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* Media entity
* Copyright (C) 2010 Nokia Corporation
* Contacts: Laurent Pinchart <>
* Sakari Ailus <>
* 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
* 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
#include <linux/bitops.h>
#include <linux/kernel.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 - 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 {
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;
} dev;
/* Sub-device specifications */
/* Nothing needed yet */
} info;
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;
struct media_entity_graph {
struct {
struct media_entity *entity;
int link;
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);
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);
#define media_entity_call(entity, operation, args...) \
(((entity)->ops && (entity)->ops->operation) ? \
(entity)->ops->operation((entity) , ##args) : -ENOIOCTLCMD)