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);
180 spin_lock_irqsave(&queue->irqlock, flags);
181 ret = (queue->flags & UVC_QUEUE_PAUSED) != 0;
182 queue->flags &= ~UVC_QUEUE_PAUSED;
183 spin_unlock_irqrestore(&queue->irqlock, flags);
184 mutex_unlock(&queue->mutex);
190 * Dequeue a video buffer. If nonblocking is false, block until a buffer is
193 static int uvc_dequeue_buffer(struct uvc_video_queue *queue,
194 struct v4l2_buffer *buf, int nonblocking)
198 mutex_lock(&queue->mutex);
199 ret = vb2_dqbuf(&queue->queue, buf, nonblocking);
200 mutex_unlock(&queue->mutex);
206 * Poll the video queue.
208 * This function implements video queue polling and is intended to be used by
209 * the device poll handler.
211 static unsigned int uvc_queue_poll(struct uvc_video_queue *queue,
212 struct file *file, poll_table *wait)
216 mutex_lock(&queue->mutex);
217 ret = vb2_poll(&queue->queue, file, wait);
218 mutex_unlock(&queue->mutex);
223 static int uvc_queue_mmap(struct uvc_video_queue *queue,
224 struct vm_area_struct *vma)
228 mutex_lock(&queue->mutex);
229 ret = vb2_mmap(&queue->queue, vma);
230 mutex_unlock(&queue->mutex);
239 * NO-MMU arch need this function to make mmap() work correctly.
241 static unsigned long uvc_queue_get_unmapped_area(struct uvc_video_queue *queue,
246 mutex_lock(&queue->mutex);
247 ret = vb2_get_unmapped_area(&queue->queue, 0, 0, pgoff, 0);
248 mutex_unlock(&queue->mutex);
254 * Cancel the video buffers queue.
256 * Cancelling the queue marks all buffers on the irq queue as erroneous,
257 * wakes them up and removes them from the queue.
259 * If the disconnect parameter is set, further calls to uvc_queue_buffer will
262 * This function acquires the irq spinlock and can be called from interrupt
265 static void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
267 struct uvc_buffer *buf;
270 spin_lock_irqsave(&queue->irqlock, flags);
271 while (!list_empty(&queue->irqqueue)) {
272 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
274 list_del(&buf->queue);
275 buf->state = UVC_BUF_STATE_ERROR;
276 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_ERROR);
278 /* This must be protected by the irqlock spinlock to avoid race
279 * conditions between uvc_queue_buffer and the disconnection event that
280 * could result in an interruptible wait in uvc_dequeue_buffer. Do not
281 * blindly replace this logic by checking for the UVC_DEV_DISCONNECTED
282 * state outside the queue code.
285 queue->flags |= UVC_QUEUE_DISCONNECTED;
286 spin_unlock_irqrestore(&queue->irqlock, flags);
290 * Enable or disable the video buffers queue.
292 * The queue must be enabled before starting video acquisition and must be
293 * disabled after stopping it. This ensures that the video buffers queue
294 * state can be properly initialized before buffers are accessed from the
297 * Enabling the video queue initializes parameters (such as sequence number,
298 * sync pattern, ...). If the queue is already enabled, return -EBUSY.
300 * Disabling the video queue cancels the queue and removes all buffers from
303 * This function can't be called from interrupt context. Use
304 * uvc_queue_cancel() instead.
306 static int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
311 mutex_lock(&queue->mutex);
313 ret = vb2_streamon(&queue->queue, queue->queue.type);
320 ret = vb2_streamoff(&queue->queue, queue->queue.type);
324 spin_lock_irqsave(&queue->irqlock, flags);
325 INIT_LIST_HEAD(&queue->irqqueue);
328 * FIXME: We need to clear the DISCONNECTED flag to ensure that
329 * applications will be able to queue buffers for the next
330 * streaming run. However, clearing it here doesn't guarantee
331 * that the device will be reconnected in the meantime.
333 queue->flags &= ~UVC_QUEUE_DISCONNECTED;
334 spin_unlock_irqrestore(&queue->irqlock, flags);
338 mutex_unlock(&queue->mutex);
342 /* called with &queue_irqlock held.. */
343 static struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue,
344 struct uvc_buffer *buf)
346 struct uvc_buffer *nextbuf;
348 if ((queue->flags & UVC_QUEUE_DROP_INCOMPLETE) &&
349 buf->length != buf->bytesused) {
350 buf->state = UVC_BUF_STATE_QUEUED;
351 vb2_set_plane_payload(&buf->buf, 0, 0);
355 list_del(&buf->queue);
356 if (!list_empty(&queue->irqqueue))
357 nextbuf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
363 * FIXME: with videobuf2, the sequence number or timestamp fields
364 * are valid only for video capture devices and the UVC gadget usually
365 * is a video output device. Keeping these until the specs are clear on
368 buf->buf.v4l2_buf.sequence = queue->sequence++;
369 do_gettimeofday(&buf->buf.v4l2_buf.timestamp);
371 vb2_set_plane_payload(&buf->buf, 0, buf->bytesused);
372 vb2_buffer_done(&buf->buf, VB2_BUF_STATE_DONE);
377 static struct uvc_buffer *uvc_queue_head(struct uvc_video_queue *queue)
379 struct uvc_buffer *buf = NULL;
381 if (!list_empty(&queue->irqqueue))
382 buf = list_first_entry(&queue->irqqueue, struct uvc_buffer,
385 queue->flags |= UVC_QUEUE_PAUSED;