linux/include/media/media-entity.h
Laurent Pinchart e02188c90f [media] media: Pipelines and media streams
Drivers often need to associate pipeline objects to entities, and to
take stream state into account when configuring entities and links. The
pipeline API helps drivers manage that information.

When starting streaming, drivers call media_entity_pipeline_start(). The
function marks all entities connected to the given entity through
enabled links, either directly or indirectly, as streaming. Similarly,
when stopping the stream, drivers call media_entity_pipeline_stop().

The media_entity_pipeline_start() function takes a pointer to a media
pipeline and stores it in every entity in the graph. Drivers should
embed the media_pipeline structure in higher-level pipeline structures
and can then access the pipeline through the media_entity structure.

Link configuration will fail with -EBUSY by default if either end of the
link is a streaming entity, unless the link is marked with the
MEDIA_LNK_FL_DYNAMIC flag.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2011-03-22 04:53:17 -03:00

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4.6 KiB
C

/*
* 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