Merge tag 'media/v4.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media

Pull second batch of media updates from Mauro Carvalho Chehab:
 "This is the second part of the media patches.  It contains the media
  controller next generation patches, with is the result of one year of
  discussions and development.  It also contains patches to enable media
  controller support at the DVB subsystem.

  The goal is to improve the media controller to allow proper support
  for other types of Video4Linux devices (radio and TV ones) and to
  extend the media controller functionality to allow it to be used by
  other subsystems like DVB, ALSA and IIO.

  In order to use the new functionality, a new ioctl is needed
  (MEDIA_IOC_G_TOPOLOGY).  As we're still discussing how to pack the
  struct fields of this ioctl in order to avoid compat32 issues, I
  decided to add a patch at the end of this series commenting out the
  new ioctl, in order to postpone the addition of the new ioctl to the
  next Kernel version (4.6).

  With that, no userspace visible changes should happen at the media
  controller API, as the existing ioctls are untouched.  Yet, it helps
  DVB, ALSA and IIO developers to develop and test the patches adding
  media controller support there, as the core will contain all required
  internal changes to allow adding support for devices that belong to
  those subsystems"

* tag 'media/v4.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (177 commits)
  [media] Postpone the addition of MEDIA_IOC_G_TOPOLOGY
  [media] mxl111sf: Add a tuner entity
  [media] dvbdev: create links on devices with multiple frontends
  [media] media-entitiy: add a function to create multiple links
  [media] dvb-usb-v2: postpone removal of media_device
  [media] dvbdev: Add RF connector if needed
  [media] dvbdev: remove two dead functions if !CONFIG_MEDIA_CONTROLLER_DVB
  [media] call media_device_init() before registering the V4L2 device
  [media] uapi/media.h: Use u32 for the number of graph objects
  [media] media-entity: don't sleep at media_device_register_entity()
  [media] media-entity: increase max number of PADs
  [media] media-entity.h: document the remaining functions
  [media] media-device.h: use just one u32 counter for object ID
  [media] media-entity.h fix documentation for several parameters
  [media] DocBook: document media_entity_graph_walk_cleanup()
  [media] move documentation to the header files
  [media] media: Move MEDIA_ENTITY_MAX_PADS from media-entity.h to media-entity.c
  [media] media: Remove pre-allocated entity enumeration bitmap
  [media] staging: v4l: davinci_vpbe: Use the new media graph walk interface
  [media] staging: v4l: omap4iss: Use the new media graph walk interface
  ...

1 files changed, 492 insertions, 228 deletions

diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index 767fe55ba08e..e89d85a7d31b 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -26,65 +26,198 @@
 #include <media/media-entity.h>
 #include <media/media-device.h>
 
+static inline const char *gobj_type(enum media_gobj_type type)
+{
+	switch (type) {
+	case MEDIA_GRAPH_ENTITY:
+		return "entity";
+	case MEDIA_GRAPH_PAD:
+		return "pad";
+	case MEDIA_GRAPH_LINK:
+		return "link";
+	case MEDIA_GRAPH_INTF_DEVNODE:
+		return "intf-devnode";
+	default:
+		return "unknown";
+	}
+}
+
+static inline const char *intf_type(struct media_interface *intf)
+{
+	switch (intf->type) {
+	case MEDIA_INTF_T_DVB_FE:
+		return "frontend";
+	case MEDIA_INTF_T_DVB_DEMUX:
+		return "demux";
+	case MEDIA_INTF_T_DVB_DVR:
+		return "DVR";
+	case MEDIA_INTF_T_DVB_CA:
+		return  "CA";
+	case MEDIA_INTF_T_DVB_NET:
+		return "dvbnet";
+	case MEDIA_INTF_T_V4L_VIDEO:
+		return "video";
+	case MEDIA_INTF_T_V4L_VBI:
+		return "vbi";
+	case MEDIA_INTF_T_V4L_RADIO:
+		return "radio";
+	case MEDIA_INTF_T_V4L_SUBDEV:
+		return "v4l2-subdev";
+	case MEDIA_INTF_T_V4L_SWRADIO:
+		return "swradio";
+	default:
+		return "unknown-intf";
+	}
+};
+
+__must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
+					  int idx_max)
+{
+	ent_enum->bmap = kcalloc(DIV_ROUND_UP(idx_max, BITS_PER_LONG),
+				 sizeof(long), GFP_KERNEL);
+	if (!ent_enum->bmap)
+		return -ENOMEM;
+
+	bitmap_zero(ent_enum->bmap, idx_max);
+	ent_enum->idx_max = idx_max;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__media_entity_enum_init);
+
+void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
+{
+	kfree(ent_enum->bmap);
+}
+EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
+
 /**
- * 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.
+ *  dev_dbg_obj - Prints in debug mode a change on some object
  *
- * 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.
+ * @event_name:	Name of the event to report. Could be __func__
+ * @gobj:	Pointer to the object
  *
- * 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.
+ * Enabled only if DEBUG or CONFIG_DYNAMIC_DEBUG. Otherwise, it
+ * won't produce any code.
  */
-int
-media_entity_init(struct media_entity *entity, u16 num_pads,
-		  struct media_pad *pads, u16 extra_links)
+static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 {
-	struct media_link *links;
-	unsigned int max_links = num_pads + extra_links;
-	unsigned int i;
+#if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
+	switch (media_type(gobj)) {
+	case MEDIA_GRAPH_ENTITY:
+		dev_dbg(gobj->mdev->dev,
+			"%s id %u: entity '%s'\n",
+			event_name, media_id(gobj),
+			gobj_to_entity(gobj)->name);
+		break;
+	case MEDIA_GRAPH_LINK:
+	{
+		struct media_link *link = gobj_to_link(gobj);
 
-	links = kzalloc(max_links * sizeof(links[0]), GFP_KERNEL);
-	if (links == NULL)
-		return -ENOMEM;
+		dev_dbg(gobj->mdev->dev,
+			"%s id %u: %s link id %u ==> id %u\n",
+			event_name, media_id(gobj),
+			media_type(link->gobj0) == MEDIA_GRAPH_PAD ?
+				"data" : "interface",
+			media_id(link->gobj0),
+			media_id(link->gobj1));
+		break;
+	}
+	case MEDIA_GRAPH_PAD:
+	{
+		struct media_pad *pad = gobj_to_pad(gobj);
+
+		dev_dbg(gobj->mdev->dev,
+			"%s id %u: %s%spad '%s':%d\n",
+			event_name, media_id(gobj),
+			pad->flags & MEDIA_PAD_FL_SINK   ? "sink " : "",
+			pad->flags & MEDIA_PAD_FL_SOURCE ? "source " : "",
+			pad->entity->name, pad->index);
+		break;
+	}
+	case MEDIA_GRAPH_INTF_DEVNODE:
+	{
+		struct media_interface *intf = gobj_to_intf(gobj);
+		struct media_intf_devnode *devnode = intf_to_devnode(intf);
+
+		dev_dbg(gobj->mdev->dev,
+			"%s id %u: intf_devnode %s - major: %d, minor: %d\n",
+			event_name, media_id(gobj),
+			intf_type(intf),
+			devnode->major, devnode->minor);
+		break;
+	}
+	}
+#endif
+}
+
+void media_gobj_create(struct media_device *mdev,
+			   enum media_gobj_type type,
+			   struct media_gobj *gobj)
+{
+	BUG_ON(!mdev);
+
+	gobj->mdev = mdev;
+
+	/* Create a per-type unique object ID */
+	gobj->id = media_gobj_gen_id(type, ++mdev->id);
+
+	switch (type) {
+	case MEDIA_GRAPH_ENTITY:
+		list_add_tail(&gobj->list, &mdev->entities);
+		break;
+	case MEDIA_GRAPH_PAD:
+		list_add_tail(&gobj->list, &mdev->pads);
+		break;
+	case MEDIA_GRAPH_LINK:
+		list_add_tail(&gobj->list, &mdev->links);
+		break;
+	case MEDIA_GRAPH_INTF_DEVNODE:
+		list_add_tail(&gobj->list, &mdev->interfaces);
+		break;
+	}
+
+	mdev->topology_version++;
+
+	dev_dbg_obj(__func__, gobj);
+}
+
+void media_gobj_destroy(struct media_gobj *gobj)
+{
+	dev_dbg_obj(__func__, gobj);
+
+	gobj->mdev->topology_version++;
+
+	/* Remove the object from mdev list */
+	list_del(&gobj->list);
+}
+
+int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
+			   struct media_pad *pads)
+{
+	struct media_device *mdev = entity->graph_obj.mdev;
+	unsigned int i;
 
-	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;
+
+	if (mdev)
+		spin_lock(&mdev->lock);
 
 	for (i = 0; i < num_pads; i++) {
 		pads[i].entity = entity;
 		pads[i].index = i;
+		if (mdev)
+			media_gobj_create(mdev, MEDIA_GRAPH_PAD,
+					&entity->pads[i].graph_obj);
 	}
 
-	return 0;
-}
-EXPORT_SYMBOL_GPL(media_entity_init);
+	if (mdev)
+		spin_unlock(&mdev->lock);
 
-void
-media_entity_cleanup(struct media_entity *entity)
-{
-	kfree(entity->links);
+	return 0;
 }
-EXPORT_SYMBOL_GPL(media_entity_cleanup);
+EXPORT_SYMBOL_GPL(media_entity_pads_init);
 
 /* -----------------------------------------------------------------------------
  * Graph traversal
@@ -108,7 +241,7 @@ static void stack_push(struct media_entity_graph *graph,
 		return;
 	}
 	graph->top++;
-	graph->stack[graph->top].link = 0;
+	graph->stack[graph->top].link = entity->links.next;
 	graph->stack[graph->top].entity = entity;
 }
 
@@ -125,43 +258,51 @@ static struct media_entity *stack_pop(struct media_entity_graph *graph)
 #define link_top(en)	((en)->stack[(en)->top].link)
 #define stack_top(en)	((en)->stack[(en)->top].entity)
 
+/*
+ * TODO: Get rid of this.
+ */
+#define MEDIA_ENTITY_MAX_PADS		512
+
 /**
- * media_entity_graph_walk_start - Start walking the media graph at a given entity
+ * media_entity_graph_walk_init - Allocate resources for graph walk
  * @graph: Media graph structure that will be used to walk the graph
- * @entity: Starting entity
+ * @mdev: Media device
+ *
+ * Reserve resources for graph walk in media device's current
+ * state. The memory must be released using
+ * media_entity_graph_walk_free().
  *
- * 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.
+ * Returns error on failure, zero on success.
  */
+__must_check int media_entity_graph_walk_init(
+	struct media_entity_graph *graph, struct media_device *mdev)
+{
+	return media_entity_enum_init(&graph->ent_enum, mdev);
+}
+EXPORT_SYMBOL_GPL(media_entity_graph_walk_init);
+
+/**
+ * media_entity_graph_walk_cleanup - Release resources related to graph walking
+ * @graph: Media graph structure that was used to walk the graph
+ */
+void media_entity_graph_walk_cleanup(struct media_entity_graph *graph)
+{
+	media_entity_enum_cleanup(&graph->ent_enum);
+}
+EXPORT_SYMBOL_GPL(media_entity_graph_walk_cleanup);
+
 void media_entity_graph_walk_start(struct media_entity_graph *graph,
 				   struct media_entity *entity)
 {
+	media_entity_enum_zero(&graph->ent_enum);
+	media_entity_enum_set(&graph->ent_enum, 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)
 {
@@ -173,30 +314,30 @@ media_entity_graph_walk_next(struct media_entity_graph *graph)
 	 * top of the stack until no more entities on the level can be
 	 * found.
 	 */
-	while (link_top(graph) < stack_top(graph)->num_links) {
+	while (link_top(graph) != &stack_top(graph)->links) {
 		struct media_entity *entity = stack_top(graph);
-		struct media_link *link = &entity->links[link_top(graph)];
+		struct media_link *link;
 		struct media_entity *next;
 
+		link = list_entry(link_top(graph), typeof(*link), list);
+
 		/* The link is not enabled so we do not follow. */
 		if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
-			link_top(graph)++;
+			link_top(graph) = link_top(graph)->next;
 			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)++;
+		if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
+			link_top(graph) = link_top(graph)->next;
 			continue;
 		}
 
 		/* Push the new entity to stack and start over. */
-		link_top(graph)++;
+		link_top(graph) = link_top(graph)->next;
 		stack_push(graph, next);
 	}
 
@@ -208,39 +349,36 @@ 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_device *mdev = entity->graph_obj.mdev;
+	struct media_entity_graph *graph = &pipe->graph;
 	struct media_entity *entity_err = entity;
+	struct media_link *link;
 	int ret;
 
 	mutex_lock(&mdev->graph_mutex);
 
-	media_entity_graph_walk_start(&graph, entity);
+	if (!pipe->streaming_count++) {
+		ret = media_entity_graph_walk_init(&pipe->graph, mdev);
+		if (ret)
+			goto error_graph_walk_start;
+	}
 
-	while ((entity = media_entity_graph_walk_next(&graph))) {
+	media_entity_graph_walk_start(&pipe->graph, entity);
+
+	while ((entity = media_entity_graph_walk_next(graph))) {
 		DECLARE_BITMAP(active, MEDIA_ENTITY_MAX_PADS);
 		DECLARE_BITMAP(has_no_links, MEDIA_ENTITY_MAX_PADS);
-		unsigned int i;
 
 		entity->stream_count++;
-		WARN_ON(entity->pipe && entity->pipe != pipe);
+
+		if (WARN_ON(entity->pipe && entity->pipe != pipe)) {
+			ret = -EBUSY;
+			goto error;
+		}
+
 		entity->pipe = pipe;
 
 		/* Already streaming --- no need to check. */
@@ -253,8 +391,7 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
 		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];
+		list_for_each_entry(link, &entity->links, list) {
 			struct media_pad *pad = link->sink->entity == entity
 						? link->sink : link->source;
 
@@ -280,7 +417,7 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
 
 			ret = entity->ops->link_validate(link);
 			if (ret < 0 && ret != -ENOIOCTLCMD) {
-				dev_dbg(entity->parent->dev,
+				dev_dbg(entity->graph_obj.mdev->dev,
 					"link validation failed for \"%s\":%u -> \"%s\":%u, error %d\n",
 					link->source->entity->name,
 					link->source->index,
@@ -294,7 +431,7 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
 
 		if (!bitmap_full(active, entity->num_pads)) {
 			ret = -EPIPE;
-			dev_dbg(entity->parent->dev,
+			dev_dbg(entity->graph_obj.mdev->dev,
 				"\"%s\":%u must be connected by an enabled link\n",
 				entity->name,
 				(unsigned)find_first_zero_bit(
@@ -312,9 +449,9 @@ error:
 	 * Link validation on graph failed. We revert what we did and
 	 * return the error.
 	 */
-	media_entity_graph_walk_start(&graph, entity_err);
+	media_entity_graph_walk_start(graph, entity_err);
 
-	while ((entity_err = media_entity_graph_walk_next(&graph))) {
+	while ((entity_err = media_entity_graph_walk_next(graph))) {
 		entity_err->stream_count--;
 		if (entity_err->stream_count == 0)
 			entity_err->pipe = NULL;
@@ -327,39 +464,36 @@ error:
 			break;
 	}
 
+error_graph_walk_start:
+	if (!--pipe->streaming_count)
+		media_entity_graph_walk_cleanup(graph);
+
 	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;
+	struct media_device *mdev = entity->graph_obj.mdev;
+	struct media_entity_graph *graph = &entity->pipe->graph;
+	struct media_pipeline *pipe = entity->pipe;
 
 	mutex_lock(&mdev->graph_mutex);
 
-	media_entity_graph_walk_start(&graph, entity);
+	WARN_ON(!pipe->streaming_count);
+	media_entity_graph_walk_start(graph, entity);
 
-	while ((entity = media_entity_graph_walk_next(&graph))) {
+	while ((entity = media_entity_graph_walk_next(graph))) {
 		entity->stream_count--;
 		if (entity->stream_count == 0)
 			entity->pipe = NULL;
 	}
 
+	if (!--pipe->streaming_count)
+		media_entity_graph_walk_cleanup(graph);
+
 	mutex_unlock(&mdev->graph_mutex);
 }
 EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);
@@ -368,44 +502,26 @@ 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))
+	if (entity->graph_obj.mdev->dev &&
+	    !try_module_get(entity->graph_obj.mdev->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);
+	if (entity->graph_obj.mdev->dev)
+		module_put(entity->graph_obj.mdev->dev->driver->owner);
 }
 EXPORT_SYMBOL_GPL(media_entity_put);
 
@@ -413,29 +529,52 @@ EXPORT_SYMBOL_GPL(media_entity_put);
  * Links management
  */
 
-static struct media_link *media_entity_add_link(struct media_entity *entity)
+static struct media_link *media_add_link(struct list_head *head)
+{
+	struct media_link *link;
+
+	link = kzalloc(sizeof(*link), GFP_KERNEL);
+	if (link == NULL)
+		return NULL;
+
+	list_add_tail(&link->list, head);
+
+	return link;
+}
+
+static void __media_entity_remove_link(struct media_entity *entity,
+				       struct media_link *link)
 {
-	if (entity->num_links >= entity->max_links) {
-		struct media_link *links = entity->links;
-		unsigned int max_links = entity->max_links + 2;
-		unsigned int i;
+	struct media_link *rlink, *tmp;
+	struct media_entity *remote;
 
-		links = krealloc(links, max_links * sizeof(*links), GFP_KERNEL);
-		if (links == NULL)
-			return NULL;
+	if (link->source->entity == entity)
+		remote = link->sink->entity;
+	else
+		remote = link->source->entity;
+
+	list_for_each_entry_safe(rlink, tmp, &remote->links, list) {
+		if (rlink != link->reverse)
+			continue;
 
-		for (i = 0; i < entity->num_links; i++)
-			links[i].reverse->reverse = &links[i];
+		if (link->source->entity == entity)
+			remote->num_backlinks--;
 
-		entity->max_links = max_links;
-		entity->links = links;
-	}
+		/* Remove the remote link */
+		list_del(&rlink->list);
+		media_gobj_destroy(&rlink->graph_obj);
+		kfree(rlink);
 
-	return &entity->links[entity->num_links++];
+		if (--remote->num_links == 0)
+			break;
+	}
+	list_del(&link->list);
+	media_gobj_destroy(&link->graph_obj);
+	kfree(link);
 }
 
 int
-media_entity_create_link(struct media_entity *source, u16 source_pad,
+media_create_pad_link(struct media_entity *source, u16 source_pad,
 			 struct media_entity *sink, u16 sink_pad, u32 flags)
 {
 	struct media_link *link;
@@ -445,68 +584,118 @@ media_entity_create_link(struct media_entity *source, u16 source_pad,
 	BUG_ON(source_pad >= source->num_pads);
 	BUG_ON(sink_pad >= sink->num_pads);
 
-	link = media_entity_add_link(source);
+	link = media_add_link(&source->links);
 	if (link == NULL)
 		return -ENOMEM;
 
 	link->source = &source->pads[source_pad];
 	link->sink = &sink->pads[sink_pad];
-	link->flags = flags;
+	link->flags = flags & ~MEDIA_LNK_FL_INTERFACE_LINK;
+
+	/* Initialize graph object embedded at the new link */
+	media_gobj_create(source->graph_obj.mdev, MEDIA_GRAPH_LINK,
+			&link->graph_obj);
 
 	/* Create the backlink. Backlinks are used to help graph traversal and
 	 * are not reported to userspace.
 	 */
-	backlink = media_entity_add_link(sink);
+	backlink = media_add_link(&sink->links);
 	if (backlink == NULL) {
-		source->num_links--;
+		__media_entity_remove_link(source, link);
 		return -ENOMEM;
 	}
 
 	backlink->source = &source->pads[source_pad];
 	backlink->sink = &sink->pads[sink_pad];
 	backlink->flags = flags;
+	backlink->is_backlink = true;
+
+	/* Initialize graph object embedded at the new link */
+	media_gobj_create(sink->graph_obj.mdev, MEDIA_GRAPH_LINK,
+			&backlink->graph_obj);
 
 	link->reverse = backlink;
 	backlink->reverse = link;
 
 	sink->num_backlinks++;
+	sink->num_links++;
+	source->num_links++;
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(media_entity_create_link);
+EXPORT_SYMBOL_GPL(media_create_pad_link);
 
-void __media_entity_remove_links(struct media_entity *entity)
+int media_create_pad_links(const struct media_device *mdev,
+			   const u32 source_function,
+			   struct media_entity *source,
+			   const u16 source_pad,
+			   const u32 sink_function,
+			   struct media_entity *sink,
+			   const u16 sink_pad,
+			   u32 flags,
+			   const bool allow_both_undefined)
 {
-	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;
+	struct media_entity *entity;
+	unsigned function;
+	int ret;
 
-		while (r < remote->num_links) {
-			struct media_link *rlink = &remote->links[r];
+	/* Trivial case: 1:1 relation */
+	if (source && sink)
+		return media_create_pad_link(source, source_pad,
+					     sink, sink_pad, flags);
 
-			if (rlink != link->reverse) {
-				r++;
+	/* Worse case scenario: n:n relation */
+	if (!source && !sink) {
+		if (!allow_both_undefined)
+			return 0;
+		media_device_for_each_entity(source, mdev) {
+			if (source->function != source_function)
 				continue;
+			media_device_for_each_entity(sink, mdev) {
+				if (sink->function != sink_function)
+					continue;
+				ret = media_create_pad_link(source, source_pad,
+							    sink, sink_pad,
+							    flags);
+				if (ret)
+					return ret;
+				flags &= ~(MEDIA_LNK_FL_ENABLED |
+					   MEDIA_LNK_FL_IMMUTABLE);
 			}
+		}
+		return 0;
+	}
 
-			if (link->source->entity == entity)
-				remote->num_backlinks--;
+	/* Handle 1:n and n:1 cases */
+	if (source)
+		function = sink_function;
+	else
+		function = source_function;
 
-			if (--remote->num_links == 0)
-				break;
+	media_device_for_each_entity(entity, mdev) {
+		if (entity->function != function)
+			continue;
 
-			/* Insert last entry in place of the dropped link. */
-			*rlink = remote->links[remote->num_links];
-		}
+		if (source)
+			ret = media_create_pad_link(source, source_pad,
+						    entity, sink_pad, flags);
+		else
+			ret = media_create_pad_link(entity, source_pad,
+						    sink, sink_pad, flags);
+		if (ret)
+			return ret;
+		flags &= ~(MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE);
 	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(media_create_pad_links);
+
+void __media_entity_remove_links(struct media_entity *entity)
+{
+	struct media_link *link, *tmp;
+
+	list_for_each_entry_safe(link, tmp, &entity->links, list)
+		__media_entity_remove_link(entity, link);
 
 	entity->num_links = 0;
 	entity->num_backlinks = 0;
@@ -515,13 +704,15 @@ EXPORT_SYMBOL_GPL(__media_entity_remove_links);
 
 void media_entity_remove_links(struct media_entity *entity)
 {
+	struct media_device *mdev = entity->graph_obj.mdev;
+
 	/* Do nothing if the entity is not registered. */
-	if (entity->parent == NULL)
+	if (mdev == NULL)
 		return;
 
-	mutex_lock(&entity->parent->graph_mutex);
+	spin_lock(&mdev->lock);
 	__media_entity_remove_links(entity);
-	mutex_unlock(&entity->parent->graph_mutex);
+	spin_unlock(&mdev->lock);
 }
 EXPORT_SYMBOL_GPL(media_entity_remove_links);
 
@@ -549,20 +740,6 @@ static int __media_entity_setup_link_notify(struct media_link *link, u32 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;
@@ -590,7 +767,7 @@ int __media_entity_setup_link(struct media_link *link, u32 flags)
 	    (source->stream_count || sink->stream_count))
 		return -EBUSY;
 
-	mdev = source->parent;
+	mdev = source->graph_obj.mdev;
 
 	if (mdev->link_notify) {
 		ret = mdev->link_notify(link, flags,
@@ -611,31 +788,20 @@ int media_entity_setup_link(struct media_link *link, u32 flags)
 {
 	int ret;
 
-	mutex_lock(&link->source->entity->parent->graph_mutex);
+	mutex_lock(&link->graph_obj.mdev->graph_mutex);
 	ret = __media_entity_setup_link(link, flags);
-	mutex_unlock(&link->source->entity->parent->graph_mutex);
+	mutex_unlock(&link->graph_obj.mdev->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];
 
+	list_for_each_entry(link, &source->entity->links, list) {
 		if (link->source->entity == source->entity &&
 		    link->source->index == source->index &&
 		    link->sink->entity == sink->entity &&
@@ -647,23 +813,11 @@ media_entity_find_link(struct media_pad *source, struct media_pad *sink)
 }
 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];
+	struct media_link *link;
 
+	list_for_each_entry(link, &pad->entity->links, list) {
 		if (!(link->flags & MEDIA_LNK_FL_ENABLED))
 			continue;
 
@@ -678,3 +832,113 @@ struct media_pad *media_entity_remote_pad(struct media_pad *pad)
 
 }
 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
+
+static void media_interface_init(struct media_device *mdev,
+				 struct media_interface *intf,
+				 u32 gobj_type,
+				 u32 intf_type, u32 flags)
+{
+	intf->type = intf_type;
+	intf->flags = flags;
+	INIT_LIST_HEAD(&intf->links);
+
+	media_gobj_create(mdev, gobj_type, &intf->graph_obj);
+}
+
+/* Functions related to the media interface via device nodes */
+
+struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
+						u32 type, u32 flags,
+						u32 major, u32 minor)
+{
+	struct media_intf_devnode *devnode;
+
+	devnode = kzalloc(sizeof(*devnode), GFP_KERNEL);
+	if (!devnode)
+		return NULL;
+
+	devnode->major = major;
+	devnode->minor = minor;
+
+	media_interface_init(mdev, &devnode->intf, MEDIA_GRAPH_INTF_DEVNODE,
+			     type, flags);
+
+	return devnode;
+}
+EXPORT_SYMBOL_GPL(media_devnode_create);
+
+void media_devnode_remove(struct media_intf_devnode *devnode)
+{
+	media_remove_intf_links(&devnode->intf);
+	media_gobj_destroy(&devnode->intf.graph_obj);
+	kfree(devnode);
+}
+EXPORT_SYMBOL_GPL(media_devnode_remove);
+
+struct media_link *media_create_intf_link(struct media_entity *entity,
+					    struct media_interface *intf,
+					    u32 flags)
+{
+	struct media_link *link;
+
+	link = media_add_link(&intf->links);
+	if (link == NULL)
+		return NULL;
+
+	link->intf = intf;
+	link->entity = entity;
+	link->flags = flags | MEDIA_LNK_FL_INTERFACE_LINK;
+
+	/* Initialize graph object embedded at the new link */
+	media_gobj_create(intf->graph_obj.mdev, MEDIA_GRAPH_LINK,
+			&link->graph_obj);
+
+	return link;
+}
+EXPORT_SYMBOL_GPL(media_create_intf_link);
+
+void __media_remove_intf_link(struct media_link *link)
+{
+	list_del(&link->list);
+	media_gobj_destroy(&link->graph_obj);
+	kfree(link);
+}
+EXPORT_SYMBOL_GPL(__media_remove_intf_link);
+
+void media_remove_intf_link(struct media_link *link)
+{
+	struct media_device *mdev = link->graph_obj.mdev;
+
+	/* Do nothing if the intf is not registered. */
+	if (mdev == NULL)
+		return;
+
+	spin_lock(&mdev->lock);
+	__media_remove_intf_link(link);
+	spin_unlock(&mdev->lock);
+}
+EXPORT_SYMBOL_GPL(media_remove_intf_link);
+
+void __media_remove_intf_links(struct media_interface *intf)
+{
+	struct media_link *link, *tmp;
+
+	list_for_each_entry_safe(link, tmp, &intf->links, list)
+		__media_remove_intf_link(link);
+
+}
+EXPORT_SYMBOL_GPL(__media_remove_intf_links);
+
+void media_remove_intf_links(struct media_interface *intf)
+{
+	struct media_device *mdev = intf->graph_obj.mdev;
+
+	/* Do nothing if the intf is not registered. */
+	if (mdev == NULL)
+		return;
+
+	spin_lock(&mdev->lock);
+	__media_remove_intf_links(intf);
+	spin_unlock(&mdev->lock);
+}
+EXPORT_SYMBOL_GPL(media_remove_intf_links);