Re: [PATCH RFC v3 02/16] media: Add a common embeed struct for all media graph objects

[Mauro Carvalho Chehab <mchehab@osg.samsung.com>]

Em Fri, 14 Aug 2015 16:08:34 +0300
Sakari Ailus <sakari.ailus@iki.fi> escreveu:

> Hi Mauro,
> 
> Thank you for the patchset!
> 
> On Wed, Aug 12, 2015 at 05:14:46PM -0300, Mauro Carvalho Chehab wrote:
> > Due to the MC API proposed changes, we'll need to:
> > 	- have an unique object ID for all graph objects;
> > 	- be able to dynamically create/remove objects;
> > 	- be able to group objects;
> > 	- keep the object in memory until we stop use it.
> > 
> > Due to that, create a struct media_graph_obj and put there the
> > common elements that all media objects will have in common.
> > 
> > Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
> > 
> > diff --git a/include/media/media-entity.h b/include/media/media-entity.h
> > index 0c003d817493..051aa3f8bbfe 100644
> > --- a/include/media/media-entity.h
> > +++ b/include/media/media-entity.h
> > @@ -28,10 +28,50 @@
> >  #include <linux/list.h>
> >  #include <linux/media.h>
> >  
> > +/* Enums used internally at the media controller to represent graphs */
> > +
> > +/**
> > + * enum media_graph_type - type of a graph element
> > + *
> > + * @MEDIA_GRAPH_ENTITY:		Identify a media entity
> > + * @MEDIA_GRAPH_PAD:		Identify a media PAD
> > + * @MEDIA_GRAPH_LINK:		Identify a media link
> > + */
> > +enum media_graph_type {
> > +	MEDIA_GRAPH_ENTITY,
> > +	MEDIA_GRAPH_PAD,
> > +	MEDIA_GRAPH_LINK,
> > +};
> > +
> > +
> > +/* Structs to represent the objects that belong to a media graph */
> > +
> > +/**
> > + * struct media_graph_obj - Define a graph object.
> > + *
> > + * @list:		List of media graph objects
> > + * @obj_id:		Non-zero object ID identifier. The ID should be unique
> > + *			inside a media_device
> > + * @type:		Type of the graph object
> > + * @mdev:		Media device that contains the object
> > + *			object before stopping using it
> > + *
> > + * All elements on the media graph should have this struct embedded
> > + */
> > +struct media_graph_obj {
> > +	struct list_head	list;
> > +	struct list_head	group;
> 
> What's group for?

I'm actually thinking on replacing group_id by a group list object type.

Anyway, I'm simplifying this patch series. So, I'll drop this field
for now. We can add it when needed.

> 
> > +	u32			obj_id;
> 
> I'd just call this "id".

OK.

> 
> > +	enum media_graph_type	type;
> > +	struct media_device	*mdev;
> > +};
> > +
> > +
> >  struct media_pipeline {
> >  };
> >  
> >  struct media_link {
> > +	struct media_graph_obj			graph_obj;
> >  	struct media_pad *source;	/* Source pad */
> >  	struct media_pad *sink;		/* Sink pad  */
> >  	struct media_link *reverse;	/* Link in the reverse direction */
> > @@ -39,6 +79,7 @@ struct media_link {
> >  };
> >  
> >  struct media_pad {
> > +	struct media_graph_obj			graph_obj;
> >  	struct media_entity *entity;	/* Entity this pad belongs to */
> >  	u16 index;			/* Pad index in the entity pads array */
> >  	unsigned long flags;		/* Pad flags (MEDIA_PAD_FL_*) */
> > @@ -61,6 +102,7 @@ struct media_entity_operations {
> >  };
> >  
> >  struct media_entity {
> > +	struct media_graph_obj			graph_obj;
> >  	struct list_head list;
> >  	struct media_device *parent;	/* Media device this entity belongs to*/
> >  	u32 id;				/* Entity ID, unique in the parent media
> 
> Will entity id be different from the media_graph_obj obj_id of the object?

No. I'm right now writing a patch removing entity->id.

Regards,
Mauro