/*
* 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/bitmap.h>
#include <linux/bug.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_ID (32 - MEDIA_BITS_PER_TYPE)
#define MEDIA_ID_MASK GENMASK_ULL(MEDIA_BITS_PER_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_ID to store the 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;
};
#define MEDIA_ENTITY_ENUM_MAX_DEPTH 16
/**
* struct media_entity_enum - An enumeration of media entities.
*
* @bmap: Bit map in which each bit represents one entity at struct
* media_entity->internal_idx.
* @idx_max: Number of bits in bmap
*/
struct media_entity_enum {
unsigned long *bmap;
int idx_max;
};
/**
* struct media_entity_graph - Media graph traversal state
*
* @stack: Graph traversal stack; the stack contains information
* on the path the media entities to be walked and the
* links through which they were reached.
* @ent_enum: Visited entities
* @top: The top of the stack
*/
struct media_entity_graph {
struct {
struct media_entity *entity;
struct list_head *link;
} stack[MEDIA_ENTITY_ENUM_MAX_DEPTH];
struct media_entity_enum ent_enum;
int top;
};
/**
* struct media_pipeline - Media pipeline related information
*
* @streaming_count: Streaming start count - streaming stop count
* @graph: Media graph walk during pipeline start / stop
*/
struct media_pipeline {
int streaming_count;
struct media_entity_graph graph;
};
/**
* 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.
*
* .. note:: Those these callbacks are called with struct media_device.@graph_mutex
* mutex held.
*/
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);
};
/**
* enum media_entity_type - Media entity type
*
* @MEDIA_ENTITY_TYPE_BASE:
* The entity isn't embedded in another subsystem structure.
* @MEDIA_ENTITY_TYPE_VIDEO_DEVICE:
* The entity is embedded in a struct video_device instance.
* @MEDIA_ENTITY_TYPE_V4L2_SUBDEV:
* The entity is embedded in a struct v4l2_subdev instance.
*
* Media entity objects are often not instantiated directly, but the media
* entity structure is inherited by (through embedding) other subsystem-specific
* structures. The media entity type identifies the type of the subclass
* structure that implements a media entity instance.
*
* This allows runtime type identification of media entities and safe casting to
* the correct object type. For instance, a media entity structure instance
* embedded in a v4l2_subdev structure instance will have the type
* MEDIA_ENTITY_TYPE_V4L2_SUBDEV and can safely be cast to a v4l2_subdev
* structure using the container_of() macro.
*/
enum media_entity_type {
MEDIA_ENTITY_TYPE_BASE,
MEDIA_ENTITY_TYPE_VIDEO_DEVICE,
MEDIA_ENTITY_TYPE_V4L2_SUBDEV,
};
/**
* struct media_entity - A media entity graph object.
*
* @graph_obj: Embedded structure containing the media object common data.
* @name: Entity name.
* @obj_type: Type of the object that implements the media_entity.
* @function: Entity main function, as defined in uapi/media.h
* (MEDIA_ENT_F_*)
* @flags: Entity flags, as defined in uapi/media.h (MEDIA_ENT_FL_*)
* @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
* @internal_idx: An unique internal entity specific number. The numbers are
* re-used if entities are unregistered or registered again.
* @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;
enum media_entity_type obj_type;
u32 function;
unsigned long flags;
u16 num_pads;
u16 num_links;
u16 num_backlinks;
int internal_idx;
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;
};
/**
* media_entity_id() - return the media entity graph object id
*
* @entity: pointer to entity
*/
static inline u32 media_entity_id(struct media_entity *entity)
{
return entity->graph_obj.id;
}
/**
* media_type() - return the media object type
*
* @gobj: pointer to the media graph object
*/
static inline enum media_gobj_type media_type(struct media_gobj *gobj)
{
return gobj->id >> MEDIA_BITS_PER_ID;
}
/**
* media_id() - return the media object ID
*
* @gobj: pointer to the media graph object
*/
static inline u32 media_id(struct media_gobj *gobj)
{
return gobj->id & MEDIA_ID_MASK;
}
/**
* media_gobj_gen_id() - encapsulates type and ID on at the object ID
*
* @type: object type as define at enum &media_gobj_type.
* @local_id: next ID, from struct &media_device.@id.
*/
static inline u32 media_gobj_gen_id(enum media_gobj_type type, u64 local_id)
{
u32 id;
id = type << MEDIA_BITS_PER_ID;
id |= local_id & MEDIA_ID_MASK;
return id;
}
/**
* is_media_entity_v4l2_video_device() - Check if the entity is a video_device
* @entity: pointer to entity
*
* Return: true if the entity is an instance of a video_device object and can
* safely be cast to a struct video_device using the container_of() macro, or
* false otherwise.
*/
static inline bool is_media_entity_v4l2_video_device(struct media_entity *entity)
{
return entity && entity->obj_type == MEDIA_ENTITY_TYPE_VIDEO_DEVICE;
}
/**
* is_media_entity_v4l2_subdev() - Check if the entity is a v4l2_subdev
* @entity: pointer to entity
*
* Return: true if the entity is an instance of a v4l2_subdev object and can
* safely be cast to a struct v4l2_subdev using the container_of() macro, or
* false otherwise.
*/
static inline bool is_media_entity_v4l2_subdev(struct media_entity *entity)
{
return entity && entity->obj_type == MEDIA_ENTITY_TYPE_V4L2_SUBDEV;
}
/**
* __media_entity_enum_init - Initialise an entity enumeration
*
* @ent_enum: Entity enumeration to be initialised
* @idx_max: Maximum number of entities in the enumeration
*
* Return: Returns zero on success or a negative error code.
*/
__must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
int idx_max);
/**
* media_entity_enum_cleanup - Release resources of an entity enumeration
*
* @ent_enum: Entity enumeration to be released
*/
void media_entity_enum_cleanup(struct media_entity_enum *ent_enum);
/**
* media_entity_enum_zero - Clear the entire enum
*
* @ent_enum: Entity enumeration to be cleared
*/
static inline void media_entity_enum_zero(struct media_entity_enum *ent_enum)
{
bitmap_zero(ent_enum->bmap, ent_enum->idx_max);
}
/**
* media_entity_enum_set - Mark a single entity in the enum
*
* @ent_enum: Entity enumeration
* @entity: Entity to be marked
*/
static inline void media_entity_enum_set(struct media_entity_enum *ent_enum,
struct media_entity *entity)
{
if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
return;
__set_bit(entity->internal_idx, ent_enum->bmap);
}
/**
* media_entity_enum_clear - Unmark a single entity in the enum
*
* @ent_enum: Entity enumeration
* @entity: Entity to be unmarked
*/
static inline void media_entity_enum_clear(struct media_entity_enum *ent_enum,
struct media_entity *entity)
{
if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
return;
__clear_bit(entity->internal_idx, ent_enum->bmap);
}
/**
* media_entity_enum_test - Test whether the entity is marked
*
* @ent_enum: Entity enumeration
* @entity: Entity to be tested
*
* Returns true if the entity was marked.
*/
static inline bool media_entity_enum_test(struct media_entity_enum *ent_enum,
struct media_entity *entity)
{
if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
return true;
return test_bit(entity->internal_idx, ent_enum->bmap);
}
/**
* media_entity_enum_test - Test whether the entity is marked, and mark it
*
* @ent_enum: Entity enumeration
* @entity: Entity to be tested
*
* Returns true if the entity was marked, and mark it before doing so.
*/
static inline bool
media_entity_enum_test_and_set(struct media_entity_enum *ent_enum,
struct media_entity *entity)
{
if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
return true;
return __test_and_set_bit(entity->internal_idx, ent_enum->bmap);
}
/**
* media_entity_enum_empty - Test whether the entire enum is empty
*
* @ent_enum: Entity enumeration
*
* Returns true if the entity was marked.
*/
static inline bool media_entity_enum_empty(struct media_entity_enum *ent_enum)
{
return bitmap_empty(ent_enum->bmap, ent_enum->idx_max);
}
/**
* media_entity_enum_intersects - Test whether two enums intersect
*
* @ent_enum1: First entity enumeration
* @ent_enum2: Second entity enumeration
*
* Returns true if entity enumerations e and f intersect, otherwise false.
*/
static inline bool media_entity_enum_intersects(
struct media_entity_enum *ent_enum1,
struct media_entity_enum *ent_enum2)
{
WARN_ON(ent_enum1->idx_max != ent_enum2->idx_max);
return bitmap_intersects(ent_enum1->bmap, ent_enum2->bmap,
min(ent_enum1->idx_max, ent_enum2->idx_max));
}
#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)
/**
* media_gobj_create - Initialize a graph object
*
* @mdev: Pointer to the media_device that contains the object
* @type: Type of the object
* @gobj: Pointer to the graph object
*
* This routine initializes the embedded struct media_gobj inside a
* media graph object. It is called automatically if media_*_create()
* calls are used. However, if the object (entity, link, pad, interface)
* is embedded on some other object, this function should be called before
* registering the object at the media controller.
*/
void media_gobj_create(struct media_device *mdev,
enum media_gobj_type type,
struct media_gobj *gobj);
/**
* media_gobj_destroy - Stop using a graph object on a media device
*
* @gobj: Pointer to the graph object
*
* This should be called by all routines like media_device_unregister()
* that remove/destroy media graph objects.
*/
void media_gobj_destroy(struct media_gobj *gobj);
/**
* media_entity_pads_init() - Initialize the entity pads
*
* @entity: entity where the pads belong
* @num_pads: total number of sink and source pads
* @pads: Array of @num_pads pads.
*
* The pads array is managed by the entity driver and passed to
* media_entity_pads_init() where its pointer will be stored in the entity
* structure.
*
* If no pads are needed, drivers could either directly fill
* &media_entity->@num_pads with 0 and &media_entity->@pads with NULL or call
* this function that will do the same.
*
* As the number of pads is known in advance, the pads array is not allocated
* dynamically but is managed by the entity driver. Most drivers will embed the
* pads array in a driver-specific structure, avoiding dynamic allocation.
*
* Drivers must set the direction of every pad in the pads array before calling
* media_entity_pads_init(). The function will initialize the other pads fields.
*/
int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
struct media_pad *pads);
/**
* media_entity_cleanup() - free resources associated with an entity
*
* @entity: entity where the pads belong
*
* This function must be called during the cleanup phase after unregistering
* the entity (currently, it does nothing).
*/
static inline void media_entity_cleanup(struct media_entity *entity) {};
/**
* media_create_pad_link() - creates a link between two entities.
*
* @source: pointer to &media_entity of the source pad.
* @source_pad: number of the source pad in the pads array
* @sink: pointer to &media_entity of the sink pad.
* @sink_pad: number of the sink pad in the pads array.
* @flags: Link flags, as defined in include/uapi/linux/media.h.
*
* Valid values for flags:
*
* - A %MEDIA_LNK_FL_ENABLED flag indicates that the link is enabled and can
* be used to transfer media data. When two or more links target a sink pad,
* only one of them can be enabled at a time.
*
* - A %MEDIA_LNK_FL_IMMUTABLE flag indicates that the link enabled state can't
* be modified at runtime. If %MEDIA_LNK_FL_IMMUTABLE is set, then
* %MEDIA_LNK_FL_ENABLED must also be set since an immutable link is
* always enabled.
*
* .. note::
*
* Before calling this function, media_entity_pads_init() and
* media_device_register_entity() should be called previously for both ends.
*/
__must_check int media_create_pad_link(struct media_entity *source,
u16 source_pad, struct media_entity *sink,
u16 sink_pad, u32 flags);
/**
* media_create_pad_links() - creates a link between two entities.
*
* @mdev: Pointer to the media_device that contains the object
* @source_function: Function of the source entities. Used only if @source is
* NULL.
* @source: pointer to &media_entity of the source pad. If NULL, it will use
* all entities that matches the @sink_function.
* @source_pad: number of the source pad in the pads array
* @sink_function: Function of the sink entities. Used only if @sink is NULL.
* @sink: pointer to &media_entity of the sink pad. If NULL, it will use
* all entities that matches the @sink_function.
* @sink_pad: number of the sink pad in the pads array.
* @flags: Link flags, as defined in include/uapi/linux/media.h.
* @allow_both_undefined: if true, then both @source and @sink can be NULL.
* In such case, it will create a crossbar between all entities that
* matches @source_function to all entities that matches @sink_function.
* If false, it will return 0 and won't create any link if both @source
* and @sink are NULL.
*
* Valid values for flags:
*
* A %MEDIA_LNK_FL_ENABLED flag indicates that the link is enabled and can be
* used to transfer media data. If multiple links are created and this
* flag is passed as an argument, only the first created link will have
* this flag.
*
* A %MEDIA_LNK_FL_IMMUTABLE flag indicates that the link enabled state can't
* be modified at runtime. If %MEDIA_LNK_FL_IMMUTABLE is set, then
* %MEDIA_LNK_FL_ENABLED must also be set since an immutable link is
* always enabled.
*
* It is common for some devices to have multiple source and/or sink entities
* of the same type that should be linked. While media_create_pad_link()
* creates link by link, this function is meant to allow 1:n, n:1 and even
* cross-bar (n:n) links.
*
* NOTE: Before calling this function, media_entity_pads_init() and
* media_device_register_entity() should be called previously for the entities
* to be linked.
*/
int media_create_pad_links(const struct media_device *mdev,
const u32 source_function,
struct media_entity *source,
const u16 source_pad,
const u32 sink_function,
struct media_entity *sink,
const u16 sink_pad,
u32 flags,
const bool allow_both_undefined);
void __media_entity_remove_links(struct media_entity *entity);
/**
* media_entity_remove_links() - remove all links associated with an entity
*
* @entity: pointer to &media_entity
*
* .. note::
*
* This is called automatically when an entity is unregistered via
* media_device_register_entity().
*/
void media_entity_remove_links(struct media_entity *entity);
/**
* __media_entity_setup_link - Configure a media link without locking
* @link: The link being configured
* @flags: Link configuration flags
*
* The bulk of link setup is handled by the two entities connected through the
* link. This function notifies both entities of the link configuration change.
*
* If the link is immutable or if the current and new configuration are
* identical, return immediately.
*
* The user is expected to hold link->source->parent->mutex. If not,
* media_entity_setup_link() should be used instead.
*/
int __media_entity_setup_link(struct media_link *link, u32 flags);
/**
* media_entity_setup_link() - changes the link flags properties in runtime
*
* @link: pointer to &media_link
* @flags: the requested new link flags
*
* The only configurable property is the %MEDIA_LNK_FL_ENABLED link flag
* flag to enable/disable a link. Links marked with the
* %MEDIA_LNK_FL_IMMUTABLE link flag can not be enabled or disabled.
*
* When a link is enabled or disabled, the media framework calls the
* link_setup operation for the two entities at the source and sink of the
* link, in that order. If the second link_setup call fails, another
* link_setup call is made on the first entity to restore the original link
* flags.
*
* Media device drivers can be notified of link setup operations by setting the
* media_device::link_notify pointer to a callback function. If provided, the
* notification callback will be called before enabling and after disabling
* links.
*
* Entity drivers must implement the link_setup operation if any of their links
* is non-immutable. The operation must either configure the hardware or store
* the configuration information to be applied later.
*
* Link configuration must not have any side effect on other links. If an
* enabled link at a sink pad prevents another link at the same pad from
* being enabled, the link_setup operation must return -EBUSY and can't
* implicitly disable the first enabled link.
*
* .. note::
*
* The valid values of the flags for the link is the same as described
* on media_create_pad_link(), for pad to pad links or the same as described
* on media_create_intf_link(), for interface to entity links.
*/
int media_entity_setup_link(struct media_link *link, u32 flags);
/**
* media_entity_find_link - Find a link between two pads
* @source: Source pad
* @sink: Sink pad
*
* Return a pointer to the link between the two entities. If no such link
* exists, return NULL.
*/
struct media_link *media_entity_find_link(struct media_pad *source,
struct media_pad *sink);
/**
* media_entity_remote_pad - Find the pad at the remote end of a link
* @pad: Pad at the local end of the link
*
* Search for a remote pad connected to the given pad by iterating over all
* links originating or terminating at that pad until an enabled link is found.
*
* Return a pointer to the pad at the remote end of the first found enabled
* link, or NULL if no enabled link has been found.
*/
struct media_pad *media_entity_remote_pad(struct media_pad *pad);
/**
* media_entity_get - Get a reference to the parent module
*
* @entity: The entity
*
* Get a reference to the parent media device module.
*
* The function will return immediately if @entity is NULL.
*
* Return a pointer to the entity on success or NULL on failure.
*/
struct media_entity *media_entity_get(struct media_entity *entity);
__must_check int media_entity_graph_walk_init(
struct media_entity_graph *graph, struct media_device *mdev);
/**
* media_entity_graph_walk_cleanup - Release resources used by graph walk.
*
* @graph: Media graph structure that will be used to walk the graph
*/
void media_entity_graph_walk_cleanup(struct media_entity_graph *graph);
/**
* media_entity_put - Release the reference to the parent module
*
* @entity: The entity
*
* Release the reference count acquired by media_entity_get().
*
* The function will return immediately if @entity is NULL.
*/
void media_entity_put(struct media_entity *entity);
/**
* media_entity_graph_walk_start - Start walking the media graph at a given entity
* @graph: Media graph structure that will be used to walk the graph
* @entity: Starting entity
*
* Before using this function, media_entity_graph_walk_init() must be
* used to allocate resources used for walking the graph. This
* function initializes the graph traversal structure to walk the
* entities graph starting at the given entity. The traversal
* structure must not be modified by the caller during graph
* traversal. After the graph walk, the resources must be released
* using media_entity_graph_walk_cleanup().
*/
void media_entity_graph_walk_start(struct media_entity_graph *graph,
struct media_entity *entity);
/**
* media_entity_graph_walk_next - Get the next entity in the graph
* @graph: Media graph structure
*
* Perform a depth-first traversal of the given media entities graph.
*
* The graph structure must have been previously initialized with a call to
* media_entity_graph_walk_start().
*
* Return the next entity in the graph or NULL if the whole graph have been
* traversed.
*/
struct media_entity *
media_entity_graph_walk_next(struct media_entity_graph *graph);
/**
* media_entity_pipeline_start - Mark a pipeline as streaming
* @entity: Starting entity
* @pipe: Media pipeline to be assigned to all entities in the pipeline.
*
* Mark all entities connected to a given entity through enabled links, either
* directly or indirectly, as streaming. The given pipeline object is assigned to
* every entity in the pipeline and stored in the media_entity pipe field.
*
* Calls to this function can be nested, in which case the same number of
* media_entity_pipeline_stop() calls will be required to stop streaming. The
* pipeline pointer must be identical for all nested calls to
* media_entity_pipeline_start().
*/
__must_check int media_entity_pipeline_start(struct media_entity *entity,
struct media_pipeline *pipe);
/**
* __media_entity_pipeline_start - Mark a pipeline as streaming
*
* @entity: Starting entity
* @pipe: Media pipeline to be assigned to all entities in the pipeline.
*
* ..note:: This is the non-locking version of media_entity_pipeline_start()
*/
__must_check int __media_entity_pipeline_start(struct media_entity *entity,
struct media_pipeline *pipe);
/**
* media_entity_pipeline_stop - Mark a pipeline as not streaming
* @entity: Starting entity
*
* Mark all entities connected to a given entity through enabled links, either
* directly or indirectly, as not streaming. The media_entity pipe field is
* reset to NULL.
*
* If multiple calls to media_entity_pipeline_start() have been made, the same
* number of calls to this function are required to mark the pipeline as not
* streaming.
*/
void media_entity_pipeline_stop(struct media_entity *entity);
/**
* __media_entity_pipeline_stop - Mark a pipeline as not streaming
*
* @entity: Starting entity
*
* .. note:: This is the non-locking version of media_entity_pipeline_stop()
*/
void __media_entity_pipeline_stop(struct media_entity *entity);
/**
* media_devnode_create() - creates and initializes a device node interface
*
* @mdev: pointer to struct &media_device
* @type: type of the interface, as given by MEDIA_INTF_T_* macros
* as defined in the uapi/media/media.h header.
* @flags: Interface flags as defined in uapi/media/media.h.
* @major: Device node major number.
* @minor: Device node minor number.
*
* Return: if succeeded, returns a pointer to the newly allocated
* &media_intf_devnode pointer.
*/
struct media_intf_devnode *
__must_check media_devnode_create(struct media_device *mdev,
u32 type, u32 flags,
u32 major, u32 minor);
/**
* media_devnode_remove() - removes a device node interface
*
* @devnode: pointer to &media_intf_devnode to be freed.
*
* When a device node interface is removed, all links to it are automatically
* removed.
*/
void media_devnode_remove(struct media_intf_devnode *devnode);
struct media_link *
/**
* media_create_intf_link() - creates a link between an entity and an interface
*
* @entity: pointer to %media_entity
* @intf: pointer to %media_interface
* @flags: Link flags, as defined in include/uapi/linux/media.h.
*
*
* Valid values for flags:
*
* - The %MEDIA_LNK_FL_ENABLED flag indicates that the interface is connected to
* the entity hardware. That's the default value for interfaces. An
* interface may be disabled if the hardware is busy due to the usage
* of some other interface that it is currently controlling the hardware.
* A typical example is an hybrid TV device that handle only one type of
* stream on a given time. So, when the digital TV is streaming,
* the V4L2 interfaces won't be enabled, as such device is not able to
* also stream analog TV or radio.
*
* .. note::
*
* Before calling this function, media_devnode_create() should be called for
* the interface and media_device_register_entity() should be called for the
* interface that will be part of the link.
*/
__must_check media_create_intf_link(struct media_entity *entity,
struct media_interface *intf,
u32 flags);
/**
* __media_remove_intf_link() - remove a single interface link
*
* @link: pointer to &media_link.
*
* .. note:: This is an unlocked version of media_remove_intf_link()
*/
void __media_remove_intf_link(struct media_link *link);
/**
* media_remove_intf_link() - remove a single interface link
*
* @link: pointer to &media_link.
*
* .. note:: Prefer to use this one, instead of __media_remove_intf_link()
*/
void media_remove_intf_link(struct media_link *link);
/**
* __media_remove_intf_links() - remove all links associated with an interface
*
* @intf: pointer to &media_interface
*
* .. note:: This is an unlocked version of media_remove_intf_links().
*/
void __media_remove_intf_links(struct media_interface *intf);
/**
* media_remove_intf_links() - remove all links associated with an interface
*
* @intf: pointer to &media_interface
*
* ..note::
*
* - This is called automatically when an entity is unregistered via
* media_device_register_entity() and by media_devnode_remove().
*
* - Prefer to use this one, instead of __media_remove_intf_links().
*/
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
