[media] media: Add link_validate() op to check links to the sink pad
The purpose of the link_validate() op is to allow an entity driver to ensure
that the properties of the pads at the both ends of the link are suitable
for starting the pipeline. link_validate is called on sink pads on active
links which belong to the active part of the graph.
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index 056138f..e1cd132 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -214,23 +214,76 @@
* pipeline pointer must be identical for all nested calls to
* media_entity_pipeline_start().
*/
-void media_entity_pipeline_start(struct media_entity *entity,
- struct media_pipeline *pipe)
+__must_check int media_entity_pipeline_start(struct media_entity *entity,
+ struct media_pipeline *pipe)
{
struct media_device *mdev = entity->parent;
struct media_entity_graph graph;
+ struct media_entity *entity_err = entity;
+ int ret;
mutex_lock(&mdev->graph_mutex);
media_entity_graph_walk_start(&graph, entity);
while ((entity = media_entity_graph_walk_next(&graph))) {
+ unsigned int i;
+
entity->stream_count++;
WARN_ON(entity->pipe && entity->pipe != pipe);
entity->pipe = pipe;
+
+ /* Already streaming --- no need to check. */
+ if (entity->stream_count > 1)
+ continue;
+
+ if (!entity->ops || !entity->ops->link_validate)
+ continue;
+
+ for (i = 0; i < entity->num_links; i++) {
+ struct media_link *link = &entity->links[i];
+
+ /* Is this pad part of an enabled link? */
+ if (!(link->flags & MEDIA_LNK_FL_ENABLED))
+ continue;
+
+ /* Are we the sink or not? */
+ if (link->sink->entity != entity)
+ continue;
+
+ ret = entity->ops->link_validate(link);
+ if (ret < 0 && ret != -ENOIOCTLCMD)
+ goto error;
+ }
}
mutex_unlock(&mdev->graph_mutex);
+
+ return 0;
+
+error:
+ /*
+ * Link validation on graph failed. We revert what we did and
+ * return the error.
+ */
+ media_entity_graph_walk_start(&graph, entity_err);
+
+ while ((entity_err = media_entity_graph_walk_next(&graph))) {
+ entity_err->stream_count--;
+ if (entity_err->stream_count == 0)
+ entity_err->pipe = NULL;
+
+ /*
+ * We haven't increased stream_count further than this
+ * so we quit here.
+ */
+ if (entity_err == entity)
+ break;
+ }
+
+ mutex_unlock(&mdev->graph_mutex);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(media_entity_pipeline_start);