[media] uvcvideo: Implement vb2 queue start and stop stream operations

To work propertly the videobuf2 core code needs to be in charge of
stream start/stop control. Implement the start_streaming and
stop_streaming vb2 operations and move video enable/disable code to
them.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/usb/uvc/uvc_queue.c

@@ -135,13 +135,38 @@ static void uvc_wait_finish(struct vb2_queue *vq)
 	mutex_lock(&queue->mutex);
 }
 
+static int uvc_start_streaming(struct vb2_queue *vq, unsigned int count)
+{
+	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
+	struct uvc_streaming *stream = uvc_queue_to_stream(queue);
+
+	queue->buf_used = 0;
+
+	return uvc_video_enable(stream, 1);
+}
+
+static void uvc_stop_streaming(struct vb2_queue *vq)
+{
+	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
+	struct uvc_streaming *stream = uvc_queue_to_stream(queue);
+	unsigned long flags;
+
+	uvc_video_enable(stream, 0);
+
+	spin_lock_irqsave(&queue->irqlock, flags);
+	INIT_LIST_HEAD(&queue->irqqueue);
+	spin_unlock_irqrestore(&queue->irqlock, flags);
+}
+
 static struct vb2_ops uvc_queue_qops = {
 	.queue_setup = uvc_queue_setup,
 	.buf_prepare = uvc_buffer_prepare,
 	.buf_queue = uvc_buffer_queue,
 	.buf_finish = uvc_buffer_finish,
 	.wait_prepare = uvc_wait_prepare,
 	.wait_finish = uvc_wait_finish,
+	.start_streaming = uvc_start_streaming,
+	.stop_streaming = uvc_stop_streaming,
 };
 
 int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
@@ -310,27 +335,15 @@ int uvc_queue_allocated(struct uvc_video_queue *queue)
  */
 int uvc_queue_enable(struct uvc_video_queue *queue, int enable)
 {
-	unsigned long flags;
 	int ret;
 
 	mutex_lock(&queue->mutex);
-	if (enable) {
-		ret = vb2_streamon(&queue->queue, queue->queue.type);
-		if (ret < 0)
-			goto done;
 
-		queue->buf_used = 0;
-	} else {
+	if (enable)
+		ret = vb2_streamon(&queue->queue, queue->queue.type);
+	else
 		ret = vb2_streamoff(&queue->queue, queue->queue.type);
-		if (ret < 0)
-			goto done;
-
-		spin_lock_irqsave(&queue->irqlock, flags);
-		INIT_LIST_HEAD(&queue->irqqueue);
-		spin_unlock_irqrestore(&queue->irqlock, flags);
-	}
 
-done:
 	mutex_unlock(&queue->mutex);
 	return ret;
 }

drivers/media/usb/uvc/uvc_v4l2.c

@@ -531,7 +531,6 @@ static int uvc_v4l2_release(struct file *file)
 
 	/* Only free resources if this is a privileged handle. */
 	if (uvc_has_privileges(handle)) {
-		uvc_video_enable(stream, 0);
 		uvc_queue_enable(&stream->queue, 0);
 		uvc_free_buffers(&stream->queue);
 	}
@@ -768,14 +767,6 @@ static int uvc_ioctl_streamon(struct file *file, void *fh,
 
 	mutex_lock(&stream->mutex);
 	ret = uvc_queue_enable(&stream->queue, 1);
-	if (ret < 0)
-		goto done;
-
-	ret = uvc_video_enable(stream, 1);
-	if (ret < 0)
-		uvc_queue_enable(&stream->queue, 0);
-
-done:
 	mutex_unlock(&stream->mutex);
 
 	return ret;
@@ -794,7 +785,6 @@ static int uvc_ioctl_streamoff(struct file *file, void *fh,
 		return -EBUSY;
 
 	mutex_lock(&stream->mutex);
-	uvc_video_enable(stream, 0);
 	uvc_queue_enable(&stream->queue, 0);
 	mutex_unlock(&stream->mutex);