2 * uvc_queue.c -- USB Video Class driver - Buffers management
4 * Copyright (C) 2005-2010
5 * Laurent Pinchart (laurent.pinchart@ideasonboard.com)
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.
13 #include <linux/atomic.h>
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>
23 #include <media/videobuf2-vmalloc.h>
27 /* ------------------------------------------------------------------------
28 * Video buffers queue management.
30 * Video queues is initialized by uvc_queue_init(). The function performs
31 * basic initialization of the uvc_video_queue struct and never fails.
33 * Video buffers are managed by videobuf2. The driver uses a mutex to protect
34 * the videobuf2 queue operations by serializing calls to videobuf2 and a
35 * spinlock to protect the IRQ queue that holds the buffers to be processed by
39 /* -----------------------------------------------------------------------------
40 * videobuf2 queue operations
43 static int uvc_queue_setup(struct vb2_queue *vq, const struct v4l2_format *fmt,
44 unsigned int *nbuffers, unsigned int *nplanes,
45 unsigned int sizes[], void *alloc_ctxs[])
47 struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
48 struct uvc_video *video = container_of(queue, struct uvc_video, queue);
50 if (*nbuffers > UVC_MAX_VIDEO_BUFFERS)
51 *nbuffers = UVC_MAX_VIDEO_BUFFERS;
55 sizes[0] = video->imagesize;
60 static int uvc_buffer_prepare(struct vb2_buffer *vb)
62 struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
63 struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
65 if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_OUTPUT &&
66 vb2_get_plane_payload(vb, 0) > vb2_plane_size(vb, 0)) {
67 uvc_trace(UVC_TRACE_CAPTURE, "[E] Bytes used out of bounds.\n");
71 if (unlikely(queue->flags & UVC_QUEUE_DISCONNECTED))
74 buf->state = UVC_BUF_STATE_QUEUED;
75 buf->mem = vb2_plane_vaddr(vb, 0);
76 buf->length = vb2_plane_size(vb, 0);
77 if (vb->v4l2_buf.type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
80 buf->bytesused = vb2_get_plane_payload(vb, 0);
85 static void uvc_buffer_queue(struct vb2_buffer *vb)
87 struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
88 struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
91 spin_lock_irqsave(&queue->irqlock, flags);
93 if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) {
94 list_add_tail(&buf->queue, &queue->irqqueue);
96 /* If the device is disconnected return the buffer to userspace
97 * directly. The next QBUF call will fail with -ENODEV.
99 buf->state = UVC_BUF_STATE_ERROR;
100 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
103 spin_unlock_irqrestore(&queue->irqlock, flags);
106 static struct vb2_ops uvc_queue_qops = {
107 .queue_setup = uvc_queue_setup,
108 .buf_prepare = uvc_buffer_prepare,
109 .buf_queue = uvc_buffer_queue,
112 static int uvc_queue_init(struct uvc_video_queue *queue,
113 enum v4l2_buf_type type)
117 queue->queue.type = type;
118 queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
119 queue->queue.drv_priv = queue;
120 queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
121 queue->queue.ops = &uvc_queue_qops;
122 queue->queue.mem_ops = &vb2_vmalloc_memops;
123 ret = vb2_queue_init(&queue->queue);
127 mutex_init(&queue->mutex);
128 spin_lock_init(&queue->irqlock);
129 INIT_LIST_HEAD(&queue->irqqueue);
136 * Free the video buffers.
138 static void uvc_free_buffers(struct uvc_video_queue *queue)
140 mutex_lock(&queue->mutex);
141 vb2_queue_release(&queue->queue);
142 mutex_unlock(&queue->mutex);
146 * Allocate the video buffers.
148 static int uvc_alloc_buffers(struct uvc_video_queue *queue,
149 struct v4l2_requestbuffers *rb)
153 mutex_lock(&queue->mutex);
154 ret = vb2_reqbufs(&queue->queue, rb);
155 mutex_unlock(&queue->mutex);
157 return ret ? ret : rb->count;
160 static int uvc_query_buffer(struct uvc_video_queue *queue,
161 struct v4l2_buffer *buf)
165 mutex_lock(&queue->mutex);
166 ret = vb2_querybuf(&queue->queue, buf);
167 mutex_unlock(&queue->mutex);
172 static int uvc_queue_buffer(struct uvc_video_queue *queue,
173 struct v4l2_buffer *buf)
178 mutex_lock(&queue->mutex);
179 ret = vb2_qbuf(&queue->queue, buf);
183 spin_lock_irqsave(&queue->irqlock, flags);
184 ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
185 queue->flags &= ~UVC_QUEUE_PAUSED;
186 spin_unlock_irqrestore(&queue->irqlock, flags);
189 mutex_unlock(&queue->mutex);
194 * Dequeue a video buffer. If nonblocking is false, block until a buffer is
197 static int uvc_dequeue_buffer(struct uvc_video_queue *queue,
198 struct v4l2_buffer *buf, int nonblocking)
202 mutex_lock(&queue->mutex);
203 ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
204 mutex_unlock(&queue->mutex);
210 * Poll the video queue.
212 * This function implements video queue polling and is intended to be used by
213 * the device poll handler.
215 static unsigned int uvc_queue_poll(struct uvc_video_queue *queue,
216 struct file *file, poll_table *wait)
220 mutex_lock(&queue->mutex);
221 ret = vb2_poll(&queue->queue, file, wait);
222 mutex_unlock(&queue->mutex);
227 static int uvc_queue_mmap(struct uvc_video_queue *queue,
228 struct vm_area_struct *vma)
232 mutex_lock(&queue->mutex);
233 ret = vb2_mmap(&queue->queue, vma);
234 mutex_unlock(&queue->mutex);
243 * NO-MMU arch need this function to make mmap() work correctly.
245 static unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
250 mutex_lock(&queue->mutex);
251 ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
252 mutex_unlock(&queue->mutex);
258 * Cancel the video buffers queue.
260 * Cancelling the queue marks all buffers on the irq queue as erroneous,
261 * wakes them up and removes them from the queue.
263 * If the disconnect parameter is set, further calls to uvc_queue_buffer will
266 * This function acquires the irq spinlock and can be called from interrupt
269 static void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
271 struct uvc_buffer *buf;
274 spin_lock_irqsave(&queue->irqlock, flags);
275 while (!list_empty(&queue->irqqueue)) {
276 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
278 list_del(&buf->queue);
279 buf->state = UVC_BUF_STATE_ERROR;
280 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
282 /* This must be protected by the irqlock spinlock to avoid race
283 * conditions between uvc_queue_buffer and the disconnection event that
284 * could result in an interruptible wait in uvc_dequeue_buffer. Do not
285 * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
286 * state outside the queue code.
289 queue->flags |= UVC_QUEUE_DISCONNECTED;
290 spin_unlock_irqrestore(&queue->irqlock, flags);
294 * Enable or disable the video buffers queue.
296 * The queue must be enabled before starting video acquisition and must be
297 * disabled after stopping it. This ensures that the video buffers queue
298 * state can be properly initialized before buffers are accessed from the
301 * Enabling the video queue initializes parameters (such as sequence number,
302 * sync pattern, ...). If the queue is already enabled, return -EBUSY.
304 * Disabling the video queue cancels the queue and removes all buffers from
307 * This function can't be called from interrupt context. Use
308 * uvc_queue_cancel() instead.
310 static int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
315 mutex_lock(&queue->mutex);
317 ret = vb2_streamon(&queue->queue, queue->queue.type);
324 ret = vb2_streamoff(&queue->queue, queue->queue.type);
328 spin_lock_irqsave(&queue->irqlock, flags);
329 INIT_LIST_HEAD(&queue->irqqueue);
332 * FIXME: We need to clear the DISCONNECTED flag to ensure that
333 * applications will be able to queue buffers for the next
334 * streaming run. However, clearing it here doesn't guarantee
335 * that the device will be reconnected in the meantime.
337 queue->flags &= ~UVC_QUEUE_DISCONNECTED;
338 spin_unlock_irqrestore(&queue->irqlock, flags);
342 mutex_unlock(&queue->mutex);
346 /* called with &queue_irqlock held.. */
347 static struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
348 struct uvc_buffer *buf)
350 struct uvc_buffer *nextbuf;
352 if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
353 buf->length != buf->bytesused) {
354 buf->state = UVC_BUF_STATE_QUEUED;
355 vb2_set_plane_payload(&buf->buf, 0, 0);
359 list_del(&buf->queue);
360 if (!list_empty(&queue->irqqueue))
361 nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
367 * FIXME: with videobuf2, the sequence number or timestamp fields
368 * are valid only for video capture devices and the UVC gadget usually
369 * is a video output device. Keeping these until the specs are clear on
372 buf->buf.v4l2_buf.sequence = queue->sequence++;
373 do_gettimeofday(&buf->buf.v4l2_buf.timestamp);
375 vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
376 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);
381 static struct uvc_buffer *uvc_queue_head(struct uvc_video_queue *queue)
383 struct uvc_buffer *buf = NULL;
385 if (!list_empty(&queue->irqqueue))
386 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
389 queue->flags |= UVC_QUEUE_PAUSED;