
26 | /* ------------------------------------------------------------------------ | |
27 | * Video buffers queue management. | |
28 | * | |
29 | * Video queues is initialized by uvc_queue_init(). The function performs | |
30 | * basic initialization of the uvc_video_queue struct and never fails. | |
31 | * | |
32 | * Video buffer allocation and freeing are performed by uvc_alloc_buffers and | |
33 | * uvc_free_buffers respectively. The former acquires the video queue lock, | |
34 | * while the later must be called with the lock held (so that allocation can | |
35 | * free previously allocated buffers). Trying to free buffers that are mapped | |
36 | * to user space will return -EBUSY. | |
37 | * | |
38 | * Video buffers are managed using two queues. However, unlike most USB video | |
2c2d264b LP |
39 | * drivers that use an in queue and an out queue, we use a main queue to hold |
40 | * all queued buffers (both 'empty' and 'done' buffers), and an irq queue to | |
41 | * hold empty buffers. This design (copied from video-buf) minimizes locking | |
42 | * in interrupt, as only one queue is shared between interrupt and user | |
43 | * contexts. | |
c0efd232 LP |
44 | * |
45 | * Use cases | |
46 | * --------- | |
47 | * | |
2c2d264b | 48 | * Unless stated otherwise, all operations that modify the irq buffers queue |
c0efd232 LP |
49 | * are protected by the irq spinlock. |
50 | * | |
51 | * 1. The user queues the buffers, starts streaming and dequeues a buffer. | |
52 | * | |
53 | * The buffers are added to the main and irq queues. Both operations are | |
2c2d264b | 54 | * protected by the queue lock, and the later is protected by the irq |
c0efd232 LP |
55 | * spinlock as well. |
56 | * | |
57 | * The completion handler fetches a buffer from the irq queue and fills it | |
58 | * with video data. If no buffer is available (irq queue empty), the handler | |
59 | * returns immediately. | |
60 | * | |
61 | * When the buffer is full, the completion handler removes it from the irq | |
d7c0d439 | 62 | * queue, marks it as done (UVC_BUF_STATE_DONE) and wakes its wait queue. |
c0efd232 | 63 | * At that point, any process waiting on the buffer will be woken up. If a |
d7c0d439 | 64 | * process tries to dequeue a buffer after it has been marked done, the |
c0efd232 LP |
65 | * dequeing will succeed immediately. |
66 | * | |
67 | * 2. Buffers are queued, user is waiting on a buffer and the device gets | |
68 | * disconnected. | |
69 | * | |
70 | * When the device is disconnected, the kernel calls the completion handler | |
71 | * with an appropriate status code. The handler marks all buffers in the | |
72 | * irq queue as being erroneous (UVC_BUF_STATE_ERROR) and wakes them up so | |
73 | * that any process waiting on a buffer gets woken up. | |
74 | * | |
75 | * Waking up up the first buffer on the irq list is not enough, as the | |
76 | * process waiting on the buffer might restart the dequeue operation | |
77 | * immediately. | |
78 | * | |
79 | */ | |
80 | ||
9bde9f26 LP |
81 | void uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type, |
82 | int drop_corrupted) | |
c0efd232 LP |
83 | { |
84 | mutex_init(&queue->mutex); | |
85 | spin_lock_init(&queue->irqlock); | |
86 | INIT_LIST_HEAD(&queue->mainqueue); | |
87 | INIT_LIST_HEAD(&queue->irqqueue); | |
9bde9f26 | 88 | queue->flags = drop_corrupted ? UVC_QUEUE_DROP_CORRUPTED : 0; |
ff924203 | 89 | queue->type = type; |
c0efd232 LP |
90 | } |
91 | ||
8e815e17 LP |
92 | /* |
93 | * Free the video buffers. | |
94 | * | |
95 | * This function must be called with the queue lock held. | |
96 | */ | |
97 | static int __uvc_free_buffers(struct uvc_video_queue *queue) | |
98 | { | |
99 | unsigned int i; | |
100 | ||
101 | for (i = 0; i < queue->count; ++i) { | |
102 | if (queue->buffer[i].vma_use_count != 0) | |
103 | return -EBUSY; | |
104 | } | |
105 | ||
106 | if (queue->count) { | |
8ca2c80b SS |
107 | uvc_queue_cancel(queue, 0); |
108 | INIT_LIST_HEAD(&queue->mainqueue); | |
8e815e17 LP |
109 | vfree(queue->mem); |
110 | queue->count = 0; | |
111 | } | |
112 | ||
113 | return 0; | |
114 | } | |
115 | ||
116 | int uvc_free_buffers(struct uvc_video_queue *queue) | |
117 | { | |
118 | int ret; | |
119 | ||
120 | mutex_lock(&queue->mutex); | |
121 | ret = __uvc_free_buffers(queue); | |
122 | mutex_unlock(&queue->mutex); | |
123 | ||
124 | return ret; | |
125 | } | |
126 | ||
c0efd232 LP |
127 | /* |
128 | * Allocate the video buffers. | |
129 | * | |
2c2d264b LP |
130 | * Pages are reserved to make sure they will not be swapped, as they will be |
131 | * filled in the URB completion handler. | |
c0efd232 LP |
132 | * |
133 | * Buffers will be individually mapped, so they must all be page aligned. | |
134 | */ | |
135 | int uvc_alloc_buffers(struct uvc_video_queue *queue, unsigned int nbuffers, | |
136 | unsigned int buflength) | |
137 | { | |
138 | unsigned int bufsize = PAGE_ALIGN(buflength); | |
139 | unsigned int i; | |
140 | void *mem = NULL; | |
141 | int ret; | |
142 | ||
143 | if (nbuffers > UVC_MAX_VIDEO_BUFFERS) | |
144 | nbuffers = UVC_MAX_VIDEO_BUFFERS; | |
145 | ||
146 | mutex_lock(&queue->mutex); | |
147 | ||
8e815e17 | 148 | if ((ret = __uvc_free_buffers(queue)) < 0) |
c0efd232 LP |
149 | goto done; |
150 | ||
151 | /* Bail out if no buffers should be allocated. */ | |
152 | if (nbuffers == 0) | |
153 | goto done; | |
154 | ||
155 | /* Decrement the number of buffers until allocation succeeds. */ | |
156 | for (; nbuffers > 0; --nbuffers) { | |
157 | mem = vmalloc_32(nbuffers * bufsize); | |
158 | if (mem != NULL) | |
159 | break; | |
160 | } | |
161 | ||
162 | if (mem == NULL) { | |
163 | ret = -ENOMEM; | |
164 | goto done; | |
165 | } | |
166 | ||
167 | for (i = 0; i < nbuffers; ++i) { | |
168 | memset(&queue->buffer[i], 0, sizeof queue->buffer[i]); | |
169 | queue->buffer[i].buf.index = i; | |
170 | queue->buffer[i].buf.m.offset = i * bufsize; | |
171 | queue->buffer[i].buf.length = buflength; | |
ff924203 | 172 | queue->buffer[i].buf.type = queue->type; |
c0efd232 LP |
173 | queue->buffer[i].buf.field = V4L2_FIELD_NONE; |
174 | queue->buffer[i].buf.memory = V4L2_MEMORY_MMAP; | |
175 | queue->buffer[i].buf.flags = 0; | |
3d95e932 LP |
176 | |
177 | queue->buffer[i].mem = queue->mem + i * bufsize; | |
178 | queue->buffer[i].length = buflength; | |
c0efd232 LP |
179 | init_waitqueue_head(&queue->buffer[i].wait); |
180 | } | |
181 | ||
182 | queue->mem = mem; | |
183 | queue->count = nbuffers; | |
184 | queue->buf_size = bufsize; | |
185 | ret = nbuffers; | |
186 | ||
187 | done: | |
188 | mutex_unlock(&queue->mutex); | |
189 | return ret; | |
190 | } | |
191 | ||
23ff6043 LP |
192 | /* |
193 | * Check if buffers have been allocated. | |
194 | */ | |
195 | int uvc_queue_allocated(struct uvc_video_queue *queue) | |
196 | { | |
197 | int allocated; | |
198 | ||
199 | mutex_lock(&queue->mutex); | |
200 | allocated = queue->count != 0; | |
201 | mutex_unlock(&queue->mutex); | |
202 | ||
203 | return allocated; | |
204 | } | |
205 | ||
c0efd232 LP |
206 | static void __uvc_query_buffer(struct uvc_buffer *buf, |
207 | struct v4l2_buffer *v4l2_buf) | |
208 | { | |
209 | memcpy(v4l2_buf, &buf->buf, sizeof *v4l2_buf); | |
210 | ||
211 | if (buf->vma_use_count) | |
212 | v4l2_buf->flags |= V4L2_BUF_FLAG_MAPPED; | |
213 | ||
214 | switch (buf->state) { | |
215 | case UVC_BUF_STATE_ERROR: | |
216 | case UVC_BUF_STATE_DONE: | |
217 | v4l2_buf->flags |= V4L2_BUF_FLAG_DONE; | |
218 | break; | |
219 | case UVC_BUF_STATE_QUEUED: | |
220 | case UVC_BUF_STATE_ACTIVE: | |
d7c0d439 | 221 | case UVC_BUF_STATE_READY: |
c0efd232 LP |
222 | v4l2_buf->flags |= V4L2_BUF_FLAG_QUEUED; |
223 | break; | |
224 | case UVC_BUF_STATE_IDLE: | |
225 | default: | |
226 | break; | |
227 | } | |
228 | } | |
229 | ||
230 | int uvc_query_buffer(struct uvc_video_queue *queue, | |
231 | struct v4l2_buffer *v4l2_buf) | |
232 | { | |
233 | int ret = 0; | |
234 | ||
235 | mutex_lock(&queue->mutex); | |
236 | if (v4l2_buf->index >= queue->count) { | |
237 | ret = -EINVAL; | |
238 | goto done; | |
239 | } | |
240 | ||
241 | __uvc_query_buffer(&queue->buffer[v4l2_buf->index], v4l2_buf); | |
242 | ||
243 | done: | |
2c2d264b LP |
244 | mutex_unlock(&queue->mutex); |
245 | return ret; | |
c0efd232 LP |
246 | } |
247 | ||
248 | /* | |
249 | * Queue a video buffer. Attempting to queue a buffer that has already been | |
250 | * queued will return -EINVAL. | |
251 | */ | |
252 | int uvc_queue_buffer(struct uvc_video_queue *queue, | |
253 | struct v4l2_buffer *v4l2_buf) | |
254 | { | |
255 | struct uvc_buffer *buf; | |
256 | unsigned long flags; | |
257 | int ret = 0; | |
258 | ||
259 | uvc_trace(UVC_TRACE_CAPTURE, "Queuing buffer %u.\n", v4l2_buf->index); | |
260 | ||
ff924203 | 261 | if (v4l2_buf->type != queue->type || |
c0efd232 LP |
262 | v4l2_buf->memory != V4L2_MEMORY_MMAP) { |
263 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) " | |
264 | "and/or memory (%u).\n", v4l2_buf->type, | |
265 | v4l2_buf->memory); | |
266 | return -EINVAL; | |
267 | } | |
268 | ||
269 | mutex_lock(&queue->mutex); | |
2c2d264b | 270 | if (v4l2_buf->index >= queue->count) { |
c0efd232 LP |
271 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Out of range index.\n"); |
272 | ret = -EINVAL; | |
273 | goto done; | |
274 | } | |
275 | ||
276 | buf = &queue->buffer[v4l2_buf->index]; | |
277 | if (buf->state != UVC_BUF_STATE_IDLE) { | |
278 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state " | |
279 | "(%u).\n", buf->state); | |
280 | ret = -EINVAL; | |
281 | goto done; | |
282 | } | |
283 | ||
ff924203 LP |
284 | if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_OUTPUT && |
285 | v4l2_buf->bytesused > buf->buf.length) { | |
286 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n"); | |
287 | ret = -EINVAL; | |
288 | goto done; | |
289 | } | |
290 | ||
c0efd232 LP |
291 | spin_lock_irqsave(&queue->irqlock, flags); |
292 | if (queue->flags & UVC_QUEUE_DISCONNECTED) { | |
293 | spin_unlock_irqrestore(&queue->irqlock, flags); | |
294 | ret = -ENODEV; | |
295 | goto done; | |
296 | } | |
297 | buf->state = UVC_BUF_STATE_QUEUED; | |
ff924203 | 298 | if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) |
3d95e932 | 299 | buf->bytesused = 0; |
ff924203 | 300 | else |
3d95e932 | 301 | buf->bytesused = v4l2_buf->bytesused; |
ff924203 | 302 | |
c0efd232 LP |
303 | list_add_tail(&buf->stream, &queue->mainqueue); |
304 | list_add_tail(&buf->queue, &queue->irqqueue); | |
305 | spin_unlock_irqrestore(&queue->irqlock, flags); | |
306 | ||
307 | done: | |
308 | mutex_unlock(&queue->mutex); | |
309 | return ret; | |
310 | } | |
311 | ||
312 | static int uvc_queue_waiton(struct uvc_buffer *buf, int nonblocking) | |
313 | { | |
314 | if (nonblocking) { | |
315 | return (buf->state != UVC_BUF_STATE_QUEUED && | |
d7c0d439 LP |
316 | buf->state != UVC_BUF_STATE_ACTIVE && |
317 | buf->state != UVC_BUF_STATE_READY) | |
c0efd232 LP |
318 | ? 0 : -EAGAIN; |
319 | } | |
320 | ||
321 | return wait_event_interruptible(buf->wait, | |
322 | buf->state != UVC_BUF_STATE_QUEUED && | |
d7c0d439 LP |
323 | buf->state != UVC_BUF_STATE_ACTIVE && |
324 | buf->state != UVC_BUF_STATE_READY); | |
c0efd232 LP |
325 | } |
326 | ||
327 | /* | |
328 | * Dequeue a video buffer. If nonblocking is false, block until a buffer is | |
329 | * available. | |
330 | */ | |
331 | int uvc_dequeue_buffer(struct uvc_video_queue *queue, | |
332 | struct v4l2_buffer *v4l2_buf, int nonblocking) | |
333 | { | |
334 | struct uvc_buffer *buf; | |
335 | int ret = 0; | |
336 | ||
ff924203 | 337 | if (v4l2_buf->type != queue->type || |
c0efd232 LP |
338 | v4l2_buf->memory != V4L2_MEMORY_MMAP) { |
339 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) " | |
340 | "and/or memory (%u).\n", v4l2_buf->type, | |
341 | v4l2_buf->memory); | |
342 | return -EINVAL; | |
343 | } | |
344 | ||
345 | mutex_lock(&queue->mutex); | |
346 | if (list_empty(&queue->mainqueue)) { | |
347 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Empty buffer queue.\n"); | |
348 | ret = -EINVAL; | |
349 | goto done; | |
350 | } | |
351 | ||
352 | buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream); | |
353 | if ((ret = uvc_queue_waiton(buf, nonblocking)) < 0) | |
354 | goto done; | |
355 | ||
356 | uvc_trace(UVC_TRACE_CAPTURE, "Dequeuing buffer %u (%u, %u bytes).\n", | |
357 | buf->buf.index, buf->state, buf->buf.bytesused); | |
358 | ||
359 | switch (buf->state) { | |
360 | case UVC_BUF_STATE_ERROR: | |
361 | uvc_trace(UVC_TRACE_CAPTURE, "[W] Corrupted data " | |
362 | "(transmission error).\n"); | |
363 | ret = -EIO; | |
364 | case UVC_BUF_STATE_DONE: | |
365 | buf->state = UVC_BUF_STATE_IDLE; | |
366 | break; | |
367 | ||
368 | case UVC_BUF_STATE_IDLE: | |
369 | case UVC_BUF_STATE_QUEUED: | |
370 | case UVC_BUF_STATE_ACTIVE: | |
d7c0d439 | 371 | case UVC_BUF_STATE_READY: |
c0efd232 LP |
372 | default: |
373 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state %u " | |
374 | "(driver bug?).\n", buf->state); | |
375 | ret = -EINVAL; | |
376 | goto done; | |
377 | } | |
378 | ||
379 | list_del(&buf->stream); | |
380 | __uvc_query_buffer(buf, v4l2_buf); | |
381 | ||
382 | done: | |
383 | mutex_unlock(&queue->mutex); | |
384 | return ret; | |
385 | } | |
386 | ||
4aa27597 LP |
387 | /* |
388 | * VMA operations. | |
389 | */ | |
390 | static void uvc_vm_open(struct vm_area_struct *vma) | |
391 | { | |
392 | struct uvc_buffer *buffer = vma->vm_private_data; | |
393 | buffer->vma_use_count++; | |
394 | } | |
395 | ||
396 | static void uvc_vm_close(struct vm_area_struct *vma) | |
397 | { | |
398 | struct uvc_buffer *buffer = vma->vm_private_data; | |
399 | buffer->vma_use_count--; | |
400 | } | |
401 | ||
402 | static const struct vm_operations_struct uvc_vm_ops = { | |
403 | .open = uvc_vm_open, | |
404 | .close = uvc_vm_close, | |
405 | }; | |
406 | ||
407 | /* | |
408 | * Memory-map a video buffer. | |
409 | * | |
410 | * This function implements video buffers memory mapping and is intended to be | |
411 | * used by the device mmap handler. | |
412 | */ | |
413 | int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma) | |
414 | { | |
415 | struct uvc_buffer *uninitialized_var(buffer); | |
416 | struct page *page; | |
417 | unsigned long addr, start, size; | |
418 | unsigned int i; | |
419 | int ret = 0; | |
420 | ||
421 | start = vma->vm_start; | |
422 | size = vma->vm_end - vma->vm_start; | |
423 | ||
424 | mutex_lock(&queue->mutex); | |
425 | ||
426 | for (i = 0; i < queue->count; ++i) { | |
427 | buffer = &queue->buffer[i]; | |
428 | if ((buffer->buf.m.offset >> PAGE_SHIFT) == vma->vm_pgoff) | |
429 | break; | |
430 | } | |
431 | ||
72969447 | 432 | if (i == queue->count || PAGE_ALIGN(size) != queue->buf_size) { |
4aa27597 LP |
433 | ret = -EINVAL; |
434 | goto done; | |
435 | } | |
436 | ||
437 | /* | |
438 | * VM_IO marks the area as being an mmaped region for I/O to a | |
439 | * device. It also prevents the region from being core dumped. | |
440 | */ | |
441 | vma->vm_flags |= VM_IO; | |
442 | ||
3d95e932 | 443 | addr = (unsigned long)buffer->mem; |
72969447 | 444 | #ifdef CONFIG_MMU |
4aa27597 LP |
445 | while (size > 0) { |
446 | page = vmalloc_to_page((void *)addr); | |
447 | if ((ret = vm_insert_page(vma, start, page)) < 0) | |
448 | goto done; | |
449 | ||
450 | start += PAGE_SIZE; | |
451 | addr += PAGE_SIZE; | |
452 | size -= PAGE_SIZE; | |
453 | } | |
72969447 | 454 | #endif |
4aa27597 LP |
455 | |
456 | vma->vm_ops = &uvc_vm_ops; | |
457 | vma->vm_private_data = buffer; | |
458 | uvc_vm_open(vma); | |
459 | ||
460 | done: | |
461 | mutex_unlock(&queue->mutex); | |
462 | return ret; | |
463 | } | |
464 | ||
c0efd232 LP |
465 | /* |
466 | * Poll the video queue. | |
467 | * | |
468 | * This function implements video queue polling and is intended to be used by | |
469 | * the device poll handler. | |
470 | */ | |
471 | unsigned int uvc_queue_poll(struct uvc_video_queue *queue, struct file *file, | |
472 | poll_table *wait) | |
473 | { | |
474 | struct uvc_buffer *buf; | |
475 | unsigned int mask = 0; | |
476 | ||
477 | mutex_lock(&queue->mutex); | |
478 | if (list_empty(&queue->mainqueue)) { | |
479 | mask |= POLLERR; | |
480 | goto done; | |
481 | } | |
482 | buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream); | |
483 | ||
484 | poll_wait(file, &buf->wait, wait); | |
485 | if (buf->state == UVC_BUF_STATE_DONE || | |
ed3de601 LP |
486 | buf->state == UVC_BUF_STATE_ERROR) { |
487 | if (queue->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) | |
488 | mask |= POLLIN | POLLRDNORM; | |
489 | else | |
490 | mask |= POLLOUT | POLLWRNORM; | |
491 | } | |
c0efd232 LP |
492 | |
493 | done: | |
494 | mutex_unlock(&queue->mutex); | |
495 | return mask; | |
496 | } | |
497 | ||
72969447 BL |
498 | #ifndef CONFIG_MMU |
499 | /* | |
500 | * Get unmapped area. | |
501 | * | |
502 | * NO-MMU arch need this function to make mmap() work correctly. | |
503 | */ | |
504 | unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue, | |
505 | unsigned long pgoff) | |
506 | { | |
507 | struct uvc_buffer *buffer; | |
508 | unsigned int i; | |
509 | unsigned long ret; | |
510 | ||
511 | mutex_lock(&queue->mutex); | |
512 | for (i = 0; i < queue->count; ++i) { | |
513 | buffer = &queue->buffer[i]; | |
514 | if ((buffer->buf.m.offset >> PAGE_SHIFT) == pgoff) | |
515 | break; | |
516 | } | |
517 | if (i == queue->count) { | |
518 | ret = -EINVAL; | |
519 | goto done; | |
520 | } | |
3d95e932 | 521 | ret = (unsigned long)buf->mem; |
72969447 BL |
522 | done: |
523 | mutex_unlock(&queue->mutex); | |
524 | return ret; | |
525 | } | |
526 | #endif | |
527 | ||
c0efd232 LP |
528 | /* |
529 | * Enable or disable the video buffers queue. | |
530 | * | |
531 | * The queue must be enabled before starting video acquisition and must be | |
532 | * disabled after stopping it. This ensures that the video buffers queue | |
533 | * state can be properly initialized before buffers are accessed from the | |
534 | * interrupt handler. | |
535 | * | |
650b95fe | 536 | * Enabling the video queue returns -EBUSY if the queue is already enabled. |
c0efd232 LP |
537 | * |
538 | * Disabling the video queue cancels the queue and removes all buffers from | |
539 | * the main queue. | |
540 | * | |
541 | * This function can't be called from interrupt context. Use | |
542 | * uvc_queue_cancel() instead. | |
543 | */ | |
544 | int uvc_queue_enable(struct uvc_video_queue *queue, int enable) | |
545 | { | |
546 | unsigned int i; | |
547 | int ret = 0; | |
548 | ||
549 | mutex_lock(&queue->mutex); | |
550 | if (enable) { | |
551 | if (uvc_queue_streaming(queue)) { | |
552 | ret = -EBUSY; | |
553 | goto done; | |
554 | } | |
c0efd232 | 555 | queue->flags |= UVC_QUEUE_STREAMING; |
ff924203 | 556 | queue->buf_used = 0; |
c0efd232 LP |
557 | } else { |
558 | uvc_queue_cancel(queue, 0); | |
559 | INIT_LIST_HEAD(&queue->mainqueue); | |
560 | ||
9bde9f26 LP |
561 | for (i = 0; i < queue->count; ++i) { |
562 | queue->buffer[i].error = 0; | |
c0efd232 | 563 | queue->buffer[i].state = UVC_BUF_STATE_IDLE; |
9bde9f26 | 564 | } |
c0efd232 LP |
565 | |
566 | queue->flags &= ~UVC_QUEUE_STREAMING; | |
567 | } | |
568 | ||
569 | done: | |
570 | mutex_unlock(&queue->mutex); | |
571 | return ret; | |
572 | } | |
573 | ||
574 | /* | |
575 | * Cancel the video buffers queue. | |
576 | * | |
577 | * Cancelling the queue marks all buffers on the irq queue as erroneous, | |
2c2d264b | 578 | * wakes them up and removes them from the queue. |
c0efd232 LP |
579 | * |
580 | * If the disconnect parameter is set, further calls to uvc_queue_buffer will | |
581 | * fail with -ENODEV. | |
582 | * | |
583 | * This function acquires the irq spinlock and can be called from interrupt | |
584 | * context. | |
585 | */ | |
586 | void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect) | |
587 | { | |
588 | struct uvc_buffer *buf; | |
589 | unsigned long flags; | |
590 | ||
591 | spin_lock_irqsave(&queue->irqlock, flags); | |
592 | while (!list_empty(&queue->irqqueue)) { | |
593 | buf = list_first_entry(&queue->irqqueue, struct uvc_buffer, | |
594 | queue); | |
595 | list_del(&buf->queue); | |
596 | buf->state = UVC_BUF_STATE_ERROR; | |
597 | wake_up(&buf->wait); | |
598 | } | |
599 | /* This must be protected by the irqlock spinlock to avoid race | |
600 | * conditions between uvc_queue_buffer and the disconnection event that | |
601 | * could result in an interruptible wait in uvc_dequeue_buffer. Do not | |
602 | * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED | |
603 | * state outside the queue code. | |
604 | */ | |
605 | if (disconnect) | |
606 | queue->flags |= UVC_QUEUE_DISCONNECTED; | |
607 | spin_unlock_irqrestore(&queue->irqlock, flags); | |
608 | } | |
609 | ||
610 | struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue, | |
611 | struct uvc_buffer *buf) | |
612 | { | |
613 | struct uvc_buffer *nextbuf; | |
614 | unsigned long flags; | |
615 | ||
9bde9f26 LP |
616 | if ((queue->flags & UVC_QUEUE_DROP_CORRUPTED) && buf->error) { |
617 | buf->error = 0; | |
c0efd232 LP |
618 | buf->state = UVC_BUF_STATE_QUEUED; |
619 | buf->buf.bytesused = 0; | |
620 | return buf; | |
621 | } | |
622 | ||
623 | spin_lock_irqsave(&queue->irqlock, flags); | |
624 | list_del(&buf->queue); | |
9bde9f26 | 625 | buf->error = 0; |
d7c0d439 | 626 | buf->state = UVC_BUF_STATE_DONE; |
3d95e932 | 627 | buf->buf.bytesused = buf->bytesused; |
c0efd232 LP |
628 | if (!list_empty(&queue->irqqueue)) |
629 | nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer, | |
630 | queue); | |
631 | else | |
632 | nextbuf = NULL; | |
633 | spin_unlock_irqrestore(&queue->irqlock, flags); | |
634 | ||
c0efd232 LP |
635 | wake_up(&buf->wait); |
636 | return nextbuf; | |
637 | } | |
f87086e3 | 638 |