xref: /openbmc/linux/include/media/media-entity.h (revision 9fb29c73)
1 /*
2  * Media entity
3  *
4  * Copyright (C) 2010 Nokia Corporation
5  *
6  * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
7  *	     Sakari Ailus <sakari.ailus@iki.fi>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  */
18 
19 #ifndef _MEDIA_ENTITY_H
20 #define _MEDIA_ENTITY_H
21 
22 #include <linux/bitmap.h>
23 #include <linux/bug.h>
24 #include <linux/fwnode.h>
25 #include <linux/kernel.h>
26 #include <linux/list.h>
27 #include <linux/media.h>
28 
29 /* Enums used internally at the media controller to represent graphs */
30 
31 /**
32  * enum media_gobj_type - type of a graph object
33  *
34  * @MEDIA_GRAPH_ENTITY:		Identify a media entity
35  * @MEDIA_GRAPH_PAD:		Identify a media pad
36  * @MEDIA_GRAPH_LINK:		Identify a media link
37  * @MEDIA_GRAPH_INTF_DEVNODE:	Identify a media Kernel API interface via
38  *				a device node
39  */
40 enum media_gobj_type {
41 	MEDIA_GRAPH_ENTITY,
42 	MEDIA_GRAPH_PAD,
43 	MEDIA_GRAPH_LINK,
44 	MEDIA_GRAPH_INTF_DEVNODE,
45 };
46 
47 #define MEDIA_BITS_PER_TYPE		8
48 #define MEDIA_BITS_PER_ID		(32 - MEDIA_BITS_PER_TYPE)
49 #define MEDIA_ID_MASK			 GENMASK_ULL(MEDIA_BITS_PER_ID - 1, 0)
50 
51 /* Structs to represent the objects that belong to a media graph */
52 
53 /**
54  * struct media_gobj - Define a graph object.
55  *
56  * @mdev:	Pointer to the struct &media_device that owns the object
57  * @id:		Non-zero object ID identifier. The ID should be unique
58  *		inside a media_device, as it is composed by
59  *		%MEDIA_BITS_PER_TYPE to store the type plus
60  *		%MEDIA_BITS_PER_ID to store the ID
61  * @list:	List entry stored in one of the per-type mdev object lists
62  *
63  * All objects on the media graph should have this struct embedded
64  */
65 struct media_gobj {
66 	struct media_device	*mdev;
67 	u32			id;
68 	struct list_head	list;
69 };
70 
71 #define MEDIA_ENTITY_ENUM_MAX_DEPTH	16
72 
73 /**
74  * struct media_entity_enum - An enumeration of media entities.
75  *
76  * @bmap:	Bit map in which each bit represents one entity at struct
77  *		media_entity->internal_idx.
78  * @idx_max:	Number of bits in bmap
79  */
80 struct media_entity_enum {
81 	unsigned long *bmap;
82 	int idx_max;
83 };
84 
85 /**
86  * struct media_graph - Media graph traversal state
87  *
88  * @stack:		Graph traversal stack; the stack contains information
89  *			on the path the media entities to be walked and the
90  *			links through which they were reached.
91  * @stack.entity:	pointer to &struct media_entity at the graph.
92  * @stack.link:		pointer to &struct list_head.
93  * @ent_enum:		Visited entities
94  * @top:		The top of the stack
95  */
96 struct media_graph {
97 	struct {
98 		struct media_entity *entity;
99 		struct list_head *link;
100 	} stack[MEDIA_ENTITY_ENUM_MAX_DEPTH];
101 
102 	struct media_entity_enum ent_enum;
103 	int top;
104 };
105 
106 /**
107  * struct media_pipeline - Media pipeline related information
108  *
109  * @streaming_count:	Streaming start count - streaming stop count
110  * @graph:		Media graph walk during pipeline start / stop
111  */
112 struct media_pipeline {
113 	int streaming_count;
114 	struct media_graph graph;
115 };
116 
117 /**
118  * struct media_link - A link object part of a media graph.
119  *
120  * @graph_obj:	Embedded structure containing the media object common data
121  * @list:	Linked list associated with an entity or an interface that
122  *		owns the link.
123  * @gobj0:	Part of a union. Used to get the pointer for the first
124  *		graph_object of the link.
125  * @source:	Part of a union. Used only if the first object (gobj0) is
126  *		a pad. In that case, it represents the source pad.
127  * @intf:	Part of a union. Used only if the first object (gobj0) is
128  *		an interface.
129  * @gobj1:	Part of a union. Used to get the pointer for the second
130  *		graph_object of the link.
131  * @sink:	Part of a union. Used only if the second object (gobj1) is
132  *		a pad. In that case, it represents the sink pad.
133  * @entity:	Part of a union. Used only if the second object (gobj1) is
134  *		an entity.
135  * @reverse:	Pointer to the link for the reverse direction of a pad to pad
136  *		link.
137  * @flags:	Link flags, as defined in uapi/media.h (MEDIA_LNK_FL_*)
138  * @is_backlink: Indicate if the link is a backlink.
139  */
140 struct media_link {
141 	struct media_gobj graph_obj;
142 	struct list_head list;
143 	union {
144 		struct media_gobj *gobj0;
145 		struct media_pad *source;
146 		struct media_interface *intf;
147 	};
148 	union {
149 		struct media_gobj *gobj1;
150 		struct media_pad *sink;
151 		struct media_entity *entity;
152 	};
153 	struct media_link *reverse;
154 	unsigned long flags;
155 	bool is_backlink;
156 };
157 
158 /**
159  * enum media_pad_signal_type - type of the signal inside a media pad
160  *
161  * @PAD_SIGNAL_DEFAULT:
162  *	Default signal. Use this when all inputs or all outputs are
163  *	uniquely identified by the pad number.
164  * @PAD_SIGNAL_ANALOG:
165  *	The pad contains an analog signal. It can be Radio Frequency,
166  *	Intermediate Frequency, a baseband signal or sub-cariers.
167  *	Tuner inputs, IF-PLL demodulators, composite and s-video signals
168  *	should use it.
169  * @PAD_SIGNAL_DV:
170  *	Contains a digital video signal, with can be a bitstream of samples
171  *	taken from an analog TV video source. On such case, it usually
172  *	contains the VBI data on it.
173  * @PAD_SIGNAL_AUDIO:
174  *	Contains an Intermediate Frequency analog signal from an audio
175  *	sub-carrier or an audio bitstream. IF signals are provided by tuners
176  *	and consumed by	audio AM/FM decoders. Bitstream audio is provided by
177  *	an audio decoder.
178  */
179 enum media_pad_signal_type {
180 	PAD_SIGNAL_DEFAULT = 0,
181 	PAD_SIGNAL_ANALOG,
182 	PAD_SIGNAL_DV,
183 	PAD_SIGNAL_AUDIO,
184 };
185 
186 /**
187  * struct media_pad - A media pad graph object.
188  *
189  * @graph_obj:	Embedded structure containing the media object common data
190  * @entity:	Entity this pad belongs to
191  * @index:	Pad index in the entity pads array, numbered from 0 to n
192  * @sig_type:	Type of the signal inside a media pad
193  * @flags:	Pad flags, as defined in
194  *		:ref:`include/uapi/linux/media.h <media_header>`
195  *		(seek for ``MEDIA_PAD_FL_*``)
196  */
197 struct media_pad {
198 	struct media_gobj graph_obj;	/* must be first field in struct */
199 	struct media_entity *entity;
200 	u16 index;
201 	enum media_pad_signal_type sig_type;
202 	unsigned long flags;
203 };
204 
205 /**
206  * struct media_entity_operations - Media entity operations
207  * @get_fwnode_pad:	Return the pad number based on a fwnode endpoint or
208  *			a negative value on error. This operation can be used
209  *			to map a fwnode to a media pad number. Optional.
210  * @link_setup:		Notify the entity of link changes. The operation can
211  *			return an error, in which case link setup will be
212  *			cancelled. Optional.
213  * @link_validate:	Return whether a link is valid from the entity point of
214  *			view. The media_pipeline_start() function
215  *			validates all links by calling this operation. Optional.
216  *
217  * .. note::
218  *
219  *    Those these callbacks are called with struct &media_device.graph_mutex
220  *    mutex held.
221  */
222 struct media_entity_operations {
223 	int (*get_fwnode_pad)(struct fwnode_endpoint *endpoint);
224 	int (*link_setup)(struct media_entity *entity,
225 			  const struct media_pad *local,
226 			  const struct media_pad *remote, u32 flags);
227 	int (*link_validate)(struct media_link *link);
228 };
229 
230 /**
231  * enum media_entity_type - Media entity type
232  *
233  * @MEDIA_ENTITY_TYPE_BASE:
234  *	The entity isn't embedded in another subsystem structure.
235  * @MEDIA_ENTITY_TYPE_VIDEO_DEVICE:
236  *	The entity is embedded in a struct video_device instance.
237  * @MEDIA_ENTITY_TYPE_V4L2_SUBDEV:
238  *	The entity is embedded in a struct v4l2_subdev instance.
239  *
240  * Media entity objects are often not instantiated directly, but the media
241  * entity structure is inherited by (through embedding) other subsystem-specific
242  * structures. The media entity type identifies the type of the subclass
243  * structure that implements a media entity instance.
244  *
245  * This allows runtime type identification of media entities and safe casting to
246  * the correct object type. For instance, a media entity structure instance
247  * embedded in a v4l2_subdev structure instance will have the type
248  * %MEDIA_ENTITY_TYPE_V4L2_SUBDEV and can safely be cast to a &v4l2_subdev
249  * structure using the container_of() macro.
250  */
251 enum media_entity_type {
252 	MEDIA_ENTITY_TYPE_BASE,
253 	MEDIA_ENTITY_TYPE_VIDEO_DEVICE,
254 	MEDIA_ENTITY_TYPE_V4L2_SUBDEV,
255 };
256 
257 /**
258  * struct media_entity - A media entity graph object.
259  *
260  * @graph_obj:	Embedded structure containing the media object common data.
261  * @name:	Entity name.
262  * @obj_type:	Type of the object that implements the media_entity.
263  * @function:	Entity main function, as defined in
264  *		:ref:`include/uapi/linux/media.h <media_header>`
265  *		(seek for ``MEDIA_ENT_F_*``)
266  * @flags:	Entity flags, as defined in
267  *		:ref:`include/uapi/linux/media.h <media_header>`
268  *		(seek for ``MEDIA_ENT_FL_*``)
269  * @num_pads:	Number of sink and source pads.
270  * @num_links:	Total number of links, forward and back, enabled and disabled.
271  * @num_backlinks: Number of backlinks
272  * @internal_idx: An unique internal entity specific number. The numbers are
273  *		re-used if entities are unregistered or registered again.
274  * @pads:	Pads array with the size defined by @num_pads.
275  * @links:	List of data links.
276  * @ops:	Entity operations.
277  * @stream_count: Stream count for the entity.
278  * @use_count:	Use count for the entity.
279  * @pipe:	Pipeline this entity belongs to.
280  * @info:	Union with devnode information.  Kept just for backward
281  *		compatibility.
282  * @info.dev:	Contains device major and minor info.
283  * @info.dev.major: device node major, if the device is a devnode.
284  * @info.dev.minor: device node minor, if the device is a devnode.
285  * @major:	Devnode major number (zero if not applicable). Kept just
286  *		for backward compatibility.
287  * @minor:	Devnode minor number (zero if not applicable). Kept just
288  *		for backward compatibility.
289  *
290  * .. note::
291  *
292  *    @stream_count and @use_count reference counts must never be
293  *    negative, but are signed integers on purpose: a simple ``WARN_ON(<0)``
294  *    check can be used to detect reference count bugs that would make them
295  *    negative.
296  */
297 struct media_entity {
298 	struct media_gobj graph_obj;	/* must be first field in struct */
299 	const char *name;
300 	enum media_entity_type obj_type;
301 	u32 function;
302 	unsigned long flags;
303 
304 	u16 num_pads;
305 	u16 num_links;
306 	u16 num_backlinks;
307 	int internal_idx;
308 
309 	struct media_pad *pads;
310 	struct list_head links;
311 
312 	const struct media_entity_operations *ops;
313 
314 	int stream_count;
315 	int use_count;
316 
317 	struct media_pipeline *pipe;
318 
319 	union {
320 		struct {
321 			u32 major;
322 			u32 minor;
323 		} dev;
324 	} info;
325 };
326 
327 /**
328  * struct media_interface - A media interface graph object.
329  *
330  * @graph_obj:		embedded graph object
331  * @links:		List of links pointing to graph entities
332  * @type:		Type of the interface as defined in
333  *			:ref:`include/uapi/linux/media.h <media_header>`
334  *			(seek for ``MEDIA_INTF_T_*``)
335  * @flags:		Interface flags as defined in
336  *			:ref:`include/uapi/linux/media.h <media_header>`
337  *			(seek for ``MEDIA_INTF_FL_*``)
338  *
339  * .. note::
340  *
341  *    Currently, no flags for &media_interface is defined.
342  */
343 struct media_interface {
344 	struct media_gobj		graph_obj;
345 	struct list_head		links;
346 	u32				type;
347 	u32				flags;
348 };
349 
350 /**
351  * struct media_intf_devnode - A media interface via a device node.
352  *
353  * @intf:	embedded interface object
354  * @major:	Major number of a device node
355  * @minor:	Minor number of a device node
356  */
357 struct media_intf_devnode {
358 	struct media_interface		intf;
359 
360 	/* Should match the fields at media_v2_intf_devnode */
361 	u32				major;
362 	u32				minor;
363 };
364 
365 /**
366  * media_entity_id() - return the media entity graph object id
367  *
368  * @entity:	pointer to &media_entity
369  */
370 static inline u32 media_entity_id(struct media_entity *entity)
371 {
372 	return entity->graph_obj.id;
373 }
374 
375 /**
376  * media_type() - return the media object type
377  *
378  * @gobj:	Pointer to the struct &media_gobj graph object
379  */
380 static inline enum media_gobj_type media_type(struct media_gobj *gobj)
381 {
382 	return gobj->id >> MEDIA_BITS_PER_ID;
383 }
384 
385 /**
386  * media_id() - return the media object ID
387  *
388  * @gobj:	Pointer to the struct &media_gobj graph object
389  */
390 static inline u32 media_id(struct media_gobj *gobj)
391 {
392 	return gobj->id & MEDIA_ID_MASK;
393 }
394 
395 /**
396  * media_gobj_gen_id() - encapsulates type and ID on at the object ID
397  *
398  * @type:	object type as define at enum &media_gobj_type.
399  * @local_id:	next ID, from struct &media_device.id.
400  */
401 static inline u32 media_gobj_gen_id(enum media_gobj_type type, u64 local_id)
402 {
403 	u32 id;
404 
405 	id = type << MEDIA_BITS_PER_ID;
406 	id |= local_id & MEDIA_ID_MASK;
407 
408 	return id;
409 }
410 
411 /**
412  * is_media_entity_v4l2_video_device() - Check if the entity is a video_device
413  * @entity:	pointer to entity
414  *
415  * Return: %true if the entity is an instance of a video_device object and can
416  * safely be cast to a struct video_device using the container_of() macro, or
417  * %false otherwise.
418  */
419 static inline bool is_media_entity_v4l2_video_device(struct media_entity *entity)
420 {
421 	return entity && entity->obj_type == MEDIA_ENTITY_TYPE_VIDEO_DEVICE;
422 }
423 
424 /**
425  * is_media_entity_v4l2_subdev() - Check if the entity is a v4l2_subdev
426  * @entity:	pointer to entity
427  *
428  * Return: %true if the entity is an instance of a &v4l2_subdev object and can
429  * safely be cast to a struct &v4l2_subdev using the container_of() macro, or
430  * %false otherwise.
431  */
432 static inline bool is_media_entity_v4l2_subdev(struct media_entity *entity)
433 {
434 	return entity && entity->obj_type == MEDIA_ENTITY_TYPE_V4L2_SUBDEV;
435 }
436 
437 /**
438  * __media_entity_enum_init - Initialise an entity enumeration
439  *
440  * @ent_enum: Entity enumeration to be initialised
441  * @idx_max: Maximum number of entities in the enumeration
442  *
443  * Return: Returns zero on success or a negative error code.
444  */
445 __must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
446 					  int idx_max);
447 
448 /**
449  * media_entity_enum_cleanup - Release resources of an entity enumeration
450  *
451  * @ent_enum: Entity enumeration to be released
452  */
453 void media_entity_enum_cleanup(struct media_entity_enum *ent_enum);
454 
455 /**
456  * media_entity_enum_zero - Clear the entire enum
457  *
458  * @ent_enum: Entity enumeration to be cleared
459  */
460 static inline void media_entity_enum_zero(struct media_entity_enum *ent_enum)
461 {
462 	bitmap_zero(ent_enum->bmap, ent_enum->idx_max);
463 }
464 
465 /**
466  * media_entity_enum_set - Mark a single entity in the enum
467  *
468  * @ent_enum: Entity enumeration
469  * @entity: Entity to be marked
470  */
471 static inline void media_entity_enum_set(struct media_entity_enum *ent_enum,
472 					 struct media_entity *entity)
473 {
474 	if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
475 		return;
476 
477 	__set_bit(entity->internal_idx, ent_enum->bmap);
478 }
479 
480 /**
481  * media_entity_enum_clear - Unmark a single entity in the enum
482  *
483  * @ent_enum: Entity enumeration
484  * @entity: Entity to be unmarked
485  */
486 static inline void media_entity_enum_clear(struct media_entity_enum *ent_enum,
487 					   struct media_entity *entity)
488 {
489 	if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
490 		return;
491 
492 	__clear_bit(entity->internal_idx, ent_enum->bmap);
493 }
494 
495 /**
496  * media_entity_enum_test - Test whether the entity is marked
497  *
498  * @ent_enum: Entity enumeration
499  * @entity: Entity to be tested
500  *
501  * Returns %true if the entity was marked.
502  */
503 static inline bool media_entity_enum_test(struct media_entity_enum *ent_enum,
504 					  struct media_entity *entity)
505 {
506 	if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
507 		return true;
508 
509 	return test_bit(entity->internal_idx, ent_enum->bmap);
510 }
511 
512 /**
513  * media_entity_enum_test_and_set - Test whether the entity is marked,
514  *	and mark it
515  *
516  * @ent_enum: Entity enumeration
517  * @entity: Entity to be tested
518  *
519  * Returns %true if the entity was marked, and mark it before doing so.
520  */
521 static inline bool
522 media_entity_enum_test_and_set(struct media_entity_enum *ent_enum,
523 			       struct media_entity *entity)
524 {
525 	if (WARN_ON(entity->internal_idx >= ent_enum->idx_max))
526 		return true;
527 
528 	return __test_and_set_bit(entity->internal_idx, ent_enum->bmap);
529 }
530 
531 /**
532  * media_entity_enum_empty - Test whether the entire enum is empty
533  *
534  * @ent_enum: Entity enumeration
535  *
536  * Return: %true if the entity was empty.
537  */
538 static inline bool media_entity_enum_empty(struct media_entity_enum *ent_enum)
539 {
540 	return bitmap_empty(ent_enum->bmap, ent_enum->idx_max);
541 }
542 
543 /**
544  * media_entity_enum_intersects - Test whether two enums intersect
545  *
546  * @ent_enum1: First entity enumeration
547  * @ent_enum2: Second entity enumeration
548  *
549  * Return: %true if entity enumerations @ent_enum1 and @ent_enum2 intersect,
550  * otherwise %false.
551  */
552 static inline bool media_entity_enum_intersects(
553 	struct media_entity_enum *ent_enum1,
554 	struct media_entity_enum *ent_enum2)
555 {
556 	WARN_ON(ent_enum1->idx_max != ent_enum2->idx_max);
557 
558 	return bitmap_intersects(ent_enum1->bmap, ent_enum2->bmap,
559 				 min(ent_enum1->idx_max, ent_enum2->idx_max));
560 }
561 
562 /**
563  * gobj_to_entity - returns the struct &media_entity pointer from the
564  *	@gobj contained on it.
565  *
566  * @gobj: Pointer to the struct &media_gobj graph object
567  */
568 #define gobj_to_entity(gobj) \
569 		container_of(gobj, struct media_entity, graph_obj)
570 
571 /**
572  * gobj_to_pad - returns the struct &media_pad pointer from the
573  *	@gobj contained on it.
574  *
575  * @gobj: Pointer to the struct &media_gobj graph object
576  */
577 #define gobj_to_pad(gobj) \
578 		container_of(gobj, struct media_pad, graph_obj)
579 
580 /**
581  * gobj_to_link - returns the struct &media_link pointer from the
582  *	@gobj contained on it.
583  *
584  * @gobj: Pointer to the struct &media_gobj graph object
585  */
586 #define gobj_to_link(gobj) \
587 		container_of(gobj, struct media_link, graph_obj)
588 
589 /**
590  * gobj_to_intf - returns the struct &media_interface pointer from the
591  *	@gobj contained on it.
592  *
593  * @gobj: Pointer to the struct &media_gobj graph object
594  */
595 #define gobj_to_intf(gobj) \
596 		container_of(gobj, struct media_interface, graph_obj)
597 
598 /**
599  * intf_to_devnode - returns the struct media_intf_devnode pointer from the
600  *	@intf contained on it.
601  *
602  * @intf: Pointer to struct &media_intf_devnode
603  */
604 #define intf_to_devnode(intf) \
605 		container_of(intf, struct media_intf_devnode, intf)
606 
607 /**
608  *  media_gobj_create - Initialize a graph object
609  *
610  * @mdev:	Pointer to the &media_device that contains the object
611  * @type:	Type of the object
612  * @gobj:	Pointer to the struct &media_gobj graph object
613  *
614  * This routine initializes the embedded struct &media_gobj inside a
615  * media graph object. It is called automatically if ``media_*_create``
616  * function calls are used. However, if the object (entity, link, pad,
617  * interface) is embedded on some other object, this function should be
618  * called before registering the object at the media controller.
619  */
620 void media_gobj_create(struct media_device *mdev,
621 		    enum media_gobj_type type,
622 		    struct media_gobj *gobj);
623 
624 /**
625  *  media_gobj_destroy - Stop using a graph object on a media device
626  *
627  * @gobj:	Pointer to the struct &media_gobj graph object
628  *
629  * This should be called by all routines like media_device_unregister()
630  * that remove/destroy media graph objects.
631  */
632 void media_gobj_destroy(struct media_gobj *gobj);
633 
634 /**
635  * media_entity_pads_init() - Initialize the entity pads
636  *
637  * @entity:	entity where the pads belong
638  * @num_pads:	total number of sink and source pads
639  * @pads:	Array of @num_pads pads.
640  *
641  * The pads array is managed by the entity driver and passed to
642  * media_entity_pads_init() where its pointer will be stored in the
643  * &media_entity structure.
644  *
645  * If no pads are needed, drivers could either directly fill
646  * &media_entity->num_pads with 0 and &media_entity->pads with %NULL or call
647  * this function that will do the same.
648  *
649  * As the number of pads is known in advance, the pads array is not allocated
650  * dynamically but is managed by the entity driver. Most drivers will embed the
651  * pads array in a driver-specific structure, avoiding dynamic allocation.
652  *
653  * Drivers must set the direction of every pad in the pads array before calling
654  * media_entity_pads_init(). The function will initialize the other pads fields.
655  */
656 int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
657 		      struct media_pad *pads);
658 
659 /**
660  * media_entity_cleanup() - free resources associated with an entity
661  *
662  * @entity:	entity where the pads belong
663  *
664  * This function must be called during the cleanup phase after unregistering
665  * the entity (currently, it does nothing).
666  */
667 #if IS_ENABLED(CONFIG_MEDIA_CONTROLLER)
668 static inline void media_entity_cleanup(struct media_entity *entity) {}
669 #else
670 #define media_entity_cleanup(entity) do { } while (false)
671 #endif
672 
673 /**
674  * media_get_pad_index() - retrieves a pad index from an entity
675  *
676  * @entity:	entity where the pads belong
677  * @is_sink:	true if the pad is a sink, false if it is a source
678  * @sig_type:	type of signal of the pad to be search
679  *
680  * This helper function finds the first pad index inside an entity that
681  * satisfies both @is_sink and @sig_type conditions.
682  *
683  * Return:
684  *
685  * On success, return the pad number. If the pad was not found or the media
686  * entity is a NULL pointer, return -EINVAL.
687  */
688 int media_get_pad_index(struct media_entity *entity, bool is_sink,
689 			enum media_pad_signal_type sig_type);
690 
691 /**
692  * media_create_pad_link() - creates a link between two entities.
693  *
694  * @source:	pointer to &media_entity of the source pad.
695  * @source_pad:	number of the source pad in the pads array
696  * @sink:	pointer to &media_entity of the sink pad.
697  * @sink_pad:	number of the sink pad in the pads array.
698  * @flags:	Link flags, as defined in
699  *		:ref:`include/uapi/linux/media.h <media_header>`
700  *		( seek for ``MEDIA_LNK_FL_*``)
701  *
702  * Valid values for flags:
703  *
704  * %MEDIA_LNK_FL_ENABLED
705  *   Indicates that the link is enabled and can be used to transfer media data.
706  *   When two or more links target a sink pad, only one of them can be
707  *   enabled at a time.
708  *
709  * %MEDIA_LNK_FL_IMMUTABLE
710  *   Indicates that the link enabled state can't be modified at runtime. If
711  *   %MEDIA_LNK_FL_IMMUTABLE is set, then %MEDIA_LNK_FL_ENABLED must also be
712  *   set, since an immutable link is always enabled.
713  *
714  * .. note::
715  *
716  *    Before calling this function, media_entity_pads_init() and
717  *    media_device_register_entity() should be called previously for both ends.
718  */
719 __must_check int media_create_pad_link(struct media_entity *source,
720 			u16 source_pad, struct media_entity *sink,
721 			u16 sink_pad, u32 flags);
722 
723 /**
724  * media_create_pad_links() - creates a link between two entities.
725  *
726  * @mdev: Pointer to the media_device that contains the object
727  * @source_function: Function of the source entities. Used only if @source is
728  *	NULL.
729  * @source: pointer to &media_entity of the source pad. If NULL, it will use
730  *	all entities that matches the @sink_function.
731  * @source_pad: number of the source pad in the pads array
732  * @sink_function: Function of the sink entities. Used only if @sink is NULL.
733  * @sink: pointer to &media_entity of the sink pad. If NULL, it will use
734  *	all entities that matches the @sink_function.
735  * @sink_pad: number of the sink pad in the pads array.
736  * @flags: Link flags, as defined in include/uapi/linux/media.h.
737  * @allow_both_undefined: if %true, then both @source and @sink can be NULL.
738  *	In such case, it will create a crossbar between all entities that
739  *	matches @source_function to all entities that matches @sink_function.
740  *	If %false, it will return 0 and won't create any link if both @source
741  *	and @sink are NULL.
742  *
743  * Valid values for flags:
744  *
745  * A %MEDIA_LNK_FL_ENABLED flag indicates that the link is enabled and can be
746  *	used to transfer media data. If multiple links are created and this
747  *	flag is passed as an argument, only the first created link will have
748  *	this flag.
749  *
750  * A %MEDIA_LNK_FL_IMMUTABLE flag indicates that the link enabled state can't
751  *	be modified at runtime. If %MEDIA_LNK_FL_IMMUTABLE is set, then
752  *	%MEDIA_LNK_FL_ENABLED must also be set since an immutable link is
753  *	always enabled.
754  *
755  * It is common for some devices to have multiple source and/or sink entities
756  * of the same type that should be linked. While media_create_pad_link()
757  * creates link by link, this function is meant to allow 1:n, n:1 and even
758  * cross-bar (n:n) links.
759  *
760  * .. note::
761  *
762  *    Before calling this function, media_entity_pads_init() and
763  *    media_device_register_entity() should be called previously for the
764  *    entities to be linked.
765  */
766 int media_create_pad_links(const struct media_device *mdev,
767 			   const u32 source_function,
768 			   struct media_entity *source,
769 			   const u16 source_pad,
770 			   const u32 sink_function,
771 			   struct media_entity *sink,
772 			   const u16 sink_pad,
773 			   u32 flags,
774 			   const bool allow_both_undefined);
775 
776 void __media_entity_remove_links(struct media_entity *entity);
777 
778 /**
779  * media_entity_remove_links() - remove all links associated with an entity
780  *
781  * @entity:	pointer to &media_entity
782  *
783  * .. note::
784  *
785  *    This is called automatically when an entity is unregistered via
786  *    media_device_register_entity().
787  */
788 void media_entity_remove_links(struct media_entity *entity);
789 
790 /**
791  * __media_entity_setup_link - Configure a media link without locking
792  * @link: The link being configured
793  * @flags: Link configuration flags
794  *
795  * The bulk of link setup is handled by the two entities connected through the
796  * link. This function notifies both entities of the link configuration change.
797  *
798  * If the link is immutable or if the current and new configuration are
799  * identical, return immediately.
800  *
801  * The user is expected to hold link->source->parent->mutex. If not,
802  * media_entity_setup_link() should be used instead.
803  */
804 int __media_entity_setup_link(struct media_link *link, u32 flags);
805 
806 /**
807  * media_entity_setup_link() - changes the link flags properties in runtime
808  *
809  * @link:	pointer to &media_link
810  * @flags:	the requested new link flags
811  *
812  * The only configurable property is the %MEDIA_LNK_FL_ENABLED link flag
813  * flag to enable/disable a link. Links marked with the
814  * %MEDIA_LNK_FL_IMMUTABLE link flag can not be enabled or disabled.
815  *
816  * When a link is enabled or disabled, the media framework calls the
817  * link_setup operation for the two entities at the source and sink of the
818  * link, in that order. If the second link_setup call fails, another
819  * link_setup call is made on the first entity to restore the original link
820  * flags.
821  *
822  * Media device drivers can be notified of link setup operations by setting the
823  * &media_device.link_notify pointer to a callback function. If provided, the
824  * notification callback will be called before enabling and after disabling
825  * links.
826  *
827  * Entity drivers must implement the link_setup operation if any of their links
828  * is non-immutable. The operation must either configure the hardware or store
829  * the configuration information to be applied later.
830  *
831  * Link configuration must not have any side effect on other links. If an
832  * enabled link at a sink pad prevents another link at the same pad from
833  * being enabled, the link_setup operation must return %-EBUSY and can't
834  * implicitly disable the first enabled link.
835  *
836  * .. note::
837  *
838  *    The valid values of the flags for the link is the same as described
839  *    on media_create_pad_link(), for pad to pad links or the same as described
840  *    on media_create_intf_link(), for interface to entity links.
841  */
842 int media_entity_setup_link(struct media_link *link, u32 flags);
843 
844 /**
845  * media_entity_find_link - Find a link between two pads
846  * @source: Source pad
847  * @sink: Sink pad
848  *
849  * Return: returns a pointer to the link between the two entities. If no
850  * such link exists, return %NULL.
851  */
852 struct media_link *media_entity_find_link(struct media_pad *source,
853 		struct media_pad *sink);
854 
855 /**
856  * media_entity_remote_pad - Find the pad at the remote end of a link
857  * @pad: Pad at the local end of the link
858  *
859  * Search for a remote pad connected to the given pad by iterating over all
860  * links originating or terminating at that pad until an enabled link is found.
861  *
862  * Return: returns a pointer to the pad at the remote end of the first found
863  * enabled link, or %NULL if no enabled link has been found.
864  */
865 struct media_pad *media_entity_remote_pad(const struct media_pad *pad);
866 
867 /**
868  * media_entity_get - Get a reference to the parent module
869  *
870  * @entity: The entity
871  *
872  * Get a reference to the parent media device module.
873  *
874  * The function will return immediately if @entity is %NULL.
875  *
876  * Return: returns a pointer to the entity on success or %NULL on failure.
877  */
878 struct media_entity *media_entity_get(struct media_entity *entity);
879 
880 /**
881  * media_entity_get_fwnode_pad - Get pad number from fwnode
882  *
883  * @entity: The entity
884  * @fwnode: Pointer to the fwnode_handle which should be used to find the pad
885  * @direction_flags: Expected direction of the pad, as defined in
886  *		     :ref:`include/uapi/linux/media.h <media_header>`
887  *		     (seek for ``MEDIA_PAD_FL_*``)
888  *
889  * This function can be used to resolve the media pad number from
890  * a fwnode. This is useful for devices which use more complex
891  * mappings of media pads.
892  *
893  * If the entity does not implement the get_fwnode_pad() operation
894  * then this function searches the entity for the first pad that
895  * matches the @direction_flags.
896  *
897  * Return: returns the pad number on success or a negative error code.
898  */
899 int media_entity_get_fwnode_pad(struct media_entity *entity,
900 				struct fwnode_handle *fwnode,
901 				unsigned long direction_flags);
902 
903 /**
904  * media_graph_walk_init - Allocate resources used by graph walk.
905  *
906  * @graph: Media graph structure that will be used to walk the graph
907  * @mdev: Pointer to the &media_device that contains the object
908  */
909 __must_check int media_graph_walk_init(
910 	struct media_graph *graph, struct media_device *mdev);
911 
912 /**
913  * media_graph_walk_cleanup - Release resources used by graph walk.
914  *
915  * @graph: Media graph structure that will be used to walk the graph
916  */
917 void media_graph_walk_cleanup(struct media_graph *graph);
918 
919 /**
920  * media_entity_put - Release the reference to the parent module
921  *
922  * @entity: The entity
923  *
924  * Release the reference count acquired by media_entity_get().
925  *
926  * The function will return immediately if @entity is %NULL.
927  */
928 void media_entity_put(struct media_entity *entity);
929 
930 /**
931  * media_graph_walk_start - Start walking the media graph at a
932  *	given entity
933  *
934  * @graph: Media graph structure that will be used to walk the graph
935  * @entity: Starting entity
936  *
937  * Before using this function, media_graph_walk_init() must be
938  * used to allocate resources used for walking the graph. This
939  * function initializes the graph traversal structure to walk the
940  * entities graph starting at the given entity. The traversal
941  * structure must not be modified by the caller during graph
942  * traversal. After the graph walk, the resources must be released
943  * using media_graph_walk_cleanup().
944  */
945 void media_graph_walk_start(struct media_graph *graph,
946 			    struct media_entity *entity);
947 
948 /**
949  * media_graph_walk_next - Get the next entity in the graph
950  * @graph: Media graph structure
951  *
952  * Perform a depth-first traversal of the given media entities graph.
953  *
954  * The graph structure must have been previously initialized with a call to
955  * media_graph_walk_start().
956  *
957  * Return: returns the next entity in the graph or %NULL if the whole graph
958  * have been traversed.
959  */
960 struct media_entity *media_graph_walk_next(struct media_graph *graph);
961 
962 /**
963  * media_pipeline_start - Mark a pipeline as streaming
964  * @entity: Starting entity
965  * @pipe: Media pipeline to be assigned to all entities in the pipeline.
966  *
967  * Mark all entities connected to a given entity through enabled links, either
968  * directly or indirectly, as streaming. The given pipeline object is assigned
969  * to every entity in the pipeline and stored in the media_entity pipe field.
970  *
971  * Calls to this function can be nested, in which case the same number of
972  * media_pipeline_stop() calls will be required to stop streaming. The
973  * pipeline pointer must be identical for all nested calls to
974  * media_pipeline_start().
975  */
976 __must_check int media_pipeline_start(struct media_entity *entity,
977 				      struct media_pipeline *pipe);
978 /**
979  * __media_pipeline_start - Mark a pipeline as streaming
980  *
981  * @entity: Starting entity
982  * @pipe: Media pipeline to be assigned to all entities in the pipeline.
983  *
984  * ..note:: This is the non-locking version of media_pipeline_start()
985  */
986 __must_check int __media_pipeline_start(struct media_entity *entity,
987 					struct media_pipeline *pipe);
988 
989 /**
990  * media_pipeline_stop - Mark a pipeline as not streaming
991  * @entity: Starting entity
992  *
993  * Mark all entities connected to a given entity through enabled links, either
994  * directly or indirectly, as not streaming. The media_entity pipe field is
995  * reset to %NULL.
996  *
997  * If multiple calls to media_pipeline_start() have been made, the same
998  * number of calls to this function are required to mark the pipeline as not
999  * streaming.
1000  */
1001 void media_pipeline_stop(struct media_entity *entity);
1002 
1003 /**
1004  * __media_pipeline_stop - Mark a pipeline as not streaming
1005  *
1006  * @entity: Starting entity
1007  *
1008  * .. note:: This is the non-locking version of media_pipeline_stop()
1009  */
1010 void __media_pipeline_stop(struct media_entity *entity);
1011 
1012 /**
1013  * media_devnode_create() - creates and initializes a device node interface
1014  *
1015  * @mdev:	pointer to struct &media_device
1016  * @type:	type of the interface, as given by
1017  *		:ref:`include/uapi/linux/media.h <media_header>`
1018  *		( seek for ``MEDIA_INTF_T_*``) macros.
1019  * @flags:	Interface flags, as defined in
1020  *		:ref:`include/uapi/linux/media.h <media_header>`
1021  *		( seek for ``MEDIA_INTF_FL_*``)
1022  * @major:	Device node major number.
1023  * @minor:	Device node minor number.
1024  *
1025  * Return: if succeeded, returns a pointer to the newly allocated
1026  *	&media_intf_devnode pointer.
1027  *
1028  * .. note::
1029  *
1030  *    Currently, no flags for &media_interface is defined.
1031  */
1032 struct media_intf_devnode *
1033 __must_check media_devnode_create(struct media_device *mdev,
1034 				  u32 type, u32 flags,
1035 				  u32 major, u32 minor);
1036 /**
1037  * media_devnode_remove() - removes a device node interface
1038  *
1039  * @devnode:	pointer to &media_intf_devnode to be freed.
1040  *
1041  * When a device node interface is removed, all links to it are automatically
1042  * removed.
1043  */
1044 void media_devnode_remove(struct media_intf_devnode *devnode);
1045 struct media_link *
1046 
1047 /**
1048  * media_create_intf_link() - creates a link between an entity and an interface
1049  *
1050  * @entity:	pointer to %media_entity
1051  * @intf:	pointer to %media_interface
1052  * @flags:	Link flags, as defined in
1053  *		:ref:`include/uapi/linux/media.h <media_header>`
1054  *		( seek for ``MEDIA_LNK_FL_*``)
1055  *
1056  *
1057  * Valid values for flags:
1058  *
1059  * %MEDIA_LNK_FL_ENABLED
1060  *   Indicates that the interface is connected to the entity hardware.
1061  *   That's the default value for interfaces. An interface may be disabled if
1062  *   the hardware is busy due to the usage of some other interface that it is
1063  *   currently controlling the hardware.
1064  *
1065  *   A typical example is an hybrid TV device that handle only one type of
1066  *   stream on a given time. So, when the digital TV is streaming,
1067  *   the V4L2 interfaces won't be enabled, as such device is not able to
1068  *   also stream analog TV or radio.
1069  *
1070  * .. note::
1071  *
1072  *    Before calling this function, media_devnode_create() should be called for
1073  *    the interface and media_device_register_entity() should be called for the
1074  *    interface that will be part of the link.
1075  */
1076 __must_check media_create_intf_link(struct media_entity *entity,
1077 				    struct media_interface *intf,
1078 				    u32 flags);
1079 /**
1080  * __media_remove_intf_link() - remove a single interface link
1081  *
1082  * @link:	pointer to &media_link.
1083  *
1084  * .. note:: This is an unlocked version of media_remove_intf_link()
1085  */
1086 void __media_remove_intf_link(struct media_link *link);
1087 
1088 /**
1089  * media_remove_intf_link() - remove a single interface link
1090  *
1091  * @link:	pointer to &media_link.
1092  *
1093  * .. note:: Prefer to use this one, instead of __media_remove_intf_link()
1094  */
1095 void media_remove_intf_link(struct media_link *link);
1096 
1097 /**
1098  * __media_remove_intf_links() - remove all links associated with an interface
1099  *
1100  * @intf:	pointer to &media_interface
1101  *
1102  * .. note:: This is an unlocked version of media_remove_intf_links().
1103  */
1104 void __media_remove_intf_links(struct media_interface *intf);
1105 
1106 /**
1107  * media_remove_intf_links() - remove all links associated with an interface
1108  *
1109  * @intf:	pointer to &media_interface
1110  *
1111  * .. note::
1112  *
1113  *   #) This is called automatically when an entity is unregistered via
1114  *      media_device_register_entity() and by media_devnode_remove().
1115  *
1116  *   #) Prefer to use this one, instead of __media_remove_intf_links().
1117  */
1118 void media_remove_intf_links(struct media_interface *intf);
1119 
1120 /**
1121  * media_entity_call - Calls a struct media_entity_operations operation on
1122  *	an entity
1123  *
1124  * @entity: entity where the @operation will be called
1125  * @operation: type of the operation. Should be the name of a member of
1126  *	struct &media_entity_operations.
1127  *
1128  * This helper function will check if @operation is not %NULL. On such case,
1129  * it will issue a call to @operation\(@entity, @args\).
1130  */
1131 
1132 #define media_entity_call(entity, operation, args...)			\
1133 	(((entity)->ops && (entity)->ops->operation) ?			\
1134 	 (entity)->ops->operation((entity) , ##args) : -ENOIOCTLCMD)
1135 
1136 #endif
1137