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(dst: ent_enum->bmap, nbits: 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(src: ent_enum->bmap, nbits: 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(src1: ent_enum1->bmap, src2: 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
1453

source code of linux/include/media/media-entity.h