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);