[media] videobuf2: add trace events

Add videobuf2 specific vb2_qbuf and vb2_dqbuf trace events that mirror the
v4l2_qbuf and v4l2_dqbuf trace events, only they include additional
information about queue fill state and are emitted right before the buffer
is enqueued in the driver or userspace is woken up. This allows to make
sense of the timeline of trace events in combination with others that might
be triggered by __enqueue_in_driver.

Also two new trace events vb2_buf_queue and vb2_buf_done are added,
allowing to trace the handover between videobuf2 framework and driver.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/v4l2-core/videobuf2-core.c

@@ -30,6 +30,8 @@
 #include <media/v4l2-common.h>
 #include <media/videobuf2-core.h>
 
+#include <trace/events/v4l2.h>
+
 static int debug;
 module_param(debug, int, 0644);
 
@@ -1207,6 +1209,8 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
 	atomic_dec(&q->owned_by_drv_count);
 	spin_unlock_irqrestore(&q->done_lock, flags);
 
+	trace_vb2_buf_done(q, vb);
+
 	if (state == VB2_BUF_STATE_QUEUED) {
 		if (q->start_streaming_called)
 			__enqueue_in_driver(vb);
@@ -1629,6 +1633,8 @@ static void __enqueue_in_driver(struct vb2_buffer *vb)
 	vb->state = VB2_BUF_STATE_ACTIVE;
 	atomic_inc(&q->owned_by_drv_count);
 
+	trace_vb2_buf_queue(q, vb);
+
 	/* sync buffers */
 	for (plane = 0; plane < vb->num_planes; ++plane)
 		call_void_memop(vb, prepare, vb->planes[plane].mem_priv);
@@ -1878,6 +1884,8 @@ static int vb2_internal_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
 			vb->v4l2_buf.timecode = b->timecode;
 	}
 
+	trace_vb2_qbuf(q, vb);
+
 	/*
 	 * If already streaming, give the buffer to driver for processing.
 	 * If not, the buffer will be given to driver on next streamon.
@@ -2123,6 +2131,9 @@ static int vb2_internal_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool n
 	/* Remove from videobuf queue */
 	list_del(&vb->queued_entry);
 	q->queued_count--;
+
+	trace_vb2_dqbuf(q, vb);
+
 	if (!V4L2_TYPE_IS_OUTPUT(q->type) &&
 	    vb->v4l2_buf.flags & V4L2_BUF_FLAG_LAST)
 		q->last_buffer_dequeued = true;

include/trace/events/v4l2.h

@@ -174,6 +174,103 @@ DEFINE_EVENT(v4l2_event_class, v4l2_qbuf,
 	TP_ARGS(minor, buf)
 );
 
+DECLARE_EVENT_CLASS(vb2_event_class,
+	TP_PROTO(struct vb2_queue *q, struct vb2_buffer *vb),
+	TP_ARGS(q, vb),
+
+	TP_STRUCT__entry(
+		__field(int, minor)
+		__field(u32, queued_count)
+		__field(int, owned_by_drv_count)
+		__field(u32, index)
+		__field(u32, type)
+		__field(u32, bytesused)
+		__field(u32, flags)
+		__field(u32, field)
+		__field(s64, timestamp)
+		__field(u32, timecode_type)
+		__field(u32, timecode_flags)
+		__field(u8, timecode_frames)
+		__field(u8, timecode_seconds)
+		__field(u8, timecode_minutes)
+		__field(u8, timecode_hours)
+		__field(u8, timecode_userbits0)
+		__field(u8, timecode_userbits1)
+		__field(u8, timecode_userbits2)
+		__field(u8, timecode_userbits3)
+		__field(u32, sequence)
+	),
+
+	TP_fast_assign(
+		__entry->minor = q->owner ? q->owner->vdev->minor : -1;
+		__entry->queued_count = q->queued_count;
+		__entry->owned_by_drv_count =
+			atomic_read(&q->owned_by_drv_count);
+		__entry->index = vb->v4l2_buf.index;
+		__entry->type = vb->v4l2_buf.type;
+		__entry->bytesused = vb->v4l2_planes[0].bytesused;
+		__entry->flags = vb->v4l2_buf.flags;
+		__entry->field = vb->v4l2_buf.field;
+		__entry->timestamp = timeval_to_ns(&vb->v4l2_buf.timestamp);
+		__entry->timecode_type = vb->v4l2_buf.timecode.type;
+		__entry->timecode_flags = vb->v4l2_buf.timecode.flags;
+		__entry->timecode_frames = vb->v4l2_buf.timecode.frames;
+		__entry->timecode_seconds = vb->v4l2_buf.timecode.seconds;
+		__entry->timecode_minutes = vb->v4l2_buf.timecode.minutes;
+		__entry->timecode_hours = vb->v4l2_buf.timecode.hours;
+		__entry->timecode_userbits0 = vb->v4l2_buf.timecode.userbits[0];
+		__entry->timecode_userbits1 = vb->v4l2_buf.timecode.userbits[1];
+		__entry->timecode_userbits2 = vb->v4l2_buf.timecode.userbits[2];
+		__entry->timecode_userbits3 = vb->v4l2_buf.timecode.userbits[3];
+		__entry->sequence = vb->v4l2_buf.sequence;
+	),
+
+	TP_printk("minor = %d, queued = %u, owned_by_drv = %d, index = %u, "
+		  "type = %s, bytesused = %u, flags = %s, field = %s, "
+		  "timestamp = %llu, timecode = { type = %s, flags = %s, "
+		  "frames = %u, seconds = %u, minutes = %u, hours = %u, "
+		  "userbits = { %u %u %u %u } }, sequence = %u", __entry->minor,
+		  __entry->queued_count,
+		  __entry->owned_by_drv_count,
+		  __entry->index, show_type(__entry->type),
+		  __entry->bytesused,
+		  show_flags(__entry->flags),
+		  show_field(__entry->field),
+		  __entry->timestamp,
+		  show_timecode_type(__entry->timecode_type),
+		  show_timecode_flags(__entry->timecode_flags),
+		  __entry->timecode_frames,
+		  __entry->timecode_seconds,
+		  __entry->timecode_minutes,
+		  __entry->timecode_hours,
+		  __entry->timecode_userbits0,
+		  __entry->timecode_userbits1,
+		  __entry->timecode_userbits2,
+		  __entry->timecode_userbits3,
+		  __entry->sequence
+	)
+)
+
+DEFINE_EVENT(vb2_event_class, vb2_buf_done,
+	TP_PROTO(struct vb2_queue *q, struct vb2_buffer *vb),
+	TP_ARGS(q, vb)
+);
+
+DEFINE_EVENT(vb2_event_class, vb2_buf_queue,
+	TP_PROTO(struct vb2_queue *q, struct vb2_buffer *vb),
+	TP_ARGS(q, vb)
+);
+
+DEFINE_EVENT(vb2_event_class, vb2_dqbuf,
+	TP_PROTO(struct vb2_queue *q, struct vb2_buffer *vb),
+	TP_ARGS(q, vb)
+);
+
+DEFINE_EVENT(vb2_event_class, vb2_qbuf,
+	TP_PROTO(struct vb2_queue *q, struct vb2_buffer *vb),
+	TP_ARGS(q, vb)
+);
+
 #endif /* if !defined(_TRACE_V4L2_H) || defined(TRACE_HEADER_MULTI_READ) */
 
 /* This part must be outside protection */