1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * Media entity
   4 *
   5 * Copyright (C) 2010 Nokia Corporation
   6 *
   7 * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
   8 *	     Sakari Ailus <sakari.ailus@iki.fi>
   9 */
  10
  11#ifndef _MEDIA_ENTITY_H
  12#define _MEDIA_ENTITY_H
  13
  14#include <linux/bitmap.h>
  15#include <linux/bug.h>
  16#include <linux/container_of.h>
  17#include <linux/fwnode.h>
  18#include <linux/list.h>
  19#include <linux/media.h>
  20#include <linux/minmax.h>
  21#include <linux/types.h>
  22
  23/* Enums used internally at the media controller to represent graphs */
  24
  25/**
  26 * enum media_gobj_type - type of a graph object
  27 *
  28 * @MEDIA_GRAPH_ENTITY:		Identify a media entity
  29 * @MEDIA_GRAPH_PAD:		Identify a media pad
  30 * @MEDIA_GRAPH_LINK:		Identify a media link
  31 * @MEDIA_GRAPH_INTF_DEVNODE:	Identify a media Kernel API interface via
  32 *				a device node
  33 */
  34enum media_gobj_type {
  35	MEDIA_GRAPH_ENTITY,
  36	MEDIA_GRAPH_PAD,
  37	MEDIA_GRAPH_LINK,
  38	MEDIA_GRAPH_INTF_DEVNODE,
  39};
  40
  41#define MEDIA_BITS_PER_TYPE		8
  42#define MEDIA_BITS_PER_ID		(32 - MEDIA_BITS_PER_TYPE)
  43#define MEDIA_ID_MASK			 GENMASK_ULL(MEDIA_BITS_PER_ID - 1, 0)
  44
  45/* Structs to represent the objects that belong to a media graph */
  46
  47/**
  48 * struct media_gobj - Define a graph object.
  49 *
  50 * @mdev:	Pointer to the struct &media_device that owns the object
  51 * @id:		Non-zero object ID identifier. The ID should be unique
  52 *		inside a media_device, as it is composed by
  53 *		%MEDIA_BITS_PER_TYPE to store the type plus
  54 *		%MEDIA_BITS_PER_ID to store the ID
  55 * @list:	List entry stored in one of the per-type mdev object lists
  56 *
  57 * All objects on the media graph should have this struct embedded
  58 */
  59struct media_gobj {
  60	struct media_device	*mdev;
  61	u32			id;
  62	struct list_head	list;
  63};
  64
  65#define MEDIA_ENTITY_ENUM_MAX_DEPTH	16
  66
  67/**
  68 * struct media_entity_enum - An enumeration of media entities.
  69 *
  70 * @bmap:	Bit map in which each bit represents one entity at struct
  71 *		media_entity->internal_idx.
  72 * @idx_max:	Number of bits in bmap
  73 */
  74struct media_entity_enum {
  75	unsigned long *bmap;
  76	int idx_max;
  77};
  78
  79/**
  80 * struct media_graph - Media graph traversal state
  81 *
  82 * @stack:		Graph traversal stack; the stack contains information
  83 *			on the path the media entities to be walked and the
  84 *			links through which they were reached.
  85 * @stack.entity:	pointer to &struct media_entity at the graph.
  86 * @stack.link:		pointer to &struct list_head.
  87 * @ent_enum:		Visited entities
  88 * @top:		The top of the stack
  89 */
  90struct media_graph {
  91	struct {
  92		struct media_entity *entity;
  93		struct list_head *link;
  94	} stack[MEDIA_ENTITY_ENUM_MAX_DEPTH];
  95
  96	struct media_entity_enum ent_enum;
  97	int top;
  98};
  99
 100/**
 101 * struct media_pipeline - Media pipeline related information
 102 *
 103 * @allocated:		Media pipeline allocated and freed by the framework
 104 * @mdev:		The media device the pipeline is part of
 105 * @pads:		List of media_pipeline_pad
 106 * @start_count:	Media pipeline start - stop count
 107 */
 108struct media_pipeline {
 109	bool allocated;
 110	struct media_device *mdev;
 111	struct list_head pads;
 112	int start_count;
 113};
 114
 115/**
 116 * struct media_pipeline_pad - A pad part of a media pipeline
 117 *
 118 * @list:		Entry in the media_pad pads list
 119 * @pipe:		The media_pipeline that the pad is part of
 120 * @pad:		The media pad
 121 *
 122 * This structure associate a pad with a media pipeline. Instances of
 123 * media_pipeline_pad are created by media_pipeline_start() when it builds the
 124 * pipeline, and stored in the &media_pad.pads list. media_pipeline_stop()
 125 * removes the entries from the list and deletes them.
 126 */
 127struct media_pipeline_pad {
 128	struct list_head list;
 129	struct media_pipeline *pipe;
 130	struct media_pad *pad;
 131};
 132
 133/**
 134 * struct media_pipeline_pad_iter - Iterator for media_pipeline_for_each_pad
 135 *
 136 * @cursor: The current element
 137 */
 138struct media_pipeline_pad_iter {
 139	struct list_head *cursor;
 140};
 141
 142/**
 143 * struct media_pipeline_entity_iter - Iterator for media_pipeline_for_each_entity
 144 *
 145 * @ent_enum: The entity enumeration tracker
 146 * @cursor: The current element
 147 */
 148struct media_pipeline_entity_iter {
 149	struct media_entity_enum ent_enum;
 150	struct list_head *cursor;
 151};
 152
 153/**
 154 * struct media_link - A link object part of a media graph.
 155 *
 156 * @graph_obj:	Embedded structure containing the media object common data
 157 * @list:	Linked list associated with an entity or an interface that
 158 *		owns the link.
 159 * @gobj0:	Part of a union. Used to get the pointer for the first
 160 *		graph_object of the link.
 161 * @source:	Part of a union. Used only if the first object (gobj0) is
 162 *		a pad. In that case, it represents the source pad.
 163 * @intf:	Part of a union. Used only if the first object (gobj0) is
 164 *		an interface.
 165 * @gobj1:	Part of a union. Used to get the pointer for the second
 166 *		graph_object of the link.
 167 * @sink:	Part of a union. Used only if the second object (gobj1) is
 168 *		a pad. In that case, it represents the sink pad.
 169 * @entity:	Part of a union. Used only if the second object (gobj1) is
 170 *		an entity.
 171 * @reverse:	Pointer to the link for the reverse direction of a pad to pad
 172 *		link.
 173 * @flags:	Link flags, as defined in uapi/media.h (MEDIA_LNK_FL_*)
 174 * @is_backlink: Indicate if the link is a backlink.
 175 */
 176struct media_link {
 177	struct media_gobj graph_obj;
 178	struct list_head list;
 179	union {
 180		struct media_gobj *gobj0;
 181		struct media_pad *source;
 182		struct media_interface *intf;
 183	};
 184	union {
 185		struct media_gobj *gobj1;
 186		struct media_pad *sink;
 187		struct media_entity *entity;
 188	};
 189	struct media_link *reverse;
 190	unsigned long flags;
 191	bool is_backlink;
 192};
 193
 194/**
 195 * enum media_pad_signal_type - type of the signal inside a media pad
 196 *
 197 * @PAD_SIGNAL_DEFAULT:
 198 *	Default signal. Use this when all inputs or all outputs are
 199 *	uniquely identified by the pad number.
 200 * @PAD_SIGNAL_ANALOG:
 201 *	The pad contains an analog signal. It can be Radio Frequency,
 202 *	Intermediate Frequency, a baseband signal or sub-carriers.
 203 *	Tuner inputs, IF-PLL demodulators, composite and s-video signals
 204 *	should use it.
 205 * @PAD_SIGNAL_DV:
 206 *	Contains a digital video signal, with can be a bitstream of samples
 207 *	taken from an analog TV video source. On such case, it usually
 208 *	contains the VBI data on it.
 209 * @PAD_SIGNAL_AUDIO:
 210 *	Contains an Intermediate Frequency analog signal from an audio
 211 *	sub-carrier or an audio bitstream. IF signals are provided by tuners
 212 *	and consumed by	audio AM/FM decoders. Bitstream audio is provided by
 213 *	an audio decoder.
 214 */
 215enum media_pad_signal_type {
 216	PAD_SIGNAL_DEFAULT = 0,
 217	PAD_SIGNAL_ANALOG,
 218	PAD_SIGNAL_DV,
 219	PAD_SIGNAL_AUDIO,
 220};
 221
 222/**
 223 * struct media_pad - A media pad graph object.
 224 *
 225 * @graph_obj:	Embedded structure containing the media object common data
 226 * @entity:	Entity this pad belongs to
 227 * @index:	Pad index in the entity pads array, numbered from 0 to n
 228 * @sig_type:	Type of the signal inside a media pad
 229 * @flags:	Pad flags, as defined in
 230 *		:ref:`include/uapi/linux/media.h <media_header>`
 231 *		(seek for ``MEDIA_PAD_FL_*``)
 232 * @pipe:	Pipeline this pad belongs to. Use media_entity_pipeline() to
 233 *		access this field.
 234 */
 235struct media_pad {
 236	struct media_gobj graph_obj;	/* must be first field in struct */
 237	struct media_entity *entity;
 238	u16 index;
 239	enum media_pad_signal_type sig_type;
 240	unsigned long flags;
 241
 242	/*
 243	 * The fields below are private, and should only be accessed via
 244	 * appropriate functions.
 245	 */
 246	struct media_pipeline *pipe;
 247};
 248
 249/**
 250 * struct media_entity_operations - Media entity operations
 251 * @get_fwnode_pad:	Return the pad number based on a fwnode endpoint or
 252 *			a negative value on error. This operation can be used
 253 *			to map a fwnode to a media pad number. Optional.
 254 * @link_setup:		Notify the entity of link changes. The operation can
 255 *			return an error, in which case link setup will be
 256 *			cancelled. Optional.
 257 * @link_validate:	Return whether a link is valid from the entity point of
 258 *			view. The media_pipeline_start() function
 259 *			validates all links by calling this operation. Optional.
 260 * @has_pad_interdep:	Return whether two pads of the entity are
 261 *			interdependent. If two pads are interdependent they are
 262 *			part of the same pipeline and enabling one of the pads
 263 *			means that the other pad will become "locked" and
 264 *			doesn't allow configuration changes. pad0 and pad1 are
 265 *			guaranteed to not both be sinks or sources. Never call
 266 *			the .has_pad_interdep() operation directly, always use
 267 *			media_entity_has_pad_interdep().
 268 *			Optional: If the operation isn't implemented all pads
 269 *			will be considered as interdependent.
 270 *
 271 * .. note::
 272 *
 273 *    Those these callbacks are called with struct &media_device.graph_mutex
 274 *    mutex held.
 275 */
 276struct media_entity_operations {
 277	int (*get_fwnode_pad)(struct media_entity *entity,
 278			      struct fwnode_endpoint *endpoint);
 279	int (*link_setup)(struct media_entity *entity,
 280			  const struct media_pad *local,
 281			  const struct media_pad *remote, u32 flags);
 282	int (*link_validate)(struct media_link *link);
 283	bool (*has_pad_interdep)(struct media_entity *entity, unsigned int pad0,
 284				 unsigned int pad1);
 285};
 286
 287/**
 288 * enum media_entity_type - Media entity type
 289 *
 290 * @MEDIA_ENTITY_TYPE_BASE:
 291 *	The entity isn't embedded in another subsystem structure.
 292 * @MEDIA_ENTITY_TYPE_VIDEO_DEVICE:
 293 *	The entity is embedded in a struct video_device instance.
 294 * @MEDIA_ENTITY_TYPE_V4L2_SUBDEV:
 295 *	The entity is embedded in a struct v4l2_subdev instance.
 296 *
 297 * Media entity objects are often not instantiated directly, but the media
 298 * entity structure is inherited by (through embedding) other subsystem-specific
 299 * structures. The media entity type identifies the type of the subclass
 300 * structure that implements a media entity instance.
 301 *
 302 * This allows runtime type identification of media entities and safe casting to
 303 * the correct object type. For instance, a media entity structure instance
 304 * embedded in a v4l2_subdev structure instance will have the type
 305 * %MEDIA_ENTITY_TYPE_V4L2_SUBDEV and can safely be cast to a &v4l2_subdev
 306 * structure using the container_of() macro.
 307 */
 308enum media_entity_type {
 309	MEDIA_ENTITY_TYPE_BASE,
 310	MEDIA_ENTITY_TYPE_VIDEO_DEVICE,
 311	MEDIA_ENTITY_TYPE_V4L2_SUBDEV,
 312};
 313
 314/**
 315 * struct media_entity - A media entity graph object.
 316 *
 317 * @graph_obj:	Embedded structure containing the media object common data.
 318 * @name:	Entity name.
 319 * @obj_type:	Type of the object that implements the media_entity.
 320 * @function:	Entity main function, as defined in
 321 *		:ref:`include/uapi/linux/media.h <media_header>`
 322 *		(seek for ``MEDIA_ENT_F_*``)
 323 * @flags:	Entity flags, as defined in
 324 *		:ref:`include/uapi/linux/media.h <media_header>`
 325 *		(seek for ``MEDIA_ENT_FL_*``)
 326 * @num_pads:	Number of sink and source pads.
 327 * @num_links:	Total number of links, forward and back, enabled and disabled.
 328 * @num_backlinks: Number of backlinks
 329 * @internal_idx: An unique internal entity specific number. The numbers are
 330 *		re-used if entities are unregistered or registered again.
 331 * @pads:	Pads array with the size defined by @num_pads.
 332 * @links:	List of data links.
 333 * @ops:	Entity operations.
 334 * @use_count:	Use count for the entity.
 335 * @info:	Union with devnode information.  Kept just for backward
 336 *		compatibility.
 337 * @info.dev:	Contains device major and minor info.
 338 * @info.dev.major: device node major, if the device is a devnode.
 339 * @info.dev.minor: device node minor, if the device is a devnode.
 340 * @major:	Devnode major number (zero if not applicable). Kept just
 341 *		for backward compatibility.
 342 * @minor:	Devnode minor number (zero if not applicable). Kept just
 343 *		for backward compatibility.
 344 *
 345 * .. note::
 346 *
 347 *    The @use_count reference count must never be negative, but is a signed
 348 *    integer on purpose: a simple ``WARN_ON(<0)`` check can be used to detect
 349 *    reference count bugs that would make it negative.
 350 */
 351struct media_entity {
 352	struct media_gobj graph_obj;	/* must be first field in struct */
 353	const char *name;
 354	enum media_entity_type obj_type;
 355	u32 function;
 356	unsigned long flags;
 357
 358	u16 num_pads;
 359	u16 num_links;
 360	u16 num_backlinks;
 361	int internal_idx;
 362
 363	struct media_pad *pads;
 364	struct list_head links;
 365
 366	const struct media_entity_operations *ops;
 367
 368	int use_count;
 369
 370	union {
 371		struct {
 372			u32 major;
 373			u32 minor;
 374		} dev;
 375	} info;
 376};
 377
 378/**
 379 * media_entity_for_each_pad - Iterate on all pads in an entity
 380 * @entity: The entity the pads belong to
 381 * @iter: The iterator pad
 382 *
 383 * Iterate on all pads in a media entity.
 384 */
 385#define media_entity_for_each_pad(entity, iter)			\
 386	for (iter = (entity)->pads;				\
 387	     iter < &(entity)->pads[(entity)->num_pads];	\
 388	     ++iter)
 389
 390/**
 391 * struct media_interface - A media interface graph object.
 392 *
 393 * @graph_obj:		embedded graph object
 394 * @links:		List of links pointing to graph entities
 395 * @type:		Type of the interface as defined in
 396 *			:ref:`include/uapi/linux/media.h <media_header>`
 397 *			(seek for ``MEDIA_INTF_T_*``)
 398 * @flags:		Interface flags as defined in
 399 *			:ref:`include/uapi/linux/media.h <media_header>`
 400 *			(seek for ``MEDIA_INTF_FL_*``)
 401 *
 402 * .. note::
 403 *
 404 *    Currently, no flags for &media_interface is defined.
 405 */
 406struct media_interface {
 407	struct media_gobj		graph_obj;
 408	struct list_head		links;
 409	u32				type;
 410	u32				flags;
 411};
 412
 413/**
 414 * struct media_intf_devnode - A media interface via a device node.
 415 *
 416 * @intf:	embedded interface object
 417 * @major:	Major number of a device node
 418 * @minor:	Minor number of a device node
 419 */
 420struct media_intf_devnode {
 421	struct media_interface		intf;
 422
 423	/* Should match the fields at media_v2_intf_devnode */
 424	u32				major;
 425	u32				minor;
 426};
 427
 428/**
 429 * media_entity_id() - return the media entity graph object id
 430 *
 431 * @entity:	pointer to &media_entity
 432 */
 433static inline u32 media_entity_id(struct media_entity *entity)
 434{
 435	return entity->graph_obj.id;
 436}
 437
 438/**
 439 * media_type() - return the media object type
 440 *
 441 * @gobj:	Pointer to the struct &media_gobj graph object
 442 */
 443static inline enum media_gobj_type media_type(struct media_gobj *gobj)
 444{
 445	return gobj->id >> MEDIA_BITS_PER_ID;
 446}
 447
 448/**
 449 * media_id() - return the media object ID
 450 *
 451 * @gobj:	Pointer to the struct &media_gobj graph object
 452 */
 453static inline u32 media_id(struct media_gobj *gobj)
 454{
 455	return gobj->id & MEDIA_ID_MASK;
 456}
 457
 458/**
 459 * media_gobj_gen_id() - encapsulates type and ID on at the object ID
 460 *
 461 * @type:	object type as define at enum &media_gobj_type.
 462 * @local_id:	next ID, from struct &media_device.id.
 463 */
 464static inline u32 media_gobj_gen_id(enum media_gobj_type type, u64 local_id)
 465{
 466	u32 id;
 467
 468	id = type << MEDIA_BITS_PER_ID;
 469	id |= local_id & MEDIA_ID_MASK;
 470
 471	return id;
 472}
 473
 474/**
 475 * is_media_entity_v4l2_video_device() - Check if the entity is a video_device
 476 * @entity:	pointer to entity
 477 *
 478 * Return: %true if the entity is an instance of a video_device object and can
 479 * safely be cast to a struct video_device using the container_of() macro, or
 480 * %false otherwise.
 481 */
 482static inline bool is_media_entity_v4l2_video_device(struct media_entity *entity)
 483{
 484	return entity && entity->obj_type == MEDIA_ENTITY_TYPE_VIDEO_DEVICE;
 485}
 486
 487/**
 488 * is_media_entity_v4l2_subdev() - Check if the entity is a v4l2_subdev
 489 * @entity:	pointer to entity
 490 *
 491 * Return: %true if the entity is an instance of a &v4l2_subdev object and can
 492 * safely be cast to a struct &v4l2_subdev using the container_of() macro, or
 493 * %false otherwise.
 494 */
 495static inline bool is_media_entity_v4l2_subdev(struct media_entity *entity)
 496{
 497	return entity && entity->obj_type == MEDIA_ENTITY_TYPE_V4L2_SUBDEV;
 498}
 499
 500/**
 501 * media_entity_enum_init - Initialise an entity enumeration
 502 *
 503 * @ent_enum: Entity enumeration to be initialised
 504 * @mdev: The related media device
 505 *
 506 * Return: zero on success or a negative error code.
 507 */
 508__must_check int media_entity_enum_init(struct media_entity_enum *ent_enum,
 509					struct media_device *mdev);
 510
 511/**
 512 * media_entity_enum_cleanup - Release resources of an entity enumeration
 513 *
 514 * @ent_enum: Entity enumeration to be released
 515 */
 516void media_entity_enum_cleanup(struct media_entity_enum *ent_enum);
 517
 518/**
 519 * media_entity_enum_zero - Clear the entire enum
 520 *
 521 * @ent_enum: Entity enumeration to be cleared
 522 */
 523static inline void media_entity_enum_zero(struct media_entity_enum *ent_enum)
 524{
 525	bitmap_zero(ent_enum->bmap, ent_enum->idx_max);
 526}
 527
 528/**
 529 * media_entity_enum_set - Mark a single entity in the enum
 530 *
 531 * @ent_enum: Entity enumeration
 532 * @entity: Entity to be marked
 533 */
 534static inline void media_entity_enum_set(struct media_entity_enum *ent_enum,
 535					 struct media_entity *entity)
 536{
 537	if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
 538		return;
 539
 540	__set_bit(entity->internal_idx, ent_enum->bmap);
 541}
 542
 543/**
 544 * media_entity_enum_clear - Unmark a single entity in the enum
 545 *
 546 * @ent_enum: Entity enumeration
 547 * @entity: Entity to be unmarked
 548 */
 549static inline void media_entity_enum_clear(struct media_entity_enum *ent_enum,
 550					   struct media_entity *entity)
 551{
 552	if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
 553		return;
 554
 555	__clear_bit(entity->internal_idx, ent_enum->bmap);
 556}
 557
 558/**
 559 * media_entity_enum_test - Test whether the entity is marked
 560 *
 561 * @ent_enum: Entity enumeration
 562 * @entity: Entity to be tested
 563 *
 564 * Returns %true if the entity was marked.
 565 */
 566static inline bool media_entity_enum_test(struct media_entity_enum *ent_enum,
 567					  struct media_entity *entity)
 568{
 569	if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
 570		return true;
 571
 572	return test_bit(entity->internal_idx, ent_enum->bmap);
 573}
 574
 575/**
 576 * media_entity_enum_test_and_set - Test whether the entity is marked,
 577 *	and mark it
 578 *
 579 * @ent_enum: Entity enumeration
 580 * @entity: Entity to be tested
 581 *
 582 * Returns %true if the entity was marked, and mark it before doing so.
 583 */
 584static inline bool
 585media_entity_enum_test_and_set(struct media_entity_enum *ent_enum,
 586			       struct media_entity *entity)
 587{
 588	if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
 589		return true;
 590
 591	return __test_and_set_bit(entity->internal_idx, ent_enum->bmap);
 592}
 593
 594/**
 595 * media_entity_enum_empty - Test whether the entire enum is empty
 596 *
 597 * @ent_enum: Entity enumeration
 598 *
 599 * Return: %true if the entity was empty.
 600 */
 601static inline bool media_entity_enum_empty(struct media_entity_enum *ent_enum)
 602{
 603	return bitmap_empty(ent_enum->bmap, ent_enum->idx_max);
 604}
 605
 606/**
 607 * media_entity_enum_intersects - Test whether two enums intersect
 608 *
 609 * @ent_enum1: First entity enumeration
 610 * @ent_enum2: Second entity enumeration
 611 *
 612 * Return: %true if entity enumerations @ent_enum1 and @ent_enum2 intersect,
 613 * otherwise %false.
 614 */
 615static inline bool media_entity_enum_intersects(
 616	struct media_entity_enum *ent_enum1,
 617	struct media_entity_enum *ent_enum2)
 618{
 619	WARN_ON(ent_enum1->idx_max != ent_enum2->idx_max);
 620
 621	return bitmap_intersects(ent_enum1->bmap, ent_enum2->bmap,
 622				 min(ent_enum1->idx_max, ent_enum2->idx_max));
 623}
 624
 625/**
 626 * gobj_to_entity - returns the struct &media_entity pointer from the
 627 *	@gobj contained on it.
 628 *
 629 * @gobj: Pointer to the struct &media_gobj graph object
 630 */
 631#define gobj_to_entity(gobj) \
 632		container_of(gobj, struct media_entity, graph_obj)
 633
 634/**
 635 * gobj_to_pad - returns the struct &media_pad pointer from the
 636 *	@gobj contained on it.
 637 *
 638 * @gobj: Pointer to the struct &media_gobj graph object
 639 */
 640#define gobj_to_pad(gobj) \
 641		container_of(gobj, struct media_pad, graph_obj)
 642
 643/**
 644 * gobj_to_link - returns the struct &media_link pointer from the
 645 *	@gobj contained on it.
 646 *
 647 * @gobj: Pointer to the struct &media_gobj graph object
 648 */
 649#define gobj_to_link(gobj) \
 650		container_of(gobj, struct media_link, graph_obj)
 651
 652/**
 653 * gobj_to_intf - returns the struct &media_interface pointer from the
 654 *	@gobj contained on it.
 655 *
 656 * @gobj: Pointer to the struct &media_gobj graph object
 657 */
 658#define gobj_to_intf(gobj) \
 659		container_of(gobj, struct media_interface, graph_obj)
 660
 661/**
 662 * intf_to_devnode - returns the struct media_intf_devnode pointer from the
 663 *	@intf contained on it.
 664 *
 665 * @intf: Pointer to struct &media_intf_devnode
 666 */
 667#define intf_to_devnode(intf) \
 668		container_of(intf, struct media_intf_devnode, intf)
 669
 670/**
 671 *  media_gobj_create - Initialize a graph object
 672 *
 673 * @mdev:	Pointer to the &media_device that contains the object
 674 * @type:	Type of the object
 675 * @gobj:	Pointer to the struct &media_gobj graph object
 676 *
 677 * This routine initializes the embedded struct &media_gobj inside a
 678 * media graph object. It is called automatically if ``media_*_create``
 679 * function calls are used. However, if the object (entity, link, pad,
 680 * interface) is embedded on some other object, this function should be
 681 * called before registering the object at the media controller.
 682 */
 683void media_gobj_create(struct media_device *mdev,
 684		    enum media_gobj_type type,
 685		    struct media_gobj *gobj);
 686
 687/**
 688 *  media_gobj_destroy - Stop using a graph object on a media device
 689 *
 690 * @gobj:	Pointer to the struct &media_gobj graph object
 691 *
 692 * This should be called by all routines like media_device_unregister()
 693 * that remove/destroy media graph objects.
 694 */
 695void media_gobj_destroy(struct media_gobj *gobj);
 696
 697/**
 698 * media_entity_pads_init() - Initialize the entity pads
 699 *
 700 * @entity:	entity where the pads belong
 701 * @num_pads:	total number of sink and source pads
 702 * @pads:	Array of @num_pads pads.
 703 *
 704 * The pads array is managed by the entity driver and passed to
 705 * media_entity_pads_init() where its pointer will be stored in the
 706 * &media_entity structure.
 707 *
 708 * If no pads are needed, drivers could either directly fill
 709 * &media_entity->num_pads with 0 and &media_entity->pads with %NULL or call
 710 * this function that will do the same.
 711 *
 712 * As the number of pads is known in advance, the pads array is not allocated
 713 * dynamically but is managed by the entity driver. Most drivers will embed the
 714 * pads array in a driver-specific structure, avoiding dynamic allocation.
 715 *
 716 * Drivers must set the direction of every pad in the pads array before calling
 717 * media_entity_pads_init(). The function will initialize the other pads fields.
 718 */
 719int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
 720		      struct media_pad *pads);
 721
 722/**
 723 * media_entity_cleanup() - free resources associated with an entity
 724 *
 725 * @entity:	entity where the pads belong
 726 *
 727 * This function must be called during the cleanup phase after unregistering
 728 * the entity (currently, it does nothing).
 729 *
 730 * Calling media_entity_cleanup() on a media_entity whose memory has been
 731 * zeroed but that has not been initialized with media_entity_pad_init() is
 732 * valid and is a no-op.
 733 */
 734#if IS_ENABLED(CONFIG_MEDIA_CONTROLLER)
 735static inline void media_entity_cleanup(struct media_entity *entity) {}
 736#else
 737#define media_entity_cleanup(entity) do { } while (false)
 738#endif
 739
 740/**
 741 * media_get_pad_index() - retrieves a pad index from an entity
 742 *
 743 * @entity:	entity where the pads belong
 744 * @pad_type:	the type of the pad, one of MEDIA_PAD_FL_* pad types
 745 * @sig_type:	type of signal of the pad to be search
 746 *
 747 * This helper function finds the first pad index inside an entity that
 748 * satisfies both @is_sink and @sig_type conditions.
 749 *
 750 * Return:
 751 *
 752 * On success, return the pad number. If the pad was not found or the media
 753 * entity is a NULL pointer, return -EINVAL.
 754 */
 755int media_get_pad_index(struct media_entity *entity, u32 pad_type,
 756			enum media_pad_signal_type sig_type);
 757
 758/**
 759 * media_create_pad_link() - creates a link between two entities.
 760 *
 761 * @source:	pointer to &media_entity of the source pad.
 762 * @source_pad:	number of the source pad in the pads array
 763 * @sink:	pointer to &media_entity of the sink pad.
 764 * @sink_pad:	number of the sink pad in the pads array.
 765 * @flags:	Link flags, as defined in
 766 *		:ref:`include/uapi/linux/media.h <media_header>`
 767 *		( seek for ``MEDIA_LNK_FL_*``)
 768 *
 769 * Valid values for flags:
 770 *
 771 * %MEDIA_LNK_FL_ENABLED
 772 *   Indicates that the link is enabled and can be used to transfer media data.
 773 *   When two or more links target a sink pad, only one of them can be
 774 *   enabled at a time.
 775 *
 776 * %MEDIA_LNK_FL_IMMUTABLE
 777 *   Indicates that the link enabled state can't be modified at runtime. If
 778 *   %MEDIA_LNK_FL_IMMUTABLE is set, then %MEDIA_LNK_FL_ENABLED must also be
 779 *   set, since an immutable link is always enabled.
 780 *
 781 * .. note::
 782 *
 783 *    Before calling this function, media_entity_pads_init() and
 784 *    media_device_register_entity() should be called previously for both ends.
 785 */
 786__must_check int media_create_pad_link(struct media_entity *source,
 787			u16 source_pad, struct media_entity *sink,
 788			u16 sink_pad, u32 flags);
 789
 790/**
 791 * media_create_pad_links() - creates a link between two entities.
 792 *
 793 * @mdev: Pointer to the media_device that contains the object
 794 * @source_function: Function of the source entities. Used only if @source is
 795 *	NULL.
 796 * @source: pointer to &media_entity of the source pad. If NULL, it will use
 797 *	all entities that matches the @sink_function.
 798 * @source_pad: number of the source pad in the pads array
 799 * @sink_function: Function of the sink entities. Used only if @sink is NULL.
 800 * @sink: pointer to &media_entity of the sink pad. If NULL, it will use
 801 *	all entities that matches the @sink_function.
 802 * @sink_pad: number of the sink pad in the pads array.
 803 * @flags: Link flags, as defined in include/uapi/linux/media.h.
 804 * @allow_both_undefined: if %true, then both @source and @sink can be NULL.
 805 *	In such case, it will create a crossbar between all entities that
 806 *	matches @source_function to all entities that matches @sink_function.
 807 *	If %false, it will return 0 and won't create any link if both @source
 808 *	and @sink are NULL.
 809 *
 810 * Valid values for flags:
 811 *
 812 * A %MEDIA_LNK_FL_ENABLED flag indicates that the link is enabled and can be
 813 *	used to transfer media data. If multiple links are created and this
 814 *	flag is passed as an argument, only the first created link will have
 815 *	this flag.
 816 *
 817 * A %MEDIA_LNK_FL_IMMUTABLE flag indicates that the link enabled state can't
 818 *	be modified at runtime. If %MEDIA_LNK_FL_IMMUTABLE is set, then
 819 *	%MEDIA_LNK_FL_ENABLED must also be set since an immutable link is
 820 *	always enabled.
 821 *
 822 * It is common for some devices to have multiple source and/or sink entities
 823 * of the same type that should be linked. While media_create_pad_link()
 824 * creates link by link, this function is meant to allow 1:n, n:1 and even
 825 * cross-bar (n:n) links.
 826 *
 827 * .. note::
 828 *
 829 *    Before calling this function, media_entity_pads_init() and
 830 *    media_device_register_entity() should be called previously for the
 831 *    entities to be linked.
 832 */
 833int media_create_pad_links(const struct media_device *mdev,
 834			   const u32 source_function,
 835			   struct media_entity *source,
 836			   const u16 source_pad,
 837			   const u32 sink_function,
 838			   struct media_entity *sink,
 839			   const u16 sink_pad,
 840			   u32 flags,
 841			   const bool allow_both_undefined);
 842
 843void __media_entity_remove_links(struct media_entity *entity);
 844
 845/**
 846 * media_entity_remove_links() - remove all links associated with an entity
 847 *
 848 * @entity:	pointer to &media_entity
 849 *
 850 * .. note::
 851 *
 852 *    This is called automatically when an entity is unregistered via
 853 *    media_device_register_entity().
 854 */
 855void media_entity_remove_links(struct media_entity *entity);
 856
 857/**
 858 * __media_entity_setup_link - Configure a media link without locking
 859 * @link: The link being configured
 860 * @flags: Link configuration flags
 861 *
 862 * The bulk of link setup is handled by the two entities connected through the
 863 * link. This function notifies both entities of the link configuration change.
 864 *
 865 * If the link is immutable or if the current and new configuration are
 866 * identical, return immediately.
 867 *
 868 * The user is expected to hold link->source->parent->mutex. If not,
 869 * media_entity_setup_link() should be used instead.
 870 */
 871int __media_entity_setup_link(struct media_link *link, u32 flags);
 872
 873/**
 874 * media_entity_setup_link() - changes the link flags properties in runtime
 875 *
 876 * @link:	pointer to &media_link
 877 * @flags:	the requested new link flags
 878 *
 879 * The only configurable property is the %MEDIA_LNK_FL_ENABLED link flag
 880 * to enable/disable a link. Links marked with the
 881 * %MEDIA_LNK_FL_IMMUTABLE link flag can not be enabled or disabled.
 882 *
 883 * When a link is enabled or disabled, the media framework calls the
 884 * link_setup operation for the two entities at the source and sink of the
 885 * link, in that order. If the second link_setup call fails, another
 886 * link_setup call is made on the first entity to restore the original link
 887 * flags.
 888 *
 889 * Media device drivers can be notified of link setup operations by setting the
 890 * &media_device.link_notify pointer to a callback function. If provided, the
 891 * notification callback will be called before enabling and after disabling
 892 * links.
 893 *
 894 * Entity drivers must implement the link_setup operation if any of their links
 895 * is non-immutable. The operation must either configure the hardware or store
 896 * the configuration information to be applied later.
 897 *
 898 * Link configuration must not have any side effect on other links. If an
 899 * enabled link at a sink pad prevents another link at the same pad from
 900 * being enabled, the link_setup operation must return %-EBUSY and can't
 901 * implicitly disable the first enabled link.
 902 *
 903 * .. note::
 904 *
 905 *    The valid values of the flags for the link is the same as described
 906 *    on media_create_pad_link(), for pad to pad links or the same as described
 907 *    on media_create_intf_link(), for interface to entity links.
 908 */
 909int media_entity_setup_link(struct media_link *link, u32 flags);
 910
 911/**
 912 * media_entity_find_link - Find a link between two pads
 913 * @source: Source pad
 914 * @sink: Sink pad
 915 *
 916 * Return: returns a pointer to the link between the two entities. If no
 917 * such link exists, return %NULL.
 918 */
 919struct media_link *media_entity_find_link(struct media_pad *source,
 920		struct media_pad *sink);
 921
 922/**
 923 * media_pad_remote_pad_first - Find the first pad at the remote end of a link
 924 * @pad: Pad at the local end of the link
 925 *
 926 * Search for a remote pad connected to the given pad by iterating over all
 927 * links originating or terminating at that pad until an enabled link is found.
 928 *
 929 * Return: returns a pointer to the pad at the remote end of the first found
 930 * enabled link, or %NULL if no enabled link has been found.
 931 */
 932struct media_pad *media_pad_remote_pad_first(const struct media_pad *pad);
 933
 934/**
 935 * media_pad_remote_pad_unique - Find a remote pad connected to a pad
 936 * @pad: The pad
 937 *
 938 * Search for and return a remote pad connected to @pad through an enabled
 939 * link. If multiple (or no) remote pads are found, an error is returned.
 940 *
 941 * The uniqueness constraint makes this helper function suitable for entities
 942 * that support a single active source at a time on a given pad.
 943 *
 944 * Return: A pointer to the remote pad, or one of the following error pointers
 945 * if an error occurs:
 946 *
 947 * * -ENOTUNIQ - Multiple links are enabled
 948 * * -ENOLINK - No connected pad found
 949 */
 950struct media_pad *media_pad_remote_pad_unique(const struct media_pad *pad);
 951
 952/**
 953 * media_entity_remote_pad_unique - Find a remote pad connected to an entity
 954 * @entity: The entity
 955 * @type: The type of pad to find (MEDIA_PAD_FL_SINK or MEDIA_PAD_FL_SOURCE)
 956 *
 957 * Search for and return a remote pad of @type connected to @entity through an
 958 * enabled link. If multiple (or no) remote pads match these criteria, an error
 959 * is returned.
 960 *
 961 * The uniqueness constraint makes this helper function suitable for entities
 962 * that support a single active source or sink at a time.
 963 *
 964 * Return: A pointer to the remote pad, or one of the following error pointers
 965 * if an error occurs:
 966 *
 967 * * -ENOTUNIQ - Multiple links are enabled
 968 * * -ENOLINK - No connected pad found
 969 */
 970struct media_pad *
 971media_entity_remote_pad_unique(const struct media_entity *entity,
 972			       unsigned int type);
 973
 974/**
 975 * media_entity_remote_source_pad_unique - Find a remote source pad connected to
 976 *	an entity
 977 * @entity: The entity
 978 *
 979 * Search for and return a remote source pad connected to @entity through an
 980 * enabled link. If multiple (or no) remote pads match these criteria, an error
 981 * is returned.
 982 *
 983 * The uniqueness constraint makes this helper function suitable for entities
 984 * that support a single active source at a time.
 985 *
 986 * Return: A pointer to the remote pad, or one of the following error pointers
 987 * if an error occurs:
 988 *
 989 * * -ENOTUNIQ - Multiple links are enabled
 990 * * -ENOLINK - No connected pad found
 991 */
 992static inline struct media_pad *
 993media_entity_remote_source_pad_unique(const struct media_entity *entity)
 994{
 995	return media_entity_remote_pad_unique(entity, MEDIA_PAD_FL_SOURCE);
 996}
 997
 998/**
 999 * media_pad_is_streaming - Test if a pad is part of a streaming pipeline
1000 * @pad: The pad
1001 *
1002 * Return: True if the pad is part of a pipeline started with the
1003 * media_pipeline_start() function, false otherwise.
1004 */
1005static inline bool media_pad_is_streaming(const struct media_pad *pad)
1006{
1007	return pad->pipe;
1008}
1009
1010/**
1011 * media_entity_is_streaming - Test if an entity is part of a streaming pipeline
1012 * @entity: The entity
1013 *
1014 * Return: True if the entity is part of a pipeline started with the
1015 * media_pipeline_start() function, false otherwise.
1016 */
1017static inline bool media_entity_is_streaming(const struct media_entity *entity)
1018{
1019	struct media_pad *pad;
1020
1021	media_entity_for_each_pad(entity, pad) {
1022		if (media_pad_is_streaming(pad))
1023			return true;
1024	}
1025
1026	return false;
1027}
1028
1029/**
1030 * media_entity_pipeline - Get the media pipeline an entity is part of
1031 * @entity: The entity
1032 *
1033 * DEPRECATED: use media_pad_pipeline() instead.
1034 *
1035 * This function returns the media pipeline that an entity has been associated
1036 * with when constructing the pipeline with media_pipeline_start(). The pointer
1037 * remains valid until media_pipeline_stop() is called.
1038 *
1039 * In general, entities can be part of multiple pipelines, when carrying
1040 * multiple streams (either on different pads, or on the same pad using
1041 * multiplexed streams). This function is to be used only for entities that
1042 * do not support multiple pipelines.
1043 *
1044 * Return: The media_pipeline the entity is part of, or NULL if the entity is
1045 * not part of any pipeline.
1046 */
1047struct media_pipeline *media_entity_pipeline(struct media_entity *entity);
1048
1049/**
1050 * media_pad_pipeline - Get the media pipeline a pad is part of
1051 * @pad: The pad
1052 *
1053 * This function returns the media pipeline that a pad has been associated
1054 * with when constructing the pipeline with media_pipeline_start(). The pointer
1055 * remains valid until media_pipeline_stop() is called.
1056 *
1057 * Return: The media_pipeline the pad is part of, or NULL if the pad is
1058 * not part of any pipeline.
1059 */
1060struct media_pipeline *media_pad_pipeline(struct media_pad *pad);
1061
1062/**
1063 * media_entity_get_fwnode_pad - Get pad number from fwnode
1064 *
1065 * @entity: The entity
1066 * @fwnode: Pointer to the fwnode_handle which should be used to find the pad
1067 * @direction_flags: Expected direction of the pad, as defined in
1068 *		     :ref:`include/uapi/linux/media.h <media_header>`
1069 *		     (seek for ``MEDIA_PAD_FL_*``)
1070 *
1071 * This function can be used to resolve the media pad number from
1072 * a fwnode. This is useful for devices which use more complex
1073 * mappings of media pads.
1074 *
1075 * If the entity does not implement the get_fwnode_pad() operation
1076 * then this function searches the entity for the first pad that
1077 * matches the @direction_flags.
1078 *
1079 * Return: returns the pad number on success or a negative error code.
1080 */
1081int media_entity_get_fwnode_pad(struct media_entity *entity,
1082				const struct fwnode_handle *fwnode,
1083				unsigned long direction_flags);
1084
1085/**
1086 * media_graph_walk_init - Allocate resources used by graph walk.
1087 *
1088 * @graph: Media graph structure that will be used to walk the graph
1089 * @mdev: Pointer to the &media_device that contains the object
1090 *
1091 * This function is deprecated, use media_pipeline_for_each_pad() instead.
1092 *
1093 * The caller is required to hold the media_device graph_mutex during the graph
1094 * walk until the graph state is released.
1095 *
1096 * Returns zero on success or a negative error code otherwise.
1097 */
1098__must_check int media_graph_walk_init(
1099	struct media_graph *graph, struct media_device *mdev);
1100
1101/**
1102 * media_graph_walk_cleanup - Release resources used by graph walk.
1103 *
1104 * @graph: Media graph structure that will be used to walk the graph
1105 *
1106 * This function is deprecated, use media_pipeline_for_each_pad() instead.
1107 */
1108void media_graph_walk_cleanup(struct media_graph *graph);
1109
1110/**
1111 * media_graph_walk_start - Start walking the media graph at a
1112 *	given entity
1113 *
1114 * @graph: Media graph structure that will be used to walk the graph
1115 * @entity: Starting entity
1116 *
1117 * This function is deprecated, use media_pipeline_for_each_pad() instead.
1118 *
1119 * Before using this function, media_graph_walk_init() must be
1120 * used to allocate resources used for walking the graph. This
1121 * function initializes the graph traversal structure to walk the
1122 * entities graph starting at the given entity. The traversal
1123 * structure must not be modified by the caller during graph
1124 * traversal. After the graph walk, the resources must be released
1125 * using media_graph_walk_cleanup().
1126 */
1127void media_graph_walk_start(struct media_graph *graph,
1128			    struct media_entity *entity);
1129
1130/**
1131 * media_graph_walk_next - Get the next entity in the graph
1132 * @graph: Media graph structure
1133 *
1134 * This function is deprecated, use media_pipeline_for_each_pad() instead.
1135 *
1136 * Perform a depth-first traversal of the given media entities graph.
1137 *
1138 * The graph structure must have been previously initialized with a call to
1139 * media_graph_walk_start().
1140 *
1141 * Return: returns the next entity in the graph or %NULL if the whole graph
1142 * have been traversed.
1143 */
1144struct media_entity *media_graph_walk_next(struct media_graph *graph);
1145
1146/**
1147 * media_pipeline_start - Mark a pipeline as streaming
1148 * @pad: Starting pad
1149 * @pipe: Media pipeline to be assigned to all pads in the pipeline.
1150 *
1151 * Mark all pads connected to a given pad through enabled links, either
1152 * directly or indirectly, as streaming. The given pipeline object is assigned
1153 * to every pad in the pipeline and stored in the media_pad pipe field.
1154 *
1155 * Calls to this function can be nested, in which case the same number of
1156 * media_pipeline_stop() calls will be required to stop streaming. The
1157 * pipeline pointer must be identical for all nested calls to
1158 * media_pipeline_start().
1159 */
1160__must_check int media_pipeline_start(struct media_pad *pad,
1161				      struct media_pipeline *pipe);
1162/**
1163 * __media_pipeline_start - Mark a pipeline as streaming
1164 *
1165 * @pad: Starting pad
1166 * @pipe: Media pipeline to be assigned to all pads in the pipeline.
1167 *
1168 * ..note:: This is the non-locking version of media_pipeline_start()
1169 */
1170__must_check int __media_pipeline_start(struct media_pad *pad,
1171					struct media_pipeline *pipe);
1172
1173/**
1174 * media_pipeline_stop - Mark a pipeline as not streaming
1175 * @pad: Starting pad
1176 *
1177 * Mark all pads connected to a given pad through enabled links, either
1178 * directly or indirectly, as not streaming. The media_pad pipe field is
1179 * reset to %NULL.
1180 *
1181 * If multiple calls to media_pipeline_start() have been made, the same
1182 * number of calls to this function are required to mark the pipeline as not
1183 * streaming.
1184 */
1185void media_pipeline_stop(struct media_pad *pad);
1186
1187/**
1188 * __media_pipeline_stop - Mark a pipeline as not streaming
1189 *
1190 * @pad: Starting pad
1191 *
1192 * .. note:: This is the non-locking version of media_pipeline_stop()
1193 */
1194void __media_pipeline_stop(struct media_pad *pad);
1195
1196struct media_pad *
1197__media_pipeline_pad_iter_next(struct media_pipeline *pipe,
1198			       struct media_pipeline_pad_iter *iter,
1199			       struct media_pad *pad);
1200
1201/**
1202 * media_pipeline_for_each_pad - Iterate on all pads in a media pipeline
1203 * @pipe: The pipeline
1204 * @iter: The iterator (struct media_pipeline_pad_iter)
1205 * @pad: The iterator pad
1206 *
1207 * Iterate on all pads in a media pipeline. This is only valid after the
1208 * pipeline has been built with media_pipeline_start() and before it gets
1209 * destroyed with media_pipeline_stop().
1210 */
1211#define media_pipeline_for_each_pad(pipe, iter, pad)			\
1212	for (pad = __media_pipeline_pad_iter_next((pipe), iter, NULL);	\
1213	     pad != NULL;						\
1214	     pad = __media_pipeline_pad_iter_next((pipe), iter, pad))
1215
1216/**
1217 * media_pipeline_entity_iter_init - Initialize a pipeline entity iterator
1218 * @pipe: The pipeline
1219 * @iter: The iterator
1220 *
1221 * This function must be called to initialize the iterator before using it in a
1222 * media_pipeline_for_each_entity() loop. The iterator must be destroyed by a
1223 * call to media_pipeline_entity_iter_cleanup after the loop (including in code
1224 * paths that break from the loop).
1225 *
1226 * The same iterator can be used in multiple consecutive loops without being
1227 * destroyed and reinitialized.
1228 *
1229 * Return: 0 on success or a negative error code otherwise.
1230 */
1231int media_pipeline_entity_iter_init(struct media_pipeline *pipe,
1232				    struct media_pipeline_entity_iter *iter);
1233
1234/**
1235 * media_pipeline_entity_iter_cleanup - Destroy a pipeline entity iterator
1236 * @iter: The iterator
1237 *
1238 * This function must be called to destroy iterators initialized with
1239 * media_pipeline_entity_iter_init().
1240 */
1241void media_pipeline_entity_iter_cleanup(struct media_pipeline_entity_iter *iter);
1242
1243struct media_entity *
1244__media_pipeline_entity_iter_next(struct media_pipeline *pipe,
1245				  struct media_pipeline_entity_iter *iter,
1246				  struct media_entity *entity);
1247
1248/**
1249 * media_pipeline_for_each_entity - Iterate on all entities in a media pipeline
1250 * @pipe: The pipeline
1251 * @iter: The iterator (struct media_pipeline_entity_iter)
1252 * @entity: The iterator entity
1253 *
1254 * Iterate on all entities in a media pipeline. This is only valid after the
1255 * pipeline has been built with media_pipeline_start() and before it gets
1256 * destroyed with media_pipeline_stop(). The iterator must be initialized with
1257 * media_pipeline_entity_iter_init() before iteration, and destroyed with
1258 * media_pipeline_entity_iter_cleanup() after (including in code paths that
1259 * break from the loop).
1260 */
1261#define media_pipeline_for_each_entity(pipe, iter, entity)			\
1262	for (entity = __media_pipeline_entity_iter_next((pipe), iter, NULL);	\
1263	     entity != NULL;							\
1264	     entity = __media_pipeline_entity_iter_next((pipe), iter, entity))
1265
1266/**
1267 * media_pipeline_alloc_start - Mark a pipeline as streaming
1268 * @pad: Starting pad
1269 *
1270 * media_pipeline_alloc_start() is similar to media_pipeline_start() but instead
1271 * of working on a given pipeline the function will use an existing pipeline if
1272 * the pad is already part of a pipeline, or allocate a new pipeline.
1273 *
1274 * Calls to media_pipeline_alloc_start() must be matched with
1275 * media_pipeline_stop().
1276 */
1277__must_check int media_pipeline_alloc_start(struct media_pad *pad);
1278
1279/**
1280 * media_devnode_create() - creates and initializes a device node interface
1281 *
1282 * @mdev:	pointer to struct &media_device
1283 * @type:	type of the interface, as given by
1284 *		:ref:`include/uapi/linux/media.h <media_header>`
1285 *		( seek for ``MEDIA_INTF_T_*``) macros.
1286 * @flags:	Interface flags, as defined in
1287 *		:ref:`include/uapi/linux/media.h <media_header>`
1288 *		( seek for ``MEDIA_INTF_FL_*``)
1289 * @major:	Device node major number.
1290 * @minor:	Device node minor number.
1291 *
1292 * Return: if succeeded, returns a pointer to the newly allocated
1293 *	&media_intf_devnode pointer.
1294 *
1295 * .. note::
1296 *
1297 *    Currently, no flags for &media_interface is defined.
1298 */
1299struct media_intf_devnode *
1300__must_check media_devnode_create(struct media_device *mdev,
1301				  u32 type, u32 flags,
1302				  u32 major, u32 minor);
1303/**
1304 * media_devnode_remove() - removes a device node interface
1305 *
1306 * @devnode:	pointer to &media_intf_devnode to be freed.
1307 *
1308 * When a device node interface is removed, all links to it are automatically
1309 * removed.
1310 */
1311void media_devnode_remove(struct media_intf_devnode *devnode);
1312
1313/**
1314 * media_create_intf_link() - creates a link between an entity and an interface
1315 *
1316 * @entity:	pointer to %media_entity
1317 * @intf:	pointer to %media_interface
1318 * @flags:	Link flags, as defined in
1319 *		:ref:`include/uapi/linux/media.h <media_header>`
1320 *		( seek for ``MEDIA_LNK_FL_*``)
1321 *
1322 *
1323 * Valid values for flags:
1324 *
1325 * %MEDIA_LNK_FL_ENABLED
1326 *   Indicates that the interface is connected to the entity hardware.
1327 *   That's the default value for interfaces. An interface may be disabled if
1328 *   the hardware is busy due to the usage of some other interface that it is
1329 *   currently controlling the hardware.
1330 *
1331 *   A typical example is an hybrid TV device that handle only one type of
1332 *   stream on a given time. So, when the digital TV is streaming,
1333 *   the V4L2 interfaces won't be enabled, as such device is not able to
1334 *   also stream analog TV or radio.
1335 *
1336 * .. note::
1337 *
1338 *    Before calling this function, media_devnode_create() should be called for
1339 *    the interface and media_device_register_entity() should be called for the
1340 *    interface that will be part of the link.
1341 */
1342struct media_link *
1343__must_check media_create_intf_link(struct media_entity *entity,
1344				    struct media_interface *intf,
1345				    u32 flags);
1346/**
1347 * __media_remove_intf_link() - remove a single interface link
1348 *
1349 * @link:	pointer to &media_link.
1350 *
1351 * .. note:: This is an unlocked version of media_remove_intf_link()
1352 */
1353void __media_remove_intf_link(struct media_link *link);
1354
1355/**
1356 * media_remove_intf_link() - remove a single interface link
1357 *
1358 * @link:	pointer to &media_link.
1359 *
1360 * .. note:: Prefer to use this one, instead of __media_remove_intf_link()
1361 */
1362void media_remove_intf_link(struct media_link *link);
1363
1364/**
1365 * __media_remove_intf_links() - remove all links associated with an interface
1366 *
1367 * @intf:	pointer to &media_interface
1368 *
1369 * .. note:: This is an unlocked version of media_remove_intf_links().
1370 */
1371void __media_remove_intf_links(struct media_interface *intf);
1372
1373/**
1374 * media_remove_intf_links() - remove all links associated with an interface
1375 *
1376 * @intf:	pointer to &media_interface
1377 *
1378 * .. note::
1379 *
1380 *   #) This is called automatically when an entity is unregistered via
1381 *      media_device_register_entity() and by media_devnode_remove().
1382 *
1383 *   #) Prefer to use this one, instead of __media_remove_intf_links().
1384 */
1385void media_remove_intf_links(struct media_interface *intf);
1386
1387/**
1388 * media_entity_call - Calls a struct media_entity_operations operation on
1389 *	an entity
1390 *
1391 * @entity: entity where the @operation will be called
1392 * @operation: type of the operation. Should be the name of a member of
1393 *	struct &media_entity_operations.
1394 *
1395 * This helper function will check if @operation is not %NULL. On such case,
1396 * it will issue a call to @operation\(@entity, @args\).
1397 */
1398
1399#define media_entity_call(entity, operation, args...)			\
1400	(((entity)->ops && (entity)->ops->operation) ?			\
1401	 (entity)->ops->operation((entity) , ##args) : -ENOIOCTLCMD)
1402
1403/**
1404 * media_create_ancillary_link() - create an ancillary link between two
1405 *				   instances of &media_entity
1406 *
1407 * @primary:	pointer to the primary &media_entity
1408 * @ancillary:	pointer to the ancillary &media_entity
1409 *
1410 * Create an ancillary link between two entities, indicating that they
1411 * represent two connected pieces of hardware that form a single logical unit.
1412 * A typical example is a camera lens controller being linked to the sensor that
1413 * it is supporting.
1414 *
1415 * The function sets both MEDIA_LNK_FL_ENABLED and MEDIA_LNK_FL_IMMUTABLE for
1416 * the new link.
1417 */
1418struct media_link *
1419media_create_ancillary_link(struct media_entity *primary,
1420			    struct media_entity *ancillary);
1421
1422/**
1423 * __media_entity_next_link() - Iterate through a &media_entity's links
1424 *
1425 * @entity:	pointer to the &media_entity
1426 * @link:	pointer to a &media_link to hold the iterated values
1427 * @link_type:	one of the MEDIA_LNK_FL_LINK_TYPE flags
1428 *
1429 * Return the next link against an entity matching a specific link type. This
1430 * allows iteration through an entity's links whilst guaranteeing all of the
1431 * returned links are of the given type.
1432 */
1433struct media_link *__media_entity_next_link(struct media_entity *entity,
1434					    struct media_link *link,
1435					    unsigned long link_type);
1436
1437/**
1438 * for_each_media_entity_data_link() - Iterate through an entity's data links
1439 *
1440 * @entity:	pointer to the &media_entity
1441 * @link:	pointer to a &media_link to hold the iterated values
1442 *
1443 * Iterate over a &media_entity's data links
1444 */
1445#define for_each_media_entity_data_link(entity, link)			\
1446	for (link = __media_entity_next_link(entity, NULL,		\
1447					     MEDIA_LNK_FL_DATA_LINK);	\
1448	     link;							\
1449	     link = __media_entity_next_link(entity, link,		\
1450					     MEDIA_LNK_FL_DATA_LINK))
1451
1452#endif