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Commit b76a2a8c authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Mauro Carvalho Chehab
Browse files

[media] media: Add obj_type field to struct media_entity 



Code that processes media entities can require knowledge of the
structure type that embeds a particular media entity instance in order
to cast the entity to the proper object type. This needs is shown by the
presence of the is_media_entity_v4l2_io and is_media_entity_v4l2_subdev
functions.

The implementation of those two functions relies on the entity function
field, which is both a wrong and an inefficient design, without even
mentioning the maintenance issue involved in updating the functions
every time a new entity function is added. Fix this by adding add an
obj_type field to the media entity structure to carry the information.

Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Acked-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
parent 1d260123

drivers/media/v4l2-core/v4l2-dev.c

+1 −0
Original line number Diff line number Diff line
@@ -735,6 +735,7 @@ static int video_register_media_controller(struct video_device *vdev, int type) 
	if (!vdev->v4l2_dev->mdev)

		return 0;



	vdev->entity.obj_type = MEDIA_ENTITY_TYPE_VIDEO_DEVICE;

	vdev->entity.function = MEDIA_ENT_F_UNKNOWN;



	switch (type) {

drivers/media/v4l2-core/v4l2-subdev.c

+1 −0
Original line number Diff line number Diff line
@@ -584,6 +584,7 @@ void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops) 
	sd->host_priv = NULL;

#if defined(CONFIG_MEDIA_CONTROLLER)

	sd->entity.name = sd->name;

	sd->entity.obj_type = MEDIA_ENTITY_TYPE_V4L2_SUBDEV;

	sd->entity.function = MEDIA_ENT_F_V4L2_SUBDEV_UNKNOWN;

#endif

}

include/media/media-entity.h

+39 −37
Original line number Diff line number Diff line
@@ -187,11 +187,39 @@ struct media_entity_operations { 
	int (*link_validate)(struct media_link *link);

};



/**

 * enum media_entity_type - Media entity type

 *

 * @MEDIA_ENTITY_TYPE_BASE:

 *	The entity isn't embedded in another subsystem structure.

 * @MEDIA_ENTITY_TYPE_VIDEO_DEVICE:

 *	The entity is embedded in a struct video_device instance.

 * @MEDIA_ENTITY_TYPE_V4L2_SUBDEV:

 *	The entity is embedded in a struct v4l2_subdev instance.

 *

 * Media entity objects are often not instantiated directly, but the media

 * entity structure is inherited by (through embedding) other subsystem-specific

 * structures. The media entity type identifies the type of the subclass

 * structure that implements a media entity instance.

 *

 * This allows runtime type identification of media entities and safe casting to

 * the correct object type. For instance, a media entity structure instance

 * embedded in a v4l2_subdev structure instance will have the type

 * MEDIA_ENTITY_TYPE_V4L2_SUBDEV and can safely be cast to a v4l2_subdev

 * structure using the container_of() macro.

 */

enum media_entity_type {

	MEDIA_ENTITY_TYPE_BASE,

	MEDIA_ENTITY_TYPE_VIDEO_DEVICE,

	MEDIA_ENTITY_TYPE_V4L2_SUBDEV,

};



/**

 * struct media_entity - A media entity graph object.

 *

 * @graph_obj:	Embedded structure containing the media object common data.

 * @name:	Entity name.

 * @obj_type:	Type of the object that implements the media_entity.

 * @function:	Entity main function, as defined in uapi/media.h

 *		(MEDIA_ENT_F_*)

 * @flags:	Entity flags, as defined in uapi/media.h (MEDIA_ENT_FL_*)
@@ -220,6 +248,7 @@ struct media_entity_operations { 
struct media_entity {

	struct media_gobj graph_obj;	/* must be first field in struct */

	const char *name;

	enum media_entity_type obj_type;

	u32 function;

	unsigned long flags;
@@ -329,56 +358,29 @@ static inline u32 media_gobj_gen_id(enum media_gobj_type type, u64 local_id) 
}



/**

 * is_media_entity_v4l2_io() - identify if the entity main function

 *			       is a V4L2 I/O

 *

 * is_media_entity_v4l2_io() - Check if the entity is a video_device

 * @entity:	pointer to entity

 *

 * Return: true if the entity main function is one of the V4L2 I/O types

 *	(video, VBI or SDR radio); false otherwise.

 * Return: true if the entity is an instance of a video_device object and can

 * safely be cast to a struct video_device using the container_of() macro, or

 * false otherwise.

 */

static inline bool is_media_entity_v4l2_io(struct media_entity *entity)

{

	if (!entity)

		return false;



	switch (entity->function) {

	case MEDIA_ENT_F_IO_V4L:

	case MEDIA_ENT_F_IO_VBI:

	case MEDIA_ENT_F_IO_SWRADIO:

		return true;

	default:

		return false;

	}

	return entity && entity->obj_type == MEDIA_ENTITY_TYPE_VIDEO_DEVICE;

}



/**

 * is_media_entity_v4l2_subdev - return true if the entity main function is

 *				 associated with the V4L2 API subdev usage

 *

 * is_media_entity_v4l2_subdev() - Check if the entity is a v4l2_subdev

 * @entity:	pointer to entity

 *

 * This is an ancillary function used by subdev-based V4L2 drivers.

 * It checks if the entity function is one of functions used by a V4L2 subdev,

 * e. g. camera-relatef functions, analog TV decoder, TV tuner, V4L2 DSPs.

 * Return: true if the entity is an instance of a v4l2_subdev object and can

 * safely be cast to a struct v4l2_subdev using the container_of() macro, or

 * false otherwise.

 */

static inline bool is_media_entity_v4l2_subdev(struct media_entity *entity)

{

	if (!entity)

		return false;



	switch (entity->function) {

	case MEDIA_ENT_F_V4L2_SUBDEV_UNKNOWN:

	case MEDIA_ENT_F_CAM_SENSOR:

	case MEDIA_ENT_F_FLASH:

	case MEDIA_ENT_F_LENS:

	case MEDIA_ENT_F_ATV_DECODER:

	case MEDIA_ENT_F_TUNER:

		return true;



	default:

		return false;

	}

	return entity && entity->obj_type == MEDIA_ENTITY_TYPE_V4L2_SUBDEV;

}



/**