2 * uvc_queue.c -- USB Video Class driver - Buffers management
4 * Copyright (C) 2005-2009
5 * Laurent Pinchart (laurent.pinchart@skynet.be)
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.
14 #include <linux/kernel.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>
26 /* ------------------------------------------------------------------------
27 * Video buffers queue management.
29 * Video queues is initialized by uvc_queue_init(). The function performs
30 * basic initialization of the uvc_video_queue struct and never fails.
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.
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
48 * Unless stated otherwise, all operations that modify the irq buffers queue
49 * are protected by the irq spinlock.
51 * 1. The user queues the buffers, starts streaming and dequeues a buffer.
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
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.
61 * When the buffer is full, the completion handler removes it from the irq
62 * queue, marks it as done (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 done, the
65 * dequeing will succeed immediately.
67 * 2. Buffers are queued, user is waiting on a buffer and the device gets
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.
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
81 void uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
84 mutex_init(&queue->mutex);
85 spin_lock_init(&queue->irqlock);
86 INIT_LIST_HEAD(&queue->mainqueue);
87 INIT_LIST_HEAD(&queue->irqqueue);
88 init_waitqueue_head(&queue->wait); /* ddl@rock-chips.com : This design copied from video-buf */
89 queue->flags = drop_corrupted ? UVC_QUEUE_DROP_CORRUPTED : 0;
94 * Allocate the video buffers.
96 * Pages are reserved to make sure they will not be swapped, as they will be
97 * filled in the URB completion handler.
99 * Buffers will be individually mapped, so they must all be page aligned.
101 int uvc_alloc_buffers(struct uvc_video_queue *queue, unsigned int nbuffers,
102 unsigned int buflength)
104 unsigned int bufsize = PAGE_ALIGN(buflength);
109 if (nbuffers > UVC_MAX_VIDEO_BUFFERS)
110 nbuffers = UVC_MAX_VIDEO_BUFFERS;
112 mutex_lock(&queue->mutex);
114 if ((ret = uvc_free_buffers(queue)) < 0)
117 /* Bail out if no buffers should be allocated. */
121 /* Decrement the number of buffers until allocation succeeds. */
122 for (; nbuffers > 0; --nbuffers) {
123 mem = vmalloc_32(nbuffers * bufsize);
133 for (i = 0; i < nbuffers; ++i) {
134 memset(&queue->buffer[i], 0, sizeof queue->buffer[i]);
135 queue->buffer[i].buf.index = i;
136 queue->buffer[i].buf.m.offset = i * bufsize;
137 queue->buffer[i].buf.length = buflength;
138 queue->buffer[i].buf.type = queue->type;
139 queue->buffer[i].buf.sequence = 0;
140 queue->buffer[i].buf.field = V4L2_FIELD_NONE;
141 queue->buffer[i].buf.memory = V4L2_MEMORY_MMAP;
142 queue->buffer[i].buf.flags = 0;
143 init_waitqueue_head(&queue->buffer[i].wait);
147 queue->count = nbuffers;
148 queue->buf_size = bufsize;
152 mutex_unlock(&queue->mutex);
157 * Free the video buffers.
159 * This function must be called with the queue lock held.
161 int uvc_free_buffers(struct uvc_video_queue *queue)
165 for (i = 0; i < queue->count; ++i) {
166 if (queue->buffer[i].vma_use_count != 0)
179 * Check if buffers have been allocated.
181 int uvc_queue_allocated(struct uvc_video_queue *queue)
185 mutex_lock(&queue->mutex);
186 allocated = queue->count != 0;
187 mutex_unlock(&queue->mutex);
192 static void __uvc_query_buffer(struct uvc_buffer *buf,
193 struct v4l2_buffer *v4l2_buf)
195 memcpy(v4l2_buf, &buf->buf, sizeof *v4l2_buf);
197 if (buf->vma_use_count)
198 v4l2_buf->flags |= V4L2_BUF_FLAG_MAPPED;
200 switch (buf->state) {
201 case UVC_BUF_STATE_ERROR:
202 case UVC_BUF_STATE_DONE:
203 v4l2_buf->flags |= V4L2_BUF_FLAG_DONE;
205 case UVC_BUF_STATE_QUEUED:
206 case UVC_BUF_STATE_ACTIVE:
207 case UVC_BUF_STATE_READY:
208 v4l2_buf->flags |= V4L2_BUF_FLAG_QUEUED;
210 case UVC_BUF_STATE_IDLE:
216 int uvc_query_buffer(struct uvc_video_queue *queue,
217 struct v4l2_buffer *v4l2_buf)
221 mutex_lock(&queue->mutex);
222 if (v4l2_buf->index >= queue->count) {
227 __uvc_query_buffer(&queue->buffer[v4l2_buf->index], v4l2_buf);
230 mutex_unlock(&queue->mutex);
235 * Queue a video buffer. Attempting to queue a buffer that has already been
236 * queued will return -EINVAL.
238 int uvc_queue_buffer(struct uvc_video_queue *queue,
239 struct v4l2_buffer *v4l2_buf)
241 struct uvc_buffer *buf;
245 uvc_trace(UVC_TRACE_CAPTURE, "Queuing buffer %u.\n", v4l2_buf->index);
247 if (v4l2_buf->type != queue->type ||
248 v4l2_buf->memory != V4L2_MEMORY_MMAP) {
249 uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) "
250 "and/or memory (%u).\n", v4l2_buf->type,
255 mutex_lock(&queue->mutex);
256 if (v4l2_buf->index >= queue->count) {
257 uvc_trace(UVC_TRACE_CAPTURE, "[E] Out of range index.\n");
262 buf = &queue->buffer[v4l2_buf->index];
263 if (buf->state != UVC_BUF_STATE_IDLE) {
264 uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state "
265 "(%u).\n", buf->state);
270 if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
271 v4l2_buf->bytesused > buf->buf.length) {
272 uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
277 spin_lock_irqsave(&queue->irqlock, flags);
278 if (queue->flags & UVC_QUEUE_DISCONNECTED) {
279 spin_unlock_irqrestore(&queue->irqlock, flags);
283 buf->state = UVC_BUF_STATE_QUEUED;
284 if (v4l2_buf->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
285 buf->buf.bytesused = 0;
287 buf->buf.bytesused = v4l2_buf->bytesused;
289 list_add_tail(&buf->stream, &queue->mainqueue);
290 list_add_tail(&buf->queue, &queue->irqqueue);
291 spin_unlock_irqrestore(&queue->irqlock, flags);
293 wake_up_interruptible_sync(&queue->wait); /* ddl@rock-chips.com : This design copied from video-buf */
296 mutex_unlock(&queue->mutex);
300 static int uvc_queue_waiton(struct uvc_buffer *buf, int nonblocking)
303 return (buf->state != UVC_BUF_STATE_QUEUED &&
304 buf->state != UVC_BUF_STATE_ACTIVE &&
305 buf->state != UVC_BUF_STATE_READY)
309 return wait_event_interruptible(buf->wait,
310 buf->state != UVC_BUF_STATE_QUEUED &&
311 buf->state != UVC_BUF_STATE_ACTIVE &&
312 buf->state != UVC_BUF_STATE_READY);
314 /* ddl@rock-chips.com: wait_event_interruptible -> wait_event_interruptible_timeout */
315 return wait_event_interruptible_timeout(buf->wait,
316 buf->state != UVC_BUF_STATE_QUEUED &&
317 buf->state != UVC_BUF_STATE_ACTIVE &&
318 buf->state != UVC_BUF_STATE_READYi,
319 msecs_to_jiffies(800);
323 * Dequeue a video buffer. If nonblocking is false, block until a buffer is
326 int uvc_dequeue_buffer(struct uvc_video_queue *queue,
327 struct v4l2_buffer *v4l2_buf, int nonblocking)
329 struct uvc_buffer *buf;
332 if (v4l2_buf->type != queue->type ||
333 v4l2_buf->memory != V4L2_MEMORY_MMAP) {
334 uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer type (%u) "
335 "and/or memory (%u).\n", v4l2_buf->type,
340 mutex_lock(&queue->mutex);
341 /* ddl@rock-chips.com : This design copied from video-buf */
343 if (list_empty(&queue->mainqueue)) {
345 uvc_trace(UVC_TRACE_CAPTURE, "[E] Empty buffer queue.\n");
349 //uvc_trace(UVC_TRACE_CAPTURE, "dequeue_buffer: waiting on buffer\n");
350 printk("dequeue_buffer: waiting on buffer\n");
351 /* Drop lock to avoid deadlock with qbuf */
352 mutex_unlock(&queue->mutex);
354 /* Checking list_empty and streaming is safe without
355 * locks because we goto checks to validate while
356 * holding locks before proceeding */
357 ret = wait_event_interruptible(queue->wait,
358 ((!list_empty(&queue->mainqueue)) || (!(queue->flags & UVC_QUEUE_STREAMING))));
359 mutex_lock(&queue->mutex);
368 buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream);
369 if ((ret = uvc_queue_waiton(buf, nonblocking)) <= 0) {
370 /* ddl@rock-chips.com: It is timeout */
373 printk(KERN_ERR "uvcvideo: uvc_dequeue_buffer is timeout!!");
375 printk(KERN_ERR "uvcvideo: uvc_dequeue_buffer is failed!!(ret:%d)",ret);
380 uvc_trace(UVC_TRACE_CAPTURE, "Dequeuing buffer %u (%u, %u bytes).\n",
381 buf->buf.index, buf->state, buf->buf.bytesused);
383 switch (buf->state) {
384 case UVC_BUF_STATE_ERROR:
385 uvc_trace(UVC_TRACE_CAPTURE, "[W] Corrupted data "
386 "(transmission error).\n");
388 case UVC_BUF_STATE_DONE:
389 buf->state = UVC_BUF_STATE_IDLE;
392 case UVC_BUF_STATE_IDLE:
393 case UVC_BUF_STATE_QUEUED:
394 case UVC_BUF_STATE_ACTIVE:
395 case UVC_BUF_STATE_READY:
397 uvc_trace(UVC_TRACE_CAPTURE, "[E] Invalid buffer state %u "
398 "(driver bug?).\n", buf->state);
403 list_del(&buf->stream);
404 __uvc_query_buffer(buf, v4l2_buf);
407 mutex_unlock(&queue->mutex);
412 * Poll the video queue.
414 * This function implements video queue polling and is intended to be used by
415 * the device poll handler.
417 unsigned int uvc_queue_poll(struct uvc_video_queue *queue, struct file *file,
420 struct uvc_buffer *buf;
421 unsigned int mask = 0;
423 mutex_lock(&queue->mutex);
424 if (list_empty(&queue->mainqueue)) {
428 buf = list_first_entry(&queue->mainqueue, struct uvc_buffer, stream);
430 poll_wait(file, &buf->wait, wait);
431 if (buf->state == UVC_BUF_STATE_DONE ||
432 buf->state == UVC_BUF_STATE_ERROR) {
433 if (queue->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
434 mask |= POLLIN | POLLRDNORM;
436 mask |= POLLOUT | POLLWRNORM;
440 mutex_unlock(&queue->mutex);
445 * Enable or disable the video buffers queue.
447 * The queue must be enabled before starting video acquisition and must be
448 * disabled after stopping it. This ensures that the video buffers queue
449 * state can be properly initialized before buffers are accessed from the
452 * Enabling the video queue initializes parameters (such as sequence number,
453 * sync pattern, ...). If the queue is already enabled, return -EBUSY.
455 * Disabling the video queue cancels the queue and removes all buffers from
458 * This function can't be called from interrupt context. Use
459 * uvc_queue_cancel() instead.
461 int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
466 mutex_lock(&queue->mutex);
468 if (uvc_queue_streaming(queue)) {
473 queue->flags |= UVC_QUEUE_STREAMING;
476 uvc_queue_cancel(queue, 0);
477 INIT_LIST_HEAD(&queue->mainqueue);
479 for (i = 0; i < queue->count; ++i) {
480 queue->buffer[i].error = 0;
481 queue->buffer[i].state = UVC_BUF_STATE_IDLE;
484 queue->flags &= ~UVC_QUEUE_STREAMING;
488 mutex_unlock(&queue->mutex);
493 * Cancel the video buffers queue.
495 * Cancelling the queue marks all buffers on the irq queue as erroneous,
496 * wakes them up and removes them from the queue.
498 * If the disconnect parameter is set, further calls to uvc_queue_buffer will
501 * This function acquires the irq spinlock and can be called from interrupt
504 void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
506 struct uvc_buffer *buf;
509 wake_up_interruptible_sync(&queue->wait); /* ddl@rock-chips.com : This design copied from video-buf */
511 spin_lock_irqsave(&queue->irqlock, flags);
512 while (!list_empty(&queue->irqqueue)) {
513 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
515 list_del(&buf->queue);
516 buf->state = UVC_BUF_STATE_ERROR;
519 /* This must be protected by the irqlock spinlock to avoid race
520 * conditions between uvc_queue_buffer and the disconnection event that
521 * could result in an interruptible wait in uvc_dequeue_buffer. Do not
522 * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
523 * state outside the queue code.
526 queue->flags |= UVC_QUEUE_DISCONNECTED;
527 spin_unlock_irqrestore(&queue->irqlock, flags);
530 struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
531 struct uvc_buffer *buf)
533 struct uvc_buffer *nextbuf;
536 if ((queue->flags & UVC_QUEUE_DROP_CORRUPTED) && buf->error) {
538 buf->state = UVC_BUF_STATE_QUEUED;
539 buf->buf.bytesused = 0;
543 spin_lock_irqsave(&queue->irqlock, flags);
544 list_del(&buf->queue);
546 buf->state = UVC_BUF_STATE_DONE;
547 if (!list_empty(&queue->irqqueue))
548 nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
552 spin_unlock_irqrestore(&queue->irqlock, flags);
554 buf->buf.sequence = queue->sequence++;