diff options
Diffstat (limited to 'drivers/media/media-entity.c')
| -rw-r--r-- | drivers/media/media-entity.c | 536 |
1 files changed, 536 insertions, 0 deletions
diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c new file mode 100644 index 000000000000..23640ed44d85 --- /dev/null +++ b/drivers/media/media-entity.c @@ -0,0 +1,536 @@ +/* + * 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/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 stack_peek(en) ((en)->stack[(en)->top - 1].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; + 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); + + /* Was it the entity we came here from? */ + if (next == stack_peek(graph)) { + 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(). + */ +void media_entity_pipeline_start(struct media_entity *entity, + struct media_pipeline *pipe) +{ + 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++; + WARN_ON(entity->pipe && entity->pipe != pipe); + entity->pipe = pipe; + } + + mutex_unlock(&mdev->graph_mutex); +} +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); + +static int __media_entity_setup_link_notify(struct media_link *link, u32 flags) +{ + const u32 mask = MEDIA_LNK_FL_ENABLED; + 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 = (link->flags & ~mask) | (flags & mask); + 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) +{ + struct media_device *mdev; + struct media_entity *source, *sink; + int ret = -EBUSY; + + if (link == NULL) + 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 ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify) { + ret = mdev->link_notify(link->source, link->sink, + MEDIA_LNK_FL_ENABLED); + if (ret < 0) + return ret; + } + + ret = __media_entity_setup_link_notify(link, flags); + if (ret < 0) + goto err; + + if (!(flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify) + mdev->link_notify(link->source, link->sink, 0); + + return 0; + +err: + if ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify) + mdev->link_notify(link->source, link->sink, 0); + + 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_source - Find the source pad at the remote end of a link + * @pad: Sink pad at the local end of the link + * + * Search for a remote source pad connected to the given sink 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_source(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_source); |