[mirror_ubuntu-bionic-kernel.git] / drivers / media / media-entity.c

/*
 * Media entity
 *
 * Copyright (C) 2010 Nokia Corporation
 *
 * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 *	     Sakari Ailus <sakari.ailus@iki.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/bitmap.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <media/media-entity.h>
#include <media/media-device.h>

/**
 * media_entity_init - Initialize a media entity
 *
 * @num_pads: Total number of sink and source pads.
 * @extra_links: Initial estimate of the number of extra links.
 * @pads: Array of 'num_pads' pads.
 *
 * The total number of pads is an intrinsic property of entities known by the
 * entity driver, while the total number of links depends on hardware design
 * and is an extrinsic property unknown to the entity driver. However, in most
 * use cases the entity driver can guess the number of links which can safely
 * be assumed to be equal to or larger than the number of pads.
 *
 * For those reasons the links array can be preallocated based on the entity
 * driver guess and will be reallocated later if extra links need to be
 * created.
 *
 * This function allocates a links array with enough space to hold at least
 * 'num_pads' + 'extra_links' elements. The media_entity::max_links field will
 * be set to the number of allocated elements.
 *
 * The pads array is managed by the entity driver and passed to
 * media_entity_init() where its pointer will be stored in the entity structure.
 */
int
media_entity_init(struct media_entity *entity, u16 num_pads,
		  struct media_pad *pads, u16 extra_links)
{
	struct media_link *links;
	unsigned int max_links = num_pads + extra_links;
	unsigned int i;

	links = kzalloc(max_links * sizeof(links[0]), GFP_KERNEL);
	if (links == NULL)
		return -ENOMEM;

	entity->group_id = 0;
	entity->max_links = max_links;
	entity->num_links = 0;
	entity->num_backlinks = 0;
	entity->num_pads = num_pads;
	entity->pads = pads;
	entity->links = links;

	for (i = 0; i < num_pads; i++) {
		pads[i].entity = entity;
		pads[i].index = i;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(media_entity_init);

void
media_entity_cleanup(struct media_entity *entity)
{
	kfree(entity->links);
}
EXPORT_SYMBOL_GPL(media_entity_cleanup);

/* -----------------------------------------------------------------------------
 * Graph traversal
 */

static struct media_entity *
media_entity_other(struct media_entity *entity, struct media_link *link)
{
	if (link->source->entity == entity)
		return link->sink->entity;
	else
		return link->source->entity;
}

/* push an entity to traversal stack */
static void stack_push(struct media_entity_graph *graph,
		       struct media_entity *entity)
{
	if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
		WARN_ON(1);
		return;
	}
	graph->top++;
	graph->stack[graph->top].link = 0;
	graph->stack[graph->top].entity = entity;
}

static struct media_entity *stack_pop(struct media_entity_graph *graph)
{
	struct media_entity *entity;

	entity = graph->stack[graph->top].entity;
	graph->top--;

	return entity;
}

#define link_top(en)	((en)->stack[(en)->top].link)
#define stack_top(en)	((en)->stack[(en)->top].entity)

/**
 * media_entity_graph_walk_start - Start walking the media graph at a given entity
 * @graph: Media graph structure that will be used to walk the graph
 * @entity: Starting entity
 *
 * This function initializes the graph traversal structure to walk the entities
 * graph starting at the given entity. The traversal structure must not be
 * modified by the caller during graph traversal. When done the structure can
 * safely be freed.
 */
void media_entity_graph_walk_start(struct media_entity_graph *graph,
				   struct media_entity *entity)
{
	graph->top = 0;
	graph->stack[graph->top].entity = NULL;
	bitmap_zero(graph->entities, MEDIA_ENTITY_ENUM_MAX_ID);

	if (WARN_ON(entity->id >= MEDIA_ENTITY_ENUM_MAX_ID))
		return;

	__set_bit(entity->id, graph->entities);
	stack_push(graph, entity);
}
EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);

/**
 * media_entity_graph_walk_next - Get the next entity in the graph
 * @graph: Media graph structure
 *
 * Perform a depth-first traversal of the given media entities graph.
 *
 * The graph structure must have been previously initialized with a call to
 * media_entity_graph_walk_start().
 *
 * Return the next entity in the graph or NULL if the whole graph have been
 * traversed.
 */
struct media_entity *
media_entity_graph_walk_next(struct media_entity_graph *graph)
{
	if (stack_top(graph) == NULL)
		return NULL;

	/*
	 * Depth first search. Push entity to stack and continue from
	 * top of the stack until no more entities on the level can be
	 * found.
	 */
	while (link_top(graph) < stack_top(graph)->num_links) {
		struct media_entity *entity = stack_top(graph);
		struct media_link *link = &entity->links[link_top(graph)];
		struct media_entity *next;

		/* The link is not enabled so we do not follow. */
		if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
			link_top(graph)++;
			continue;
		}

		/* Get the entity in the other end of the link . */
		next = media_entity_other(entity, link);
		if (WARN_ON(next->id >= MEDIA_ENTITY_ENUM_MAX_ID))
			return NULL;

		/* Has the entity already been visited? */
		if (__test_and_set_bit(next->id, graph->entities)) {
			link_top(graph)++;
			continue;
		}

		/* Push the new entity to stack and start over. */
		link_top(graph)++;
		stack_push(graph, next);
	}

	return stack_pop(graph);
}
EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);

/* -----------------------------------------------------------------------------
 * Pipeline management
 */

/**
 * media_entity_pipeline_start - Mark a pipeline as streaming
 * @entity: Starting entity
 * @pipe: Media pipeline to be assigned to all entities in the pipeline.
 *
 * Mark all entities connected to a given entity through enabled links, either
 * directly or indirectly, as streaming. The given pipeline object is assigned to
 * every entity in the pipeline and stored in the media_entity pipe field.
 *
 * Calls to this function can be nested, in which case the same number of
 * media_entity_pipeline_stop() calls will be required to stop streaming. The
 * pipeline pointer must be identical for all nested calls to
 * media_entity_pipeline_start().
 */
__must_check int media_entity_pipeline_start(struct media_entity *entity,
					     struct media_pipeline *pipe)
{
	struct media_device *mdev = entity->parent;
	struct media_entity_graph graph;
	struct media_entity *entity_err = entity;
	int ret;

	mutex_lock(&mdev->graph_mutex);

	media_entity_graph_walk_start(&graph, entity);

	while ((entity = media_entity_graph_walk_next(&graph))) {
		DECLARE_BITMAP(active, entity->num_pads);
		DECLARE_BITMAP(has_no_links, entity->num_pads);
		unsigned int i;

		entity->stream_count++;
		WARN_ON(entity->pipe && entity->pipe != pipe);
		entity->pipe = pipe;

		/* Already streaming --- no need to check. */
		if (entity->stream_count > 1)
			continue;

		if (!entity->ops || !entity->ops->link_validate)
			continue;

		bitmap_zero(active, entity->num_pads);
		bitmap_fill(has_no_links, entity->num_pads);

		for (i = 0; i < entity->num_links; i++) {
			struct media_link *link = &entity->links[i];
			struct media_pad *pad = link->sink->entity == entity
						? link->sink : link->source;

			/* Mark that a pad is connected by a link. */
			bitmap_clear(has_no_links, pad->index, 1);

			/*
			 * Pads that either do not need to connect or
			 * are connected through an enabled link are
			 * fine.
			 */
			if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
			    link->flags & MEDIA_LNK_FL_ENABLED)
				bitmap_set(active, pad->index, 1);

			/*
			 * Link validation will only take place for
			 * sink ends of the link that are enabled.
			 */
			if (link->sink != pad ||
			    !(link->flags & MEDIA_LNK_FL_ENABLED))
				continue;

			ret = entity->ops->link_validate(link);
			if (ret < 0 && ret != -ENOIOCTLCMD)
				goto error;
		}

		/* Either no links or validated links are fine. */
		bitmap_or(active, active, has_no_links, entity->num_pads);

		if (!bitmap_full(active, entity->num_pads)) {
			ret = -EPIPE;
			goto error;
		}
	}

	mutex_unlock(&mdev->graph_mutex);

	return 0;

error:
	/*
	 * Link validation on graph failed. We revert what we did and
	 * return the error.
	 */
	media_entity_graph_walk_start(&graph, entity_err);

	while ((entity_err = media_entity_graph_walk_next(&graph))) {
		entity_err->stream_count--;
		if (entity_err->stream_count == 0)
			entity_err->pipe = NULL;

		/*
		 * We haven't increased stream_count further than this
		 * so we quit here.
		 */
		if (entity_err == entity)
			break;
	}

	mutex_unlock(&mdev->graph_mutex);

	return ret;
}
EXPORT_SYMBOL_GPL(media_entity_pipeline_start);

/**
 * media_entity_pipeline_stop - Mark a pipeline as not streaming
 * @entity: Starting entity
 *
 * Mark all entities connected to a given entity through enabled links, either
 * directly or indirectly, as not streaming. The media_entity pipe field is
 * reset to NULL.
 *
 * If multiple calls to media_entity_pipeline_start() have been made, the same
 * number of calls to this function are required to mark the pipeline as not
 * streaming.
 */
void media_entity_pipeline_stop(struct media_entity *entity)
{
	struct media_device *mdev = entity->parent;
	struct media_entity_graph graph;

	mutex_lock(&mdev->graph_mutex);

	media_entity_graph_walk_start(&graph, entity);

	while ((entity = media_entity_graph_walk_next(&graph))) {
		entity->stream_count--;
		if (entity->stream_count == 0)
			entity->pipe = NULL;
	}

	mutex_unlock(&mdev->graph_mutex);
}
EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);

/* -----------------------------------------------------------------------------
 * Module use count
 */

/*
 * media_entity_get - Get a reference to the parent module
 * @entity: The entity
 *
 * Get a reference to the parent media device module.
 *
 * The function will return immediately if @entity is NULL.
 *
 * Return a pointer to the entity on success or NULL on failure.
 */
struct media_entity *media_entity_get(struct media_entity *entity)
{
	if (entity == NULL)
		return NULL;

	if (entity->parent->dev &&
	    !try_module_get(entity->parent->dev->driver->owner))
		return NULL;

	return entity;
}
EXPORT_SYMBOL_GPL(media_entity_get);

/*
 * media_entity_put - Release the reference to the parent module
 * @entity: The entity
 *
 * Release the reference count acquired by media_entity_get().
 *
 * The function will return immediately if @entity is NULL.
 */
void media_entity_put(struct media_entity *entity)
{
	if (entity == NULL)
		return;

	if (entity->parent->dev)
		module_put(entity->parent->dev->driver->owner);
}
EXPORT_SYMBOL_GPL(media_entity_put);

/* -----------------------------------------------------------------------------
 * Links management
 */

static struct media_link *media_entity_add_link(struct media_entity *entity)
{
	if (entity->num_links >= entity->max_links) {
		struct media_link *links = entity->links;
		unsigned int max_links = entity->max_links + 2;
		unsigned int i;

		links = krealloc(links, max_links * sizeof(*links), GFP_KERNEL);
		if (links == NULL)
			return NULL;

		for (i = 0; i < entity->num_links; i++)
			links[i].reverse->reverse = &links[i];

		entity->max_links = max_links;
		entity->links = links;
	}

	return &entity->links[entity->num_links++];
}

int
media_entity_create_link(struct media_entity *source, u16 source_pad,
			 struct media_entity *sink, u16 sink_pad, u32 flags)
{
	struct media_link *link;
	struct media_link *backlink;

	BUG_ON(source == NULL || sink == NULL);
	BUG_ON(source_pad >= source->num_pads);
	BUG_ON(sink_pad >= sink->num_pads);

	link = media_entity_add_link(source);
	if (link == NULL)
		return -ENOMEM;

	link->source = &source->pads[source_pad];
	link->sink = &sink->pads[sink_pad];
	link->flags = flags;

	/* Create the backlink. Backlinks are used to help graph traversal and
	 * are not reported to userspace.
	 */
	backlink = media_entity_add_link(sink);
	if (backlink == NULL) {
		source->num_links--;
		return -ENOMEM;
	}

	backlink->source = &source->pads[source_pad];
	backlink->sink = &sink->pads[sink_pad];
	backlink->flags = flags;

	link->reverse = backlink;
	backlink->reverse = link;

	sink->num_backlinks++;

	return 0;
}
EXPORT_SYMBOL_GPL(media_entity_create_link);

void __media_entity_remove_links(struct media_entity *entity)
{
	unsigned int i;

	for (i = 0; i < entity->num_links; i++) {
		struct media_link *link = &entity->links[i];
		struct media_entity *remote;
		unsigned int r = 0;

		if (link->source->entity == entity)
			remote = link->sink->entity;
		else
			remote = link->source->entity;

		while (r < remote->num_links) {
			struct media_link *rlink = &remote->links[r];

			if (rlink != link->reverse) {
				r++;
				continue;
			}

			if (link->source->entity == entity)
				remote->num_backlinks--;

			if (--remote->num_links == 0)
				break;

			/* Insert last entry in place of the dropped link. */
			*rlink = remote->links[remote->num_links];
		}
	}

	entity->num_links = 0;
	entity->num_backlinks = 0;
}
EXPORT_SYMBOL_GPL(__media_entity_remove_links);

void media_entity_remove_links(struct media_entity *entity)
{
	/* Do nothing if the entity is not registered. */
	if (entity->parent == NULL)
		return;

	mutex_lock(&entity->parent->graph_mutex);
	__media_entity_remove_links(entity);
	mutex_unlock(&entity->parent->graph_mutex);
}
EXPORT_SYMBOL_GPL(media_entity_remove_links);

static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
{
	int ret;

	/* Notify both entities. */
	ret = media_entity_call(link->source->entity, link_setup,
				link->source, link->sink, flags);
	if (ret < 0 && ret != -ENOIOCTLCMD)
		return ret;

	ret = media_entity_call(link->sink->entity, link_setup,
				link->sink, link->source, flags);
	if (ret < 0 && ret != -ENOIOCTLCMD) {
		media_entity_call(link->source->entity, link_setup,
				  link->source, link->sink, link->flags);
		return ret;
	}

	link->flags = flags;
	link->reverse->flags = link->flags;

	return 0;
}

/**
 * __media_entity_setup_link - Configure a media link
 * @link: The link being configured
 * @flags: Link configuration flags
 *
 * The bulk of link setup is handled by the two entities connected through the
 * link. This function notifies both entities of the link configuration change.
 *
 * If the link is immutable or if the current and new configuration are
 * identical, return immediately.
 *
 * The user is expected to hold link->source->parent->mutex. If not,
 * media_entity_setup_link() should be used instead.
 */
int __media_entity_setup_link(struct media_link *link, u32 flags)
{
	const u32 mask = MEDIA_LNK_FL_ENABLED;
	struct media_device *mdev;
	struct media_entity *source, *sink;
	int ret = -EBUSY;

	if (link == NULL)
		return -EINVAL;

	/* The non-modifiable link flags must not be modified. */
	if ((link->flags & ~mask) != (flags & ~mask))
		return -EINVAL;

	if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
		return link->flags == flags ? 0 : -EINVAL;

	if (link->flags == flags)
		return 0;

	source = link->source->entity;
	sink = link->sink->entity;

	if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
	    (source->stream_count || sink->stream_count))
		return -EBUSY;

	mdev = source->parent;

	if (mdev->link_notify) {
		ret = mdev->link_notify(link, flags,
					MEDIA_DEV_NOTIFY_PRE_LINK_CH);
		if (ret < 0)
			return ret;
	}

	ret = __media_entity_setup_link_notify(link, flags);

	if (mdev->link_notify)
		mdev->link_notify(link, flags, MEDIA_DEV_NOTIFY_POST_LINK_CH);

	return ret;
}

int media_entity_setup_link(struct media_link *link, u32 flags)
{
	int ret;

	mutex_lock(&link->source->entity->parent->graph_mutex);
	ret = __media_entity_setup_link(link, flags);
	mutex_unlock(&link->source->entity->parent->graph_mutex);

	return ret;
}
EXPORT_SYMBOL_GPL(media_entity_setup_link);

/**
 * media_entity_find_link - Find a link between two pads
 * @source: Source pad
 * @sink: Sink pad
 *
 * Return a pointer to the link between the two entities. If no such link
 * exists, return NULL.
 */
struct media_link *
media_entity_find_link(struct media_pad *source, struct media_pad *sink)
{
	struct media_link *link;
	unsigned int i;

	for (i = 0; i < source->entity->num_links; ++i) {
		link = &source->entity->links[i];

		if (link->source->entity == source->entity &&
		    link->source->index == source->index &&
		    link->sink->entity == sink->entity &&
		    link->sink->index == sink->index)
			return link;
	}

	return NULL;
}
EXPORT_SYMBOL_GPL(media_entity_find_link);

/**
 * media_entity_remote_pad - Find the pad at the remote end of a link
 * @pad: Pad at the local end of the link
 *
 * Search for a remote pad connected to the given pad by iterating over all
 * links originating or terminating at that pad until an enabled link is found.
 *
 * Return a pointer to the pad at the remote end of the first found enabled
 * link, or NULL if no enabled link has been found.
 */
struct media_pad *media_entity_remote_pad(struct media_pad *pad)
{
	unsigned int i;

	for (i = 0; i < pad->entity->num_links; i++) {
		struct media_link *link = &pad->entity->links[i];

		if (!(link->flags & MEDIA_LNK_FL_ENABLED))
			continue;

		if (link->source == pad)
			return link->sink;

		if (link->sink == pad)
			return link->source;
	}

	return NULL;

}
EXPORT_SYMBOL_GPL(media_entity_remote_pad);
Commit	Line	Data
53e269c1 LP	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	* You should have received a copy of the GNU General Public License
	19	* along with this program; if not, write to the Free Software
	20	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	21	*/
	22
5c7b25b9	23	#include <linux/bitmap.h>
53e269c1 LP	24	#include <linux/module.h>
	25	#include <linux/slab.h>
	26	#include <media/media-entity.h>
503c3d82	27	#include <media/media-device.h>
53e269c1 LP	28
	29	/**
	30	* media_entity_init - Initialize a media entity
	31	*
	32	* @num_pads: Total number of sink and source pads.
	33	* @extra_links: Initial estimate of the number of extra links.
	34	* @pads: Array of 'num_pads' pads.
	35	*
	36	* The total number of pads is an intrinsic property of entities known by the
	37	* entity driver, while the total number of links depends on hardware design
	38	* and is an extrinsic property unknown to the entity driver. However, in most
	39	* use cases the entity driver can guess the number of links which can safely
	40	* be assumed to be equal to or larger than the number of pads.
	41	*
	42	* For those reasons the links array can be preallocated based on the entity
	43	* driver guess and will be reallocated later if extra links need to be
	44	* created.
	45	*
	46	* This function allocates a links array with enough space to hold at least
	47	* 'num_pads' + 'extra_links' elements. The media_entity::max_links field will
	48	* be set to the number of allocated elements.
	49	*
	50	* The pads array is managed by the entity driver and passed to
	51	* media_entity_init() where its pointer will be stored in the entity structure.
	52	*/
	53	int
	54	media_entity_init(struct media_entity *entity, u16 num_pads,
	55	struct media_pad *pads, u16 extra_links)
	56	{
	57	struct media_link *links;
	58	unsigned int max_links = num_pads + extra_links;
	59	unsigned int i;
	60
	61	links = kzalloc(max_links * sizeof(links[0]), GFP_KERNEL);
	62	if (links == NULL)
	63	return -ENOMEM;
	64
	65	entity->group_id = 0;
	66	entity->max_links = max_links;
	67	entity->num_links = 0;
	68	entity->num_backlinks = 0;
	69	entity->num_pads = num_pads;
	70	entity->pads = pads;
	71	entity->links = links;
	72
	73	for (i = 0; i < num_pads; i++) {
	74	pads[i].entity = entity;
	75	pads[i].index = i;
	76	}
	77
	78	return 0;
	79	}
	80	EXPORT_SYMBOL_GPL(media_entity_init);
	81
	82	void
	83	media_entity_cleanup(struct media_entity *entity)
	84	{
	85	kfree(entity->links);
	86	}
	87	EXPORT_SYMBOL_GPL(media_entity_cleanup);
	88
a5ccc48a SA	89	/* -----------------------------------------------------------------------------
	90	* Graph traversal
	91	*/
	92
	93	static struct media_entity *
	94	media_entity_other(struct media_entity entity, struct media_link link)
	95	{
	96	if (link->source->entity == entity)
	97	return link->sink->entity;
	98	else
	99	return link->source->entity;
	100	}
	101
	102	/* push an entity to traversal stack */
	103	static void stack_push(struct media_entity_graph *graph,
	104	struct media_entity *entity)
	105	{
	106	if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
	107	WARN_ON(1);
	108	return;
	109	}
	110	graph->top++;
	111	graph->stack[graph->top].link = 0;
	112	graph->stack[graph->top].entity = entity;
	113	}
	114
	115	static struct media_entity stack_pop(struct media_entity_graph graph)
	116	{
	117	struct media_entity *entity;
	118
	119	entity = graph->stack[graph->top].entity;
	120	graph->top--;
	121
	122	return entity;
	123	}
	124
a5ccc48a SA	125	#define link_top(en) ((en)->stack[(en)->top].link)
	126	#define stack_top(en) ((en)->stack[(en)->top].entity)
	127
	128	/**
	129	* media_entity_graph_walk_start - Start walking the media graph at a given entity
	130	* @graph: Media graph structure that will be used to walk the graph
	131	* @entity: Starting entity
	132	*
	133	* This function initializes the graph traversal structure to walk the entities
	134	* graph starting at the given entity. The traversal structure must not be
	135	* modified by the caller during graph traversal. When done the structure can
	136	* safely be freed.
	137	*/
	138	void media_entity_graph_walk_start(struct media_entity_graph *graph,
	139	struct media_entity *entity)
	140	{
	141	graph->top = 0;
	142	graph->stack[graph->top].entity = NULL;
5c7b25b9 LP	143	bitmap_zero(graph->entities, MEDIA_ENTITY_ENUM_MAX_ID);
	144
	145	if (WARN_ON(entity->id >= MEDIA_ENTITY_ENUM_MAX_ID))
	146	return;
	147
	148	__set_bit(entity->id, graph->entities);
a5ccc48a SA	149	stack_push(graph, entity);
	150	}
	151	EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);
	152
	153	/**
	154	* media_entity_graph_walk_next - Get the next entity in the graph
	155	* @graph: Media graph structure
	156	*
	157	* Perform a depth-first traversal of the given media entities graph.
	158	*
	159	* The graph structure must have been previously initialized with a call to
	160	* media_entity_graph_walk_start().
	161	*
	162	* Return the next entity in the graph or NULL if the whole graph have been
	163	* traversed.
	164	*/
	165	struct media_entity *
	166	media_entity_graph_walk_next(struct media_entity_graph *graph)
	167	{
	168	if (stack_top(graph) == NULL)
	169	return NULL;
	170
	171	/*
	172	* Depth first search. Push entity to stack and continue from
	173	* top of the stack until no more entities on the level can be
	174	* found.
	175	*/
	176	while (link_top(graph) < stack_top(graph)->num_links) {
	177	struct media_entity *entity = stack_top(graph);
	178	struct media_link *link = &entity->links[link_top(graph)];
	179	struct media_entity *next;
	180
	181	/* The link is not enabled so we do not follow. */
	182	if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
	183	link_top(graph)++;
	184	continue;
	185	}
	186
	187	/* Get the entity in the other end of the link . */
	188	next = media_entity_other(entity, link);
5c7b25b9 LP	189	if (WARN_ON(next->id >= MEDIA_ENTITY_ENUM_MAX_ID))
5c7b25b9 LP	190	return NULL;
a5ccc48a	191
5c7b25b9 LP	192	/* Has the entity already been visited? */
5c7b25b9 LP	193	if (__test_and_set_bit(next->id, graph->entities)) {
a5ccc48a SA	194	link_top(graph)++;
	195	continue;
	196	}
	197
	198	/* Push the new entity to stack and start over. */
	199	link_top(graph)++;
	200	stack_push(graph, next);
	201	}
	202
	203	return stack_pop(graph);
	204	}
	205	EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
	206
e02188c9 LP	207	/* -----------------------------------------------------------------------------
	208	* Pipeline management
	209	*/
	210
	211	/**
	212	* media_entity_pipeline_start - Mark a pipeline as streaming
	213	* @entity: Starting entity
	214	* @pipe: Media pipeline to be assigned to all entities in the pipeline.
	215	*
	216	* Mark all entities connected to a given entity through enabled links, either
	217	* directly or indirectly, as streaming. The given pipeline object is assigned to
	218	* every entity in the pipeline and stored in the media_entity pipe field.
	219	*
	220	* Calls to this function can be nested, in which case the same number of
	221	* media_entity_pipeline_stop() calls will be required to stop streaming. The
	222	* pipeline pointer must be identical for all nested calls to
	223	* media_entity_pipeline_start().
	224	*/
af88be38 SA	225	__must_check int media_entity_pipeline_start(struct media_entity *entity,
af88be38 SA	226	struct media_pipeline *pipe)
e02188c9 LP	227	{
	228	struct media_device *mdev = entity->parent;
	229	struct media_entity_graph graph;
af88be38 SA	230	struct media_entity *entity_err = entity;
af88be38 SA	231	int ret;
e02188c9 LP	232
	233	mutex_lock(&mdev->graph_mutex);
	234
	235	media_entity_graph_walk_start(&graph, entity);
	236
	237	while ((entity = media_entity_graph_walk_next(&graph))) {
de49c285 SA	238	DECLARE_BITMAP(active, entity->num_pads);
de49c285 SA	239	DECLARE_BITMAP(has_no_links, entity->num_pads);
af88be38 SA	240	unsigned int i;
af88be38 SA	241
e02188c9 LP	242	entity->stream_count++;
	243	WARN_ON(entity->pipe && entity->pipe != pipe);
	244	entity->pipe = pipe;
af88be38 SA	245
	246	/* Already streaming --- no need to check. */
	247	if (entity->stream_count > 1)
	248	continue;
	249
	250	if (!entity->ops \|\| !entity->ops->link_validate)
	251	continue;
	252
de49c285 SA	253	bitmap_zero(active, entity->num_pads);
	254	bitmap_fill(has_no_links, entity->num_pads);
	255
af88be38 SA	256	for (i = 0; i < entity->num_links; i++) {
af88be38 SA	257	struct media_link *link = &entity->links[i];
de49c285 SA	258	struct media_pad *pad = link->sink->entity == entity
	259	? link->sink : link->source;
	260
	261	/* Mark that a pad is connected by a link. */
	262	bitmap_clear(has_no_links, pad->index, 1);
	263
	264	/*
	265	* Pads that either do not need to connect or
	266	* are connected through an enabled link are
	267	* fine.
	268	*/
	269	if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) \|\|
	270	link->flags & MEDIA_LNK_FL_ENABLED)
	271	bitmap_set(active, pad->index, 1);
	272
	273	/*
	274	* Link validation will only take place for
	275	* sink ends of the link that are enabled.
	276	*/
	277	if (link->sink != pad \|\|
	278	!(link->flags & MEDIA_LNK_FL_ENABLED))
af88be38 SA	279	continue;
	280
	281	ret = entity->ops->link_validate(link);
	282	if (ret < 0 && ret != -ENOIOCTLCMD)
	283	goto error;
	284	}
de49c285 SA	285
	286	/* Either no links or validated links are fine. */
	287	bitmap_or(active, active, has_no_links, entity->num_pads);
	288
	289	if (!bitmap_full(active, entity->num_pads)) {
	290	ret = -EPIPE;
	291	goto error;
	292	}
e02188c9 LP	293	}
	294
	295	mutex_unlock(&mdev->graph_mutex);
af88be38 SA	296
	297	return 0;
	298
	299	error:
	300	/*
	301	* Link validation on graph failed. We revert what we did and
	302	* return the error.
	303	*/
	304	media_entity_graph_walk_start(&graph, entity_err);
	305
	306	while ((entity_err = media_entity_graph_walk_next(&graph))) {
	307	entity_err->stream_count--;
	308	if (entity_err->stream_count == 0)
	309	entity_err->pipe = NULL;
	310
	311	/*
	312	* We haven't increased stream_count further than this
	313	* so we quit here.
	314	*/
	315	if (entity_err == entity)
	316	break;
	317	}
	318
	319	mutex_unlock(&mdev->graph_mutex);
	320
	321	return ret;
e02188c9 LP	322	}
	323	EXPORT_SYMBOL_GPL(media_entity_pipeline_start);
	324
	325	/**
	326	* media_entity_pipeline_stop - Mark a pipeline as not streaming
	327	* @entity: Starting entity
	328	*
	329	* Mark all entities connected to a given entity through enabled links, either
	330	* directly or indirectly, as not streaming. The media_entity pipe field is
	331	* reset to NULL.
	332	*
	333	* If multiple calls to media_entity_pipeline_start() have been made, the same
	334	* number of calls to this function are required to mark the pipeline as not
	335	* streaming.
	336	*/
	337	void media_entity_pipeline_stop(struct media_entity *entity)
	338	{
	339	struct media_device *mdev = entity->parent;
	340	struct media_entity_graph graph;
	341
	342	mutex_lock(&mdev->graph_mutex);
	343
	344	media_entity_graph_walk_start(&graph, entity);
	345
	346	while ((entity = media_entity_graph_walk_next(&graph))) {
	347	entity->stream_count--;
	348	if (entity->stream_count == 0)
	349	entity->pipe = NULL;
	350	}
	351
	352	mutex_unlock(&mdev->graph_mutex);
	353	}
	354	EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);
	355
503c3d82 LP	356	/* -----------------------------------------------------------------------------
	357	* Module use count
	358	*/
	359
	360	/*
	361	* media_entity_get - Get a reference to the parent module
	362	* @entity: The entity
	363	*
	364	* Get a reference to the parent media device module.
	365	*
	366	* The function will return immediately if @entity is NULL.
	367	*
	368	* Return a pointer to the entity on success or NULL on failure.
	369	*/
	370	struct media_entity media_entity_get(struct media_entity entity)
	371	{
	372	if (entity == NULL)
	373	return NULL;
	374
	375	if (entity->parent->dev &&
	376	!try_module_get(entity->parent->dev->driver->owner))
	377	return NULL;
	378
	379	return entity;
	380	}
	381	EXPORT_SYMBOL_GPL(media_entity_get);
	382
	383	/*
	384	* media_entity_put - Release the reference to the parent module
	385	* @entity: The entity
	386	*
	387	* Release the reference count acquired by media_entity_get().
	388	*
	389	* The function will return immediately if @entity is NULL.
	390	*/
	391	void media_entity_put(struct media_entity *entity)
	392	{
	393	if (entity == NULL)
	394	return;
	395
	396	if (entity->parent->dev)
	397	module_put(entity->parent->dev->driver->owner);
	398	}
	399	EXPORT_SYMBOL_GPL(media_entity_put);
	400
a5ccc48a SA	401	/* -----------------------------------------------------------------------------
	402	* Links management
	403	*/
	404
53e269c1 LP	405	static struct media_link media_entity_add_link(struct media_entity entity)
	406	{
	407	if (entity->num_links >= entity->max_links) {
	408	struct media_link *links = entity->links;
	409	unsigned int max_links = entity->max_links + 2;
	410	unsigned int i;
	411
	412	links = krealloc(links, max_links * sizeof(*links), GFP_KERNEL);
	413	if (links == NULL)
	414	return NULL;
	415
	416	for (i = 0; i < entity->num_links; i++)
	417	links[i].reverse->reverse = &links[i];
	418
	419	entity->max_links = max_links;
	420	entity->links = links;
	421	}
	422
	423	return &entity->links[entity->num_links++];
	424	}
	425
	426	int
	427	media_entity_create_link(struct media_entity *source, u16 source_pad,
	428	struct media_entity *sink, u16 sink_pad, u32 flags)
	429	{
	430	struct media_link *link;
	431	struct media_link *backlink;
	432
	433	BUG_ON(source == NULL \|\| sink == NULL);
	434	BUG_ON(source_pad >= source->num_pads);
	435	BUG_ON(sink_pad >= sink->num_pads);
	436
	437	link = media_entity_add_link(source);
	438	if (link == NULL)
	439	return -ENOMEM;
	440
	441	link->source = &source->pads[source_pad];
	442	link->sink = &sink->pads[sink_pad];
	443	link->flags = flags;
	444
	445	/* Create the backlink. Backlinks are used to help graph traversal and
	446	* are not reported to userspace.
	447	*/
	448	backlink = media_entity_add_link(sink);
	449	if (backlink == NULL) {
	450	source->num_links--;
	451	return -ENOMEM;
	452	}
	453
	454	backlink->source = &source->pads[source_pad];
	455	backlink->sink = &sink->pads[sink_pad];
	456	backlink->flags = flags;
	457
	458	link->reverse = backlink;
	459	backlink->reverse = link;
	460
	461	sink->num_backlinks++;
	462
	463	return 0;
	464	}
	465	EXPORT_SYMBOL_GPL(media_entity_create_link);
97548ed4	466
7349cec1 SN	467	void __media_entity_remove_links(struct media_entity *entity)
	468	{
	469	unsigned int i;
	470
	471	for (i = 0; i < entity->num_links; i++) {
	472	struct media_link *link = &entity->links[i];
	473	struct media_entity *remote;
	474	unsigned int r = 0;
	475
	476	if (link->source->entity == entity)
	477	remote = link->sink->entity;
	478	else
	479	remote = link->source->entity;
	480
	481	while (r < remote->num_links) {
	482	struct media_link *rlink = &remote->links[r];
	483
	484	if (rlink != link->reverse) {
	485	r++;
	486	continue;
	487	}
	488
	489	if (link->source->entity == entity)
	490	remote->num_backlinks--;
	491
	492	if (--remote->num_links == 0)
	493	break;
	494
	495	/* Insert last entry in place of the dropped link. */
	496	*rlink = remote->links[remote->num_links];
	497	}
	498	}
	499
	500	entity->num_links = 0;
	501	entity->num_backlinks = 0;
	502	}
	503	EXPORT_SYMBOL_GPL(__media_entity_remove_links);
	504
	505	void media_entity_remove_links(struct media_entity *entity)
	506	{
	507	/* Do nothing if the entity is not registered. */
	508	if (entity->parent == NULL)
	509	return;
	510
	511	mutex_lock(&entity->parent->graph_mutex);
	512	__media_entity_remove_links(entity);
	513	mutex_unlock(&entity->parent->graph_mutex);
	514	}
	515	EXPORT_SYMBOL_GPL(media_entity_remove_links);
	516
97548ed4 LP	517	static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
97548ed4 LP	518	{
97548ed4 LP	519	int ret;
	520
	521	/* Notify both entities. */
	522	ret = media_entity_call(link->source->entity, link_setup,
	523	link->source, link->sink, flags);
	524	if (ret < 0 && ret != -ENOIOCTLCMD)
	525	return ret;
	526
	527	ret = media_entity_call(link->sink->entity, link_setup,
	528	link->sink, link->source, flags);
	529	if (ret < 0 && ret != -ENOIOCTLCMD) {
	530	media_entity_call(link->source->entity, link_setup,
	531	link->source, link->sink, link->flags);
	532	return ret;
	533	}
	534
7a6f0b22	535	link->flags = flags;
97548ed4 LP	536	link->reverse->flags = link->flags;
	537
	538	return 0;
	539	}
	540
	541	/**
	542	* __media_entity_setup_link - Configure a media link
	543	* @link: The link being configured
	544	* @flags: Link configuration flags
	545	*
	546	* The bulk of link setup is handled by the two entities connected through the
	547	* link. This function notifies both entities of the link configuration change.
	548	*
	549	* If the link is immutable or if the current and new configuration are
	550	* identical, return immediately.
	551	*
	552	* The user is expected to hold link->source->parent->mutex. If not,
	553	* media_entity_setup_link() should be used instead.
	554	*/
	555	int __media_entity_setup_link(struct media_link *link, u32 flags)
	556	{
7a6f0b22	557	const u32 mask = MEDIA_LNK_FL_ENABLED;
97548ed4 LP	558	struct media_device *mdev;
	559	struct media_entity source, sink;
	560	int ret = -EBUSY;
	561
	562	if (link == NULL)
	563	return -EINVAL;
	564
7a6f0b22 LP	565	/* The non-modifiable link flags must not be modified. */
	566	if ((link->flags & ~mask) != (flags & ~mask))
	567	return -EINVAL;
	568
97548ed4 LP	569	if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
	570	return link->flags == flags ? 0 : -EINVAL;
	571
	572	if (link->flags == flags)
	573	return 0;
	574
	575	source = link->source->entity;
	576	sink = link->sink->entity;
	577
e02188c9 LP	578	if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
	579	(source->stream_count \|\| sink->stream_count))
	580	return -EBUSY;
	581
97548ed4 LP	582	mdev = source->parent;
97548ed4 LP	583
813f5c0a SN	584	if (mdev->link_notify) {
	585	ret = mdev->link_notify(link, flags,
	586	MEDIA_DEV_NOTIFY_PRE_LINK_CH);
97548ed4 LP	587	if (ret < 0)
	588	return ret;
	589	}
	590
	591	ret = __media_entity_setup_link_notify(link, flags);
97548ed4	592
813f5c0a SN	593	if (mdev->link_notify)
813f5c0a SN	594	mdev->link_notify(link, flags, MEDIA_DEV_NOTIFY_POST_LINK_CH);
97548ed4 LP	595
	596	return ret;
	597	}
	598
	599	int media_entity_setup_link(struct media_link *link, u32 flags)
	600	{
	601	int ret;
	602
	603	mutex_lock(&link->source->entity->parent->graph_mutex);
	604	ret = __media_entity_setup_link(link, flags);
	605	mutex_unlock(&link->source->entity->parent->graph_mutex);
	606
	607	return ret;
	608	}
	609	EXPORT_SYMBOL_GPL(media_entity_setup_link);
	610
	611	/**
	612	* media_entity_find_link - Find a link between two pads
	613	* @source: Source pad
	614	* @sink: Sink pad
	615	*
	616	* Return a pointer to the link between the two entities. If no such link
	617	* exists, return NULL.
	618	*/
	619	struct media_link *
	620	media_entity_find_link(struct media_pad source, struct media_pad sink)
	621	{
	622	struct media_link *link;
	623	unsigned int i;
	624
	625	for (i = 0; i < source->entity->num_links; ++i) {
	626	link = &source->entity->links[i];
	627
	628	if (link->source->entity == source->entity &&
	629	link->source->index == source->index &&
	630	link->sink->entity == sink->entity &&
	631	link->sink->index == sink->index)
	632	return link;
	633	}
	634
	635	return NULL;
	636	}
	637	EXPORT_SYMBOL_GPL(media_entity_find_link);
	638
	639	/**
1bddf1b3 AH	640	* media_entity_remote_pad - Find the pad at the remote end of a link
1bddf1b3 AH	641	* @pad: Pad at the local end of the link
97548ed4	642	*
1bddf1b3 AH	643	* Search for a remote pad connected to the given pad by iterating over all
1bddf1b3 AH	644	* links originating or terminating at that pad until an enabled link is found.
97548ed4 LP	645	*
	646	* Return a pointer to the pad at the remote end of the first found enabled
	647	* link, or NULL if no enabled link has been found.
	648	*/
1bddf1b3	649	struct media_pad media_entity_remote_pad(struct media_pad pad)
97548ed4 LP	650	{
	651	unsigned int i;
	652
	653	for (i = 0; i < pad->entity->num_links; i++) {
	654	struct media_link *link = &pad->entity->links[i];
	655
	656	if (!(link->flags & MEDIA_LNK_FL_ENABLED))
	657	continue;
	658
	659	if (link->source == pad)
	660	return link->sink;
	661
	662	if (link->sink == pad)
	663	return link->source;
	664	}
	665
	666	return NULL;
	667
	668	}
1bddf1b3	669	EXPORT_SYMBOL_GPL(media_entity_remote_pad);