[media] media: add functions to allow creating interfaces

Interfaces are different than entities: they represent a
Kernel<->userspace interaction, while entities represent a
piece of hardware/firmware/software that executes a function.

Let's distinguish them by creating a separate structure to
store the interfaces.

Later patches should change the existing drivers and logic
to split the current interface embedded inside the entity
structure (device nodes) into a separate object of the graph.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/media-entity.c

@@ -44,11 +44,41 @@ static inline const char *gobj_type(enum media_gobj_type type)
 		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";
+	}
+};
+
 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 {
 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
@@ -84,6 +114,19 @@ static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 			"%s: id 0x%08x pad#%d: '%s':%d\n",
 			event_name, gobj->id, media_localid(gobj),
 			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 0x%08x intf_devnode#%d: %s - major: %d, minor: %d\n",
+			event_name, gobj->id, media_localid(gobj),
+			intf_type(intf),
+			devnode->major, devnode->minor);
+		break;
 	}
 	}
 #endif
@@ -119,6 +162,9 @@ void media_gobj_init(struct media_device *mdev,
 	case MEDIA_GRAPH_LINK:
 		gobj->id = media_gobj_gen_id(type, ++mdev->link_id);
 		break;
+	case MEDIA_GRAPH_INTF_DEVNODE:
+		gobj->id = media_gobj_gen_id(type, ++mdev->intf_devnode_id);
+		break;
 	}
 	dev_dbg_obj(__func__, gobj);
 }
@@ -793,3 +839,40 @@ struct media_pad *media_entity_remote_pad(struct media_pad *pad)
 
 }
 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
+
+
+/* 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,
+						gfp_t gfp_flags)
+{
+	struct media_intf_devnode *devnode;
+	struct media_interface *intf;
+
+	devnode = kzalloc(sizeof(*devnode), gfp_flags);
+	if (!devnode)
+		return NULL;
+
+	intf = &devnode->intf;
+
+	intf->type = type;
+	intf->flags = flags;
+
+	devnode->major = major;
+	devnode->minor = minor;
+
+	media_gobj_init(mdev, MEDIA_GRAPH_INTF_DEVNODE,
+		       &devnode->intf.graph_obj);
+
+	return devnode;
+}
+EXPORT_SYMBOL_GPL(media_devnode_create);
+
+void media_devnode_remove(struct media_intf_devnode *devnode)
+{
+	media_gobj_remove(&devnode->intf.graph_obj);
+	kfree(devnode);
+}
+EXPORT_SYMBOL_GPL(media_devnode_remove);

include/media/media-device.h

@@ -44,6 +44,7 @@ struct device;
  * @entity_id:	Unique ID used on the last entity registered
  * @pad_id:	Unique ID used on the last pad registered
  * @link_id:	Unique ID used on the last link registered
+ * @intf_devnode_id: Unique ID used on the last interface devnode registered
  * @entities:	List of registered entities
  * @lock:	Entities list lock
  * @graph_mutex: Entities graph operation lock
@@ -73,6 +74,7 @@ struct media_device {
 	u32 entity_id;
 	u32 pad_id;
 	u32 link_id;
+	u32 intf_devnode_id;
 
 	struct list_head entities;
 

include/media/media-entity.h

@@ -36,11 +36,14 @@
  * @MEDIA_GRAPH_ENTITY:		Identify a media entity
  * @MEDIA_GRAPH_PAD:		Identify a media pad
  * @MEDIA_GRAPH_LINK:		Identify a media link
+ * @MEDIA_GRAPH_INTF_DEVNODE:	Identify a media Kernel API interface via
+ *				a device node
  */
 enum media_gobj_type {
 	MEDIA_GRAPH_ENTITY,
 	MEDIA_GRAPH_PAD,
 	MEDIA_GRAPH_LINK,
+	MEDIA_GRAPH_INTF_DEVNODE,
 };
 
 #define MEDIA_BITS_PER_TYPE		8
@@ -141,6 +144,34 @@ struct media_entity {
 	} info;
 };
 
+/**
+ * struct media_intf_devnode - Define a Kernel API interface
+ *
+ * @graph_obj:		embedded graph object
+ * @type:		Type of the interface as defined at the
+ *			uapi/media/media.h header, e. g.
+ *			MEDIA_INTF_T_*
+ * @flags:		Interface flags as defined at uapi/media/media.h
+ */
+struct media_interface {
+	struct media_gobj		graph_obj;
+	u32				type;
+	u32				flags;
+};
+
+/**
+ * struct media_intf_devnode - Define a Kernel API interface via a device node
+ *
+ * @intf:	embedded interface object
+ * @major:	Major number of a device node
+ * @minor:	Minor number of a device node
+ */
+struct media_intf_devnode {
+	struct media_interface		intf;
+	u32				major;
+	u32				minor;
+};
+
 static inline u32 media_entity_type(struct media_entity *entity)
 {
 	return entity->type & MEDIA_ENT_TYPE_MASK;
@@ -205,6 +236,18 @@ struct media_entity_graph {
 #define gobj_to_link(gobj) \
 		container_of(gobj, struct media_link, graph_obj)
 
+#define gobj_to_link(gobj) \
+		container_of(gobj, struct media_link, graph_obj)
+
+#define gobj_to_pad(gobj) \
+		container_of(gobj, struct media_pad, graph_obj)
+
+#define gobj_to_intf(gobj) \
+		container_of(gobj, struct media_interface, graph_obj)
+
+#define intf_to_devnode(intf) \
+		container_of(intf, struct media_intf_devnode, intf)
+
 void media_gobj_init(struct media_device *mdev,
 		    enum media_gobj_type type,
 		    struct media_gobj *gobj);
@@ -236,6 +279,11 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
 					     struct media_pipeline *pipe);
 void media_entity_pipeline_stop(struct media_entity *entity);
 
+struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
+						u32 type, u32 flags,
+						u32 major, u32 minor,
+						gfp_t gfp_flags);
+void media_devnode_remove(struct media_intf_devnode *devnode);
 #define media_entity_call(entity, operation, args...)			\
 	(((entity)->ops && (entity)->ops->operation) ?			\
 	 (entity)->ops->operation((entity) , ##args) : -ENOIOCTLCMD)