media-entity.h

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/*
 * Media entity
 *
 * Copyright (C) 2010 Nokia Corporation
 *
 * Contacts: Laurent Pinchart <[email protected]>
 *       Sakari Ailus <[email protected]>
 *
 * 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);
    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;
        } v4l;
        struct {
            u32 major;
            u32 minor;
        } fb;
        struct {
            u32 card;
            u32 device;
            u32 subdevice;
        } alsa;
        int dvb;

        /* 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;
}

#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);
__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)

#endif