[media] uvcvideo: Add UVC timestamps support

UVC devices transmit a device timestamp along with video frames. Convert
the timestamp to a host timestamp and use it to fill the V4L2 buffer
timestamp field.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/uvc/uvc_queue.c

@@ -104,10 +104,22 @@ static void uvc_buffer_queue(struct vb2_buffer *vb)
 	spin_unlock_irqrestore(&queue->irqlock, flags);
 }
 
+static int uvc_buffer_finish(struct vb2_buffer *vb)
+{
+	struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue);
+	struct uvc_streaming *stream =
+			container_of(queue, struct uvc_streaming, queue);
+	struct uvc_buffer *buf = container_of(vb, struct uvc_buffer, buf);
+
+	uvc_video_clock_update(stream, &vb->v4l2_buf, buf);
+	return 0;
+}
+
 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,
 };
 
 void uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,

drivers/media/video/uvc/uvcvideo.h

@@ -329,6 +329,8 @@ struct uvc_buffer {
 	void *mem;
 	unsigned int length;
 	unsigned int bytesused;
+
+	u32 pts;
 };
 
 #define UVC_QUEUE_DISCONNECTED		(1 << 0)
@@ -455,6 +457,25 @@ struct uvc_streaming {
 		struct uvc_stats_frame frame;
 		struct uvc_stats_stream stream;
 	} stats;
+
+	/* Timestamps support. */
+	struct uvc_clock {
+		struct uvc_clock_sample {
+			u32 dev_stc;
+			u16 dev_sof;
+			struct timespec host_ts;
+			u16 host_sof;
+		} *samples;
+
+		unsigned int head;
+		unsigned int count;
+		unsigned int size;
+
+		u16 last_sof;
+		u16 sof_offset;
+
+		spinlock_t lock;
+	} clock;
 };
 
 enum uvc_device_state {
@@ -527,6 +548,7 @@ struct uvc_driver {
 #define UVC_TRACE_STATUS	(1 << 9)
 #define UVC_TRACE_VIDEO		(1 << 10)
 #define UVC_TRACE_STATS		(1 << 11)
+#define UVC_TRACE_CLOCK		(1 << 12)
 
 #define UVC_WARN_MINMAX		0
 #define UVC_WARN_PROBE_DEF	1
@@ -607,6 +629,9 @@ extern int uvc_probe_video(struct uvc_streaming *stream,
 		struct uvc_streaming_control *probe);
 extern int uvc_query_ctrl(struct uvc_device *dev, __u8 query, __u8 unit,
 		__u8 intfnum, __u8 cs, void *data, __u16 size);
+void uvc_video_clock_update(struct uvc_streaming *stream,
+			    struct v4l2_buffer *v4l2_buf,
+			    struct uvc_buffer *buf);
 
 /* Status */
 extern int uvc_status_init(struct uvc_device *dev);