/*
* Allocate the video buffers.
*
* Pages are reserved to make sure they will not be swaped, as they will be
* filled in URB completion handler.
*
* Buffers will be individually mapped, so they must all be page aligned.
*/
int uvc_alloc_buffers(struct uvc_video_queue *queue, unsigned int nbuffers,
unsigned int buflength)
{
unsigned int bufsize = PAGE_ALIGN(buflength);
unsigned int i;
void *mem = NULL;
int ret;
if (nbuffers > UVC_MAX_VIDEO_BUFFERS)
nbuffers = UVC_MAX_VIDEO_BUFFERS;
mutex_lock(&queue->mutex);
if ((ret = uvc_free_buffers(queue)) < 0)
goto done;
/* Bail out if no buffers should be allocated. */
if (nbuffers == 0)
goto done;
/* Decrement the number of buffers until allocation succeeds. */
for (; nbuffers > 0; --nbuffers) {
mem = vmalloc_32(nbuffers * bufsize);
if (mem != NULL)
break;
}
if (mem == NULL) {
ret = -ENOMEM;
goto done;
}
for (i = 0; i < nbuffers; ++i) {
memset(&queue->buffer[i], 0, sizeof queue->buffer[i]);
queue->buffer[i].buf.index = i;
queue->buffer[i].buf.m.offset = i * bufsize;
queue->buffer[i].buf.length = buflength;
queue->buffer[i].buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
queue->buffer[i].buf.sequence = 0;
queue->buffer[i].buf.field = V4L2_FIELD_NONE;
queue->buffer[i].buf.memory = V4L2_MEMORY_MMAP;
queue->buffer[i].buf.flags = 0;
init_waitqueue_head(&queue->buffer[i].wait);
}
queue->mem = mem;
queue->count = nbuffers;
queue->buf_size = bufsize;
ret = nbuffers;
done:
mutex_unlock(&queue->mutex);
return ret;
}
static int
uvc_v4l2_release(struct file *file)
{
struct video_device *vdev = video_devdata(file);
struct uvc_device *uvc = video_get_drvdata(vdev);
struct uvc_file_handle *handle = to_uvc_file_handle(file->private_data);
struct uvc_video *video = handle->device;
uvc_function_disconnect(uvc);
uvc_video_enable(video, 0);
mutex_lock(&video->queue.mutex);
if (uvc_free_buffers(&video->queue) < 0)
printk(KERN_ERR "uvc_v4l2_release: Unable to free "
"buffers.\n");
mutex_unlock(&video->queue.mutex);
file->private_data = NULL;
v4l2_fh_del(&handle->vfh);
v4l2_fh_exit(&handle->vfh);
kfree(handle);
return 0;
}
