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