drivers/media/media-device.c - linux - Git at Google

 /*
  * Media device
  *
  * 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/compat.h>
 #include <linux/export.h>
 #include <linux/ioctl.h>
 #include <linux/media.h>
 #include <linux/types.h>

 #include <media/media-device.h>
 #include <media/media-devnode.h>
 #include <media/media-entity.h>

 #ifdef CONFIG_MEDIA_CONTROLLER

 /* -----------------------------------------------------------------------------
  * Userspace API
  */

 static int media_device_open(struct file *filp)
 {
 	return 0;
 }

 static int media_device_close(struct file *filp)
 {
 	return 0;
 }

 static int media_device_get_info(struct media_device *dev,
 				 struct media_device_info __user *__info)
 {
 	struct media_device_info info;

 	memset(&info, 0, sizeof(info));

 	strlcpy(info.driver, dev->dev->driver->name, sizeof(info.driver));
 	strlcpy(info.model, dev->model, sizeof(info.model));
 	strlcpy(info.serial, dev->serial, sizeof(info.serial));
 	strlcpy(info.bus_info, dev->bus_info, sizeof(info.bus_info));

 	info.media_version = MEDIA_API_VERSION;
 	info.hw_revision = dev->hw_revision;
 	info.driver_version = dev->driver_version;

 	if (copy_to_user(__info, &info, sizeof(*__info)))
 		return -EFAULT;
 	return 0;
 }

 static struct media_entity *find_entity(struct media_device *mdev, u32 id)
 {
 	struct media_entity *entity;
 	int next = id & MEDIA_ENT_ID_FLAG_NEXT;

 	id &= ~MEDIA_ENT_ID_FLAG_NEXT;

 	spin_lock(&mdev->lock);

 	media_device_for_each_entity(entity, mdev) {
 		if (((media_entity_id(entity) == id) && !next) ||
 		    ((media_entity_id(entity) > 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;

 	memset(&u_ent, 0, sizeof(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 = media_entity_id(ent);
 	if (ent->name)
 		strlcpy(u_ent.name, ent->name, sizeof(u_ent.name));
 	u_ent.type = ent->type;
 	u_ent.revision = ent->revision;
 	u_ent.flags = ent->flags;
 	u_ent.group_id = ent->group_id;
 	u_ent.pads = ent->num_pads;
 	u_ent.links = ent->num_links - ent->num_backlinks;
 	memcpy(&u_ent.raw, &ent->info, sizeof(ent->info));
 	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 = media_entity_id(kpad->entity);
 	upad->index = kpad->index;
 	upad->flags = kpad->flags;
 }

 static long __media_device_enum_links(struct media_device *mdev,
 				      struct media_links_enum *links)
 {
 	struct media_entity *entity;

 	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;

 			memset(&pad, 0, sizeof(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;

 			memset(&link, 0, sizeof(link));
 			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++;
 		}
 	}

 	return 0;
 }

 static long media_device_enum_links(struct media_device *mdev,
 				    struct media_links_enum __user *ulinks)
 {
 	struct media_links_enum links;
 	int rval;

 	if (copy_from_user(&links, ulinks, sizeof(links)))
 		return -EFAULT;

 	rval = __media_device_enum_links(mdev, &links);
 	if (rval < 0)
 		return rval;

 	if (copy_to_user(ulinks, &links, sizeof(*ulinks)))
 		return -EFAULT;

 	return 0;
 }

 static long media_device_setup_link(struct media_device *mdev,
 				    struct media_link_desc __user *_ulink)
 {
 	struct media_link *link = NULL;
 	struct media_link_desc ulink;
 	struct media_entity *source;
 	struct media_entity *sink;
 	int ret;

 	if (copy_from_user(&ulink, _ulink, sizeof(ulink)))
 		return -EFAULT;

 	/* Find the source and sink entities and link.
 	 */
 	source = find_entity(mdev, ulink.source.entity);
 	sink = find_entity(mdev, ulink.sink.entity);

 	if (source == NULL || sink == NULL)
 		return -EINVAL;

 	if (ulink.source.index >= source->num_pads ||
 	    ulink.sink.index >= sink->num_pads)
 		return -EINVAL;

 	link = media_entity_find_link(&source->pads[ulink.source.index],
 				      &sink->pads[ulink.sink.index]);
 	if (link == NULL)
 		return -EINVAL;

 	/* Setup the link on both entities. */
 	ret = __media_entity_setup_link(link, ulink.flags);

 	if (copy_to_user(_ulink, &ulink, sizeof(ulink)))
 		return -EFAULT;

 	return ret;
 }

 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_DEVICE_INFO:
 		ret = media_device_get_info(dev,
 				(struct media_device_info __user *)arg);
 		break;

 	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;

 	case MEDIA_IOC_SETUP_LINK:
 		mutex_lock(&dev->graph_mutex);
 		ret = media_device_setup_link(dev,
 				(struct media_link_desc __user *)arg);
 		mutex_unlock(&dev->graph_mutex);
 		break;

 	default:
 		ret = -ENOIOCTLCMD;
 	}

 	return ret;
 }

 #ifdef CONFIG_COMPAT

 struct media_links_enum32 {
 	__u32 entity;
 	compat_uptr_t pads; /* struct media_pad_desc * */
 	compat_uptr_t links; /* struct media_link_desc * */
 	__u32 reserved[4];
 };

 static long media_device_enum_links32(struct media_device *mdev,
 				      struct media_links_enum32 __user *ulinks)
 {
 	struct media_links_enum links;
 	compat_uptr_t pads_ptr, links_ptr;

 	memset(&links, 0, sizeof(links));

 	if (get_user(links.entity, &ulinks->entity)
 	    || get_user(pads_ptr, &ulinks->pads)
 	    || get_user(links_ptr, &ulinks->links))
 		return -EFAULT;

 	links.pads = compat_ptr(pads_ptr);
 	links.links = compat_ptr(links_ptr);

 	return __media_device_enum_links(mdev, &links);
 }

 #define MEDIA_IOC_ENUM_LINKS32		_IOWR('|', 0x02, struct media_links_enum32)

 static long media_device_compat_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_DEVICE_INFO:
 	case MEDIA_IOC_ENUM_ENTITIES:
 	case MEDIA_IOC_SETUP_LINK:
 		return media_device_ioctl(filp, cmd, arg);

 	case MEDIA_IOC_ENUM_LINKS32:
 		mutex_lock(&dev->graph_mutex);
 		ret = media_device_enum_links32(dev,
 				(struct media_links_enum32 __user *)arg);
 		mutex_unlock(&dev->graph_mutex);
 		break;

 	default:
 		ret = -ENOIOCTLCMD;
 	}

 	return ret;
 }
 #endif /* CONFIG_COMPAT */

 static const struct media_file_operations media_device_fops = {
 	.owner = THIS_MODULE,
 	.open = media_device_open,
 	.ioctl = media_device_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = media_device_compat_ioctl,
 #endif /* CONFIG_COMPAT */
 	.release = media_device_close,
 };

 /* -----------------------------------------------------------------------------
  * sysfs
  */

 static ssize_t show_model(struct device *cd,
 			  struct device_attribute *attr, char *buf)
 {
 	struct media_device *mdev = to_media_device(to_media_devnode(cd));

 	return sprintf(buf, "%.*s\n", (int)sizeof(mdev->model), mdev->model);
 }

 static DEVICE_ATTR(model, S_IRUGO, show_model, NULL);

 /* -----------------------------------------------------------------------------
  * Registration/unregistration
  */

 static void media_device_release(struct media_devnode *mdev)
 {
 }

 /**
  * media_device_register - register a media device
  * @mdev:	The media device
  *
  * The caller is responsible for initializing the media device before
  * registration. The following fields must be set:
  *
  * - dev must point to the parent device
  * - model must be filled with the device model name
  */
 int __must_check __media_device_register(struct media_device *mdev,
 					 struct module *owner)
 {
 	int ret;

 	if (WARN_ON(mdev->dev == NULL || mdev->model[0] == 0))
 		return -EINVAL;

 	INIT_LIST_HEAD(&mdev->entities);
 	spin_lock_init(&mdev->lock);
 	mutex_init(&mdev->graph_mutex);

 	/* Register the device node. */
 	mdev->devnode.fops = &media_device_fops;
 	mdev->devnode.parent = mdev->dev;
 	mdev->devnode.release = media_device_release;
 	ret = media_devnode_register(&mdev->devnode, owner);
 	if (ret < 0)
 		return ret;

 	ret = device_create_file(&mdev->devnode.dev, &dev_attr_model);
 	if (ret < 0) {
 		media_devnode_unregister(&mdev->devnode);
 		return ret;
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(__media_device_register);

 /**
  * media_device_unregister - unregister a media device
  * @mdev:	The media device
  *
  */
 void media_device_unregister(struct media_device *mdev)
 {
 	struct media_entity *entity;
 	struct media_entity *next;

 	list_for_each_entry_safe(entity, next, &mdev->entities, list)
 		media_device_unregister_entity(entity);

 	device_remove_file(&mdev->devnode.dev, &dev_attr_model);
 	media_devnode_unregister(&mdev->devnode);
 }
 EXPORT_SYMBOL_GPL(media_device_unregister);

 /**
  * media_device_register_entity - Register an entity with a media device
  * @mdev:	The media device
  * @entity:	The entity
  */
 int __must_check media_device_register_entity(struct media_device *mdev,
 					      struct media_entity *entity)
 {
 	/* Warn if we apparently re-register an entity */
 	WARN_ON(entity->parent != NULL);
 	entity->parent = mdev;

 	spin_lock(&mdev->lock);
 	/* Initialize media_gobj embedded at the entity */
 	media_gobj_init(mdev, MEDIA_GRAPH_ENTITY, &entity->graph_obj);
 	list_add_tail(&entity->list, &mdev->entities);
 	spin_unlock(&mdev->lock);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(media_device_register_entity);

 /**
  * media_device_unregister_entity - Unregister an entity
  * @entity:	The entity
  *
  * If the entity has never been registered this function will return
  * immediately.
  */
 void media_device_unregister_entity(struct media_entity *entity)
 {
 	struct media_device *mdev = entity->parent;

 	if (mdev == NULL)
 		return;

 	spin_lock(&mdev->lock);
 	media_gobj_remove(&entity->graph_obj);
 	list_del(&entity->list);
 	spin_unlock(&mdev->lock);
 	entity->parent = NULL;
 }
 EXPORT_SYMBOL_GPL(media_device_unregister_entity);

 static void media_device_release_devres(struct device *dev, void *res)
 {
 }

 /*
  * media_device_get_devres() -	get media device as device resource
  *				creates if one doesn't exist
 */
 struct media_device *media_device_get_devres(struct device *dev)
 {
 	struct media_device *mdev;

 	mdev = devres_find(dev, media_device_release_devres, NULL, NULL);
 	if (mdev)
 		return mdev;

 	mdev = devres_alloc(media_device_release_devres,
 				sizeof(struct media_device), GFP_KERNEL);
 	if (!mdev)
 		return NULL;
 	return devres_get(dev, mdev, NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(media_device_get_devres);

 /*
  * media_device_find_devres() - find media device as device resource
 */
 struct media_device *media_device_find_devres(struct device *dev)
 {
 	return devres_find(dev, media_device_release_devres, NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(media_device_find_devres);

 #endif /* CONFIG_MEDIA_CONTROLLER */
	/*
	* Media device
	*
	* 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/compat.h>
	#include <linux/export.h>
	#include <linux/ioctl.h>
	#include <linux/media.h>
	#include <linux/types.h>

	#include <media/media-device.h>
	#include <media/media-devnode.h>
	#include <media/media-entity.h>

	#ifdef CONFIG_MEDIA_CONTROLLER

	/* -----------------------------------------------------------------------------
	* Userspace API
	*/

	static int media_device_open(struct file *filp)
	{
	return 0;
	}

	static int media_device_close(struct file *filp)
	{
	return 0;
	}

	static int media_device_get_info(struct media_device *dev,
	struct media_device_info __user *__info)
	{
	struct media_device_info info;

	memset(&info, 0, sizeof(info));

	strlcpy(info.driver, dev->dev->driver->name, sizeof(info.driver));
	strlcpy(info.model, dev->model, sizeof(info.model));
	strlcpy(info.serial, dev->serial, sizeof(info.serial));
	strlcpy(info.bus_info, dev->bus_info, sizeof(info.bus_info));

	info.media_version = MEDIA_API_VERSION;
	info.hw_revision = dev->hw_revision;
	info.driver_version = dev->driver_version;

	if (copy_to_user(__info, &info, sizeof(*__info)))
	return -EFAULT;
	return 0;
	}

	static struct media_entity find_entity(struct media_device mdev, u32 id)
	{
	struct media_entity *entity;
	int next = id & MEDIA_ENT_ID_FLAG_NEXT;

	id &= ~MEDIA_ENT_ID_FLAG_NEXT;

	spin_lock(&mdev->lock);

	media_device_for_each_entity(entity, mdev) {
	if (((media_entity_id(entity) == id) && !next) \|\|
	((media_entity_id(entity) > 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;

	memset(&u_ent, 0, sizeof(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 = media_entity_id(ent);
	if (ent->name)
	strlcpy(u_ent.name, ent->name, sizeof(u_ent.name));
	u_ent.type = ent->type;
	u_ent.revision = ent->revision;
	u_ent.flags = ent->flags;
	u_ent.group_id = ent->group_id;
	u_ent.pads = ent->num_pads;
	u_ent.links = ent->num_links - ent->num_backlinks;
	memcpy(&u_ent.raw, &ent->info, sizeof(ent->info));
	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 = media_entity_id(kpad->entity);
	upad->index = kpad->index;
	upad->flags = kpad->flags;
	}

	static long __media_device_enum_links(struct media_device *mdev,
	struct media_links_enum *links)
	{
	struct media_entity *entity;

	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;

	memset(&pad, 0, sizeof(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;

	memset(&link, 0, sizeof(link));
	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++;
	}
	}

	return 0;
	}

	static long media_device_enum_links(struct media_device *mdev,
	struct media_links_enum __user *ulinks)
	{
	struct media_links_enum links;
	int rval;

	if (copy_from_user(&links, ulinks, sizeof(links)))
	return -EFAULT;

	rval = __media_device_enum_links(mdev, &links);
	if (rval < 0)
	return rval;

	if (copy_to_user(ulinks, &links, sizeof(*ulinks)))
	return -EFAULT;

	return 0;
	}

	static long media_device_setup_link(struct media_device *mdev,
	struct media_link_desc __user *_ulink)
	{
	struct media_link *link = NULL;
	struct media_link_desc ulink;
	struct media_entity *source;
	struct media_entity *sink;
	int ret;

	if (copy_from_user(&ulink, _ulink, sizeof(ulink)))
	return -EFAULT;

	/* Find the source and sink entities and link.
	*/
	source = find_entity(mdev, ulink.source.entity);
	sink = find_entity(mdev, ulink.sink.entity);

	if (source == NULL \|\| sink == NULL)
	return -EINVAL;

	if (ulink.source.index >= source->num_pads \|\|
	ulink.sink.index >= sink->num_pads)
	return -EINVAL;

	link = media_entity_find_link(&source->pads[ulink.source.index],
	&sink->pads[ulink.sink.index]);
	if (link == NULL)
	return -EINVAL;

	/* Setup the link on both entities. */
	ret = __media_entity_setup_link(link, ulink.flags);

	if (copy_to_user(_ulink, &ulink, sizeof(ulink)))
	return -EFAULT;

	return ret;
	}

	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_DEVICE_INFO:
	ret = media_device_get_info(dev,
	(struct media_device_info __user *)arg);
	break;

	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;

	case MEDIA_IOC_SETUP_LINK:
	mutex_lock(&dev->graph_mutex);
	ret = media_device_setup_link(dev,
	(struct media_link_desc __user *)arg);
	mutex_unlock(&dev->graph_mutex);
	break;

	default:
	ret = -ENOIOCTLCMD;
	}

	return ret;
	}

	#ifdef CONFIG_COMPAT

	struct media_links_enum32 {
	__u32 entity;
	compat_uptr_t pads; /* struct media_pad_desc * */
	compat_uptr_t links; /* struct media_link_desc * */
	__u32 reserved[4];
	};

	static long media_device_enum_links32(struct media_device *mdev,
	struct media_links_enum32 __user *ulinks)
	{
	struct media_links_enum links;
	compat_uptr_t pads_ptr, links_ptr;

	memset(&links, 0, sizeof(links));

	if (get_user(links.entity, &ulinks->entity)
	\|\| get_user(pads_ptr, &ulinks->pads)
	\|\| get_user(links_ptr, &ulinks->links))
	return -EFAULT;

	links.pads = compat_ptr(pads_ptr);
	links.links = compat_ptr(links_ptr);

	return __media_device_enum_links(mdev, &links);
	}

	#define MEDIA_IOC_ENUM_LINKS32 _IOWR('\|', 0x02, struct media_links_enum32)

	static long media_device_compat_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_DEVICE_INFO:
	case MEDIA_IOC_ENUM_ENTITIES:
	case MEDIA_IOC_SETUP_LINK:
	return media_device_ioctl(filp, cmd, arg);

	case MEDIA_IOC_ENUM_LINKS32:
	mutex_lock(&dev->graph_mutex);
	ret = media_device_enum_links32(dev,
	(struct media_links_enum32 __user *)arg);
	mutex_unlock(&dev->graph_mutex);
	break;

	default:
	ret = -ENOIOCTLCMD;
	}

	return ret;
	}
	#endif /* CONFIG_COMPAT */

	static const struct media_file_operations media_device_fops = {
	.owner = THIS_MODULE,
	.open = media_device_open,
	.ioctl = media_device_ioctl,
	#ifdef CONFIG_COMPAT
	.compat_ioctl = media_device_compat_ioctl,
	#endif /* CONFIG_COMPAT */
	.release = media_device_close,
	};

	/* -----------------------------------------------------------------------------
	* sysfs
	*/

	static ssize_t show_model(struct device *cd,
	struct device_attribute attr, char buf)
	{
	struct media_device *mdev = to_media_device(to_media_devnode(cd));

	return sprintf(buf, "%.*s\n", (int)sizeof(mdev->model), mdev->model);
	}

	static DEVICE_ATTR(model, S_IRUGO, show_model, NULL);

	/* -----------------------------------------------------------------------------
	* Registration/unregistration
	*/

	static void media_device_release(struct media_devnode *mdev)
	{
	}

	/**
	* media_device_register - register a media device
	* @mdev: The media device
	*
	* The caller is responsible for initializing the media device before
	* registration. The following fields must be set:
	*
	* - dev must point to the parent device
	* - model must be filled with the device model name
	*/
	int __must_check __media_device_register(struct media_device *mdev,
	struct module *owner)
	{
	int ret;

	if (WARN_ON(mdev->dev == NULL \|\| mdev->model[0] == 0))
	return -EINVAL;

	INIT_LIST_HEAD(&mdev->entities);
	spin_lock_init(&mdev->lock);
	mutex_init(&mdev->graph_mutex);

	/* Register the device node. */
	mdev->devnode.fops = &media_device_fops;
	mdev->devnode.parent = mdev->dev;
	mdev->devnode.release = media_device_release;
	ret = media_devnode_register(&mdev->devnode, owner);
	if (ret < 0)
	return ret;

	ret = device_create_file(&mdev->devnode.dev, &dev_attr_model);
	if (ret < 0) {
	media_devnode_unregister(&mdev->devnode);
	return ret;
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(__media_device_register);

	/**
	* media_device_unregister - unregister a media device
	* @mdev: The media device
	*
	*/
	void media_device_unregister(struct media_device *mdev)
	{
	struct media_entity *entity;
	struct media_entity *next;

	list_for_each_entry_safe(entity, next, &mdev->entities, list)
	media_device_unregister_entity(entity);

	device_remove_file(&mdev->devnode.dev, &dev_attr_model);
	media_devnode_unregister(&mdev->devnode);
	}
	EXPORT_SYMBOL_GPL(media_device_unregister);

	/**
	* media_device_register_entity - Register an entity with a media device
	* @mdev: The media device
	* @entity: The entity
	*/
	int __must_check media_device_register_entity(struct media_device *mdev,
	struct media_entity *entity)
	{
	/* Warn if we apparently re-register an entity */
	WARN_ON(entity->parent != NULL);
	entity->parent = mdev;

	spin_lock(&mdev->lock);
	/* Initialize media_gobj embedded at the entity */
	media_gobj_init(mdev, MEDIA_GRAPH_ENTITY, &entity->graph_obj);
	list_add_tail(&entity->list, &mdev->entities);
	spin_unlock(&mdev->lock);

	return 0;
	}
	EXPORT_SYMBOL_GPL(media_device_register_entity);

	/**
	* media_device_unregister_entity - Unregister an entity
	* @entity: The entity
	*
	* If the entity has never been registered this function will return
	* immediately.
	*/
	void media_device_unregister_entity(struct media_entity *entity)
	{
	struct media_device *mdev = entity->parent;

	if (mdev == NULL)
	return;

	spin_lock(&mdev->lock);
	media_gobj_remove(&entity->graph_obj);
	list_del(&entity->list);
	spin_unlock(&mdev->lock);
	entity->parent = NULL;
	}
	EXPORT_SYMBOL_GPL(media_device_unregister_entity);

	static void media_device_release_devres(struct device dev, void res)
	{
	}

	/*
	* media_device_get_devres() - get media device as device resource
	* creates if one doesn't exist
	*/
	struct media_device media_device_get_devres(struct device dev)
	{
	struct media_device *mdev;

	mdev = devres_find(dev, media_device_release_devres, NULL, NULL);
	if (mdev)
	return mdev;

	mdev = devres_alloc(media_device_release_devres,
	sizeof(struct media_device), GFP_KERNEL);
	if (!mdev)
	return NULL;
	return devres_get(dev, mdev, NULL, NULL);
	}
	EXPORT_SYMBOL_GPL(media_device_get_devres);

	/*
	* media_device_find_devres() - find media device as device resource
	*/
	struct media_device media_device_find_devres(struct device dev)
	{
	return devres_find(dev, media_device_release_devres, NULL, NULL);
	}
	EXPORT_SYMBOL_GPL(media_device_find_devres);

	#endif /* CONFIG_MEDIA_CONTROLLER */