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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> | |
22 | #include <asm/atomic.h> | |
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 | ||
92 | /* | |
93 | * Allocate the video buffers. | |
94 | * | |
2c2d264b LP |
95 | * Pages are reserved to make sure they will not be swapped, as they will be |
96 | * filled in the URB completion handler. | |
c0efd232 LP |
97 | * |
98 | * Buffers will be individually mapped, so they must all be page aligned. | |
99 | */ | |
100 | int uvc_alloc_buffers(struct uvc_video_queue *queue, unsigned int nbuffers, | |
101 | unsigned int buflength) | |
102 | { | |
103 | unsigned int bufsize = PAGE_ALIGN(buflength); | |
104 | unsigned int i; | |
105 | void *mem = NULL; | |
106 | int ret; | |
107 | ||
108 | if (nbuffers > UVC_MAX_VIDEO_BUFFERS) | |
109 | nbuffers = UVC_MAX_VIDEO_BUFFERS; | |
110 | ||
111 | mutex_lock(&queue->mutex); | |
112 | ||
113 | if ((ret = uvc_free_buffers(queue)) < 0) | |
114 | goto done; | |
115 | ||
116 | /* Bail out if no buffers should be allocated. */ | |
117 | if (nbuffers == 0) | |
118 | goto done; | |
119 | ||
120 | /* Decrement the number of buffers until allocation succeeds. */ | |
121 | for (; nbuffers > 0; --nbuffers) { | |
122 | mem = vmalloc_32(nbuffers * bufsize); | |
123 | if (mem != NULL) | |
124 | break; | |
125 | } | |
126 | ||
127 | if (mem == NULL) { | |
128 | ret = -ENOMEM; | |
129 | goto done; | |
130 | } | |
131 | ||
132 | for (i = 0; i < nbuffers; ++i) { | |
133 | memset(&queue->buffer[i], 0, sizeof queue->buffer[i]); | |
134 | queue->buffer[i].buf.index = i; | |
135 | queue->buffer[i].buf.m.offset = i * bufsize; | |
136 | queue->buffer[i].buf.length = buflength; | |
ff924203 | 137 | queue->buffer[i].buf.type = queue->type; |
c0efd232 LP |
138 | queue->buffer[i].buf.field = V4L2_FIELD_NONE; |
139 | queue->buffer[i].buf.memory = V4L2_MEMORY_MMAP; | |
140 | queue->buffer[i].buf.flags = 0; | |
141 | init_waitqueue_head(&queue->buffer[i].wait); | |
142 | } | |
143 | ||
144 | queue->mem = mem; | |
145 | queue->count = nbuffers; | |
146 | queue->buf_size = bufsize; | |
147 | ret = nbuffers; | |
148 | ||
149 | done: | |
150 | mutex_unlock(&queue->mutex); | |
151 | return ret; | |
152 | } | |
153 | ||
154 | /* | |
155 | * Free the video buffers. | |
156 | * | |
157 | * This function must be called with the queue lock held. | |
158 | */ | |
159 | int uvc_free_buffers(struct uvc_video_queue *queue) | |
160 | { | |
161 | unsigned int i; | |
162 | ||
163 | for (i = 0; i < queue->count; ++i) { | |
164 | if (queue->buffer[i].vma_use_count != 0) | |
165 | return -EBUSY; | |
166 | } | |
167 | ||
168 | if (queue->count) { | |
169 | vfree(queue->mem); | |
170 | queue->count = 0; | |
171 | } | |
172 | ||
173 | return 0; | |
174 | } | |
175 | ||
23ff6043 LP |
176 | /* |
177 | * Check if buffers have been allocated. | |
178 | */ | |
179 | int uvc_queue_allocated(struct uvc_video_queue *queue) | |
180 | { | |
181 | int allocated; | |
182 | ||
183 | mutex_lock(&queue->mutex); | |
184 | allocated = queue->count != 0; | |
185 | mutex_unlock(&queue->mutex); | |
186 | ||
187 | return allocated; | |
188 | } | |
189 | ||
c0efd232 LP |
190 | static void __uvc_query_buffer(struct uvc_buffer *buf, |
191 | struct v4l2_buffer *v4l2_buf) | |
192 | { | |
193 | memcpy(v4l2_buf, &buf->buf, sizeof *v4l2_buf); | |
194 | ||
195 | if (buf->vma_use_count) | |
196 | v4l2_buf->flags |= V4L2_BUF_FLAG_MAPPED; | |
197 | ||
198 | switch (buf->state) { | |
199 | case UVC_BUF_STATE_ERROR: | |
200 | case UVC_BUF_STATE_DONE: | |
201 | v4l2_buf->flags |= V4L2_BUF_FLAG_DONE; | |
202 | break; | |
203 | case UVC_BUF_STATE_QUEUED: | |
204 | case UVC_BUF_STATE_ACTIVE: | |
d7c0d439 | 205 | case UVC_BUF_STATE_READY: |
c0efd232 LP |
206 | v4l2_buf->flags |= V4L2_BUF_FLAG_QUEUED; |
207 | break; | |
208 | case UVC_BUF_STATE_IDLE: | |
209 | default: | |
210 | break; | |
211 | } | |
212 | } | |
213 | ||
214 | int uvc_query_buffer(struct uvc_video_queue *queue, | |
215 | struct v4l2_buffer *v4l2_buf) | |
216 | { | |
217 | int ret = 0; | |
218 | ||
219 | mutex_lock(&queue->mutex); | |
220 | if (v4l2_buf->index >= queue->count) { | |
221 | ret = -EINVAL; | |
222 | goto done; | |
223 | } | |
224 | ||
225 | __uvc_query_buffer(&queue->buffer[v4l2_buf->index], v4l2_buf); | |
226 | ||
227 | done: | |
2c2d264b LP |
228 | mutex_unlock(&queue->mutex); |
229 | return ret; | |
c0efd232 LP |
230 | } |
231 | ||
232 | /* | |
233 | * Queue a video buffer. Attempting to queue a buffer that has already been | |
234 | * queued will return -EINVAL. | |
235 | */ | |
236 | int uvc_queue_buffer(struct uvc_video_queue *queue, | |
237 | struct v4l2_buffer *v4l2_buf) | |
238 | { | |
239 | struct uvc_buffer *buf; | |
240 | unsigned long flags; | |
241 | int ret = 0; | |
242 | ||
243 | uvc_trace(UVC_TRACE_CAPTURE, "Queuing buffer %u.\n", v4l2_buf->index); | |
244 | ||
ff924203 | 245 | if (v4l2_buf->type != queue->type || |
c0efd232 LP |
246 | v4l2_buf->memory != V4L2_MEMORY_MMAP) { |
247 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) " | |
248 | "and/or memory (%u).\n", v4l2_buf->type, | |
249 | v4l2_buf->memory); | |
250 | return -EINVAL; | |
251 | } | |
252 | ||
253 | mutex_lock(&queue->mutex); | |
2c2d264b | 254 | if (v4l2_buf->index >= queue->count) { |
c0efd232 LP |
255 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Out of range index.\n"); |
256 | ret = -EINVAL; | |
257 | goto done; | |
258 | } | |
259 | ||
260 | buf = &queue->buffer[v4l2_buf->index]; | |
261 | if (buf->state != UVC_BUF_STATE_IDLE) { | |
262 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state " | |
263 | "(%u).\n", buf->state); | |
264 | ret = -EINVAL; | |
265 | goto done; | |
266 | } | |
267 | ||
ff924203 LP |
268 | if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_OUTPUT && |
269 | v4l2_buf->bytesused > buf->buf.length) { | |
270 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n"); | |
271 | ret = -EINVAL; | |
272 | goto done; | |
273 | } | |
274 | ||
c0efd232 LP |
275 | spin_lock_irqsave(&queue->irqlock, flags); |
276 | if (queue->flags & UVC_QUEUE_DISCONNECTED) { | |
277 | spin_unlock_irqrestore(&queue->irqlock, flags); | |
278 | ret = -ENODEV; | |
279 | goto done; | |
280 | } | |
281 | buf->state = UVC_BUF_STATE_QUEUED; | |
ff924203 LP |
282 | if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) |
283 | buf->buf.bytesused = 0; | |
284 | else | |
285 | buf->buf.bytesused = v4l2_buf->bytesused; | |
286 | ||
c0efd232 LP |
287 | list_add_tail(&buf->stream, &queue->mainqueue); |
288 | list_add_tail(&buf->queue, &queue->irqqueue); | |
289 | spin_unlock_irqrestore(&queue->irqlock, flags); | |
290 | ||
291 | done: | |
292 | mutex_unlock(&queue->mutex); | |
293 | return ret; | |
294 | } | |
295 | ||
296 | static int uvc_queue_waiton(struct uvc_buffer *buf, int nonblocking) | |
297 | { | |
298 | if (nonblocking) { | |
299 | return (buf->state != UVC_BUF_STATE_QUEUED && | |
d7c0d439 LP |
300 | buf->state != UVC_BUF_STATE_ACTIVE && |
301 | buf->state != UVC_BUF_STATE_READY) | |
c0efd232 LP |
302 | ? 0 : -EAGAIN; |
303 | } | |
304 | ||
305 | return wait_event_interruptible(buf->wait, | |
306 | buf->state != UVC_BUF_STATE_QUEUED && | |
d7c0d439 LP |
307 | buf->state != UVC_BUF_STATE_ACTIVE && |
308 | buf->state != UVC_BUF_STATE_READY); | |
c0efd232 LP |
309 | } |
310 | ||
311 | /* | |
312 | * Dequeue a video buffer. If nonblocking is false, block until a buffer is | |
313 | * available. | |
314 | */ | |
315 | int uvc_dequeue_buffer(struct uvc_video_queue *queue, | |
316 | struct v4l2_buffer *v4l2_buf, int nonblocking) | |
317 | { | |
318 | struct uvc_buffer *buf; | |
319 | int ret = 0; | |
320 | ||
ff924203 | 321 | if (v4l2_buf->type != queue->type || |
c0efd232 LP |
322 | v4l2_buf->memory != V4L2_MEMORY_MMAP) { |
323 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) " | |
324 | "and/or memory (%u).\n", v4l2_buf->type, | |
325 | v4l2_buf->memory); | |
326 | return -EINVAL; | |
327 | } | |
328 | ||
329 | mutex_lock(&queue->mutex); | |
330 | if (list_empty(&queue->mainqueue)) { | |
331 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Empty buffer queue.\n"); | |
332 | ret = -EINVAL; | |
333 | goto done; | |
334 | } | |
335 | ||
336 | buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream); | |
337 | if ((ret = uvc_queue_waiton(buf, nonblocking)) < 0) | |
338 | goto done; | |
339 | ||
340 | uvc_trace(UVC_TRACE_CAPTURE, "Dequeuing buffer %u (%u, %u bytes).\n", | |
341 | buf->buf.index, buf->state, buf->buf.bytesused); | |
342 | ||
343 | switch (buf->state) { | |
344 | case UVC_BUF_STATE_ERROR: | |
345 | uvc_trace(UVC_TRACE_CAPTURE, "[W] Corrupted data " | |
346 | "(transmission error).\n"); | |
347 | ret = -EIO; | |
348 | case UVC_BUF_STATE_DONE: | |
349 | buf->state = UVC_BUF_STATE_IDLE; | |
350 | break; | |
351 | ||
352 | case UVC_BUF_STATE_IDLE: | |
353 | case UVC_BUF_STATE_QUEUED: | |
354 | case UVC_BUF_STATE_ACTIVE: | |
d7c0d439 | 355 | case UVC_BUF_STATE_READY: |
c0efd232 LP |
356 | default: |
357 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state %u " | |
358 | "(driver bug?).\n", buf->state); | |
359 | ret = -EINVAL; | |
360 | goto done; | |
361 | } | |
362 | ||
363 | list_del(&buf->stream); | |
364 | __uvc_query_buffer(buf, v4l2_buf); | |
365 | ||
366 | done: | |
367 | mutex_unlock(&queue->mutex); | |
368 | return ret; | |
369 | } | |
370 | ||
371 | /* | |
372 | * Poll the video queue. | |
373 | * | |
374 | * This function implements video queue polling and is intended to be used by | |
375 | * the device poll handler. | |
376 | */ | |
377 | unsigned int uvc_queue_poll(struct uvc_video_queue *queue, struct file *file, | |
378 | poll_table *wait) | |
379 | { | |
380 | struct uvc_buffer *buf; | |
381 | unsigned int mask = 0; | |
382 | ||
383 | mutex_lock(&queue->mutex); | |
384 | if (list_empty(&queue->mainqueue)) { | |
385 | mask |= POLLERR; | |
386 | goto done; | |
387 | } | |
388 | buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream); | |
389 | ||
390 | poll_wait(file, &buf->wait, wait); | |
391 | if (buf->state == UVC_BUF_STATE_DONE || | |
ed3de601 LP |
392 | buf->state == UVC_BUF_STATE_ERROR) { |
393 | if (queue->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) | |
394 | mask |= POLLIN | POLLRDNORM; | |
395 | else | |
396 | mask |= POLLOUT | POLLWRNORM; | |
397 | } | |
c0efd232 LP |
398 | |
399 | done: | |
400 | mutex_unlock(&queue->mutex); | |
401 | return mask; | |
402 | } | |
403 | ||
404 | /* | |
405 | * Enable or disable the video buffers queue. | |
406 | * | |
407 | * The queue must be enabled before starting video acquisition and must be | |
408 | * disabled after stopping it. This ensures that the video buffers queue | |
409 | * state can be properly initialized before buffers are accessed from the | |
410 | * interrupt handler. | |
411 | * | |
650b95fe | 412 | * Enabling the video queue returns -EBUSY if the queue is already enabled. |
c0efd232 LP |
413 | * |
414 | * Disabling the video queue cancels the queue and removes all buffers from | |
415 | * the main queue. | |
416 | * | |
417 | * This function can't be called from interrupt context. Use | |
418 | * uvc_queue_cancel() instead. | |
419 | */ | |
420 | int uvc_queue_enable(struct uvc_video_queue *queue, int enable) | |
421 | { | |
422 | unsigned int i; | |
423 | int ret = 0; | |
424 | ||
425 | mutex_lock(&queue->mutex); | |
426 | if (enable) { | |
427 | if (uvc_queue_streaming(queue)) { | |
428 | ret = -EBUSY; | |
429 | goto done; | |
430 | } | |
c0efd232 | 431 | queue->flags |= UVC_QUEUE_STREAMING; |
ff924203 | 432 | queue->buf_used = 0; |
c0efd232 LP |
433 | } else { |
434 | uvc_queue_cancel(queue, 0); | |
435 | INIT_LIST_HEAD(&queue->mainqueue); | |
436 | ||
9bde9f26 LP |
437 | for (i = 0; i < queue->count; ++i) { |
438 | queue->buffer[i].error = 0; | |
c0efd232 | 439 | queue->buffer[i].state = UVC_BUF_STATE_IDLE; |
9bde9f26 | 440 | } |
c0efd232 LP |
441 | |
442 | queue->flags &= ~UVC_QUEUE_STREAMING; | |
443 | } | |
444 | ||
445 | done: | |
446 | mutex_unlock(&queue->mutex); | |
447 | return ret; | |
448 | } | |
449 | ||
450 | /* | |
451 | * Cancel the video buffers queue. | |
452 | * | |
453 | * Cancelling the queue marks all buffers on the irq queue as erroneous, | |
2c2d264b | 454 | * wakes them up and removes them from the queue. |
c0efd232 LP |
455 | * |
456 | * If the disconnect parameter is set, further calls to uvc_queue_buffer will | |
457 | * fail with -ENODEV. | |
458 | * | |
459 | * This function acquires the irq spinlock and can be called from interrupt | |
460 | * context. | |
461 | */ | |
462 | void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect) | |
463 | { | |
464 | struct uvc_buffer *buf; | |
465 | unsigned long flags; | |
466 | ||
467 | spin_lock_irqsave(&queue->irqlock, flags); | |
468 | while (!list_empty(&queue->irqqueue)) { | |
469 | buf = list_first_entry(&queue->irqqueue, struct uvc_buffer, | |
470 | queue); | |
471 | list_del(&buf->queue); | |
472 | buf->state = UVC_BUF_STATE_ERROR; | |
473 | wake_up(&buf->wait); | |
474 | } | |
475 | /* This must be protected by the irqlock spinlock to avoid race | |
476 | * conditions between uvc_queue_buffer and the disconnection event that | |
477 | * could result in an interruptible wait in uvc_dequeue_buffer. Do not | |
478 | * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED | |
479 | * state outside the queue code. | |
480 | */ | |
481 | if (disconnect) | |
482 | queue->flags |= UVC_QUEUE_DISCONNECTED; | |
483 | spin_unlock_irqrestore(&queue->irqlock, flags); | |
484 | } | |
485 | ||
486 | struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue, | |
487 | struct uvc_buffer *buf) | |
488 | { | |
489 | struct uvc_buffer *nextbuf; | |
490 | unsigned long flags; | |
491 | ||
9bde9f26 LP |
492 | if ((queue->flags & UVC_QUEUE_DROP_CORRUPTED) && buf->error) { |
493 | buf->error = 0; | |
c0efd232 LP |
494 | buf->state = UVC_BUF_STATE_QUEUED; |
495 | buf->buf.bytesused = 0; | |
496 | return buf; | |
497 | } | |
498 | ||
499 | spin_lock_irqsave(&queue->irqlock, flags); | |
500 | list_del(&buf->queue); | |
9bde9f26 | 501 | buf->error = 0; |
d7c0d439 | 502 | buf->state = UVC_BUF_STATE_DONE; |
c0efd232 LP |
503 | if (!list_empty(&queue->irqqueue)) |
504 | nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer, | |
505 | queue); | |
506 | else | |
507 | nextbuf = NULL; | |
508 | spin_unlock_irqrestore(&queue->irqlock, flags); | |
509 | ||
c0efd232 LP |
510 | wake_up(&buf->wait); |
511 | return nextbuf; | |
512 | } | |
f87086e3 | 513 |