media-entity.h

/*
 * Media entity
 *
 * Copyright (C) 2010 Nokia Corporation
 *
 * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 *	     Sakari Ailus <sakari.ailus@iki.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef _MEDIA_ENTITY_H
#define _MEDIA_ENTITY_H

#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/media.h>

/* Enums used internally at the media controller to represent graphs */

/**
 * enum media_gobj_type - type of a graph object
 *
 * @MEDIA_GRAPH_ENTITY:		Identify a media entity
 * @MEDIA_GRAPH_PAD:		Identify a media pad
 * @MEDIA_GRAPH_LINK:		Identify a media link
 * @MEDIA_GRAPH_INTF_DEVNODE:	Identify a media Kernel API interface via
 *				a device node
 */
enum media_gobj_type {
	MEDIA_GRAPH_ENTITY,
	MEDIA_GRAPH_PAD,
	MEDIA_GRAPH_LINK,
	MEDIA_GRAPH_INTF_DEVNODE,
};

#define MEDIA_BITS_PER_TYPE		8
#define MEDIA_BITS_PER_LOCAL_ID		(32 - MEDIA_BITS_PER_TYPE)
#define MEDIA_LOCAL_ID_MASK		 GENMASK(MEDIA_BITS_PER_LOCAL_ID - 1, 0)

/* Structs to represent the objects that belong to a media graph */

/**
 * struct media_gobj - Define a graph object.
 *
 * @mdev:	Pointer to the struct media_device that owns the object
 * @id:		Non-zero object ID identifier. The ID should be unique
 *		inside a media_device, as it is composed by
 *		MEDIA_BITS_PER_TYPE to store the type plus
 *		MEDIA_BITS_PER_LOCAL_ID	to store a per-type ID
 *		(called as "local ID").
 * @list:	List entry stored in one of the per-type mdev object lists
 *
 * All objects on the media graph should have this struct embedded
 */
struct media_gobj {
	struct media_device	*mdev;
	u32			id;
	struct list_head	list;
};


struct media_pipeline {
};

/**
 * struct media_link - A link object part of a media graph.
 *
 * @graph_obj:	Embedded structure containing the media object common data
 * @list:	Linked list associated with an entity or an interface that
 *		owns the link.
 * @gobj0:	Part of a union. Used to get the pointer for the first
 *		graph_object of the link.
 * @source:	Part of a union. Used only if the first object (gobj0) is
 *		a pad. In that case, it represents the source pad.
 * @intf:	Part of a union. Used only if the first object (gobj0) is
 *		an interface.
 * @gobj1:	Part of a union. Used to get the pointer for the second
 *		graph_object of the link.
 * @source:	Part of a union. Used only if the second object (gobj1) is
 *		a pad. In that case, it represents the sink pad.
 * @entity:	Part of a union. Used only if the second object (gobj1) is
 *		an entity.
 * @reverse:	Pointer to the link for the reverse direction of a pad to pad
 *		link.
 * @flags:	Link flags, as defined in uapi/media.h (MEDIA_LNK_FL_*)
 * @is_backlink: Indicate if the link is a backlink.
 */
struct media_link {
	struct media_gobj graph_obj;
	struct list_head list;
	union {
		struct media_gobj *gobj0;
		struct media_pad *source;
		struct media_interface *intf;
	};
	union {
		struct media_gobj *gobj1;
		struct media_pad *sink;
		struct media_entity *entity;
	};
	struct media_link *reverse;
	unsigned long flags;
	bool is_backlink;
};

/**
 * struct media_pad - A media pad graph object.
 *
 * @graph_obj:	Embedded structure containing the media object common data
 * @entity:	Entity this pad belongs to
 * @index:	Pad index in the entity pads array, numbered from 0 to n
 * @flags:	Pad flags, as defined in uapi/media.h (MEDIA_PAD_FL_*)
 */
struct media_pad {
	struct media_gobj graph_obj;	/* must be first field in struct */
	struct media_entity *entity;
	u16 index;
	unsigned long flags;
};

/**
 * struct media_entity_operations - Media entity operations
 * @link_setup:		Notify the entity of link changes. The operation can
 *			return an error, in which case link setup will be
 *			cancelled. Optional.
 * @link_validate:	Return whether a link is valid from the entity point of
 *			view. The media_entity_pipeline_start() function
 *			validates all links by calling this operation. Optional.
 */
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 - A media entity graph object.
 *
 * @graph_obj:	Embedded structure containing the media object common data.
 * @name:	Entity name.
 * @function:	Entity main function, as defined in uapi/media.h
 *		(MEDIA_ENT_F_*)
 * @revision:	Entity revision - OBSOLETE - should be removed soon.
 * @flags:	Entity flags, as defined in uapi/media.h (MEDIA_ENT_FL_*)
 * @group_id:	Entity group ID - OBSOLETE - should be removed soon.
 * @num_pads:	Number of sink and source pads.
 * @num_links:	Total number of links, forward and back, enabled and disabled.
 * @num_backlinks: Number of backlinks
 * @pads:	Pads array with the size defined by @num_pads.
 * @links:	List of data links.
 * @ops:	Entity operations.
 * @stream_count: Stream count for the entity.
 * @use_count:	Use count for the entity.
 * @pipe:	Pipeline this entity belongs to.
 * @info:	Union with devnode information.  Kept just for backward
 *		compatibility.
 * @major:	Devnode major number (zero if not applicable). Kept just
 *		for backward compatibility.
 * @minor:	Devnode minor number (zero if not applicable). Kept just
 *		for backward compatibility.
 *
 * NOTE: @stream_count and @use_count reference counts must never be
 * negative, but are signed integers on purpose: a simple WARN_ON(<0) check
 * can be used to detect reference count bugs that would make them negative.
 */
struct media_entity {
	struct media_gobj graph_obj;	/* must be first field in struct */
	const char *name;
	u32 function;
	u32 revision;
	unsigned long flags;
	u32 group_id;

	u16 num_pads;
	u16 num_links;
	u16 num_backlinks;

	struct media_pad *pads;
	struct list_head links;

	const struct media_entity_operations *ops;

	/* Reference counts must never be negative, but are signed integers on
	 * purpose: a simple WARN_ON(<0) check can be used to detect reference
	 * count bugs that would make them negative.
	 */
	int stream_count;
	int use_count;

	struct media_pipeline *pipe;

	union {
		struct {
			u32 major;
			u32 minor;
		} dev;
	} info;
};

/**
 * struct media_interface - A media interface graph object.
 *
 * @graph_obj:		embedded graph object
 * @links:		List of links pointing to graph entities
 * @type:		Type of the interface as defined in the
 *			uapi/media/media.h header, e. g.
 *			MEDIA_INTF_T_*
 * @flags:		Interface flags as defined in uapi/media/media.h
 */
struct media_interface {
	struct media_gobj		graph_obj;
	struct list_head		links;
	u32				type;
	u32				flags;
};

/**
 * struct media_intf_devnode - A media interface via a device node.
 *
 * @intf:	embedded interface object
 * @major:	Major number of a device node
 * @minor:	Minor number of a device node
 */
struct media_intf_devnode {
	struct media_interface		intf;

	/* Should match the fields at media_v2_intf_devnode */
	u32				major;
	u32				minor;
};

static inline u32 media_entity_id(struct media_entity *entity)
{
	return entity->graph_obj.id;
}

static inline enum media_gobj_type media_type(struct media_gobj *gobj)
{
	return gobj->id >> MEDIA_BITS_PER_LOCAL_ID;
}

static inline u32 media_localid(struct media_gobj *gobj)
{
	return gobj->id & MEDIA_LOCAL_ID_MASK;
}

static inline u32 media_gobj_gen_id(enum media_gobj_type type, u32 local_id)
{
	u32 id;

	id = type << MEDIA_BITS_PER_LOCAL_ID;
	id |= local_id & MEDIA_LOCAL_ID_MASK;

	return id;
}

static inline bool is_media_entity_v4l2_io(struct media_entity *entity)
{
	if (!entity)
		return false;

	switch (entity->function) {
	case MEDIA_ENT_T_V4L2_VIDEO:
	case MEDIA_ENT_T_V4L2_VBI:
	case MEDIA_ENT_T_V4L2_SWRADIO:
		return true;
	default:
		return false;
	}
}

static inline bool is_media_entity_v4l2_subdev(struct media_entity *entity)
{
	if (!entity)
		return false;

	switch (entity->function) {
	case MEDIA_ENT_T_V4L2_SUBDEV_UNKNOWN:
	case MEDIA_ENT_T_V4L2_SUBDEV_SENSOR:
	case MEDIA_ENT_T_V4L2_SUBDEV_FLASH:
	case MEDIA_ENT_T_V4L2_SUBDEV_LENS:
	case MEDIA_ENT_T_V4L2_SUBDEV_DECODER:
	case MEDIA_ENT_T_V4L2_SUBDEV_TUNER:
		return true;

	default:
		return false;
	}
}

#define MEDIA_ENTITY_ENUM_MAX_DEPTH	16
#define MEDIA_ENTITY_ENUM_MAX_ID	64

/*
 * The number of pads can't be bigger than the number of entities,
 * as the worse-case scenario is to have one entity linked up to
 * MEDIA_ENTITY_ENUM_MAX_ID - 1 entities.
 */
#define MEDIA_ENTITY_MAX_PADS		(MEDIA_ENTITY_ENUM_MAX_ID - 1)

struct media_entity_graph {
	struct {
		struct media_entity *entity;
		struct list_head *link;
	} stack[MEDIA_ENTITY_ENUM_MAX_DEPTH];

	DECLARE_BITMAP(entities, MEDIA_ENTITY_ENUM_MAX_ID);
	int top;
};

#define gobj_to_entity(gobj) \
		container_of(gobj, struct media_entity, graph_obj)

#define gobj_to_pad(gobj) \
		container_of(gobj, struct media_pad, graph_obj)

#define gobj_to_link(gobj) \
		container_of(gobj, struct media_link, graph_obj)

#define gobj_to_link(gobj) \
		container_of(gobj, struct media_link, graph_obj)

#define gobj_to_pad(gobj) \
		container_of(gobj, struct media_pad, graph_obj)

#define gobj_to_intf(gobj) \
		container_of(gobj, struct media_interface, graph_obj)

#define intf_to_devnode(intf) \
		container_of(intf, struct media_intf_devnode, intf)

void media_gobj_init(struct media_device *mdev,
		    enum media_gobj_type type,
		    struct media_gobj *gobj);
void media_gobj_remove(struct media_gobj *gobj);

int media_entity_init(struct media_entity *entity, u16 num_pads,
		      struct media_pad *pads);
void media_entity_cleanup(struct media_entity *entity);

__must_check int media_create_pad_link(struct media_entity *source,
			u16 source_pad, struct media_entity *sink,
			u16 sink_pad, u32 flags);
void __media_entity_remove_links(struct media_entity *entity);
void media_entity_remove_links(struct media_entity *entity);

int __media_entity_setup_link(struct media_link *link, u32 flags);
int media_entity_setup_link(struct media_link *link, u32 flags);
struct media_link *media_entity_find_link(struct media_pad *source,
		struct media_pad *sink);
struct media_pad *media_entity_remote_pad(struct media_pad *pad);

struct media_entity *media_entity_get(struct media_entity *entity);
void media_entity_put(struct media_entity *entity);

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);
__must_check int media_entity_pipeline_start(struct media_entity *entity,
					     struct media_pipeline *pipe);
void media_entity_pipeline_stop(struct media_entity *entity);

struct media_intf_devnode *
__must_check media_devnode_create(struct media_device *mdev,
				  u32 type, u32 flags,
				  u32 major, u32 minor,
				  gfp_t gfp_flags);
void media_devnode_remove(struct media_intf_devnode *devnode);
struct media_link *
__must_check media_create_intf_link(struct media_entity *entity,
				    struct media_interface *intf,
				    u32 flags);
void __media_remove_intf_link(struct media_link *link);
void media_remove_intf_link(struct media_link *link);
void __media_remove_intf_links(struct media_interface *intf);
void media_remove_intf_links(struct media_interface *intf);


#define media_entity_call(entity, operation, args...)			\
	(((entity)->ops && (entity)->ops->operation) ?			\
	 (entity)->ops->operation((entity) , ##args) : -ENOIOCTLCMD)

#endif