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Source at commit be977234bfb4a6dca8a39e7c52165e4cd536ad71 created 12 years 9 months ago. By Lars-Peter Clausen, jz4740: Fix compile error | |
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1 | /* |
2 | * uvc_queue.c -- USB Video Class driver - Buffers management |
3 | * |
4 | * Copyright (C) 2005-2010 |
5 | * Laurent Pinchart (laurent.pinchart@ideasonboard.com) |
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> |
15 | #include <linux/mm.h> |
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 "uvc.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 |
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. |
44 | * |
45 | * Use cases |
46 | * --------- |
47 | * |
48 | * Unless stated otherwise, all operations that modify the irq buffers queue |
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 |
54 | * protected by the queue lock, and the later is protected by the irq |
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 |
62 | * queue, marks it as ready (UVC_BUF_STATE_DONE) and wakes its wait queue. |
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 | |
81 | static void |
82 | uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type) |
83 | { |
84 | mutex_init(&queue->mutex); |
85 | spin_lock_init(&queue->irqlock); |
86 | INIT_LIST_HEAD(&queue->mainqueue); |
87 | INIT_LIST_HEAD(&queue->irqqueue); |
88 | queue->type = type; |
89 | } |
90 | |
91 | /* |
92 | * Free the video buffers. |
93 | * |
94 | * This function must be called with the queue lock held. |
95 | */ |
96 | static int uvc_free_buffers(struct uvc_video_queue *queue) |
97 | { |
98 | unsigned int i; |
99 | |
100 | for (i = 0; i < queue->count; ++i) { |
101 | if (queue->buffer[i].vma_use_count != 0) |
102 | return -EBUSY; |
103 | } |
104 | |
105 | if (queue->count) { |
106 | vfree(queue->mem); |
107 | queue->count = 0; |
108 | } |
109 | |
110 | return 0; |
111 | } |
112 | |
113 | /* |
114 | * Allocate the video buffers. |
115 | * |
116 | * Pages are reserved to make sure they will not be swapped, as they will be |
117 | * filled in the URB completion handler. |
118 | * |
119 | * Buffers will be individually mapped, so they must all be page aligned. |
120 | */ |
121 | static int |
122 | uvc_alloc_buffers(struct uvc_video_queue *queue, unsigned int nbuffers, |
123 | unsigned int buflength) |
124 | { |
125 | unsigned int bufsize = PAGE_ALIGN(buflength); |
126 | unsigned int i; |
127 | void *mem = NULL; |
128 | int ret; |
129 | |
130 | if (nbuffers > UVC_MAX_VIDEO_BUFFERS) |
131 | nbuffers = UVC_MAX_VIDEO_BUFFERS; |
132 | |
133 | mutex_lock(&queue->mutex); |
134 | |
135 | if ((ret = uvc_free_buffers(queue)) < 0) |
136 | goto done; |
137 | |
138 | /* Bail out if no buffers should be allocated. */ |
139 | if (nbuffers == 0) |
140 | goto done; |
141 | |
142 | /* Decrement the number of buffers until allocation succeeds. */ |
143 | for (; nbuffers > 0; --nbuffers) { |
144 | mem = vmalloc_32(nbuffers * bufsize); |
145 | if (mem != NULL) |
146 | break; |
147 | } |
148 | |
149 | if (mem == NULL) { |
150 | ret = -ENOMEM; |
151 | goto done; |
152 | } |
153 | |
154 | for (i = 0; i < nbuffers; ++i) { |
155 | memset(&queue->buffer[i], 0, sizeof queue->buffer[i]); |
156 | queue->buffer[i].buf.index = i; |
157 | queue->buffer[i].buf.m.offset = i * bufsize; |
158 | queue->buffer[i].buf.length = buflength; |
159 | queue->buffer[i].buf.type = queue->type; |
160 | queue->buffer[i].buf.sequence = 0; |
161 | queue->buffer[i].buf.field = V4L2_FIELD_NONE; |
162 | queue->buffer[i].buf.memory = V4L2_MEMORY_MMAP; |
163 | queue->buffer[i].buf.flags = 0; |
164 | init_waitqueue_head(&queue->buffer[i].wait); |
165 | } |
166 | |
167 | queue->mem = mem; |
168 | queue->count = nbuffers; |
169 | queue->buf_size = bufsize; |
170 | ret = nbuffers; |
171 | |
172 | done: |
173 | mutex_unlock(&queue->mutex); |
174 | return ret; |
175 | } |
176 | |
177 | static void __uvc_query_buffer(struct uvc_buffer *buf, |
178 | struct v4l2_buffer *v4l2_buf) |
179 | { |
180 | memcpy(v4l2_buf, &buf->buf, sizeof *v4l2_buf); |
181 | |
182 | if (buf->vma_use_count) |
183 | v4l2_buf->flags |= V4L2_BUF_FLAG_MAPPED; |
184 | |
185 | switch (buf->state) { |
186 | case UVC_BUF_STATE_ERROR: |
187 | case UVC_BUF_STATE_DONE: |
188 | v4l2_buf->flags |= V4L2_BUF_FLAG_DONE; |
189 | break; |
190 | case UVC_BUF_STATE_QUEUED: |
191 | case UVC_BUF_STATE_ACTIVE: |
192 | v4l2_buf->flags |= V4L2_BUF_FLAG_QUEUED; |
193 | break; |
194 | case UVC_BUF_STATE_IDLE: |
195 | default: |
196 | break; |
197 | } |
198 | } |
199 | |
200 | static int |
201 | uvc_query_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *v4l2_buf) |
202 | { |
203 | int ret = 0; |
204 | |
205 | mutex_lock(&queue->mutex); |
206 | if (v4l2_buf->index >= queue->count) { |
207 | ret = -EINVAL; |
208 | goto done; |
209 | } |
210 | |
211 | __uvc_query_buffer(&queue->buffer[v4l2_buf->index], v4l2_buf); |
212 | |
213 | done: |
214 | mutex_unlock(&queue->mutex); |
215 | return ret; |
216 | } |
217 | |
218 | /* |
219 | * Queue a video buffer. Attempting to queue a buffer that has already been |
220 | * queued will return -EINVAL. |
221 | */ |
222 | static int |
223 | uvc_queue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *v4l2_buf) |
224 | { |
225 | struct uvc_buffer *buf; |
226 | unsigned long flags; |
227 | int ret = 0; |
228 | |
229 | uvc_trace(UVC_TRACE_CAPTURE, "Queuing buffer %u.\n", v4l2_buf->index); |
230 | |
231 | if (v4l2_buf->type != queue->type || |
232 | v4l2_buf->memory != V4L2_MEMORY_MMAP) { |
233 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) " |
234 | "and/or memory (%u).\n", v4l2_buf->type, |
235 | v4l2_buf->memory); |
236 | return -EINVAL; |
237 | } |
238 | |
239 | mutex_lock(&queue->mutex); |
240 | if (v4l2_buf->index >= queue->count) { |
241 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Out of range index.\n"); |
242 | ret = -EINVAL; |
243 | goto done; |
244 | } |
245 | |
246 | buf = &queue->buffer[v4l2_buf->index]; |
247 | if (buf->state != UVC_BUF_STATE_IDLE) { |
248 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state " |
249 | "(%u).\n", buf->state); |
250 | ret = -EINVAL; |
251 | goto done; |
252 | } |
253 | |
254 | if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_OUTPUT && |
255 | v4l2_buf->bytesused > buf->buf.length) { |
256 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n"); |
257 | ret = -EINVAL; |
258 | goto done; |
259 | } |
260 | |
261 | if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) |
262 | buf->buf.bytesused = 0; |
263 | else |
264 | buf->buf.bytesused = v4l2_buf->bytesused; |
265 | |
266 | spin_lock_irqsave(&queue->irqlock, flags); |
267 | if (queue->flags & UVC_QUEUE_DISCONNECTED) { |
268 | spin_unlock_irqrestore(&queue->irqlock, flags); |
269 | ret = -ENODEV; |
270 | goto done; |
271 | } |
272 | buf->state = UVC_BUF_STATE_QUEUED; |
273 | |
274 | ret = (queue->flags & UVC_QUEUE_PAUSED) != 0; |
275 | queue->flags &= ~UVC_QUEUE_PAUSED; |
276 | |
277 | list_add_tail(&buf->stream, &queue->mainqueue); |
278 | list_add_tail(&buf->queue, &queue->irqqueue); |
279 | spin_unlock_irqrestore(&queue->irqlock, flags); |
280 | |
281 | done: |
282 | mutex_unlock(&queue->mutex); |
283 | return ret; |
284 | } |
285 | |
286 | static int uvc_queue_waiton(struct uvc_buffer *buf, int nonblocking) |
287 | { |
288 | if (nonblocking) { |
289 | return (buf->state != UVC_BUF_STATE_QUEUED && |
290 | buf->state != UVC_BUF_STATE_ACTIVE) |
291 | ? 0 : -EAGAIN; |
292 | } |
293 | |
294 | return wait_event_interruptible(buf->wait, |
295 | buf->state != UVC_BUF_STATE_QUEUED && |
296 | buf->state != UVC_BUF_STATE_ACTIVE); |
297 | } |
298 | |
299 | /* |
300 | * Dequeue a video buffer. If nonblocking is false, block until a buffer is |
301 | * available. |
302 | */ |
303 | static int |
304 | uvc_dequeue_buffer(struct uvc_video_queue *queue, struct v4l2_buffer *v4l2_buf, |
305 | int nonblocking) |
306 | { |
307 | struct uvc_buffer *buf; |
308 | int ret = 0; |
309 | |
310 | if (v4l2_buf->type != queue->type || |
311 | v4l2_buf->memory != V4L2_MEMORY_MMAP) { |
312 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) " |
313 | "and/or memory (%u).\n", v4l2_buf->type, |
314 | v4l2_buf->memory); |
315 | return -EINVAL; |
316 | } |
317 | |
318 | mutex_lock(&queue->mutex); |
319 | if (list_empty(&queue->mainqueue)) { |
320 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Empty buffer queue.\n"); |
321 | ret = -EINVAL; |
322 | goto done; |
323 | } |
324 | |
325 | buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream); |
326 | if ((ret = uvc_queue_waiton(buf, nonblocking)) < 0) |
327 | goto done; |
328 | |
329 | uvc_trace(UVC_TRACE_CAPTURE, "Dequeuing buffer %u (%u, %u bytes).\n", |
330 | buf->buf.index, buf->state, buf->buf.bytesused); |
331 | |
332 | switch (buf->state) { |
333 | case UVC_BUF_STATE_ERROR: |
334 | uvc_trace(UVC_TRACE_CAPTURE, "[W] Corrupted data " |
335 | "(transmission error).\n"); |
336 | ret = -EIO; |
337 | case UVC_BUF_STATE_DONE: |
338 | buf->state = UVC_BUF_STATE_IDLE; |
339 | break; |
340 | |
341 | case UVC_BUF_STATE_IDLE: |
342 | case UVC_BUF_STATE_QUEUED: |
343 | case UVC_BUF_STATE_ACTIVE: |
344 | default: |
345 | uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state %u " |
346 | "(driver bug?).\n", buf->state); |
347 | ret = -EINVAL; |
348 | goto done; |
349 | } |
350 | |
351 | list_del(&buf->stream); |
352 | __uvc_query_buffer(buf, v4l2_buf); |
353 | |
354 | done: |
355 | mutex_unlock(&queue->mutex); |
356 | return ret; |
357 | } |
358 | |
359 | /* |
360 | * Poll the video queue. |
361 | * |
362 | * This function implements video queue polling and is intended to be used by |
363 | * the device poll handler. |
364 | */ |
365 | static unsigned int |
366 | uvc_queue_poll(struct uvc_video_queue *queue, struct file *file, |
367 | poll_table *wait) |
368 | { |
369 | struct uvc_buffer *buf; |
370 | unsigned int mask = 0; |
371 | |
372 | mutex_lock(&queue->mutex); |
373 | if (list_empty(&queue->mainqueue)) |
374 | goto done; |
375 | |
376 | buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream); |
377 | |
378 | poll_wait(file, &buf->wait, wait); |
379 | if (buf->state == UVC_BUF_STATE_DONE || |
380 | buf->state == UVC_BUF_STATE_ERROR) |
381 | mask |= POLLOUT | POLLWRNORM; |
382 | |
383 | done: |
384 | mutex_unlock(&queue->mutex); |
385 | return mask; |
386 | } |
387 | |
388 | /* |
389 | * VMA operations. |
390 | */ |
391 | static void uvc_vm_open(struct vm_area_struct *vma) |
392 | { |
393 | struct uvc_buffer *buffer = vma->vm_private_data; |
394 | buffer->vma_use_count++; |
395 | } |
396 | |
397 | static void uvc_vm_close(struct vm_area_struct *vma) |
398 | { |
399 | struct uvc_buffer *buffer = vma->vm_private_data; |
400 | buffer->vma_use_count--; |
401 | } |
402 | |
403 | static struct vm_operations_struct uvc_vm_ops = { |
404 | .open = uvc_vm_open, |
405 | .close = uvc_vm_close, |
406 | }; |
407 | |
408 | /* |
409 | * Memory-map a buffer. |
410 | * |
411 | * This function implements video buffer memory mapping and is intended to be |
412 | * used by the device mmap handler. |
413 | */ |
414 | static int |
415 | uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma) |
416 | { |
417 | struct uvc_buffer *uninitialized_var(buffer); |
418 | struct page *page; |
419 | unsigned long addr, start, size; |
420 | unsigned int i; |
421 | int ret = 0; |
422 | |
423 | start = vma->vm_start; |
424 | size = vma->vm_end - vma->vm_start; |
425 | |
426 | mutex_lock(&queue->mutex); |
427 | |
428 | for (i = 0; i < queue->count; ++i) { |
429 | buffer = &queue->buffer[i]; |
430 | if ((buffer->buf.m.offset >> PAGE_SHIFT) == vma->vm_pgoff) |
431 | break; |
432 | } |
433 | |
434 | if (i == queue->count || size != queue->buf_size) { |
435 | ret = -EINVAL; |
436 | goto done; |
437 | } |
438 | |
439 | /* |
440 | * VM_IO marks the area as being an mmaped region for I/O to a |
441 | * device. It also prevents the region from being core dumped. |
442 | */ |
443 | vma->vm_flags |= VM_IO; |
444 | |
445 | addr = (unsigned long)queue->mem + buffer->buf.m.offset; |
446 | while (size > 0) { |
447 | page = vmalloc_to_page((void *)addr); |
448 | if ((ret = vm_insert_page(vma, start, page)) < 0) |
449 | goto done; |
450 | |
451 | start += PAGE_SIZE; |
452 | addr += PAGE_SIZE; |
453 | size -= PAGE_SIZE; |
454 | } |
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 | |
465 | /* |
466 | * Cancel the video buffers queue. |
467 | * |
468 | * Cancelling the queue marks all buffers on the irq queue as erroneous, |
469 | * wakes them up and removes them from the queue. |
470 | * |
471 | * If the disconnect parameter is set, further calls to uvc_queue_buffer will |
472 | * fail with -ENODEV. |
473 | * |
474 | * This function acquires the irq spinlock and can be called from interrupt |
475 | * context. |
476 | */ |
477 | static void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect) |
478 | { |
479 | struct uvc_buffer *buf; |
480 | unsigned long flags; |
481 | |
482 | spin_lock_irqsave(&queue->irqlock, flags); |
483 | while (!list_empty(&queue->irqqueue)) { |
484 | buf = list_first_entry(&queue->irqqueue, struct uvc_buffer, |
485 | queue); |
486 | list_del(&buf->queue); |
487 | buf->state = UVC_BUF_STATE_ERROR; |
488 | wake_up(&buf->wait); |
489 | } |
490 | /* This must be protected by the irqlock spinlock to avoid race |
491 | * conditions between uvc_queue_buffer and the disconnection event that |
492 | * could result in an interruptible wait in uvc_dequeue_buffer. Do not |
493 | * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED |
494 | * state outside the queue code. |
495 | */ |
496 | if (disconnect) |
497 | queue->flags |= UVC_QUEUE_DISCONNECTED; |
498 | spin_unlock_irqrestore(&queue->irqlock, flags); |
499 | } |
500 | |
501 | /* |
502 | * Enable or disable the video buffers queue. |
503 | * |
504 | * The queue must be enabled before starting video acquisition and must be |
505 | * disabled after stopping it. This ensures that the video buffers queue |
506 | * state can be properly initialized before buffers are accessed from the |
507 | * interrupt handler. |
508 | * |
509 | * Enabling the video queue initializes parameters (such as sequence number, |
510 | * sync pattern, ...). If the queue is already enabled, return -EBUSY. |
511 | * |
512 | * Disabling the video queue cancels the queue and removes all buffers from |
513 | * the main queue. |
514 | * |
515 | * This function can't be called from interrupt context. Use |
516 | * uvc_queue_cancel() instead. |
517 | */ |
518 | static int uvc_queue_enable(struct uvc_video_queue *queue, int enable) |
519 | { |
520 | unsigned int i; |
521 | int ret = 0; |
522 | |
523 | mutex_lock(&queue->mutex); |
524 | if (enable) { |
525 | if (uvc_queue_streaming(queue)) { |
526 | ret = -EBUSY; |
527 | goto done; |
528 | } |
529 | queue->sequence = 0; |
530 | queue->flags |= UVC_QUEUE_STREAMING; |
531 | queue->buf_used = 0; |
532 | } else { |
533 | uvc_queue_cancel(queue, 0); |
534 | INIT_LIST_HEAD(&queue->mainqueue); |
535 | |
536 | for (i = 0; i < queue->count; ++i) |
537 | queue->buffer[i].state = UVC_BUF_STATE_IDLE; |
538 | |
539 | queue->flags &= ~UVC_QUEUE_STREAMING; |
540 | } |
541 | |
542 | done: |
543 | mutex_unlock(&queue->mutex); |
544 | return ret; |
545 | } |
546 | |
547 | static struct uvc_buffer * |
548 | uvc_queue_next_buffer(struct uvc_video_queue *queue, struct uvc_buffer *buf) |
549 | { |
550 | struct uvc_buffer *nextbuf; |
551 | unsigned long flags; |
552 | |
553 | if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) && |
554 | buf->buf.length != buf->buf.bytesused) { |
555 | buf->state = UVC_BUF_STATE_QUEUED; |
556 | buf->buf.bytesused = 0; |
557 | return buf; |
558 | } |
559 | |
560 | spin_lock_irqsave(&queue->irqlock, flags); |
561 | list_del(&buf->queue); |
562 | if (!list_empty(&queue->irqqueue)) |
563 | nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer, |
564 | queue); |
565 | else |
566 | nextbuf = NULL; |
567 | spin_unlock_irqrestore(&queue->irqlock, flags); |
568 | |
569 | buf->buf.sequence = queue->sequence++; |
570 | do_gettimeofday(&buf->buf.timestamp); |
571 | |
572 | wake_up(&buf->wait); |
573 | return nextbuf; |
574 | } |
575 | |
576 | static struct uvc_buffer *uvc_queue_head(struct uvc_video_queue *queue) |
577 | { |
578 | struct uvc_buffer *buf = NULL; |
579 | |
580 | if (!list_empty(&queue->irqqueue)) |
581 | buf = list_first_entry(&queue->irqqueue, struct uvc_buffer, |
582 | queue); |
583 | else |
584 | queue->flags |= UVC_QUEUE_PAUSED; |
585 | |
586 | return buf; |
587 | } |
588 | |
589 |
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