Commit | Line | Data |
---|---|---|
c0efd232 LP |
1 | /* |
2 | * uvc_queue.c -- USB Video Class driver - Buffers management | |
3 | * | |
2c2d264b | 4 | * Copyright (C) 2005-2009 |
c0efd232 LP |
5 | * Laurent Pinchart (laurent.pinchart@skynet.be) |
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 | |
2c2d264b | 62 | * queue, marks it as ready (UVC_BUF_STATE_DONE) and wakes its wait queue. |
c0efd232 LP |
63 | * At that point, any process waiting on the buffer will be woken up. If a |
64 | * process tries to dequeue a buffer after it has been marked ready, the | |
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 | ||
ff924203 | 81 | void uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type) |
c0efd232 LP |
82 | { |
83 | mutex_init(&queue->mutex); | |
84 | spin_lock_init(&queue->irqlock); | |
85 | INIT_LIST_HEAD(&queue->mainqueue); | |
86 | INIT_LIST_HEAD(&queue->irqqueue); | |
ff924203 | 87 | queue->type = type; |
c0efd232 LP |
88 | } |
89 | ||
90 | /* | |
91 | * Allocate the video buffers. | |
92 | * | |
2c2d264b LP |
93 | * Pages are reserved to make sure they will not be swapped, as they will be |
94 | * filled in the URB completion handler. | |
c0efd232 LP |
95 | * |
96 | * Buffers will be individually mapped, so they must all be page aligned. | |
97 | */ | |
98 | int uvc_alloc_buffers(struct uvc_video_queue *queue, unsigned int nbuffers, | |
99 | unsigned int buflength) | |
100 | { | |
101 | unsigned int bufsize = PAGE_ALIGN(buflength); | |
102 | unsigned int i; | |
103 | void *mem = NULL; | |
104 | int ret; | |
105 | ||
106 | if (nbuffers > UVC_MAX_VIDEO_BUFFERS) | |
107 | nbuffers = UVC_MAX_VIDEO_BUFFERS; | |
108 | ||
109 | mutex_lock(&queue->mutex); | |
110 | ||
111 | if ((ret = uvc_free_buffers(queue)) < 0) | |
112 | goto done; | |
113 | ||
114 | /* Bail out if no buffers should be allocated. */ | |
115 | if (nbuffers == 0) | |
116 | goto done; | |
117 | ||
118 | /* Decrement the number of buffers until allocation succeeds. */ | |
119 | for (; nbuffers > 0; --nbuffers) { | |
120 | mem = vmalloc_32(nbuffers * bufsize); | |
121 | if (mem != NULL) | |
122 | break; | |
123 | } | |
124 | ||
125 | if (mem == NULL) { | |
126 | ret = -ENOMEM; | |
127 | goto done; | |
128 | } | |
129 | ||
130 | for (i = 0; i < nbuffers; ++i) { | |
131 | memset(&queue->buffer[i], 0, sizeof queue->buffer[i]); | |
132 | queue->buffer[i].buf.index = i; | |
133 | queue->buffer[i].buf.m.offset = i * bufsize; | |
134 | queue->buffer[i].buf.length = buflength; | |
ff924203 | 135 | queue->buffer[i].buf.type = queue->type; |
c0efd232 LP |
136 | queue->buffer[i].buf.sequence = 0; |
137 | queue->buffer[i].buf.field = V4L2_FIELD_NONE; | |
138 | queue->buffer[i].buf.memory = V4L2_MEMORY_MMAP; | |
139 | queue->buffer[i].buf.flags = 0; | |
140 | init_waitqueue_head(&queue->buffer[i].wait); | |
141 | } | |
142 | ||
143 | queue->mem = mem; | |
144 | queue->count = nbuffers; | |
145 | queue->buf_size = bufsize; | |
146 | ret = nbuffers; | |
147 | ||
148 | done: | |
149 | mutex_unlock(&queue->mutex); | |
150 | return ret; | |
151 | } | |
152 | ||
153 | /* | |
154 | * Free the video buffers. | |
155 | * | |
156 | * This function must be called with the queue lock held. | |
157 | */ | |
158 | int uvc_free_buffers(struct uvc_video_queue *queue) | |
159 | { | |
160 | unsigned int i; | |
161 | ||
162 | for (i = 0; i < queue->count; ++i) { | |
163 | if (queue->buffer[i].vma_use_count != 0) | |
164 | return -EBUSY; | |
165 | } | |
166 | ||
167 | if (queue->count) { | |
168 | vfree(queue->mem); | |
169 | queue->count = 0; | |
170 | } | |
171 | ||
172 | return 0; | |
173 | } | |
174 | ||
175 | static void __uvc_query_buffer(struct uvc_buffer *buf, | |
176 | struct v4l2_buffer *v4l2_buf) | |
177 | { | |
178 | memcpy(v4l2_buf, &buf->buf, sizeof *v4l2_buf); | |
179 | ||
180 | if (buf->vma_use_count) | |
181 | v4l2_buf->flags |= V4L2_BUF_FLAG_MAPPED; | |
182 | ||
183 | switch (buf->state) { | |
184 | case UVC_BUF_STATE_ERROR: | |
185 | case UVC_BUF_STATE_DONE: | |
186 | v4l2_buf->flags |= V4L2_BUF_FLAG_DONE; | |
187 | break; | |
188 | case UVC_BUF_STATE_QUEUED: | |
189 | case UVC_BUF_STATE_ACTIVE: | |
190 | v4l2_buf->flags |= V4L2_BUF_FLAG_QUEUED; | |
191 | break; | |
192 | case UVC_BUF_STATE_IDLE: | |
193 | default: | |
194 | break; | |
195 | } | |
196 | } | |
197 | ||
198 | int uvc_query_buffer(struct uvc_video_queue *queue, | |
199 | struct v4l2_buffer *v4l2_buf) | |
200 | { | |
201 | int ret = 0; | |
202 | ||
203 | mutex_lock(&queue->mutex); | |
204 | if (v4l2_buf->index >= queue->count) { | |
205 | ret = -EINVAL; | |
206 | goto done; | |
207 | } | |
208 | ||
209 | __uvc_query_buffer(&queue->buffer[v4l2_buf->index], v4l2_buf); | |
210 | ||
211 | done: | |
2c2d264b LP |
212 | mutex_unlock(&queue->mutex); |
213 | return ret; | |
c0efd232 LP |
214 | } |
215 | ||
216 | /* | |
217 | * Queue a video buffer. Attempting to queue a buffer that has already been | |
218 | * queued will return -EINVAL. | |
219 | */ | |
220 | int uvc_queue_buffer(struct uvc_video_queue *queue, | |
221 | struct v4l2_buffer *v4l2_buf) | |
222 | { | |
223 | struct uvc_buffer *buf; | |
224 | unsigned long flags; | |
225 | int ret = 0; | |
226 | ||
227 | uvc_trace(UVC_TRACE_CAPTURE, "Queuing buffer %u.\n", v4l2_buf->index); | |
228 | ||
ff924203 | 229 | if (v4l2_buf->type != queue->type || |
c0efd232 LP |
230 | v4l2_buf->memory != V4L2_MEMORY_MMAP) { |
231 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) " | |
232 | "and/or memory (%u).\n", v4l2_buf->type, | |
233 | v4l2_buf->memory); | |
234 | return -EINVAL; | |
235 | } | |
236 | ||
237 | mutex_lock(&queue->mutex); | |
2c2d264b | 238 | if (v4l2_buf->index >= queue->count) { |
c0efd232 LP |
239 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Out of range index.\n"); |
240 | ret = -EINVAL; | |
241 | goto done; | |
242 | } | |
243 | ||
244 | buf = &queue->buffer[v4l2_buf->index]; | |
245 | if (buf->state != UVC_BUF_STATE_IDLE) { | |
246 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state " | |
247 | "(%u).\n", buf->state); | |
248 | ret = -EINVAL; | |
249 | goto done; | |
250 | } | |
251 | ||
ff924203 LP |
252 | if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_OUTPUT && |
253 | v4l2_buf->bytesused > buf->buf.length) { | |
254 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n"); | |
255 | ret = -EINVAL; | |
256 | goto done; | |
257 | } | |
258 | ||
c0efd232 LP |
259 | spin_lock_irqsave(&queue->irqlock, flags); |
260 | if (queue->flags & UVC_QUEUE_DISCONNECTED) { | |
261 | spin_unlock_irqrestore(&queue->irqlock, flags); | |
262 | ret = -ENODEV; | |
263 | goto done; | |
264 | } | |
265 | buf->state = UVC_BUF_STATE_QUEUED; | |
ff924203 LP |
266 | if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) |
267 | buf->buf.bytesused = 0; | |
268 | else | |
269 | buf->buf.bytesused = v4l2_buf->bytesused; | |
270 | ||
c0efd232 LP |
271 | list_add_tail(&buf->stream, &queue->mainqueue); |
272 | list_add_tail(&buf->queue, &queue->irqqueue); | |
273 | spin_unlock_irqrestore(&queue->irqlock, flags); | |
274 | ||
275 | done: | |
276 | mutex_unlock(&queue->mutex); | |
277 | return ret; | |
278 | } | |
279 | ||
280 | static int uvc_queue_waiton(struct uvc_buffer *buf, int nonblocking) | |
281 | { | |
282 | if (nonblocking) { | |
283 | return (buf->state != UVC_BUF_STATE_QUEUED && | |
284 | buf->state != UVC_BUF_STATE_ACTIVE) | |
285 | ? 0 : -EAGAIN; | |
286 | } | |
287 | ||
288 | return wait_event_interruptible(buf->wait, | |
289 | buf->state != UVC_BUF_STATE_QUEUED && | |
290 | buf->state != UVC_BUF_STATE_ACTIVE); | |
291 | } | |
292 | ||
293 | /* | |
294 | * Dequeue a video buffer. If nonblocking is false, block until a buffer is | |
295 | * available. | |
296 | */ | |
297 | int uvc_dequeue_buffer(struct uvc_video_queue *queue, | |
298 | struct v4l2_buffer *v4l2_buf, int nonblocking) | |
299 | { | |
300 | struct uvc_buffer *buf; | |
301 | int ret = 0; | |
302 | ||
ff924203 | 303 | if (v4l2_buf->type != queue->type || |
c0efd232 LP |
304 | v4l2_buf->memory != V4L2_MEMORY_MMAP) { |
305 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) " | |
306 | "and/or memory (%u).\n", v4l2_buf->type, | |
307 | v4l2_buf->memory); | |
308 | return -EINVAL; | |
309 | } | |
310 | ||
311 | mutex_lock(&queue->mutex); | |
312 | if (list_empty(&queue->mainqueue)) { | |
313 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Empty buffer queue.\n"); | |
314 | ret = -EINVAL; | |
315 | goto done; | |
316 | } | |
317 | ||
318 | buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream); | |
319 | if ((ret = uvc_queue_waiton(buf, nonblocking)) < 0) | |
320 | goto done; | |
321 | ||
322 | uvc_trace(UVC_TRACE_CAPTURE, "Dequeuing buffer %u (%u, %u bytes).\n", | |
323 | buf->buf.index, buf->state, buf->buf.bytesused); | |
324 | ||
325 | switch (buf->state) { | |
326 | case UVC_BUF_STATE_ERROR: | |
327 | uvc_trace(UVC_TRACE_CAPTURE, "[W] Corrupted data " | |
328 | "(transmission error).\n"); | |
329 | ret = -EIO; | |
330 | case UVC_BUF_STATE_DONE: | |
331 | buf->state = UVC_BUF_STATE_IDLE; | |
332 | break; | |
333 | ||
334 | case UVC_BUF_STATE_IDLE: | |
335 | case UVC_BUF_STATE_QUEUED: | |
336 | case UVC_BUF_STATE_ACTIVE: | |
337 | default: | |
338 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state %u " | |
339 | "(driver bug?).\n", buf->state); | |
340 | ret = -EINVAL; | |
341 | goto done; | |
342 | } | |
343 | ||
344 | list_del(&buf->stream); | |
345 | __uvc_query_buffer(buf, v4l2_buf); | |
346 | ||
347 | done: | |
348 | mutex_unlock(&queue->mutex); | |
349 | return ret; | |
350 | } | |
351 | ||
352 | /* | |
353 | * Poll the video queue. | |
354 | * | |
355 | * This function implements video queue polling and is intended to be used by | |
356 | * the device poll handler. | |
357 | */ | |
358 | unsigned int uvc_queue_poll(struct uvc_video_queue *queue, struct file *file, | |
359 | poll_table *wait) | |
360 | { | |
361 | struct uvc_buffer *buf; | |
362 | unsigned int mask = 0; | |
363 | ||
364 | mutex_lock(&queue->mutex); | |
365 | if (list_empty(&queue->mainqueue)) { | |
366 | mask |= POLLERR; | |
367 | goto done; | |
368 | } | |
369 | buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream); | |
370 | ||
371 | poll_wait(file, &buf->wait, wait); | |
372 | if (buf->state == UVC_BUF_STATE_DONE || | |
373 | buf->state == UVC_BUF_STATE_ERROR) | |
374 | mask |= POLLIN | POLLRDNORM; | |
375 | ||
376 | done: | |
377 | mutex_unlock(&queue->mutex); | |
378 | return mask; | |
379 | } | |
380 | ||
381 | /* | |
382 | * Enable or disable the video buffers queue. | |
383 | * | |
384 | * The queue must be enabled before starting video acquisition and must be | |
385 | * disabled after stopping it. This ensures that the video buffers queue | |
386 | * state can be properly initialized before buffers are accessed from the | |
387 | * interrupt handler. | |
388 | * | |
389 | * Enabling the video queue initializes parameters (such as sequence number, | |
390 | * sync pattern, ...). If the queue is already enabled, return -EBUSY. | |
391 | * | |
392 | * Disabling the video queue cancels the queue and removes all buffers from | |
393 | * the main queue. | |
394 | * | |
395 | * This function can't be called from interrupt context. Use | |
396 | * uvc_queue_cancel() instead. | |
397 | */ | |
398 | int uvc_queue_enable(struct uvc_video_queue *queue, int enable) | |
399 | { | |
400 | unsigned int i; | |
401 | int ret = 0; | |
402 | ||
403 | mutex_lock(&queue->mutex); | |
404 | if (enable) { | |
405 | if (uvc_queue_streaming(queue)) { | |
406 | ret = -EBUSY; | |
407 | goto done; | |
408 | } | |
409 | queue->sequence = 0; | |
410 | queue->flags |= UVC_QUEUE_STREAMING; | |
ff924203 | 411 | queue->buf_used = 0; |
c0efd232 LP |
412 | } else { |
413 | uvc_queue_cancel(queue, 0); | |
414 | INIT_LIST_HEAD(&queue->mainqueue); | |
415 | ||
416 | for (i = 0; i < queue->count; ++i) | |
417 | queue->buffer[i].state = UVC_BUF_STATE_IDLE; | |
418 | ||
419 | queue->flags &= ~UVC_QUEUE_STREAMING; | |
420 | } | |
421 | ||
422 | done: | |
423 | mutex_unlock(&queue->mutex); | |
424 | return ret; | |
425 | } | |
426 | ||
427 | /* | |
428 | * Cancel the video buffers queue. | |
429 | * | |
430 | * Cancelling the queue marks all buffers on the irq queue as erroneous, | |
2c2d264b | 431 | * wakes them up and removes them from the queue. |
c0efd232 LP |
432 | * |
433 | * If the disconnect parameter is set, further calls to uvc_queue_buffer will | |
434 | * fail with -ENODEV. | |
435 | * | |
436 | * This function acquires the irq spinlock and can be called from interrupt | |
437 | * context. | |
438 | */ | |
439 | void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect) | |
440 | { | |
441 | struct uvc_buffer *buf; | |
442 | unsigned long flags; | |
443 | ||
444 | spin_lock_irqsave(&queue->irqlock, flags); | |
445 | while (!list_empty(&queue->irqqueue)) { | |
446 | buf = list_first_entry(&queue->irqqueue, struct uvc_buffer, | |
447 | queue); | |
448 | list_del(&buf->queue); | |
449 | buf->state = UVC_BUF_STATE_ERROR; | |
450 | wake_up(&buf->wait); | |
451 | } | |
452 | /* This must be protected by the irqlock spinlock to avoid race | |
453 | * conditions between uvc_queue_buffer and the disconnection event that | |
454 | * could result in an interruptible wait in uvc_dequeue_buffer. Do not | |
455 | * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED | |
456 | * state outside the queue code. | |
457 | */ | |
458 | if (disconnect) | |
459 | queue->flags |= UVC_QUEUE_DISCONNECTED; | |
460 | spin_unlock_irqrestore(&queue->irqlock, flags); | |
461 | } | |
462 | ||
463 | struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue, | |
464 | struct uvc_buffer *buf) | |
465 | { | |
466 | struct uvc_buffer *nextbuf; | |
467 | unsigned long flags; | |
468 | ||
469 | if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) && | |
470 | buf->buf.length != buf->buf.bytesused) { | |
471 | buf->state = UVC_BUF_STATE_QUEUED; | |
472 | buf->buf.bytesused = 0; | |
473 | return buf; | |
474 | } | |
475 | ||
476 | spin_lock_irqsave(&queue->irqlock, flags); | |
477 | list_del(&buf->queue); | |
478 | if (!list_empty(&queue->irqqueue)) | |
479 | nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer, | |
480 | queue); | |
481 | else | |
482 | nextbuf = NULL; | |
483 | spin_unlock_irqrestore(&queue->irqlock, flags); | |
484 | ||
485 | buf->buf.sequence = queue->sequence++; | |
486 | do_gettimeofday(&buf->buf.timestamp); | |
487 | ||
488 | wake_up(&buf->wait); | |
489 | return nextbuf; | |
490 | } | |
f87086e3 | 491 |