diff options
| -rw-r--r-- | Documentation/media-framework.txt | 19 | ||||
| -rw-r--r-- | drivers/media/media-entity.c | 57 | ||||
| -rw-r--r-- | include/media/media-entity.h | 5 |
3 files changed, 77 insertions, 4 deletions
diff --git a/Documentation/media-framework.txt b/Documentation/media-framework.txt index 3a0f879533ce..802875413873 100644 --- a/Documentation/media-framework.txt +++ b/Documentation/media-framework.txt @@ -335,6 +335,9 @@ the media_entity pipe field. Calls to media_entity_pipeline_start() can be nested. The pipeline pointer must be identical for all nested calls to the function. +media_entity_pipeline_start() may return an error. In that case, it will +clean up any the changes it did by itself. + When stopping the stream, drivers must notify the entities with media_entity_pipeline_stop(struct media_entity *entity); @@ -351,3 +354,19 @@ If other operations need to be disallowed on streaming entities (such as changing entities configuration parameters) drivers can explicitly check the media_entity stream_count field to find out if an entity is streaming. This operation must be done with the media_device graph_mutex held. + + +Link validation +--------------- + +Link validation is performed by media_entity_pipeline_start() for any +entity which has sink pads in the pipeline. The +media_entity::link_validate() callback is used for that purpose. In +link_validate() callback, entity driver should check that the properties of +the source pad of the connected entity and its own sink pad match. It is up +to the type of the entity (and in the end, the properties of the hardware) +what matching actually means. + +Subsystems should facilitate link validation by providing subsystem specific +helper functions to provide easy access for commonly needed information, and +in the end provide a way to use driver-specific callbacks. diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c index 056138f63c7d..e1cd13283407 100644 --- a/drivers/media/media-entity.c +++ b/drivers/media/media-entity.c @@ -214,23 +214,76 @@ EXPORT_SYMBOL_GPL(media_entity_graph_walk_next); * 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); diff --git a/include/media/media-entity.h b/include/media/media-entity.h index 29e7bba78ffe..0c16f518ee09 100644 --- a/include/media/media-entity.h +++ b/include/media/media-entity.h @@ -46,6 +46,7 @@ struct media_entity_operations { int (*link_setup)(struct media_entity *entity, const struct media_pad *local, const struct media_pad *remote, u32 flags); + int (*link_validate)(struct media_link *link); }; struct media_entity { @@ -140,8 +141,8 @@ void media_entity_graph_walk_start(struct media_entity_graph *graph, struct media_entity *entity); struct media_entity * media_entity_graph_walk_next(struct media_entity_graph *graph); -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); void media_entity_pipeline_stop(struct media_entity *entity); #define media_entity_call(entity, operation, args...) \ |