* Graph traversal
*/
+/*
+ * This function checks the interdependency inside the entity between @pad0
+ * and @pad1. If two pads are interdependent they are part of the same pipeline
+ * and enabling one of the pads means that the other pad will become "locked"
+ * and doesn't allow configuration changes.
+ *
+ * For the time being all pads are considered interdependent.
+ */
+static bool media_entity_has_pad_interdep(struct media_entity *entity,
+ unsigned int pad0, unsigned int pad1)
+{
+ if (pad0 >= entity->num_pads || pad1 >= entity->num_pads)
+ return false;
+
+ if (entity->pads[pad0].flags & entity->pads[pad1].flags &
+ (MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_SOURCE))
+ return false;
+
+ return true;
+}
+
static struct media_entity *
media_entity_other(struct media_entity *entity, struct media_link *link)
{
* Pipeline management
*/
+/*
+ * The pipeline traversal stack stores pads that are reached during graph
+ * traversal, with a list of links to be visited to continue the traversal.
+ * When a new pad is reached, an entry is pushed on the top of the stack and
+ * points to the incoming pad and the first link of the entity.
+ *
+ * To find further pads in the pipeline, the traversal algorithm follows
+ * internal pad dependencies in the entity, and then links in the graph. It
+ * does so by iterating over all links of the entity, and following enabled
+ * links that originate from a pad that is internally connected to the incoming
+ * pad, as reported by the media_entity_has_pad_interdep() function.
+ */
+
+/**
+ * struct media_pipeline_walk_entry - Entry in the pipeline traversal stack
+ *
+ * @pad: The media pad being visited
+ * @links: Links left to be visited
+ */
+struct media_pipeline_walk_entry {
+ struct media_pad *pad;
+ struct list_head *links;
+};
+
+/**
+ * struct media_pipeline_walk - State used by the media pipeline traversal
+ * algorithm
+ *
+ * @mdev: The media device
+ * @stack: Depth-first search stack
+ * @stack.size: Number of allocated entries in @stack.entries
+ * @stack.top: Index of the top stack entry (-1 if the stack is empty)
+ * @stack.entries: Stack entries
+ */
+struct media_pipeline_walk {
+ struct media_device *mdev;
+
+ struct {
+ unsigned int size;
+ int top;
+ struct media_pipeline_walk_entry *entries;
+ } stack;
+};
+
+#define MEDIA_PIPELINE_STACK_GROW_STEP 16
+
+static struct media_pipeline_walk_entry *
+media_pipeline_walk_top(struct media_pipeline_walk *walk)
+{
+ return &walk->stack.entries[walk->stack.top];
+}
+
+static bool media_pipeline_walk_empty(struct media_pipeline_walk *walk)
+{
+ return walk->stack.top == -1;
+}
+
+/* Increase the stack size by MEDIA_PIPELINE_STACK_GROW_STEP elements. */
+static int media_pipeline_walk_resize(struct media_pipeline_walk *walk)
+{
+ struct media_pipeline_walk_entry *entries;
+ unsigned int new_size;
+
+ /* Safety check, to avoid stack overflows in case of bugs. */
+ if (walk->stack.size >= 256)
+ return -E2BIG;
+
+ new_size = walk->stack.size + MEDIA_PIPELINE_STACK_GROW_STEP;
+
+ entries = krealloc(walk->stack.entries,
+ new_size * sizeof(*walk->stack.entries),
+ GFP_KERNEL);
+ if (!entries)
+ return -ENOMEM;
+
+ walk->stack.entries = entries;
+ walk->stack.size = new_size;
+
+ return 0;
+}
+
+/* Push a new entry on the stack. */
+static int media_pipeline_walk_push(struct media_pipeline_walk *walk,
+ struct media_pad *pad)
+{
+ struct media_pipeline_walk_entry *entry;
+ int ret;
+
+ if (walk->stack.top + 1 >= walk->stack.size) {
+ ret = media_pipeline_walk_resize(walk);
+ if (ret)
+ return ret;
+ }
+
+ walk->stack.top++;
+ entry = media_pipeline_walk_top(walk);
+ entry->pad = pad;
+ entry->links = pad->entity->links.next;
+
+ dev_dbg(walk->mdev->dev,
+ "media pipeline: pushed entry %u: '%s':%u\n",
+ walk->stack.top, pad->entity->name, pad->index);
+
+ return 0;
+}
+
+/*
+ * Move the top entry link cursor to the next link. If all links of the entry
+ * have been visited, pop the entry itself.
+ */
+static void media_pipeline_walk_pop(struct media_pipeline_walk *walk)
+{
+ struct media_pipeline_walk_entry *entry;
+
+ if (WARN_ON(walk->stack.top < 0))
+ return;
+
+ entry = media_pipeline_walk_top(walk);
+
+ if (entry->links->next == &entry->pad->entity->links) {
+ dev_dbg(walk->mdev->dev,
+ "media pipeline: entry %u has no more links, popping\n",
+ walk->stack.top);
+
+ walk->stack.top--;
+ return;
+ }
+
+ entry->links = entry->links->next;
+
+ dev_dbg(walk->mdev->dev,
+ "media pipeline: moved entry %u to next link\n",
+ walk->stack.top);
+}
+
+/* Free all memory allocated while walking the pipeline. */
+static void media_pipeline_walk_destroy(struct media_pipeline_walk *walk)
+{
+ kfree(walk->stack.entries);
+}
+
+/* Add a pad to the pipeline and push it to the stack. */
+static int media_pipeline_add_pad(struct media_pipeline *pipe,
+ struct media_pipeline_walk *walk,
+ struct media_pad *pad)
+{
+ struct media_pipeline_pad *ppad;
+
+ list_for_each_entry(ppad, &pipe->pads, list) {
+ if (ppad->pad == pad) {
+ dev_dbg(pad->graph_obj.mdev->dev,
+ "media pipeline: already contains pad '%s':%u\n",
+ pad->entity->name, pad->index);
+ return 0;
+ }
+ }
+
+ ppad = kzalloc(sizeof(*ppad), GFP_KERNEL);
+ if (!ppad)
+ return -ENOMEM;
+
+ ppad->pipe = pipe;
+ ppad->pad = pad;
+
+ list_add_tail(&ppad->list, &pipe->pads);
+
+ dev_dbg(pad->graph_obj.mdev->dev,
+ "media pipeline: added pad '%s':%u\n",
+ pad->entity->name, pad->index);
+
+ return media_pipeline_walk_push(walk, pad);
+}
+
+/* Explore the next link of the entity at the top of the stack. */
+static int media_pipeline_explore_next_link(struct media_pipeline *pipe,
+ struct media_pipeline_walk *walk)
+{
+ struct media_pipeline_walk_entry *entry = media_pipeline_walk_top(walk);
+ struct media_pad *pad;
+ struct media_link *link;
+ struct media_pad *local;
+ struct media_pad *remote;
+ int ret;
+
+ pad = entry->pad;
+ link = list_entry(entry->links, typeof(*link), list);
+ media_pipeline_walk_pop(walk);
+
+ dev_dbg(walk->mdev->dev,
+ "media pipeline: exploring link '%s':%u -> '%s':%u\n",
+ link->source->entity->name, link->source->index,
+ link->sink->entity->name, link->sink->index);
+
+ /* Skip links that are not enabled. */
+ if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
+ dev_dbg(walk->mdev->dev,
+ "media pipeline: skipping link (disabled)\n");
+ return 0;
+ }
+
+ /* Get the local pad and remote pad. */
+ if (link->source->entity == pad->entity) {
+ local = link->source;
+ remote = link->sink;
+ } else {
+ local = link->sink;
+ remote = link->source;
+ }
+
+ /*
+ * Skip links that originate from a different pad than the incoming pad
+ * that is not connected internally in the entity to the incoming pad.
+ */
+ if (pad != local &&
+ !media_entity_has_pad_interdep(pad->entity, pad->index, local->index)) {
+ dev_dbg(walk->mdev->dev,
+ "media pipeline: skipping link (no route)\n");
+ return 0;
+ }
+
+ /*
+ * Add the local and remote pads of the link to the pipeline and push
+ * them to the stack, if they're not already present.
+ */
+ ret = media_pipeline_add_pad(pipe, walk, local);
+ if (ret)
+ return ret;
+
+ ret = media_pipeline_add_pad(pipe, walk, remote);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static void media_pipeline_cleanup(struct media_pipeline *pipe)
+{
+ while (!list_empty(&pipe->pads)) {
+ struct media_pipeline_pad *ppad;
+
+ ppad = list_first_entry(&pipe->pads, typeof(*ppad), list);
+ list_del(&ppad->list);
+ kfree(ppad);
+ }
+}
+
+static int media_pipeline_populate(struct media_pipeline *pipe,
+ struct media_pad *pad)
+{
+ struct media_pipeline_walk walk = { };
+ struct media_pipeline_pad *ppad;
+ int ret;
+
+ /*
+ * Populate the media pipeline by walking the media graph, starting
+ * from @pad.
+ */
+ INIT_LIST_HEAD(&pipe->pads);
+ pipe->mdev = pad->graph_obj.mdev;
+
+ walk.mdev = pipe->mdev;
+ walk.stack.top = -1;
+ ret = media_pipeline_add_pad(pipe, &walk, pad);
+ if (ret)
+ goto done;
+
+ /*
+ * Use a depth-first search algorithm: as long as the stack is not
+ * empty, explore the next link of the top entry. The
+ * media_pipeline_explore_next_link() function will either move to the
+ * next link, pop the entry if fully visited, or add new entries on
+ * top.
+ */
+ while (!media_pipeline_walk_empty(&walk)) {
+ ret = media_pipeline_explore_next_link(pipe, &walk);
+ if (ret)
+ goto done;
+ }
+
+ dev_dbg(pad->graph_obj.mdev->dev,
+ "media pipeline populated, found pads:\n");
+
+ list_for_each_entry(ppad, &pipe->pads, list)
+ dev_dbg(pad->graph_obj.mdev->dev, "- '%s':%u\n",
+ ppad->pad->entity->name, ppad->pad->index);
+
+ WARN_ON(walk.stack.top != -1);
+
+ ret = 0;
+
+done:
+ media_pipeline_walk_destroy(&walk);
+
+ if (ret)
+ media_pipeline_cleanup(pipe);
+
+ return ret;
+}
+
__must_check int __media_pipeline_start(struct media_entity *entity,
struct media_pipeline *pipe)
{
struct media_device *mdev = entity->graph_obj.mdev;
- struct media_graph *graph = &pipe->graph;
- struct media_entity *entity_err = entity;
- struct media_link *link;
+ struct media_pipeline_pad *err_ppad;
+ struct media_pipeline_pad *ppad;
int ret;
+ lockdep_assert_held(&mdev->graph_mutex);
+
+ /*
+ * media_pipeline_start(entity) only makes sense with entities that have
+ * a single pad.
+ */
+
+ if (WARN_ON(entity->num_pads != 1))
+ return -EINVAL;
+
+ /*
+ * If the entity is already part of a pipeline, that pipeline must
+ * be the same as the pipe given to media_pipeline_start().
+ */
+ if (WARN_ON(entity->pads->pipe && entity->pads->pipe != pipe))
+ return -EINVAL;
+
+ /*
+ * If the pipeline has already been started, it is guaranteed to be
+ * valid, so just increase the start count.
+ */
if (pipe->start_count) {
pipe->start_count++;
return 0;
}
- ret = media_graph_walk_init(&pipe->graph, mdev);
+ /*
+ * Populate the pipeline. This populates the media_pipeline pads list
+ * with media_pipeline_pad instances for each pad found during graph
+ * walk.
+ */
+ ret = media_pipeline_populate(pipe, entity->pads);
if (ret)
return ret;
- media_graph_walk_start(&pipe->graph, entity);
+ /*
+ * Now that all the pads in the pipeline have been gathered, perform
+ * the validation steps.
+ */
+
+ list_for_each_entry(ppad, &pipe->pads, list) {
+ struct media_pad *pad = ppad->pad;
+ struct media_entity *entity = pad->entity;
+ bool has_enabled_link = false;
+ bool has_link = false;
+ struct media_link *link;
- while ((entity = media_graph_walk_next(graph))) {
- DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
- DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
+ dev_dbg(mdev->dev, "Validating pad '%s':%u\n", pad->entity->name,
+ pad->index);
- if (entity->pipe && entity->pipe != pipe) {
- pr_err("Pipe active for %s. Can't start for %s\n",
- entity->name,
- entity_err->name);
+ /*
+ * 1. Ensure that the pad doesn't already belong to a different
+ * pipeline.
+ */
+ if (pad->pipe) {
+ dev_dbg(mdev->dev, "Failed to start pipeline: pad '%s':%u busy\n",
+ pad->entity->name, pad->index);
ret = -EBUSY;
goto error;
}
- /* Already streaming --- no need to check. */
- if (entity->pipe)
- continue;
-
- entity->pipe = pipe;
-
- if (!entity->ops || !entity->ops->link_validate)
- continue;
-
- bitmap_zero(active, entity->num_pads);
- bitmap_fill(has_no_links, entity->num_pads);
-
+ /*
+ * 2. Validate all active links whose sink is the current pad.
+ * Validation of the source pads is performed in the context of
+ * the connected sink pad to avoid duplicating checks.
+ */
for_each_media_entity_data_link(entity, link) {
- struct media_pad *pad = link->sink->entity == entity
- ? link->sink : link->source;
+ /* Skip links unrelated to the current pad. */
+ if (link->sink != pad && link->source != pad)
+ continue;
- /* Mark that a pad is connected by a link. */
- bitmap_clear(has_no_links, pad->index, 1);
+ /* Record if the pad has links and enabled links. */
+ if (link->flags & MEDIA_LNK_FL_ENABLED)
+ has_enabled_link = true;
+ has_link = true;
/*
- * Pads that either do not need to connect or
- * are connected through an enabled link are
- * fine.
+ * Validate the link if it's enabled and has the
+ * current pad as its sink.
*/
- if (!(pad->flags & MEDIA_PAD_FL_MUST_CONNECT) ||
- link->flags & MEDIA_LNK_FL_ENABLED)
- bitmap_set(active, pad->index, 1);
+ if (!(link->flags & MEDIA_LNK_FL_ENABLED))
+ continue;
- /*
- * 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))
+ if (link->sink != pad)
+ continue;
+
+ if (!entity->ops || !entity->ops->link_validate)
continue;
ret = entity->ops->link_validate(link);
- if (ret < 0 && ret != -ENOIOCTLCMD) {
- dev_dbg(entity->graph_obj.mdev->dev,
- "link validation failed for '%s':%u -> '%s':%u, error %d\n",
+ if (ret) {
+ dev_dbg(mdev->dev,
+ "Link '%s':%u -> '%s':%u failed validation: %d\n",
link->source->entity->name,
link->source->index,
- entity->name, link->sink->index, ret);
+ link->sink->entity->name,
+ link->sink->index, ret);
goto error;
}
- }
- /* Either no links or validated links are fine. */
- bitmap_or(active, active, has_no_links, entity->num_pads);
+ dev_dbg(mdev->dev,
+ "Link '%s':%u -> '%s':%u is valid\n",
+ link->source->entity->name,
+ link->source->index,
+ link->sink->entity->name,
+ link->sink->index);
+ }
- if (!bitmap_full(active, entity->num_pads)) {
+ /*
+ * 3. If the pad has the MEDIA_PAD_FL_MUST_CONNECT flag set,
+ * ensure that it has either no link or an enabled link.
+ */
+ if ((pad->flags & MEDIA_PAD_FL_MUST_CONNECT) && has_link &&
+ !has_enabled_link) {
+ dev_dbg(mdev->dev,
+ "Pad '%s':%u must be connected by an enabled link\n",
+ pad->entity->name, pad->index);
ret = -ENOLINK;
- dev_dbg(entity->graph_obj.mdev->dev,
- "'%s':%u must be connected by an enabled link\n",
- entity->name,
- (unsigned)find_first_zero_bit(
- active, entity->num_pads));
goto error;
}
+
+ /* Validation passed, store the pipe pointer in the pad. */
+ pad->pipe = pipe;
}
pipe->start_count++;
* Link validation on graph failed. We revert what we did and
* return the error.
*/
- media_graph_walk_start(graph, entity_err);
-
- while ((entity_err = media_graph_walk_next(graph))) {
- entity_err->pipe = NULL;
- /*
- * We haven't started entities further than this so we quit
- * here.
- */
- if (entity_err == entity)
+ list_for_each_entry(err_ppad, &pipe->pads, list) {
+ if (err_ppad == ppad)
break;
+
+ err_ppad->pad->pipe = NULL;
}
- media_graph_walk_cleanup(graph);
+ media_pipeline_cleanup(pipe);
return ret;
}
void __media_pipeline_stop(struct media_entity *entity)
{
- struct media_graph *graph = &entity->pipe->graph;
- struct media_pipeline *pipe = entity->pipe;
+ struct media_pipeline *pipe = entity->pads->pipe;
+ struct media_pipeline_pad *ppad;
/*
* If the following check fails, the driver has performed an
if (--pipe->start_count)
return;
- media_graph_walk_start(graph, entity);
+ list_for_each_entry(ppad, &pipe->pads, list)
+ ppad->pad->pipe = NULL;
- while ((entity = media_graph_walk_next(graph)))
- entity->pipe = NULL;
-
- media_graph_walk_cleanup(graph);
+ media_pipeline_cleanup(pipe);
if (pipe->allocated)
kfree(pipe);
{
const u32 mask = MEDIA_LNK_FL_ENABLED;
struct media_device *mdev;
- struct media_entity *source, *sink;
+ struct media_pad *source, *sink;
int ret = -EBUSY;
if (link == NULL)
if (link->flags == flags)
return 0;
- source = link->source->entity;
- sink = link->sink->entity;
+ source = link->source;
+ sink = link->sink;
if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
- (media_entity_is_streaming(source) ||
- media_entity_is_streaming(sink)))
+ (media_pad_is_streaming(source) || media_pad_is_streaming(sink)))
return -EBUSY;
mdev = source->graph_obj.mdev;
struct media_pipeline *media_entity_pipeline(struct media_entity *entity)
{
- return entity->pipe;
+ struct media_pad *pad;
+
+ media_entity_for_each_pad(entity, pad) {
+ if (pad->pipe)
+ return pad->pipe;
+ }
+
+ return NULL;
}
EXPORT_SYMBOL_GPL(media_entity_pipeline);
+struct media_pipeline *media_pad_pipeline(struct media_pad *pad)
+{
+ return pad->pipe;
+}
+EXPORT_SYMBOL_GPL(media_pad_pipeline);
+
static void media_interface_init(struct media_device *mdev,
struct media_interface *intf,
u32 gobj_type,
projects / linux.git / commitdiff