text: /*
   * 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/list.h>
  #include <linux/media.h>
  
  struct media_pipeline {
  };
  
  struct media_link {
  	struct media_pad *source;	/* Source pad */
  	struct media_pad *sink;		/* Sink pad  */
  	struct media_link *reverse;	/* Link in the reverse direction */
  	unsigned long flags;		/* Link flags (MEDIA_LNK_FL_*) */
  };
  
  struct media_pad {
  	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_*) */
  };
  
  struct media_entity_operations {
  	int (*link_setup)(struct media_entity *entity,
  			  const struct media_pad *local,
  			  const struct media_pad *remote, u32 flags);
  };
  
  struct media_entity {
  	struct list_head list;
  	struct media_device *parent;	/* Media device this entity belongs to*/
  	u32 id;				/* Entity ID, unique in the parent media
  					 * device context */
  	const char *name;		/* Entity name */
  	u32 type;			/* Entity type (MEDIA_ENT_T_*) */
  	u32 revision;			/* Entity revision, driver specific */
  	unsigned long flags;		/* Entity flags (MEDIA_ENT_FL_*) */
  	u32 group_id;			/* Entity group ID */
  
  	u16 num_pads;			/* Number of sink and source pads */
  	u16 num_links;			/* Number of existing links, both
  					 * enabled and disabled */
  	u16 num_backlinks;		/* Number of backlinks */
  	u16 max_links;			/* Maximum number of links */
  
  	struct media_pad *pads;		/* Pads array (num_pads elements) */
  	struct media_link *links;	/* Links array (max_links elements)*/
  
  	const struct media_entity_operations *ops;	/* Entity operations */
  
  	/* 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;		/* Stream count for the entity. */
  	int use_count;			/* Use count for the entity. */
  
  	struct media_pipeline *pipe;	/* Pipeline this entity belongs to. */
  
  	union {
  		/* Node specifications */
  		struct {
  			u32 major;
  			u32 minor;
  		} v4l;
  		struct {
  			u32 major;
  			u32 minor;
  		} fb;
  		struct {
  			u32 card;
  			u32 device;
  			u32 subdevice;
  		} alsa;
  		int dvb;
  
  		/* Sub-device specifications */
  		/* Nothing needed yet */
  	};
  };
  
  static inline u32 media_entity_type(struct media_entity *entity)
  {
  	return entity->type & MEDIA_ENT_TYPE_MASK;
  }
  
  static inline u32 media_entity_subtype(struct media_entity *entity)
  {
  	return entity->type & MEDIA_ENT_SUBTYPE_MASK;
  }
  
  #define MEDIA_ENTITY_ENUM_MAX_DEPTH	16
  
  struct media_entity_graph {
  	struct {
  		struct media_entity *entity;
  		int link;
  	} stack[MEDIA_ENTITY_ENUM_MAX_DEPTH];
  	int top;
  };
  
  int media_entity_init(struct media_entity *entity, u16 num_pads,
  		struct media_pad *pads, u16 extra_links);
  void media_entity_cleanup(struct media_entity *entity);
  
  int media_entity_create_link(struct media_entity *source, u16 source_pad,
  		struct media_entity *sink, u16 sink_pad, u32 flags);
  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_source(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);
  void 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...)			\
  	(((entity)->ops && (entity)->ops->operation) ?			\
  	 (entity)->ops->operation((entity) , ##args) : -ENOIOCTLCMD)
  
  #endif
  