[PATCH v3 4/9] media: vimc: Separate starting stream from pipeline initialisation

[Kaaira Gupta <kgupta@es.iitr.ac.in>]

Separate the process of initialising pipeline array from starting
streaming for all entities in path of a stream. This is needed because
multiple streams can stream, but only one pipeline object is needed.

Process frames only for those entities in a pipeline which are
streaming. This is known through their use counts.

Signed-off-by: Kaaira Gupta <kgupta@es.iitr.ac.in>
---
 .../media/test-drivers/vimc/vimc-streamer.c   | 95 ++++++++++++++++---
 1 file changed, 83 insertions(+), 12 deletions(-)

diff --git a/drivers/media/test-drivers/vimc/vimc-streamer.c b/drivers/media/test-drivers/vimc/vimc-streamer.c
index c1644d69686d..cc40ecabe95a 100644
--- a/drivers/media/test-drivers/vimc/vimc-streamer.c
+++ b/drivers/media/test-drivers/vimc/vimc-streamer.c
@@ -40,33 +40,30 @@ static void vimc_streamer_pipeline_terminate(struct vimc_stream *stream)
 }
 
 /**
- * vimc_streamer_pipeline_init - Initializes the stream structure
+ * vimc_streamer_stream_start - Starts streaming for all entities
+ * in a stream
  *
- * @stream: the pointer to the stream structure to be initialized
  * @ved:    the pointer to the vimc entity initializing the stream
  *
- * Initializes the stream structure. Walks through the entity graph to
- * construct the pipeline used later on the streamer thread.
- * Calls vimc_streamer_s_stream() to enable stream in all entities of
- * the pipeline.
+ * Walks through the entity graph to call vimc_streamer_s_stream()
+ * to enable stream in all entities in path of a stream.
  *
  * Return: 0 if success, error code otherwise.
  */
-static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
-				       struct vimc_ent_device *ved)
+static int vimc_streamer_stream_start(struct vimc_stream *stream,
+				      struct vimc_ent_device *ved)
 {
 	struct media_entity *entity;
 	struct video_device *vdev;
 	struct v4l2_subdev *sd;
+	int stream_size = 0;
 	int ret = 0;
 
-	stream->pipe_size = 0;
-	while (stream->pipe_size < VIMC_STREAMER_PIPELINE_MAX_SIZE) {
+	while (stream_size < VIMC_STREAMER_PIPELINE_MAX_SIZE) {
 		if (!ved) {
 			vimc_streamer_pipeline_terminate(stream);
 			return -EINVAL;
 		}
-		stream->ved_pipeline[stream->pipe_size++] = ved;
 
 		if (is_media_entity_v4l2_subdev(ved->ent)) {
 			sd = media_entity_to_v4l2_subdev(ved->ent);
@@ -104,6 +101,73 @@ static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
 					    entity);
 			ved = video_get_drvdata(vdev);
 		}
+		stream_size++;
+	}
+
+	vimc_streamer_pipeline_terminate(stream);
+	return -EINVAL;
+}
+
+/**
+ * vimc_streamer_pipeline_init - Initialises pipeline and pipe size
+ *
+ * @stream: the pointer to the stream structure
+ * @ved:    the pointer to the vimc entity initializing the stream pipeline
+ *
+ * Walks through the entity graph to initialise ved_pipeline and updates
+ * pipe_size too.
+ *
+ * Return: 0 if success, error code otherwise.
+ */
+static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
+				       struct vimc_ent_device *ved)
+{
+	struct media_entity *entity;
+	struct media_device *mdev;
+	struct media_graph graph;
+	struct video_device *vdev;
+	struct v4l2_subdev *sd;
+	int ret;
+
+	entity = ved->ent;
+	mdev = entity->graph_obj.mdev;
+
+	ret = media_graph_walk_init(&graph, mdev);
+	if (ret)
+		return ret;
+
+	media_graph_walk_start(&graph, entity);
+
+	/*
+	 * Start pipeline array initialisation from RAW Capture only to get
+	 * entities in the correct order of their frame processing.
+	 */
+	if (!strncmp(entity->name, "RGB", 3)) {
+		entity = media_graph_walk_next(&graph);
+		mdev = entity->graph_obj.mdev;
+		media_graph_walk_cleanup(&graph);
+
+		ret = media_graph_walk_init(&graph, mdev);
+		if (ret)
+			return ret;
+		media_graph_walk_start(&graph, entity);
+	}
+
+	while (stream->pipe_size < VIMC_STREAMER_PIPELINE_MAX_SIZE) {
+		if (is_media_entity_v4l2_subdev(entity)) {
+			sd = media_entity_to_v4l2_subdev(entity);
+			ved = v4l2_get_subdevdata(sd);
+		} else {
+			vdev = container_of(entity, struct video_device, entity);
+			ved = video_get_drvdata(vdev);
+		}
+		stream->ved_pipeline[stream->pipe_size++] = ved;
+		entity = media_graph_walk_next(&graph);
+
+		if (!strcmp(entity->name, stream->ved_pipeline[0]->ent->name)) {
+			media_graph_walk_cleanup(&graph);
+			return 0;
+		}
 	}
 
 	vimc_streamer_pipeline_terminate(stream);
@@ -138,8 +202,11 @@ static int vimc_streamer_thread(void *data)
 
 		for (i = stream->pipe_size - 1; i >= 0; i--) {
 			ved = stream->ved_pipeline[i];
-			ret = ved->process_frame(ved);
 
+			if (atomic_read(&ved->use_count) == 0)
+				continue;
+
+			ret = ved->process_frame(ved);
 			if (ret)
 				break;
 		}
@@ -179,6 +246,10 @@ int vimc_streamer_s_stream(struct vimc_stream *stream,
 		if (stream->kthread)
 			return 0;
 
+		ret = vimc_streamer_stream_start(stream, ved);
+		if (ret)
+			return ret;
+
 		ret = vimc_streamer_pipeline_init(stream, ved);
 		if (ret)
 			return ret;
-- 
2.17.1