diff --git a/Documentation/media-framework.txt b/Documentation/media-framework.txt
index 6d680c6..1192feb 100644
--- a/Documentation/media-framework.txt
+++ b/Documentation/media-framework.txt
@@ -273,3 +273,134 @@ required, drivers don't need to provide a set_power operation. The operation
 is allowed to fail when turning power on, in which case the media_entity_get
 function will return NULL.
 
+
+Userspace application API
+-------------------------
+
+Media devices offer an API to userspace application to discover the device
+internal topology through ioctls.
+
+	MEDIA_IOC_ENUM_ENTITIES - Enumerate entities and their properties
+	-----------------------------------------------------------------
+
+	ioctl(int fd, int request, struct media_entity_desc *argp);
+
+To query the attributes of an entity, applications set the id field of a
+media_entity_desc structure and call the MEDIA_IOC_ENUM_ENTITIES ioctl with a
+pointer to this structure. The driver fills the rest of the structure or
+returns a EINVAL error code when the id is invalid.
+
+Entities can be enumerated by or'ing the id with the MEDIA_ENTITY_ID_FLAG_NEXT
+flag. The driver will return information about the entity with the smallest id
+strictly larger than the requested one ('next entity'), or EINVAL if there is
+none.
+
+Entity IDs can be non-contiguous. Applications must *not* try to enumerate
+entities by calling MEDIA_IOC_ENUM_ENTITIES with increasing id's until they
+get an error.
+
+The media_entity_desc structure is defined as
+
+- struct media_entity_desc
+
+__u32	id		Entity id, set by the application. When the id is
+			or'ed with MEDIA_ENTITY_ID_FLAG_NEXT, the driver
+			clears the flag and returns the first entity with a
+			larger id.
+char	name[32]	Entity name. UTF-8 NULL-terminated string.
+__u32	type		Entity type.
+__u8	pads		Number of pads.
+__u32	links		Total number of outbound links. Inbound links are not
+			counted in this field.
+/* union */
+	/* struct v4l, Valid for V4L sub-devices and nodes only */
+__u32	major		V4L device node major number. For V4L sub-devices with
+			no device node, set by the driver to 0.
+__u32	minor		V4L device node minor number. For V4L sub-devices with
+			no device node, set by the driver to 0.
+	/* struct fb, Valid for frame buffer nodes only */
+__u32	major		FB device node major number
+__u32	minor		FB device node minor number
+	/* Valid for ALSA devices only */
+int	alsa		ALSA card number
+	/* Valid for DVB devices only */
+int	dvb		DVB card number
+
+Valid entity types are
+
+	MEDIA_ENTITY_TYPE_NODE - Unknown device node
+	MEDIA_ENTITY_TYPE_NODE_V4L - V4L video, radio or vbi device node
+	MEDIA_ENTITY_TYPE_NODE_FB - Frame buffer device node
+	MEDIA_ENTITY_TYPE_NODE_ALSA - ALSA card
+	MEDIA_ENTITY_TYPE_NODE_DVB - DVB card
+
+	MEDIA_ENTITY_TYPE_SUBDEV - Unknown V4L sub-device
+	MEDIA_ENTITY_TYPE_SUBDEV_VID_DECODER - Video decoder
+	MEDIA_ENTITY_TYPE_SUBDEV_VID_ENCODER - Video encoder
+	MEDIA_ENTITY_TYPE_SUBDEV_MISC - Unspecified entity subtype
+
+
+	MEDIA_IOC_ENUM_LINKS - Enumerate all pads and links for a given entity
+	----------------------------------------------------------------------
+
+	ioctl(int fd, int request, struct media_links_enum *argp);
+
+Only forward links that originate at one of the entity's source pads are
+returned during the enumeration process.
+
+To enumerate pads and/or links for a given entity, applications set the entity
+field of a media_links_enum structure and initialize the media_pad_desc and
+media_link_desc structure arrays pointed by the pads and links fields. They then
+call the MEDIA_IOC_ENUM_LINKS ioctl with a pointer to this structure.
+
+If the pads field is not NULL, the driver fills the pads array with
+information about the entity's pads. The array must have enough room to store
+all the entity's pads. The number of pads can be retrieved with the
+MEDIA_IOC_ENUM_ENTITIES ioctl.
+
+If the links field is not NULL, the driver fills the links array with
+information about the entity's outbound links. The array must have enough room
+to store all the entity's outbound links. The number of outbound links can be
+retrieved with the MEDIA_IOC_ENUM_ENTITIES ioctl.
+
+The media_pad_desc, media_link_desc and media_links_enum structures are defined
+as
+
+- struct media_pad_desc
+
+__u32		entity		ID of the entity this pad belongs to.
+__u16		index		0-based pad index.
+__u32		flags		Pad flags.
+
+Valid pad flags are
+
+	MEDIA_PAD_FLAG_INPUT -	Input pad, relative to the entity. Input pads
+				sink data and are targets of links.
+	MEDIA_PAD_FLAG_OUTPUT -	Output pad, relative to the entity. Output
+				pads source data and are origins of links.
+
+One and only one of MEDIA_PAD_FLAG_INPUT and MEDIA_PAD_FLAG_OUTPUT must be set
+for every pad.
+
+- struct media_link_desc
+
+struct media_pad_desc	source	Pad at the origin of this link.
+struct media_pad_desc	sink	Pad at the target of this link.
+__u32			flags	Link flags.
+
+Valid link flags are
+
+	MEDIA_LINK_FLAG_ACTIVE - The link is active and can be used to
+		transfer media data. When two or more links target a sink pad,
+		only one of them can be active at a time.
+	MEDIA_LINK_FLAG_IMMUTABLE - The link active state can't be modified at
+		runtime. An immutable link is always active.
+
+- struct media_links_enum
+
+__u32			entity	Entity id, set by the application.
+struct media_pad_desc	*pads	Pointer to a pads array allocated by the
+				application. Ignored if NULL.
+struct media_link_desc	*links	Pointer to a links array allocated by the
+				application. Ignored if NULL.
+
diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 6fb2e26..b32c308 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -20,13 +20,162 @@
 
 #include <linux/types.h>
 #include <linux/ioctl.h>
+#include <linux/media.h>
 
 #include <media/media-device.h>
 #include <media/media-devnode.h>
 #include <media/media-entity.h>
 
+static int media_device_open(struct file *filp)
+{
+	return 0;
+}
+
+static int media_device_close(struct file *filp)
+{
+	return 0;
+}
+
+static struct media_entity *find_entity(struct media_device *mdev, u32 id)
+{
+	struct media_entity *entity;
+	int next = id & MEDIA_ENTITY_ID_FLAG_NEXT;
+
+	id &= ~MEDIA_ENTITY_ID_FLAG_NEXT;
+
+	spin_lock(&mdev->lock);
+
+	media_device_for_each_entity(entity, mdev) {
+		if ((entity->id == id && !next) ||
+		    (entity->id > id && next)) {
+			spin_unlock(&mdev->lock);
+			return entity;
+		}
+	}
+
+	spin_unlock(&mdev->lock);
+
+	return NULL;
+}
+
+static long media_device_enum_entities(struct media_device *mdev,
+				       struct media_entity_desc __user *uent)
+{
+	struct media_entity *ent;
+	struct media_entity_desc u_ent;
+
+	if (copy_from_user(&u_ent.id, &uent->id, sizeof(u_ent.id)))
+		return -EFAULT;
+
+	ent = find_entity(mdev, u_ent.id);
+
+	if (ent == NULL)
+		return -EINVAL;
+
+	u_ent.id = ent->id;
+	u_ent.name[0] = '\0';
+	if (ent->name)
+		strlcpy(u_ent.name, ent->name, sizeof(u_ent.name));
+	u_ent.type = ent->type;
+	u_ent.pads = ent->num_pads;
+	u_ent.links = ent->num_links - ent->num_backlinks;
+	u_ent.v4l.major = ent->v4l.major;
+	u_ent.v4l.minor = ent->v4l.minor;
+	if (copy_to_user(uent, &u_ent, sizeof(u_ent)))
+		return -EFAULT;
+	return 0;
+}
+
+static void media_device_kpad_to_upad(const struct media_pad *kpad,
+				      struct media_pad_desc *upad)
+{
+	upad->entity = kpad->entity->id;
+	upad->index = kpad->index;
+	upad->flags = kpad->flags;
+}
+
+static long media_device_enum_links(struct media_device *mdev,
+				    struct media_links_enum __user *ulinks)
+{
+	struct media_entity *entity;
+	struct media_links_enum links;
+
+	if (copy_from_user(&links, ulinks, sizeof(links)))
+		return -EFAULT;
+
+	entity = find_entity(mdev, links.entity);
+	if (entity == NULL)
+		return -EINVAL;
+
+	if (links.pads) {
+		unsigned int p;
+
+		for (p = 0; p < entity->num_pads; p++) {
+			struct media_pad_desc pad;
+			media_device_kpad_to_upad(&entity->pads[p], &pad);
+			if (copy_to_user(&links.pads[p], &pad, sizeof(pad)))
+				return -EFAULT;
+		}
+	}
+
+	if (links.links) {
+		struct media_link_desc __user *ulink;
+		unsigned int l;
+
+		for (l = 0, ulink = links.links; l < entity->num_links; l++) {
+			struct media_link_desc link;
+
+			/* Ignore backlinks. */
+			if (entity->links[l].source->entity != entity)
+				continue;
+
+			media_device_kpad_to_upad(entity->links[l].source,
+						  &link.source);
+			media_device_kpad_to_upad(entity->links[l].sink,
+						  &link.sink);
+			link.flags = entity->links[l].flags;
+			if (copy_to_user(ulink, &link, sizeof(*ulink)))
+				return -EFAULT;
+			ulink++;
+		}
+	}
+	if (copy_to_user(ulinks, &links, sizeof(*ulinks)))
+		return -EFAULT;
+	return 0;
+}
+
+static long media_device_ioctl(struct file *filp, unsigned int cmd,
+			       unsigned long arg)
+{
+	struct media_devnode *devnode = media_devnode_data(filp);
+	struct media_device *dev = to_media_device(devnode);
+	long ret;
+
+	switch (cmd) {
+	case MEDIA_IOC_ENUM_ENTITIES:
+		ret = media_device_enum_entities(dev,
+				(struct media_entity_desc __user *)arg);
+		break;
+
+	case MEDIA_IOC_ENUM_LINKS:
+		mutex_lock(&dev->graph_mutex);
+		ret = media_device_enum_links(dev,
+				(struct media_links_enum __user *)arg);
+		mutex_unlock(&dev->graph_mutex);
+		break;
+
+	default:
+		ret = -ENOIOCTLCMD;
+	}
+
+	return ret;
+}
+
 static const struct media_file_operations media_device_fops = {
 	.owner = THIS_MODULE,
+	.open = media_device_open,
+	.unlocked_ioctl = media_device_ioctl,
+	.release = media_device_close,
 };
 
 static void media_device_release(struct media_devnode *mdev)
@@ -99,6 +248,9 @@ int __must_check media_device_register_entity(struct media_device *mdev,
 	WARN_ON(entity->parent != NULL);
 	entity->parent = mdev;
 
+	/* find_entity() relies on entities being stored in increasing IDs
+	 * order. Don't change that without modifying find_entity().
+	 */
 	spin_lock(&mdev->lock);
 	entity->id = mdev->entity_id++;
 	list_add_tail(&entity->list, &mdev->entities);
diff --git a/include/linux/media.h b/include/linux/media.h
new file mode 100644
index 0000000..9b8acc0
--- /dev/null
+++ b/include/linux/media.h
@@ -0,0 +1,77 @@
+#ifndef __LINUX_MEDIA_H
+#define __LINUX_MEDIA_H
+
+#define MEDIA_ENTITY_TYPE_NODE			(1 << 16)
+#define MEDIA_ENTITY_TYPE_NODE_V4L		(MEDIA_ENTITY_TYPE_NODE + 1)
+#define MEDIA_ENTITY_TYPE_NODE_FB		(MEDIA_ENTITY_TYPE_NODE + 2)
+#define MEDIA_ENTITY_TYPE_NODE_ALSA		(MEDIA_ENTITY_TYPE_NODE + 3)
+#define MEDIA_ENTITY_TYPE_NODE_DVB		(MEDIA_ENTITY_TYPE_NODE + 4)
+
+#define MEDIA_ENTITY_TYPE_SUBDEV		(2 << 16)
+#define MEDIA_ENTITY_TYPE_SUBDEV_VID_DECODER	(MEDIA_ENTITY_TYPE_SUBDEV + 1)
+#define MEDIA_ENTITY_TYPE_SUBDEV_VID_ENCODER	(MEDIA_ENTITY_TYPE_SUBDEV + 2)
+#define MEDIA_ENTITY_TYPE_SUBDEV_MISC		(MEDIA_ENTITY_TYPE_SUBDEV + 3)
+
+#define MEDIA_PAD_FLAG_INPUT			(1 << 0)
+#define MEDIA_PAD_FLAG_OUTPUT			(1 << 1)
+
+#define MEDIA_LINK_FLAG_ACTIVE			(1 << 0)
+#define MEDIA_LINK_FLAG_IMMUTABLE		(1 << 1)
+
+#define MEDIA_ENTITY_ID_FLAG_NEXT		(1 << 31)
+
+struct media_pad_desc {
+	__u32 entity;		/* entity ID */
+	__u16 index;		/* pad index */
+	__u32 flags;		/* pad flags */
+	__u32 reserved[2];
+};
+
+struct media_entity_desc {
+	__u32 id;
+	char name[32];
+	__u32 type;
+	__u8 pads;
+	__u32 links;
+
+	__u32 reserved[4];
+
+	union {
+		/* Node specifications */
+		struct {
+			__u32 major;
+			__u32 minor;
+		} v4l;
+		struct {
+			__u32 major;
+			__u32 minor;
+		} fb;
+		int alsa;
+		int dvb;
+
+		/* Sub-device specifications */
+		/* Nothing needed yet */
+		__u8 raw[64];
+	};
+};
+
+struct media_link_desc {
+	struct media_pad_desc source;
+	struct media_pad_desc sink;
+	__u32 flags;
+	__u32 reserved[2];
+};
+
+struct media_links_enum {
+	__u32 entity;
+	/* Should have enough room for pads elements */
+	struct media_pad_desc __user *pads;
+	/* Should have enough room for links elements */
+	struct media_link_desc __user *links;
+	__u32 reserved[4];
+};
+
+#define MEDIA_IOC_ENUM_ENTITIES		_IOWR('M', 1, struct media_entity_desc)
+#define MEDIA_IOC_ENUM_LINKS		_IOWR('M', 2, struct media_links_enum)
+
+#endif /* __LINUX_MEDIA_H */
diff --git a/include/media/media-device.h b/include/media/media-device.h
index 39a437c..7b09332 100644
--- a/include/media/media-device.h
+++ b/include/media/media-device.h
@@ -53,6 +53,9 @@ struct media_device {
 	struct mutex graph_mutex;
 };
 
+/* media_devnode to media_device */
+#define to_media_device(node) container_of(node, struct media_device, devnode)
+
 int __must_check media_device_register(struct media_device *mdev);
 void media_device_unregister(struct media_device *mdev);
 
diff --git a/include/media/media-entity.h b/include/media/media-entity.h
index 2205cbc..fe8a650 100644
--- a/include/media/media-entity.h
+++ b/include/media/media-entity.h
@@ -2,23 +2,7 @@
 #define _MEDIA_ENTITY_H
 
 #include <linux/list.h>
-
-#define MEDIA_ENTITY_TYPE_NODE			(1 << 16)
-#define MEDIA_ENTITY_TYPE_NODE_V4L		(MEDIA_ENTITY_TYPE_NODE + 1)
-#define MEDIA_ENTITY_TYPE_NODE_FB		(MEDIA_ENTITY_TYPE_NODE + 2)
-#define MEDIA_ENTITY_TYPE_NODE_ALSA		(MEDIA_ENTITY_TYPE_NODE + 3)
-#define MEDIA_ENTITY_TYPE_NODE_DVB		(MEDIA_ENTITY_TYPE_NODE + 4)
-
-#define MEDIA_ENTITY_TYPE_SUBDEV		(2 << 16)
-#define MEDIA_ENTITY_TYPE_SUBDEV_VID_DECODER	(MEDIA_ENTITY_TYPE_SUBDEV + 1)
-#define MEDIA_ENTITY_TYPE_SUBDEV_VID_ENCODER	(MEDIA_ENTITY_TYPE_SUBDEV + 2)
-#define MEDIA_ENTITY_TYPE_SUBDEV_MISC		(MEDIA_ENTITY_TYPE_SUBDEV + 3)
-
-#define MEDIA_LINK_FLAG_ACTIVE			(1 << 0)
-#define MEDIA_LINK_FLAG_IMMUTABLE		(1 << 1)
-
-#define MEDIA_PAD_FLAG_INPUT			(1 << 0)
-#define MEDIA_PAD_FLAG_OUTPUT			(1 << 1)
+#include <linux/media.h>
 
 struct media_link {
 	struct media_pad *source;	/* Source pad */
