1 files changed, 37 insertions, 22 deletions

diff --git a/drivers/media/platform/vimc/vimc-streamer.c b/drivers/media/platform/vimc/vimc-streamer.c
index 3b3f36357a0e..cd6b55433c9e 100644
--- a/drivers/media/platform/vimc/vimc-streamer.c
+++ b/drivers/media/platform/vimc/vimc-streamer.c
@@ -7,7 +7,6 @@
  */
 
 #include <linux/init.h>
-#include <linux/module.h>
 #include <linux/freezer.h>
 #include <linux/kthread.h>
 
@@ -20,6 +19,8 @@
  *
  * Helper function that returns the media entity containing the source pad
  * linked with the first sink pad from the given media entity pad list.
+ *
+ * Return: The source pad or NULL, if it wasn't found.
  */
 static struct media_entity *vimc_get_source_entity(struct media_entity *ent)
 {
@@ -35,7 +36,7 @@ static struct media_entity *vimc_get_source_entity(struct media_entity *ent)
 	return NULL;
 }
 
-/*
+/**
  * vimc_streamer_pipeline_terminate - Disable stream in all ved in stream
  *
  * @stream: the pointer to the stream structure with the pipeline to be
@@ -52,7 +53,6 @@ static void vimc_streamer_pipeline_terminate(struct vimc_stream *stream)
 	while (stream->pipe_size) {
 		stream->pipe_size--;
 		ved = stream->ved_pipeline[stream->pipe_size];
-		ved->stream = NULL;
 		stream->ved_pipeline[stream->pipe_size] = NULL;
 
 		if (!is_media_entity_v4l2_subdev(ved->ent))
@@ -63,15 +63,18 @@ static void vimc_streamer_pipeline_terminate(struct vimc_stream *stream)
 	}
 }
 
-/*
- * vimc_streamer_pipeline_init - initializes the stream structure
+/**
+ * vimc_streamer_pipeline_init - Initializes the stream structure
  *
  * @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 s_stream to enable stream in all entities of the pipeline.
+ * Calls vimc_streamer_s_stream() to enable stream in all entities of
+ * the pipeline.
+ *
+ * Return: 0 if success, error code otherwise.
  */
 static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
 				       struct vimc_ent_device *ved)
@@ -88,23 +91,31 @@ static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
 			return -EINVAL;
 		}
 		stream->ved_pipeline[stream->pipe_size++] = ved;
-		ved->stream = stream;
 
 		if (is_media_entity_v4l2_subdev(ved->ent)) {
 			sd = media_entity_to_v4l2_subdev(ved->ent);
 			ret = v4l2_subdev_call(sd, video, s_stream, 1);
 			if (ret && ret != -ENOIOCTLCMD) {
-				pr_err("subdev_call error %s\n",
-				       ved->ent->name);
+				dev_err(ved->dev, "subdev_call error %s\n",
+					ved->ent->name);
 				vimc_streamer_pipeline_terminate(stream);
 				return ret;
 			}
 		}
 
 		entity = vimc_get_source_entity(ved->ent);
-		/* Check if the end of the pipeline was reached*/
-		if (!entity)
+		/* Check if the end of the pipeline was reached */
+		if (!entity) {
+			/* the first entity of the pipe should be source only */
+			if (!vimc_is_source(ved->ent)) {
+				dev_err(ved->dev,
+					"first entity in the pipe '%s' is not a source\n",
+					ved->ent->name);
+				vimc_streamer_pipeline_terminate(stream);
+				return -EPIPE;
+			}
 			return 0;
+		}
 
 		/* Get the next device in the pipeline */
 		if (is_media_entity_v4l2_subdev(entity)) {
@@ -122,13 +133,17 @@ static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
 	return -EINVAL;
 }
 
-/*
- * vimc_streamer_thread - process frames through the pipeline
+/**
+ * vimc_streamer_thread - Process frames through the pipeline
  *
  * @data:	vimc_stream struct of the current stream
  *
  * From the source to the sink, gets a frame from each subdevice and send to
  * the next one of the pipeline at a fixed framerate.
+ *
+ * Return:
+ * Always zero (created as ``int`` instead of ``void`` to comply with
+ * kthread API).
  */
 static int vimc_streamer_thread(void *data)
 {
@@ -157,19 +172,20 @@ static int vimc_streamer_thread(void *data)
 	return 0;
 }
 
-/*
- * vimc_streamer_s_stream - start/stop the streaming on the media pipeline
+/**
+ * vimc_streamer_s_stream - Start/stop the streaming on the media pipeline
  *
  * @stream:	the pointer to the stream structure of the current stream
  * @ved:	pointer to the vimc entity of the entity of the stream
  * @enable:	flag to determine if stream should start/stop
  *
- * When starting, check if there is no stream->kthread allocated. This should
- * indicate that a stream is already running. Then, it initializes
- * the pipeline, creates and runs a kthread to consume buffers through the
- * pipeline.
- * When stopping, analogously check if there is a stream running, stop
- * the thread and terminates the pipeline.
+ * When starting, check if there is no ``stream->kthread`` allocated. This
+ * should indicate that a stream is already running. Then, it initializes the
+ * pipeline, creates and runs a kthread to consume buffers through the pipeline.
+ * When stopping, analogously check if there is a stream running, stop the
+ * thread and terminates the pipeline.
+ *
+ * Return: 0 if success, error code otherwise.
  */
 int vimc_streamer_s_stream(struct vimc_stream *stream,
 			   struct vimc_ent_device *ved,
@@ -209,4 +225,3 @@ int vimc_streamer_s_stream(struct vimc_stream *stream,
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(vimc_streamer_s_stream);