Re: [PATCH v7 18/44] [media] media: make media_link more generic to handle interace links

[Hans Verkuil <hverkuil@xs4all.nl>]

On 08/23/2015 10:17 PM, Mauro Carvalho Chehab wrote:
> By adding an union at media_link, we get for free a way to
> represent interface->entity links.
> 
> No need to change anything at the code, just at the internal
> header file.
> 
> 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 17bb5cbbd67d..f6e8fa801cf9 100644
> --- a/include/media/media-entity.h
> +++ b/include/media/media-entity.h
> @@ -75,14 +75,20 @@ struct media_pipeline {
>  struct media_link {
>  	struct media_gobj graph_obj;
>  	struct list_head list;
> -	struct media_pad *source;	/* Source pad */
> -	struct media_pad *sink;		/* Sink pad  */
> +	union {
> +		struct media_gobj *port0;
> +		struct media_pad *source;
> +	};
> +	union {
> +		struct media_gobj *port1;

Why add port0 and port1 here instead of intf and entity (now added in patch 20)?
port0/port1 isn't used, so I'd postpone adding that until it is needed.

Part of the reason is also that I am not convinced about the 'port' name, so
let's not add this yet.

Regards,

	Hans

> +		struct media_pad *sink;
> +	};
>  	struct media_link *reverse;	/* Link in the reverse direction */
>  	unsigned long flags;		/* Link flags (MEDIA_LNK_FL_*) */
>  };
>  
>  struct media_pad {
> -	struct media_gobj graph_obj;
> +	struct media_gobj graph_obj;	/* should be the first object */
>  	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_*) */
> @@ -105,7 +111,7 @@ struct media_entity_operations {
>  };
>  
>  struct media_entity {
> -	struct media_gobj graph_obj;
> +	struct media_gobj graph_obj;	/* should be the first object */
>  	struct list_head list;
>  	const char *name;		/* Entity name */
>  	u32 type;			/* Entity type (MEDIA_ENT_T_*) */
> @@ -119,7 +125,7 @@ struct media_entity {
>  	u16 num_backlinks;		/* Number of backlinks */
>  
>  	struct media_pad *pads;		/* Pads array (num_pads objects) */
> -	struct list_head links;		/* Links list */
> +	struct list_head links;		/* Pad-to-pad links list */
>  
>  	const struct media_entity_operations *ops;	/* Entity operations */
>  
>