xref: /linux/include/media/media-entity.h (revision da8e05f84a11c3cc3b0ba0a3c62d20e358002d99)
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  */
34 enum 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  */
59 struct 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  */
74 struct 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  */
90 struct 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  */
108 struct 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  */
127 struct media_pipeline_pad {
128 	struct list_head list;
129 	struct media_pipeline *pipe;
130 	struct media_pad *pad;
131 };
132 
133 /**
134  * struct media_link - A link object part of a media graph.
135  *
136  * @graph_obj:	Embedded structure containing the media object common data
137  * @list:	Linked list associated with an entity or an interface that
138  *		owns the link.
139  * @gobj0:	Part of a union. Used to get the pointer for the first
140  *		graph_object of the link.
141  * @source:	Part of a union. Used only if the first object (gobj0) is
142  *		a pad. In that case, it represents the source pad.
143  * @intf:	Part of a union. Used only if the first object (gobj0) is
144  *		an interface.
145  * @gobj1:	Part of a union. Used to get the pointer for the second
146  *		graph_object of the link.
147  * @sink:	Part of a union. Used only if the second object (gobj1) is
148  *		a pad. In that case, it represents the sink pad.
149  * @entity:	Part of a union. Used only if the second object (gobj1) is
150  *		an entity.
151  * @reverse:	Pointer to the link for the reverse direction of a pad to pad
152  *		link.
153  * @flags:	Link flags, as defined in uapi/media.h (MEDIA_LNK_FL_*)
154  * @is_backlink: Indicate if the link is a backlink.
155  */
156 struct media_link {
157 	struct media_gobj graph_obj;
158 	struct list_head list;
159 	union {
160 		struct media_gobj *gobj0;
161 		struct media_pad *source;
162 		struct media_interface *intf;
163 	};
164 	union {
165 		struct media_gobj *gobj1;
166 		struct media_pad *sink;
167 		struct media_entity *entity;
168 	};
169 	struct media_link *reverse;
170 	unsigned long flags;
171 	bool is_backlink;
172 };
173 
174 /**
175  * enum media_pad_signal_type - type of the signal inside a media pad
176  *
177  * @PAD_SIGNAL_DEFAULT:
178  *	Default signal. Use this when all inputs or all outputs are
179  *	uniquely identified by the pad number.
180  * @PAD_SIGNAL_ANALOG:
181  *	The pad contains an analog signal. It can be Radio Frequency,
182  *	Intermediate Frequency, a baseband signal or sub-carriers.
183  *	Tuner inputs, IF-PLL demodulators, composite and s-video signals
184  *	should use it.
185  * @PAD_SIGNAL_DV:
186  *	Contains a digital video signal, with can be a bitstream of samples
187  *	taken from an analog TV video source. On such case, it usually
188  *	contains the VBI data on it.
189  * @PAD_SIGNAL_AUDIO:
190  *	Contains an Intermediate Frequency analog signal from an audio
191  *	sub-carrier or an audio bitstream. IF signals are provided by tuners
192  *	and consumed by	audio AM/FM decoders. Bitstream audio is provided by
193  *	an audio decoder.
194  */
195 enum media_pad_signal_type {
196 	PAD_SIGNAL_DEFAULT = 0,
197 	PAD_SIGNAL_ANALOG,
198 	PAD_SIGNAL_DV,
199 	PAD_SIGNAL_AUDIO,
200 };
201 
202 /**
203  * struct media_pad - A media pad graph object.
204  *
205  * @graph_obj:	Embedded structure containing the media object common data
206  * @entity:	Entity this pad belongs to
207  * @index:	Pad index in the entity pads array, numbered from 0 to n
208  * @sig_type:	Type of the signal inside a media pad
209  * @flags:	Pad flags, as defined in
210  *		:ref:`include/uapi/linux/media.h <media_header>`
211  *		(seek for ``MEDIA_PAD_FL_*``)
212  * @pipe:	Pipeline this pad belongs to. Use media_entity_pipeline() to
213  *		access this field.
214  */
215 struct media_pad {
216 	struct media_gobj graph_obj;	/* must be first field in struct */
217 	struct media_entity *entity;
218 	u16 index;
219 	enum media_pad_signal_type sig_type;
220 	unsigned long flags;
221 
222 	/*
223 	 * The fields below are private, and should only be accessed via
224 	 * appropriate functions.
225 	 */
226 	struct media_pipeline *pipe;
227 };
228 
229 /**
230  * struct media_entity_operations - Media entity operations
231  * @get_fwnode_pad:	Return the pad number based on a fwnode endpoint or
232  *			a negative value on error. This operation can be used
233  *			to map a fwnode to a media pad number. Optional.
234  * @link_setup:		Notify the entity of link changes. The operation can
235  *			return an error, in which case link setup will be
236  *			cancelled. Optional.
237  * @link_validate:	Return whether a link is valid from the entity point of
238  *			view. The media_pipeline_start() function
239  *			validates all links by calling this operation. Optional.
240  * @has_pad_interdep:	Return whether two pads of the entity are
241  *			interdependent. If two pads are interdependent they are
242  *			part of the same pipeline and enabling one of the pads
243  *			means that the other pad will become "locked" and
244  *			doesn't allow configuration changes. pad0 and pad1 are
245  *			guaranteed to not both be sinks or sources. Never call
246  *			the .has_pad_interdep() operation directly, always use
247  *			media_entity_has_pad_interdep().
248  *			Optional: If the operation isn't implemented all pads
249  *			will be considered as interdependent.
250  *
251  * .. note::
252  *
253  *    Those these callbacks are called with struct &media_device.graph_mutex
254  *    mutex held.
255  */
256 struct media_entity_operations {
257 	int (*get_fwnode_pad)(struct media_entity *entity,
258 			      struct fwnode_endpoint *endpoint);
259 	int (*link_setup)(struct media_entity *entity,
260 			  const struct media_pad *local,
261 			  const struct media_pad *remote, u32 flags);
262 	int (*link_validate)(struct media_link *link);
263 	bool (*has_pad_interdep)(struct media_entity *entity, unsigned int pad0,
264 				 unsigned int pad1);
265 };
266 
267 /**
268  * enum media_entity_type - Media entity type
269  *
270  * @MEDIA_ENTITY_TYPE_BASE:
271  *	The entity isn't embedded in another subsystem structure.
272  * @MEDIA_ENTITY_TYPE_VIDEO_DEVICE:
273  *	The entity is embedded in a struct video_device instance.
274  * @MEDIA_ENTITY_TYPE_V4L2_SUBDEV:
275  *	The entity is embedded in a struct v4l2_subdev instance.
276  *
277  * Media entity objects are often not instantiated directly, but the media
278  * entity structure is inherited by (through embedding) other subsystem-specific
279  * structures. The media entity type identifies the type of the subclass
280  * structure that implements a media entity instance.
281  *
282  * This allows runtime type identification of media entities and safe casting to
283  * the correct object type. For instance, a media entity structure instance
284  * embedded in a v4l2_subdev structure instance will have the type
285  * %MEDIA_ENTITY_TYPE_V4L2_SUBDEV and can safely be cast to a &v4l2_subdev
286  * structure using the container_of() macro.
287  */
288 enum media_entity_type {
289 	MEDIA_ENTITY_TYPE_BASE,
290 	MEDIA_ENTITY_TYPE_VIDEO_DEVICE,
291 	MEDIA_ENTITY_TYPE_V4L2_SUBDEV,
292 };
293 
294 /**
295  * struct media_entity - A media entity graph object.
296  *
297  * @graph_obj:	Embedded structure containing the media object common data.
298  * @name:	Entity name.
299  * @obj_type:	Type of the object that implements the media_entity.
300  * @function:	Entity main function, as defined in
301  *		:ref:`include/uapi/linux/media.h <media_header>`
302  *		(seek for ``MEDIA_ENT_F_*``)
303  * @flags:	Entity flags, as defined in
304  *		:ref:`include/uapi/linux/media.h <media_header>`
305  *		(seek for ``MEDIA_ENT_FL_*``)
306  * @num_pads:	Number of sink and source pads.
307  * @num_links:	Total number of links, forward and back, enabled and disabled.
308  * @num_backlinks: Number of backlinks
309  * @internal_idx: An unique internal entity specific number. The numbers are
310  *		re-used if entities are unregistered or registered again.
311  * @pads:	Pads array with the size defined by @num_pads.
312  * @links:	List of data links.
313  * @ops:	Entity operations.
314  * @use_count:	Use count for the entity.
315  * @info:	Union with devnode information.  Kept just for backward
316  *		compatibility.
317  * @info.dev:	Contains device major and minor info.
318  * @info.dev.major: device node major, if the device is a devnode.
319  * @info.dev.minor: device node minor, if the device is a devnode.
320  * @major:	Devnode major number (zero if not applicable). Kept just
321  *		for backward compatibility.
322  * @minor:	Devnode minor number (zero if not applicable). Kept just
323  *		for backward compatibility.
324  *
325  * .. note::
326  *
327  *    The @use_count reference count must never be negative, but is a signed
328  *    integer on purpose: a simple ``WARN_ON(<0)`` check can be used to detect
329  *    reference count bugs that would make it negative.
330  */
331 struct media_entity {
332 	struct media_gobj graph_obj;	/* must be first field in struct */
333 	const char *name;
334 	enum media_entity_type obj_type;
335 	u32 function;
336 	unsigned long flags;
337 
338 	u16 num_pads;
339 	u16 num_links;
340 	u16 num_backlinks;
341 	int internal_idx;
342 
343 	struct media_pad *pads;
344 	struct list_head links;
345 
346 	const struct media_entity_operations *ops;
347 
348 	int use_count;
349 
350 	union {
351 		struct {
352 			u32 major;
353 			u32 minor;
354 		} dev;
355 	} info;
356 };
357 
358 /**
359  * media_entity_for_each_pad - Iterate on all pads in an entity
360  * @entity: The entity the pads belong to
361  * @iter: The iterator pad
362  *
363  * Iterate on all pads in a media entity.
364  */
365 #define media_entity_for_each_pad(entity, iter)			\
366 	for (iter = (entity)->pads;				\
367 	     iter < &(entity)->pads[(entity)->num_pads];	\
368 	     ++iter)
369 
370 /**
371  * struct media_interface - A media interface graph object.
372  *
373  * @graph_obj:		embedded graph object
374  * @links:		List of links pointing to graph entities
375  * @type:		Type of the interface as defined in
376  *			:ref:`include/uapi/linux/media.h <media_header>`
377  *			(seek for ``MEDIA_INTF_T_*``)
378  * @flags:		Interface flags as defined in
379  *			:ref:`include/uapi/linux/media.h <media_header>`
380  *			(seek for ``MEDIA_INTF_FL_*``)
381  *
382  * .. note::
383  *
384  *    Currently, no flags for &media_interface is defined.
385  */
386 struct media_interface {
387 	struct media_gobj		graph_obj;
388 	struct list_head		links;
389 	u32				type;
390 	u32				flags;
391 };
392 
393 /**
394  * struct media_intf_devnode - A media interface via a device node.
395  *
396  * @intf:	embedded interface object
397  * @major:	Major number of a device node
398  * @minor:	Minor number of a device node
399  */
400 struct media_intf_devnode {
401 	struct media_interface		intf;
402 
403 	/* Should match the fields at media_v2_intf_devnode */
404 	u32				major;
405 	u32				minor;
406 };
407 
408 /**
409  * media_entity_id() - return the media entity graph object id
410  *
411  * @entity:	pointer to &media_entity
412  */
413 static inline u32 media_entity_id(struct media_entity *entity)
414 {
415 	return entity->graph_obj.id;
416 }
417 
418 /**
419  * media_type() - return the media object type
420  *
421  * @gobj:	Pointer to the struct &media_gobj graph object
422  */
423 static inline enum media_gobj_type media_type(struct media_gobj *gobj)
424 {
425 	return gobj->id >> MEDIA_BITS_PER_ID;
426 }
427 
428 /**
429  * media_id() - return the media object ID
430  *
431  * @gobj:	Pointer to the struct &media_gobj graph object
432  */
433 static inline u32 media_id(struct media_gobj *gobj)
434 {
435 	return gobj->id & MEDIA_ID_MASK;
436 }
437 
438 /**
439  * media_gobj_gen_id() - encapsulates type and ID on at the object ID
440  *
441  * @type:	object type as define at enum &media_gobj_type.
442  * @local_id:	next ID, from struct &media_device.id.
443  */
444 static inline u32 media_gobj_gen_id(enum media_gobj_type type, u64 local_id)
445 {
446 	u32 id;
447 
448 	id = type << MEDIA_BITS_PER_ID;
449 	id |= local_id & MEDIA_ID_MASK;
450 
451 	return id;
452 }
453 
454 /**
455  * is_media_entity_v4l2_video_device() - Check if the entity is a video_device
456  * @entity:	pointer to entity
457  *
458  * Return: %true if the entity is an instance of a video_device object and can
459  * safely be cast to a struct video_device using the container_of() macro, or
460  * %false otherwise.
461  */
462 static inline bool is_media_entity_v4l2_video_device(struct media_entity *entity)
463 {
464 	return entity && entity->obj_type == MEDIA_ENTITY_TYPE_VIDEO_DEVICE;
465 }
466 
467 /**
468  * is_media_entity_v4l2_subdev() - Check if the entity is a v4l2_subdev
469  * @entity:	pointer to entity
470  *
471  * Return: %true if the entity is an instance of a &v4l2_subdev object and can
472  * safely be cast to a struct &v4l2_subdev using the container_of() macro, or
473  * %false otherwise.
474  */
475 static inline bool is_media_entity_v4l2_subdev(struct media_entity *entity)
476 {
477 	return entity && entity->obj_type == MEDIA_ENTITY_TYPE_V4L2_SUBDEV;
478 }
479 
480 /**
481  * media_entity_enum_init - Initialise an entity enumeration
482  *
483  * @ent_enum: Entity enumeration to be initialised
484  * @mdev: The related media device
485  *
486  * Return: zero on success or a negative error code.
487  */
488 __must_check int media_entity_enum_init(struct media_entity_enum *ent_enum,
489 					struct media_device *mdev);
490 
491 /**
492  * media_entity_enum_cleanup - Release resources of an entity enumeration
493  *
494  * @ent_enum: Entity enumeration to be released
495  */
496 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum);
497 
498 /**
499  * media_entity_enum_zero - Clear the entire enum
500  *
501  * @ent_enum: Entity enumeration to be cleared
502  */
503 static inline void media_entity_enum_zero(struct media_entity_enum *ent_enum)
504 {
505 	bitmap_zero(ent_enum->bmap, ent_enum->idx_max);
506 }
507 
508 /**
509  * media_entity_enum_set - Mark a single entity in the enum
510  *
511  * @ent_enum: Entity enumeration
512  * @entity: Entity to be marked
513  */
514 static inline void media_entity_enum_set(struct media_entity_enum *ent_enum,
515 					 struct media_entity *entity)
516 {
517 	if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
518 		return;
519 
520 	__set_bit(entity->internal_idx, ent_enum->bmap);
521 }
522 
523 /**
524  * media_entity_enum_clear - Unmark a single entity in the enum
525  *
526  * @ent_enum: Entity enumeration
527  * @entity: Entity to be unmarked
528  */
529 static inline void media_entity_enum_clear(struct media_entity_enum *ent_enum,
530 					   struct media_entity *entity)
531 {
532 	if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
533 		return;
534 
535 	__clear_bit(entity->internal_idx, ent_enum->bmap);
536 }
537 
538 /**
539  * media_entity_enum_test - Test whether the entity is marked
540  *
541  * @ent_enum: Entity enumeration
542  * @entity: Entity to be tested
543  *
544  * Returns %true if the entity was marked.
545  */
546 static inline bool media_entity_enum_test(struct media_entity_enum *ent_enum,
547 					  struct media_entity *entity)
548 {
549 	if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
550 		return true;
551 
552 	return test_bit(entity->internal_idx, ent_enum->bmap);
553 }
554 
555 /**
556  * media_entity_enum_test_and_set - Test whether the entity is marked,
557  *	and mark it
558  *
559  * @ent_enum: Entity enumeration
560  * @entity: Entity to be tested
561  *
562  * Returns %true if the entity was marked, and mark it before doing so.
563  */
564 static inline bool
565 media_entity_enum_test_and_set(struct media_entity_enum *ent_enum,
566 			       struct media_entity *entity)
567 {
568 	if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
569 		return true;
570 
571 	return __test_and_set_bit(entity->internal_idx, ent_enum->bmap);
572 }
573 
574 /**
575  * media_entity_enum_empty - Test whether the entire enum is empty
576  *
577  * @ent_enum: Entity enumeration
578  *
579  * Return: %true if the entity was empty.
580  */
581 static inline bool media_entity_enum_empty(struct media_entity_enum *ent_enum)
582 {
583 	return bitmap_empty(ent_enum->bmap, ent_enum->idx_max);
584 }
585 
586 /**
587  * media_entity_enum_intersects - Test whether two enums intersect
588  *
589  * @ent_enum1: First entity enumeration
590  * @ent_enum2: Second entity enumeration
591  *
592  * Return: %true if entity enumerations @ent_enum1 and @ent_enum2 intersect,
593  * otherwise %false.
594  */
595 static inline bool media_entity_enum_intersects(
596 	struct media_entity_enum *ent_enum1,
597 	struct media_entity_enum *ent_enum2)
598 {
599 	WARN_ON(ent_enum1->idx_max != ent_enum2->idx_max);
600 
601 	return bitmap_intersects(ent_enum1->bmap, ent_enum2->bmap,
602 				 min(ent_enum1->idx_max, ent_enum2->idx_max));
603 }
604 
605 /**
606  * gobj_to_entity - returns the struct &media_entity pointer from the
607  *	@gobj contained on it.
608  *
609  * @gobj: Pointer to the struct &media_gobj graph object
610  */
611 #define gobj_to_entity(gobj) \
612 		container_of(gobj, struct media_entity, graph_obj)
613 
614 /**
615  * gobj_to_pad - returns the struct &media_pad pointer from the
616  *	@gobj contained on it.
617  *
618  * @gobj: Pointer to the struct &media_gobj graph object
619  */
620 #define gobj_to_pad(gobj) \
621 		container_of(gobj, struct media_pad, graph_obj)
622 
623 /**
624  * gobj_to_link - returns the struct &media_link pointer from the
625  *	@gobj contained on it.
626  *
627  * @gobj: Pointer to the struct &media_gobj graph object
628  */
629 #define gobj_to_link(gobj) \
630 		container_of(gobj, struct media_link, graph_obj)
631 
632 /**
633  * gobj_to_intf - returns the struct &media_interface pointer from the
634  *	@gobj contained on it.
635  *
636  * @gobj: Pointer to the struct &media_gobj graph object
637  */
638 #define gobj_to_intf(gobj) \
639 		container_of(gobj, struct media_interface, graph_obj)
640 
641 /**
642  * intf_to_devnode - returns the struct media_intf_devnode pointer from the
643  *	@intf contained on it.
644  *
645  * @intf: Pointer to struct &media_intf_devnode
646  */
647 #define intf_to_devnode(intf) \
648 		container_of(intf, struct media_intf_devnode, intf)
649 
650 /**
651  *  media_gobj_create - Initialize a graph object
652  *
653  * @mdev:	Pointer to the &media_device that contains the object
654  * @type:	Type of the object
655  * @gobj:	Pointer to the struct &media_gobj graph object
656  *
657  * This routine initializes the embedded struct &media_gobj inside a
658  * media graph object. It is called automatically if ``media_*_create``
659  * function calls are used. However, if the object (entity, link, pad,
660  * interface) is embedded on some other object, this function should be
661  * called before registering the object at the media controller.
662  */
663 void media_gobj_create(struct media_device *mdev,
664 		    enum media_gobj_type type,
665 		    struct media_gobj *gobj);
666 
667 /**
668  *  media_gobj_destroy - Stop using a graph object on a media device
669  *
670  * @gobj:	Pointer to the struct &media_gobj graph object
671  *
672  * This should be called by all routines like media_device_unregister()
673  * that remove/destroy media graph objects.
674  */
675 void media_gobj_destroy(struct media_gobj *gobj);
676 
677 /**
678  * media_entity_pads_init() - Initialize the entity pads
679  *
680  * @entity:	entity where the pads belong
681  * @num_pads:	total number of sink and source pads
682  * @pads:	Array of @num_pads pads.
683  *
684  * The pads array is managed by the entity driver and passed to
685  * media_entity_pads_init() where its pointer will be stored in the
686  * &media_entity structure.
687  *
688  * If no pads are needed, drivers could either directly fill
689  * &media_entity->num_pads with 0 and &media_entity->pads with %NULL or call
690  * this function that will do the same.
691  *
692  * As the number of pads is known in advance, the pads array is not allocated
693  * dynamically but is managed by the entity driver. Most drivers will embed the
694  * pads array in a driver-specific structure, avoiding dynamic allocation.
695  *
696  * Drivers must set the direction of every pad in the pads array before calling
697  * media_entity_pads_init(). The function will initialize the other pads fields.
698  */
699 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
700 		      struct media_pad *pads);
701 
702 /**
703  * media_entity_cleanup() - free resources associated with an entity
704  *
705  * @entity:	entity where the pads belong
706  *
707  * This function must be called during the cleanup phase after unregistering
708  * the entity (currently, it does nothing).
709  *
710  * Calling media_entity_cleanup() on a media_entity whose memory has been
711  * zeroed but that has not been initialized with media_entity_pad_init() is
712  * valid and is a no-op.
713  */
714 #if IS_ENABLED(CONFIG_MEDIA_CONTROLLER)
715 static inline void media_entity_cleanup(struct media_entity *entity) {}
716 #else
717 #define media_entity_cleanup(entity) do { } while (false)
718 #endif
719 
720 /**
721  * media_get_pad_index() - retrieves a pad index from an entity
722  *
723  * @entity:	entity where the pads belong
724  * @is_sink:	true if the pad is a sink, false if it is a source
725  * @sig_type:	type of signal of the pad to be search
726  *
727  * This helper function finds the first pad index inside an entity that
728  * satisfies both @is_sink and @sig_type conditions.
729  *
730  * Return:
731  *
732  * On success, return the pad number. If the pad was not found or the media
733  * entity is a NULL pointer, return -EINVAL.
734  */
735 int media_get_pad_index(struct media_entity *entity, bool is_sink,
736 			enum media_pad_signal_type sig_type);
737 
738 /**
739  * media_create_pad_link() - creates a link between two entities.
740  *
741  * @source:	pointer to &media_entity of the source pad.
742  * @source_pad:	number of the source pad in the pads array
743  * @sink:	pointer to &media_entity of the sink pad.
744  * @sink_pad:	number of the sink pad in the pads array.
745  * @flags:	Link flags, as defined in
746  *		:ref:`include/uapi/linux/media.h <media_header>`
747  *		( seek for ``MEDIA_LNK_FL_*``)
748  *
749  * Valid values for flags:
750  *
751  * %MEDIA_LNK_FL_ENABLED
752  *   Indicates that the link is enabled and can be used to transfer media data.
753  *   When two or more links target a sink pad, only one of them can be
754  *   enabled at a time.
755  *
756  * %MEDIA_LNK_FL_IMMUTABLE
757  *   Indicates that the link enabled state can't be modified at runtime. If
758  *   %MEDIA_LNK_FL_IMMUTABLE is set, then %MEDIA_LNK_FL_ENABLED must also be
759  *   set, since an immutable link is always enabled.
760  *
761  * .. note::
762  *
763  *    Before calling this function, media_entity_pads_init() and
764  *    media_device_register_entity() should be called previously for both ends.
765  */
766 __must_check int media_create_pad_link(struct media_entity *source,
767 			u16 source_pad, struct media_entity *sink,
768 			u16 sink_pad, u32 flags);
769 
770 /**
771  * media_create_pad_links() - creates a link between two entities.
772  *
773  * @mdev: Pointer to the media_device that contains the object
774  * @source_function: Function of the source entities. Used only if @source is
775  *	NULL.
776  * @source: pointer to &media_entity of the source pad. If NULL, it will use
777  *	all entities that matches the @sink_function.
778  * @source_pad: number of the source pad in the pads array
779  * @sink_function: Function of the sink entities. Used only if @sink is NULL.
780  * @sink: pointer to &media_entity of the sink pad. If NULL, it will use
781  *	all entities that matches the @sink_function.
782  * @sink_pad: number of the sink pad in the pads array.
783  * @flags: Link flags, as defined in include/uapi/linux/media.h.
784  * @allow_both_undefined: if %true, then both @source and @sink can be NULL.
785  *	In such case, it will create a crossbar between all entities that
786  *	matches @source_function to all entities that matches @sink_function.
787  *	If %false, it will return 0 and won't create any link if both @source
788  *	and @sink are NULL.
789  *
790  * Valid values for flags:
791  *
792  * A %MEDIA_LNK_FL_ENABLED flag indicates that the link is enabled and can be
793  *	used to transfer media data. If multiple links are created and this
794  *	flag is passed as an argument, only the first created link will have
795  *	this flag.
796  *
797  * A %MEDIA_LNK_FL_IMMUTABLE flag indicates that the link enabled state can't
798  *	be modified at runtime. If %MEDIA_LNK_FL_IMMUTABLE is set, then
799  *	%MEDIA_LNK_FL_ENABLED must also be set since an immutable link is
800  *	always enabled.
801  *
802  * It is common for some devices to have multiple source and/or sink entities
803  * of the same type that should be linked. While media_create_pad_link()
804  * creates link by link, this function is meant to allow 1:n, n:1 and even
805  * cross-bar (n:n) links.
806  *
807  * .. note::
808  *
809  *    Before calling this function, media_entity_pads_init() and
810  *    media_device_register_entity() should be called previously for the
811  *    entities to be linked.
812  */
813 int media_create_pad_links(const struct media_device *mdev,
814 			   const u32 source_function,
815 			   struct media_entity *source,
816 			   const u16 source_pad,
817 			   const u32 sink_function,
818 			   struct media_entity *sink,
819 			   const u16 sink_pad,
820 			   u32 flags,
821 			   const bool allow_both_undefined);
822 
823 void __media_entity_remove_links(struct media_entity *entity);
824 
825 /**
826  * media_entity_remove_links() - remove all links associated with an entity
827  *
828  * @entity:	pointer to &media_entity
829  *
830  * .. note::
831  *
832  *    This is called automatically when an entity is unregistered via
833  *    media_device_register_entity().
834  */
835 void media_entity_remove_links(struct media_entity *entity);
836 
837 /**
838  * __media_entity_setup_link - Configure a media link without locking
839  * @link: The link being configured
840  * @flags: Link configuration flags
841  *
842  * The bulk of link setup is handled by the two entities connected through the
843  * link. This function notifies both entities of the link configuration change.
844  *
845  * If the link is immutable or if the current and new configuration are
846  * identical, return immediately.
847  *
848  * The user is expected to hold link->source->parent->mutex. If not,
849  * media_entity_setup_link() should be used instead.
850  */
851 int __media_entity_setup_link(struct media_link *link, u32 flags);
852 
853 /**
854  * media_entity_setup_link() - changes the link flags properties in runtime
855  *
856  * @link:	pointer to &media_link
857  * @flags:	the requested new link flags
858  *
859  * The only configurable property is the %MEDIA_LNK_FL_ENABLED link flag
860  * to enable/disable a link. Links marked with the
861  * %MEDIA_LNK_FL_IMMUTABLE link flag can not be enabled or disabled.
862  *
863  * When a link is enabled or disabled, the media framework calls the
864  * link_setup operation for the two entities at the source and sink of the
865  * link, in that order. If the second link_setup call fails, another
866  * link_setup call is made on the first entity to restore the original link
867  * flags.
868  *
869  * Media device drivers can be notified of link setup operations by setting the
870  * &media_device.link_notify pointer to a callback function. If provided, the
871  * notification callback will be called before enabling and after disabling
872  * links.
873  *
874  * Entity drivers must implement the link_setup operation if any of their links
875  * is non-immutable. The operation must either configure the hardware or store
876  * the configuration information to be applied later.
877  *
878  * Link configuration must not have any side effect on other links. If an
879  * enabled link at a sink pad prevents another link at the same pad from
880  * being enabled, the link_setup operation must return %-EBUSY and can't
881  * implicitly disable the first enabled link.
882  *
883  * .. note::
884  *
885  *    The valid values of the flags for the link is the same as described
886  *    on media_create_pad_link(), for pad to pad links or the same as described
887  *    on media_create_intf_link(), for interface to entity links.
888  */
889 int media_entity_setup_link(struct media_link *link, u32 flags);
890 
891 /**
892  * media_entity_find_link - Find a link between two pads
893  * @source: Source pad
894  * @sink: Sink pad
895  *
896  * Return: returns a pointer to the link between the two entities. If no
897  * such link exists, return %NULL.
898  */
899 struct media_link *media_entity_find_link(struct media_pad *source,
900 		struct media_pad *sink);
901 
902 /**
903  * media_pad_remote_pad_first - Find the first pad at the remote end of a link
904  * @pad: Pad at the local end of the link
905  *
906  * Search for a remote pad connected to the given pad by iterating over all
907  * links originating or terminating at that pad until an enabled link is found.
908  *
909  * Return: returns a pointer to the pad at the remote end of the first found
910  * enabled link, or %NULL if no enabled link has been found.
911  */
912 struct media_pad *media_pad_remote_pad_first(const struct media_pad *pad);
913 
914 /**
915  * media_pad_remote_pad_unique - Find a remote pad connected to a pad
916  * @pad: The pad
917  *
918  * Search for and return a remote pad connected to @pad through an enabled
919  * link. If multiple (or no) remote pads are found, an error is returned.
920  *
921  * The uniqueness constraint makes this helper function suitable for entities
922  * that support a single active source at a time on a given pad.
923  *
924  * Return: A pointer to the remote pad, or one of the following error pointers
925  * if an error occurs:
926  *
927  * * -ENOTUNIQ - Multiple links are enabled
928  * * -ENOLINK - No connected pad found
929  */
930 struct media_pad *media_pad_remote_pad_unique(const struct media_pad *pad);
931 
932 /**
933  * media_entity_remote_pad_unique - Find a remote pad connected to an entity
934  * @entity: The entity
935  * @type: The type of pad to find (MEDIA_PAD_FL_SINK or MEDIA_PAD_FL_SOURCE)
936  *
937  * Search for and return a remote pad of @type connected to @entity through an
938  * enabled link. If multiple (or no) remote pads match these criteria, an error
939  * is returned.
940  *
941  * The uniqueness constraint makes this helper function suitable for entities
942  * that support a single active source or sink at a time.
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  */
950 struct media_pad *
951 media_entity_remote_pad_unique(const struct media_entity *entity,
952 			       unsigned int type);
953 
954 /**
955  * media_entity_remote_source_pad_unique - Find a remote source pad connected to
956  *	an entity
957  * @entity: The entity
958  *
959  * Search for and return a remote source pad connected to @entity through an
960  * enabled link. If multiple (or no) remote pads match these criteria, an error
961  * is returned.
962  *
963  * The uniqueness constraint makes this helper function suitable for entities
964  * that support a single active source at a time.
965  *
966  * Return: A pointer to the remote pad, or one of the following error pointers
967  * if an error occurs:
968  *
969  * * -ENOTUNIQ - Multiple links are enabled
970  * * -ENOLINK - No connected pad found
971  */
972 static inline struct media_pad *
973 media_entity_remote_source_pad_unique(const struct media_entity *entity)
974 {
975 	return media_entity_remote_pad_unique(entity, MEDIA_PAD_FL_SOURCE);
976 }
977 
978 /**
979  * media_pad_is_streaming - Test if a pad is part of a streaming pipeline
980  * @pad: The pad
981  *
982  * Return: True if the pad is part of a pipeline started with the
983  * media_pipeline_start() function, false otherwise.
984  */
985 static inline bool media_pad_is_streaming(const struct media_pad *pad)
986 {
987 	return pad->pipe;
988 }
989 
990 /**
991  * media_entity_is_streaming - Test if an entity is part of a streaming pipeline
992  * @entity: The entity
993  *
994  * Return: True if the entity is part of a pipeline started with the
995  * media_pipeline_start() function, false otherwise.
996  */
997 static inline bool media_entity_is_streaming(const struct media_entity *entity)
998 {
999 	struct media_pad *pad;
1000 
1001 	media_entity_for_each_pad(entity, pad) {
1002 		if (media_pad_is_streaming(pad))
1003 			return true;
1004 	}
1005 
1006 	return false;
1007 }
1008 
1009 /**
1010  * media_entity_pipeline - Get the media pipeline an entity is part of
1011  * @entity: The entity
1012  *
1013  * DEPRECATED: use media_pad_pipeline() instead.
1014  *
1015  * This function returns the media pipeline that an entity has been associated
1016  * with when constructing the pipeline with media_pipeline_start(). The pointer
1017  * remains valid until media_pipeline_stop() is called.
1018  *
1019  * In general, entities can be part of multiple pipelines, when carrying
1020  * multiple streams (either on different pads, or on the same pad using
1021  * multiplexed streams). This function is to be used only for entities that
1022  * do not support multiple pipelines.
1023  *
1024  * Return: The media_pipeline the entity is part of, or NULL if the entity is
1025  * not part of any pipeline.
1026  */
1027 struct media_pipeline *media_entity_pipeline(struct media_entity *entity);
1028 
1029 /**
1030  * media_pad_pipeline - Get the media pipeline a pad is part of
1031  * @pad: The pad
1032  *
1033  * This function returns the media pipeline that a pad has been associated
1034  * with when constructing the pipeline with media_pipeline_start(). The pointer
1035  * remains valid until media_pipeline_stop() is called.
1036  *
1037  * Return: The media_pipeline the pad is part of, or NULL if the pad is
1038  * not part of any pipeline.
1039  */
1040 struct media_pipeline *media_pad_pipeline(struct media_pad *pad);
1041 
1042 /**
1043  * media_entity_get_fwnode_pad - Get pad number from fwnode
1044  *
1045  * @entity: The entity
1046  * @fwnode: Pointer to the fwnode_handle which should be used to find the pad
1047  * @direction_flags: Expected direction of the pad, as defined in
1048  *		     :ref:`include/uapi/linux/media.h <media_header>`
1049  *		     (seek for ``MEDIA_PAD_FL_*``)
1050  *
1051  * This function can be used to resolve the media pad number from
1052  * a fwnode. This is useful for devices which use more complex
1053  * mappings of media pads.
1054  *
1055  * If the entity does not implement the get_fwnode_pad() operation
1056  * then this function searches the entity for the first pad that
1057  * matches the @direction_flags.
1058  *
1059  * Return: returns the pad number on success or a negative error code.
1060  */
1061 int media_entity_get_fwnode_pad(struct media_entity *entity,
1062 				struct fwnode_handle *fwnode,
1063 				unsigned long direction_flags);
1064 
1065 /**
1066  * media_graph_walk_init - Allocate resources used by graph walk.
1067  *
1068  * @graph: Media graph structure that will be used to walk the graph
1069  * @mdev: Pointer to the &media_device that contains the object
1070  *
1071  * The caller is required to hold the media_device graph_mutex during the graph
1072  * walk until the graph state is released.
1073  *
1074  * Returns zero on success or a negative error code otherwise.
1075  */
1076 __must_check int media_graph_walk_init(
1077 	struct media_graph *graph, struct media_device *mdev);
1078 
1079 /**
1080  * media_graph_walk_cleanup - Release resources used by graph walk.
1081  *
1082  * @graph: Media graph structure that will be used to walk the graph
1083  */
1084 void media_graph_walk_cleanup(struct media_graph *graph);
1085 
1086 /**
1087  * media_graph_walk_start - Start walking the media graph at a
1088  *	given entity
1089  *
1090  * @graph: Media graph structure that will be used to walk the graph
1091  * @entity: Starting entity
1092  *
1093  * Before using this function, media_graph_walk_init() must be
1094  * used to allocate resources used for walking the graph. This
1095  * function initializes the graph traversal structure to walk the
1096  * entities graph starting at the given entity. The traversal
1097  * structure must not be modified by the caller during graph
1098  * traversal. After the graph walk, the resources must be released
1099  * using media_graph_walk_cleanup().
1100  */
1101 void media_graph_walk_start(struct media_graph *graph,
1102 			    struct media_entity *entity);
1103 
1104 /**
1105  * media_graph_walk_next - Get the next entity in the graph
1106  * @graph: Media graph structure
1107  *
1108  * Perform a depth-first traversal of the given media entities graph.
1109  *
1110  * The graph structure must have been previously initialized with a call to
1111  * media_graph_walk_start().
1112  *
1113  * Return: returns the next entity in the graph or %NULL if the whole graph
1114  * have been traversed.
1115  */
1116 struct media_entity *media_graph_walk_next(struct media_graph *graph);
1117 
1118 /**
1119  * media_pipeline_start - Mark a pipeline as streaming
1120  * @pad: Starting pad
1121  * @pipe: Media pipeline to be assigned to all pads in the pipeline.
1122  *
1123  * Mark all pads connected to a given pad through enabled links, either
1124  * directly or indirectly, as streaming. The given pipeline object is assigned
1125  * to every pad in the pipeline and stored in the media_pad pipe field.
1126  *
1127  * Calls to this function can be nested, in which case the same number of
1128  * media_pipeline_stop() calls will be required to stop streaming. The
1129  * pipeline pointer must be identical for all nested calls to
1130  * media_pipeline_start().
1131  */
1132 __must_check int media_pipeline_start(struct media_pad *pad,
1133 				      struct media_pipeline *pipe);
1134 /**
1135  * __media_pipeline_start - Mark a pipeline as streaming
1136  *
1137  * @pad: Starting pad
1138  * @pipe: Media pipeline to be assigned to all pads in the pipeline.
1139  *
1140  * ..note:: This is the non-locking version of media_pipeline_start()
1141  */
1142 __must_check int __media_pipeline_start(struct media_pad *pad,
1143 					struct media_pipeline *pipe);
1144 
1145 /**
1146  * media_pipeline_stop - Mark a pipeline as not streaming
1147  * @pad: Starting pad
1148  *
1149  * Mark all pads connected to a given pad through enabled links, either
1150  * directly or indirectly, as not streaming. The media_pad pipe field is
1151  * reset to %NULL.
1152  *
1153  * If multiple calls to media_pipeline_start() have been made, the same
1154  * number of calls to this function are required to mark the pipeline as not
1155  * streaming.
1156  */
1157 void media_pipeline_stop(struct media_pad *pad);
1158 
1159 /**
1160  * __media_pipeline_stop - Mark a pipeline as not streaming
1161  *
1162  * @pad: Starting pad
1163  *
1164  * .. note:: This is the non-locking version of media_pipeline_stop()
1165  */
1166 void __media_pipeline_stop(struct media_pad *pad);
1167 
1168 /**
1169  * media_pipeline_alloc_start - Mark a pipeline as streaming
1170  * @pad: Starting pad
1171  *
1172  * media_pipeline_alloc_start() is similar to media_pipeline_start() but instead
1173  * of working on a given pipeline the function will use an existing pipeline if
1174  * the pad is already part of a pipeline, or allocate a new pipeline.
1175  *
1176  * Calls to media_pipeline_alloc_start() must be matched with
1177  * media_pipeline_stop().
1178  */
1179 __must_check int media_pipeline_alloc_start(struct media_pad *pad);
1180 
1181 /**
1182  * media_devnode_create() - creates and initializes a device node interface
1183  *
1184  * @mdev:	pointer to struct &media_device
1185  * @type:	type of the interface, as given by
1186  *		:ref:`include/uapi/linux/media.h <media_header>`
1187  *		( seek for ``MEDIA_INTF_T_*``) macros.
1188  * @flags:	Interface flags, as defined in
1189  *		:ref:`include/uapi/linux/media.h <media_header>`
1190  *		( seek for ``MEDIA_INTF_FL_*``)
1191  * @major:	Device node major number.
1192  * @minor:	Device node minor number.
1193  *
1194  * Return: if succeeded, returns a pointer to the newly allocated
1195  *	&media_intf_devnode pointer.
1196  *
1197  * .. note::
1198  *
1199  *    Currently, no flags for &media_interface is defined.
1200  */
1201 struct media_intf_devnode *
1202 __must_check media_devnode_create(struct media_device *mdev,
1203 				  u32 type, u32 flags,
1204 				  u32 major, u32 minor);
1205 /**
1206  * media_devnode_remove() - removes a device node interface
1207  *
1208  * @devnode:	pointer to &media_intf_devnode to be freed.
1209  *
1210  * When a device node interface is removed, all links to it are automatically
1211  * removed.
1212  */
1213 void media_devnode_remove(struct media_intf_devnode *devnode);
1214 
1215 /**
1216  * media_create_intf_link() - creates a link between an entity and an interface
1217  *
1218  * @entity:	pointer to %media_entity
1219  * @intf:	pointer to %media_interface
1220  * @flags:	Link flags, as defined in
1221  *		:ref:`include/uapi/linux/media.h <media_header>`
1222  *		( seek for ``MEDIA_LNK_FL_*``)
1223  *
1224  *
1225  * Valid values for flags:
1226  *
1227  * %MEDIA_LNK_FL_ENABLED
1228  *   Indicates that the interface is connected to the entity hardware.
1229  *   That's the default value for interfaces. An interface may be disabled if
1230  *   the hardware is busy due to the usage of some other interface that it is
1231  *   currently controlling the hardware.
1232  *
1233  *   A typical example is an hybrid TV device that handle only one type of
1234  *   stream on a given time. So, when the digital TV is streaming,
1235  *   the V4L2 interfaces won't be enabled, as such device is not able to
1236  *   also stream analog TV or radio.
1237  *
1238  * .. note::
1239  *
1240  *    Before calling this function, media_devnode_create() should be called for
1241  *    the interface and media_device_register_entity() should be called for the
1242  *    interface that will be part of the link.
1243  */
1244 struct media_link *
1245 __must_check media_create_intf_link(struct media_entity *entity,
1246 				    struct media_interface *intf,
1247 				    u32 flags);
1248 /**
1249  * __media_remove_intf_link() - remove a single interface link
1250  *
1251  * @link:	pointer to &media_link.
1252  *
1253  * .. note:: This is an unlocked version of media_remove_intf_link()
1254  */
1255 void __media_remove_intf_link(struct media_link *link);
1256 
1257 /**
1258  * media_remove_intf_link() - remove a single interface link
1259  *
1260  * @link:	pointer to &media_link.
1261  *
1262  * .. note:: Prefer to use this one, instead of __media_remove_intf_link()
1263  */
1264 void media_remove_intf_link(struct media_link *link);
1265 
1266 /**
1267  * __media_remove_intf_links() - remove all links associated with an interface
1268  *
1269  * @intf:	pointer to &media_interface
1270  *
1271  * .. note:: This is an unlocked version of media_remove_intf_links().
1272  */
1273 void __media_remove_intf_links(struct media_interface *intf);
1274 
1275 /**
1276  * media_remove_intf_links() - remove all links associated with an interface
1277  *
1278  * @intf:	pointer to &media_interface
1279  *
1280  * .. note::
1281  *
1282  *   #) This is called automatically when an entity is unregistered via
1283  *      media_device_register_entity() and by media_devnode_remove().
1284  *
1285  *   #) Prefer to use this one, instead of __media_remove_intf_links().
1286  */
1287 void media_remove_intf_links(struct media_interface *intf);
1288 
1289 /**
1290  * media_entity_call - Calls a struct media_entity_operations operation on
1291  *	an entity
1292  *
1293  * @entity: entity where the @operation will be called
1294  * @operation: type of the operation. Should be the name of a member of
1295  *	struct &media_entity_operations.
1296  *
1297  * This helper function will check if @operation is not %NULL. On such case,
1298  * it will issue a call to @operation\(@entity, @args\).
1299  */
1300 
1301 #define media_entity_call(entity, operation, args...)			\
1302 	(((entity)->ops && (entity)->ops->operation) ?			\
1303 	 (entity)->ops->operation((entity) , ##args) : -ENOIOCTLCMD)
1304 
1305 /**
1306  * media_create_ancillary_link() - create an ancillary link between two
1307  *				   instances of &media_entity
1308  *
1309  * @primary:	pointer to the primary &media_entity
1310  * @ancillary:	pointer to the ancillary &media_entity
1311  *
1312  * Create an ancillary link between two entities, indicating that they
1313  * represent two connected pieces of hardware that form a single logical unit.
1314  * A typical example is a camera lens controller being linked to the sensor that
1315  * it is supporting.
1316  *
1317  * The function sets both MEDIA_LNK_FL_ENABLED and MEDIA_LNK_FL_IMMUTABLE for
1318  * the new link.
1319  */
1320 struct media_link *
1321 media_create_ancillary_link(struct media_entity *primary,
1322 			    struct media_entity *ancillary);
1323 
1324 /**
1325  * __media_entity_next_link() - Iterate through a &media_entity's links
1326  *
1327  * @entity:	pointer to the &media_entity
1328  * @link:	pointer to a &media_link to hold the iterated values
1329  * @link_type:	one of the MEDIA_LNK_FL_LINK_TYPE flags
1330  *
1331  * Return the next link against an entity matching a specific link type. This
1332  * allows iteration through an entity's links whilst guaranteeing all of the
1333  * returned links are of the given type.
1334  */
1335 struct media_link *__media_entity_next_link(struct media_entity *entity,
1336 					    struct media_link *link,
1337 					    unsigned long link_type);
1338 
1339 /**
1340  * for_each_media_entity_data_link() - Iterate through an entity's data links
1341  *
1342  * @entity:	pointer to the &media_entity
1343  * @link:	pointer to a &media_link to hold the iterated values
1344  *
1345  * Iterate over a &media_entity's data links
1346  */
1347 #define for_each_media_entity_data_link(entity, link)			\
1348 	for (link = __media_entity_next_link(entity, NULL,		\
1349 					     MEDIA_LNK_FL_DATA_LINK);	\
1350 	     link;							\
1351 	     link = __media_entity_next_link(entity, link,		\
1352 					     MEDIA_LNK_FL_DATA_LINK))
1353 
1354 #endif
1355