// SPDX-License-Identifier: GPL-2.0-only
/*
 * Media device
 *
 * Copyright (C) 2010 Nokia Corporation
 *
 * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 *           Sakari Ailus <sakari.ailus@iki.fi>
 */

#include <linux/compat.h>
#include <linux/export.h>
#include <linux/idr.h>
#include <linux/ioctl.h>
#include <linux/media.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/usb.h>
#include <linux/version.h>

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

#ifdef CONFIG_MEDIA_CONTROLLER

/*
 * Legacy defines from linux/media.h. This is the only place we need this
 * so we just define it here. The media.h header doesn't expose it to the
 * kernel to prevent it from being used by drivers, but here (and only here!)
 * we need it to handle the legacy behavior.
 */
#define MEDIA_ENT_SUBTYPE_MASK                  0x0000ffff
#define MEDIA_ENT_T_DEVNODE_UNKNOWN             (MEDIA_ENT_F_OLD_BASE | \
                                                 MEDIA_ENT_SUBTYPE_MASK)

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

static inline void __user *media_get_uptr(__u64 arg)
{
        return (void __user *)(uintptr_t)arg;
}

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

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

static long media_device_get_info(struct media_device *dev, void *arg)
{
        struct media_device_info *info = arg;

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

        if (dev->driver_name[0])
                strscpy(info->driver, dev->driver_name, sizeof(info->driver));
        else
                strscpy(info->driver, dev->dev->driver->name,
                        sizeof(info->driver));

        strscpy(info->model, dev->model, sizeof(info->model));
        strscpy(info->serial, dev->serial, sizeof(info->serial));
        strscpy(info->bus_info, dev->bus_info, sizeof(info->bus_info));

        info->media_version = LINUX_VERSION_CODE;
        info->driver_version = info->media_version;
        info->hw_revision = dev->hw_revision;

        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;

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

        return NULL;
}

static long media_device_enum_entities(struct media_device *mdev, void *arg)
{
        struct media_entity_desc *entd = arg;
        struct media_entity *ent;

        ent = find_entity(mdev, entd->id);
        if (ent == NULL)
                return -EINVAL;

        memset(entd, 0, sizeof(*entd));

        entd->id = media_entity_id(ent);
        if (ent->name)
                strscpy(entd->name, ent->name, sizeof(entd->name));
        entd->type = ent->function;
        entd->revision = 0;             /* Unused */
        entd->flags = ent->flags;
        entd->group_id = 0;             /* Unused */
        entd->pads = ent->num_pads;
        entd->links = ent->num_links - ent->num_backlinks;

        /*
         * Workaround for a bug at media-ctl <= v1.10 that makes it to
         * do the wrong thing if the entity function doesn't belong to
         * either MEDIA_ENT_F_OLD_BASE or MEDIA_ENT_F_OLD_SUBDEV_BASE
         * Ranges.
         *
         * Non-subdevices are expected to be at the MEDIA_ENT_F_OLD_BASE,
         * or, otherwise, will be silently ignored by media-ctl when
         * printing the graphviz diagram. So, map them into the devnode
         * old range.
         */
        if (ent->function < MEDIA_ENT_F_OLD_BASE ||
            ent->function > MEDIA_ENT_F_TUNER) {
                if (is_media_entity_v4l2_subdev(ent))
                        entd->type = MEDIA_ENT_F_V4L2_SUBDEV_UNKNOWN;
                else if (ent->function != MEDIA_ENT_F_IO_V4L)
                        entd->type = MEDIA_ENT_T_DEVNODE_UNKNOWN;
        }

        memcpy(&entd->raw, &ent->info, sizeof(ent->info));

        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, void *arg)
{
        struct media_links_enum *links = arg;
        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 *link;
                struct media_link_desc __user *ulink_desc = links->links;

                list_for_each_entry(link, &entity->links, list) {
                        struct media_link_desc klink_desc;

                        /* Ignore backlinks. */
                        if (link->source->entity != entity)
                                continue;
                        memset(&klink_desc, 0, sizeof(klink_desc));
                        media_device_kpad_to_upad(link->source,
                                                  &klink_desc.source);
                        media_device_kpad_to_upad(link->sink,
                                                  &klink_desc.sink);
                        klink_desc.flags = link->flags;
                        if (copy_to_user(ulink_desc, &klink_desc,
                                         sizeof(*ulink_desc)))
                                return -EFAULT;
                        ulink_desc++;
                }
        }
        memset(links->reserved, 0, sizeof(links->reserved));

        return 0;
}

static long media_device_setup_link(struct media_device *mdev, void *arg)
{
        struct media_link_desc *linkd = arg;
        struct media_link *link = NULL;
        struct media_entity *source;
        struct media_entity *sink;

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

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

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

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

        memset(linkd->reserved, 0, sizeof(linkd->reserved));

        /* Setup the link on both entities. */
        return __media_entity_setup_link(link, linkd->flags);
}

static long media_device_get_topology(struct media_device *mdev, void *arg)
{
        struct media_v2_topology *topo = arg;
        struct media_entity *entity;
        struct media_interface *intf;
        struct media_pad *pad;
        struct media_link *link;
        struct media_v2_entity kentity, __user *uentity;
        struct media_v2_interface kintf, __user *uintf;
        struct media_v2_pad kpad, __user *upad;
        struct media_v2_link klink, __user *ulink;
        unsigned int i;
        int ret = 0;

        topo->topology_version = mdev->topology_version;

        /* Get entities and number of entities */
        i = 0;
        uentity = media_get_uptr(topo->ptr_entities);
        media_device_for_each_entity(entity, mdev) {
                i++;
                if (ret || !uentity)
                        continue;

                if (i > topo->num_entities) {
                        ret = -ENOSPC;
                        continue;
                }

                /* Copy fields to userspace struct if not error */
                memset(&kentity, 0, sizeof(kentity));
                kentity.id = entity->graph_obj.id;
                kentity.function = entity->function;
                kentity.flags = entity->flags;
                strscpy(kentity.name, entity->name,
                        sizeof(kentity.name));

                if (copy_to_user(uentity, &kentity, sizeof(kentity)))
                        ret = -EFAULT;
                uentity++;
        }
        topo->num_entities = i;
        topo->reserved1 = 0;

        /* Get interfaces and number of interfaces */
        i = 0;
        uintf = media_get_uptr(topo->ptr_interfaces);
        media_device_for_each_intf(intf, mdev) {
                i++;
                if (ret || !uintf)
                        continue;

                if (i > topo->num_interfaces) {
                        ret = -ENOSPC;
                        continue;
                }

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

                /* Copy intf fields to userspace struct */
                kintf.id = intf->graph_obj.id;
                kintf.intf_type = intf->type;
                kintf.flags = intf->flags;

                if (media_type(&intf->graph_obj) == MEDIA_GRAPH_INTF_DEVNODE) {
                        struct media_intf_devnode *devnode;

                        devnode = intf_to_devnode(intf);

                        kintf.devnode.major = devnode->major;
                        kintf.devnode.minor = devnode->minor;
                }

                if (copy_to_user(uintf, &kintf, sizeof(kintf)))
                        ret = -EFAULT;
                uintf++;
        }
        topo->num_interfaces = i;
        topo->reserved2 = 0;

        /* Get pads and number of pads */
        i = 0;
        upad = media_get_uptr(topo->ptr_pads);
        media_device_for_each_pad(pad, mdev) {
                i++;
                if (ret || !upad)
                        continue;

                if (i > topo->num_pads) {
                        ret = -ENOSPC;
                        continue;
                }

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

                /* Copy pad fields to userspace struct */
                kpad.id = pad->graph_obj.id;
                kpad.entity_id = pad->entity->graph_obj.id;
                kpad.flags = pad->flags;
                kpad.index = pad->index;

                if (copy_to_user(upad, &kpad, sizeof(kpad)))
                        ret = -EFAULT;
                upad++;
        }
        topo->num_pads = i;
        topo->reserved3 = 0;

        /* Get links and number of links */
        i = 0;
        ulink = media_get_uptr(topo->ptr_links);
        media_device_for_each_link(link, mdev) {
                if (link->is_backlink)
                        continue;

                i++;

                if (ret || !ulink)
                        continue;

                if (i > topo->num_links) {
                        ret = -ENOSPC;
                        continue;
                }

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

                /* Copy link fields to userspace struct */
                klink.id = link->graph_obj.id;
                klink.source_id = link->gobj0->id;
                klink.sink_id = link->gobj1->id;
                klink.flags = link->flags;

                if (copy_to_user(ulink, &klink, sizeof(klink)))
                        ret = -EFAULT;
                ulink++;
        }
        topo->num_links = i;
        topo->reserved4 = 0;

        return ret;
}

static long media_device_request_alloc(struct media_device *mdev, void *arg)
{
        int *alloc_fd = arg;

        if (!mdev->ops || !mdev->ops->req_validate || !mdev->ops->req_queue)
                return -ENOTTY;

        return media_request_alloc(mdev, alloc_fd);
}

static long copy_arg_from_user(void *karg, void __user *uarg, unsigned int cmd)
{
        if ((_IOC_DIR(cmd) & _IOC_WRITE) &&
            copy_from_user(karg, uarg, _IOC_SIZE(cmd)))
                return -EFAULT;

        return 0;
}

static long copy_arg_to_user(void __user *uarg, void *karg, unsigned int cmd)
{
        if ((_IOC_DIR(cmd) & _IOC_READ) &&
            copy_to_user(uarg, karg, _IOC_SIZE(cmd)))
                return -EFAULT;

        return 0;
}

/* Do acquire the graph mutex */
#define MEDIA_IOC_FL_GRAPH_MUTEX        BIT(0)

#define MEDIA_IOC_ARG(__cmd, func, fl, from_user, to_user)              \
        [_IOC_NR(MEDIA_IOC_##__cmd)] = {                                \
                .cmd = MEDIA_IOC_##__cmd,                               \
                .fn = func,                                             \
                .flags = fl,                                            \
                .arg_from_user = from_user,                             \
                .arg_to_user = to_user,                                 \
        }

#define MEDIA_IOC(__cmd, func, fl)                                      \
        MEDIA_IOC_ARG(__cmd, func, fl, copy_arg_from_user, copy_arg_to_user)

/* the table is indexed by _IOC_NR(cmd) */
struct media_ioctl_info {
        unsigned int cmd;
        unsigned short flags;
        long (*fn)(struct media_device *dev, void *arg);
        long (*arg_from_user)(void *karg, void __user *uarg, unsigned int cmd);
        long (*arg_to_user)(void __user *uarg, void *karg, unsigned int cmd);
};

static const struct media_ioctl_info ioctl_info[] = {
        MEDIA_IOC(DEVICE_INFO, media_device_get_info, MEDIA_IOC_FL_GRAPH_MUTEX),
        MEDIA_IOC(ENUM_ENTITIES, media_device_enum_entities, MEDIA_IOC_FL_GRAPH_MUTEX),
        MEDIA_IOC(ENUM_LINKS, media_device_enum_links, MEDIA_IOC_FL_GRAPH_MUTEX),
        MEDIA_IOC(SETUP_LINK, media_device_setup_link, MEDIA_IOC_FL_GRAPH_MUTEX),
        MEDIA_IOC(G_TOPOLOGY, media_device_get_topology, MEDIA_IOC_FL_GRAPH_MUTEX),
        MEDIA_IOC(REQUEST_ALLOC, media_device_request_alloc, 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 = devnode->media_dev;
        const struct media_ioctl_info *info;
        void __user *arg = (void __user *)__arg;
        char __karg[256], *karg = __karg;
        long ret;

        if (_IOC_NR(cmd) >= ARRAY_SIZE(ioctl_info)
            || ioctl_info[_IOC_NR(cmd)].cmd != cmd)
                return -ENOIOCTLCMD;

        info = &ioctl_info[_IOC_NR(cmd)];

        if (_IOC_SIZE(info->cmd) > sizeof(__karg)) {
                karg = kmalloc(_IOC_SIZE(info->cmd), GFP_KERNEL);
                if (!karg)
                        return -ENOMEM;
        }

        if (info->arg_from_user) {
                ret = info->arg_from_user(karg, arg, cmd);
                if (ret)
                        goto out_free;
        }

        if (info->flags & MEDIA_IOC_FL_GRAPH_MUTEX)
                mutex_lock(&dev->graph_mutex);

        ret = info->fn(dev, karg);

        if (info->flags & MEDIA_IOC_FL_GRAPH_MUTEX)
                mutex_unlock(&dev->graph_mutex);

        if (!ret && info->arg_to_user)
                ret = info->arg_to_user(arg, karg, cmd);

out_free:
        if (karg != __karg)
                kfree(karg);

        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;
        int ret;

        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);

        ret = media_device_enum_links(mdev, &links);
        if (ret)
                return ret;

        if (copy_to_user(ulinks->reserved, links.reserved,
                         sizeof(ulinks->reserved)))
                return -EFAULT;
        return 0;
}

#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 = devnode->media_dev;
        long ret;

        switch (cmd) {
        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:
                return media_device_ioctl(filp, cmd, arg);
        }

        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 model_show(struct device *cd,
                          struct device_attribute *attr, char *buf)
{
        struct media_devnode *devnode = to_media_devnode(cd);
        struct media_device *mdev = devnode->media_dev;

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

static DEVICE_ATTR_RO(model);

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

static void media_device_release(struct media_devnode *devnode)
{
        dev_dbg(devnode->parent, "Media device released\n");
}

static void __media_device_unregister_entity(struct media_entity *entity)
{
        struct media_device *mdev = entity->graph_obj.mdev;
        struct media_link *link, *tmp;
        struct media_interface *intf;
        struct media_pad *iter;

        ida_free(&mdev->entity_internal_idx, entity->internal_idx);

        /* Remove all interface links pointing to this entity */
        list_for_each_entry(intf, &mdev->interfaces, graph_obj.list) {
                list_for_each_entry_safe(link, tmp, &intf->links, list) {
                        if (link->entity == entity)
                                __media_remove_intf_link(link);
                }
        }

        /* Remove all data links that belong to this entity */
        __media_entity_remove_links(entity);

        /* Remove all pads that belong to this entity */
        media_entity_for_each_pad(entity, iter)
                media_gobj_destroy(&iter->graph_obj);

        /* Remove the entity */
        media_gobj_destroy(&entity->graph_obj);

        /* invoke entity_notify callbacks to handle entity removal?? */
}

int __must_check media_device_register_entity(struct media_device *mdev,
                                              struct media_entity *entity)
{
        struct media_entity_notify *notify, *next;
        struct media_pad *iter;
        int ret;

        if (entity->function == MEDIA_ENT_F_V4L2_SUBDEV_UNKNOWN ||
            entity->function == MEDIA_ENT_F_UNKNOWN)
                dev_warn(mdev->dev,
                         "Entity type for entity %s was not initialized!\n",
                         entity->name);

        /* Warn if we apparently re-register an entity */
        WARN_ON(entity->graph_obj.mdev != NULL);
        entity->graph_obj.mdev = mdev;
        INIT_LIST_HEAD(&entity->links);
        entity->num_links = 0;
        entity->num_backlinks = 0;

        ret = ida_alloc_min(&mdev->entity_internal_idx, 1, GFP_KERNEL);
        if (ret < 0)
                return ret;
        entity->internal_idx = ret;

        mutex_lock(&mdev->graph_mutex);
        mdev->entity_internal_idx_max =
                max(mdev->entity_internal_idx_max, entity->internal_idx);

        /* Initialize media_gobj embedded at the entity */
        media_gobj_create(mdev, MEDIA_GRAPH_ENTITY, &entity->graph_obj);

        /* Initialize objects at the pads */
        media_entity_for_each_pad(entity, iter)
                media_gobj_create(mdev, MEDIA_GRAPH_PAD, &iter->graph_obj);

        /* invoke entity_notify callbacks */
        list_for_each_entry_safe(notify, next, &mdev->entity_notify, list)
                notify->notify(entity, notify->notify_data);

        if (mdev->entity_internal_idx_max
            >= mdev->pm_count_walk.ent_enum.idx_max) {
                struct media_graph new = { .top = 0 };

                /*
                 * Initialise the new graph walk before cleaning up
                 * the old one in order not to spoil the graph walk
                 * object of the media device if graph walk init fails.
                 */
                ret = media_graph_walk_init(&new, mdev);
                if (ret) {
                        __media_device_unregister_entity(entity);
                        mutex_unlock(&mdev->graph_mutex);
                        return ret;
                }
                media_graph_walk_cleanup(&mdev->pm_count_walk);
                mdev->pm_count_walk = new;
        }
        mutex_unlock(&mdev->graph_mutex);

        return 0;
}
EXPORT_SYMBOL_GPL(media_device_register_entity);

void media_device_unregister_entity(struct media_entity *entity)
{
        struct media_device *mdev = entity->graph_obj.mdev;

        if (mdev == NULL)
                return;

        mutex_lock(&mdev->graph_mutex);
        __media_device_unregister_entity(entity);
        mutex_unlock(&mdev->graph_mutex);
}
EXPORT_SYMBOL_GPL(media_device_unregister_entity);

#ifdef CONFIG_DEBUG_FS
/*
 * Log the state of media requests. Very useful for debugging.
 */
static int media_device_requests(struct seq_file *file, void *priv)
{
        struct media_device *dev = dev_get_drvdata(file->private);

        seq_printf(file, "number of requests: %d\n",
                   atomic_read(&dev->num_requests));
        seq_printf(file, "number of request objects: %d\n",
                   atomic_read(&dev->num_request_objects));

        return 0;
}
#endif

void media_device_init(struct media_device *mdev)
{
        INIT_LIST_HEAD(&mdev->entities);
        INIT_LIST_HEAD(&mdev->interfaces);
        INIT_LIST_HEAD(&mdev->pads);
        INIT_LIST_HEAD(&mdev->links);
        INIT_LIST_HEAD(&mdev->entity_notify);

        mutex_init(&mdev->req_queue_mutex);
        mutex_init(&mdev->graph_mutex);
        ida_init(&mdev->entity_internal_idx);

        atomic_set(&mdev->request_id, 0);

        if (!*mdev->bus_info)
                media_set_bus_info(mdev->bus_info, sizeof(mdev->bus_info),
                                   mdev->dev);

        atomic_set(&mdev->num_requests, 0);
        atomic_set(&mdev->num_request_objects, 0);

        dev_dbg(mdev->dev, "Media device initialized\n");
}
EXPORT_SYMBOL_GPL(media_device_init);

void media_device_cleanup(struct media_device *mdev)
{
        ida_destroy(&mdev->entity_internal_idx);
        mdev->entity_internal_idx_max = 0;
        media_graph_walk_cleanup(&mdev->pm_count_walk);
        mutex_destroy(&mdev->graph_mutex);
        mutex_destroy(&mdev->req_queue_mutex);
}
EXPORT_SYMBOL_GPL(media_device_cleanup);

int __must_check __media_device_register(struct media_device *mdev,
                                         struct module *owner)
{
        struct media_devnode *devnode;
        int ret;

        devnode = kzalloc_obj(*devnode);
        if (!devnode)
                return -ENOMEM;

        /* Register the device node. */
        mdev->devnode = devnode;
        devnode->fops = &media_device_fops;
        devnode->parent = mdev->dev;
        devnode->release = media_device_release;

        /* Set version 0 to indicate user-space that the graph is static */
        mdev->topology_version = 0;

        ret = media_devnode_register(mdev, devnode, owner);
        if (ret < 0) {
                /* devnode free is handled in media_devnode_*() */
                mdev->devnode = NULL;
                return ret;
        }

        ret = device_create_file(&devnode->dev, &dev_attr_model);
        if (ret < 0) {
                /* devnode free is handled in media_devnode_*() */
                mdev->devnode = NULL;
                media_devnode_unregister_prepare(devnode);
                media_devnode_unregister(devnode);
                return ret;
        }

        dev_dbg(mdev->dev, "Media device registered\n");

#ifdef CONFIG_DEBUG_FS
        if (!media_debugfs_root)
                media_debugfs_root = debugfs_create_dir("media", NULL);
        mdev->media_dir = debugfs_create_dir(dev_name(&devnode->dev),
                                             media_debugfs_root);
        debugfs_create_devm_seqfile(&devnode->dev, "requests",
                                    mdev->media_dir, media_device_requests);
#endif

        return 0;
}
EXPORT_SYMBOL_GPL(__media_device_register);

void media_device_register_entity_notify(struct media_device *mdev,
                                        struct media_entity_notify *nptr)
{
        mutex_lock(&mdev->graph_mutex);
        list_add_tail(&nptr->list, &mdev->entity_notify);
        mutex_unlock(&mdev->graph_mutex);
}
EXPORT_SYMBOL_GPL(media_device_register_entity_notify);

/*
 * Note: Should be called with mdev->lock held.
 */
static void __media_device_unregister_entity_notify(struct media_device *mdev,
                                        struct media_entity_notify *nptr)
{
        list_del(&nptr->list);
}

void media_device_unregister_entity_notify(struct media_device *mdev,
                                        struct media_entity_notify *nptr)
{
        mutex_lock(&mdev->graph_mutex);
        __media_device_unregister_entity_notify(mdev, nptr);
        mutex_unlock(&mdev->graph_mutex);
}
EXPORT_SYMBOL_GPL(media_device_unregister_entity_notify);

void media_device_unregister(struct media_device *mdev)
{
        struct media_entity *entity;
        struct media_entity *next;
        struct media_interface *intf, *tmp_intf;
        struct media_entity_notify *notify, *nextp;

        if (mdev == NULL)
                return;

        mutex_lock(&mdev->graph_mutex);

        /* Check if mdev was ever registered at all */
        if (!media_devnode_is_registered(mdev->devnode)) {
                mutex_unlock(&mdev->graph_mutex);
                return;
        }

        /* Clear the devnode register bit to avoid races with media dev open */
        media_devnode_unregister_prepare(mdev->devnode);

        /* Remove all entities from the media device */
        list_for_each_entry_safe(entity, next, &mdev->entities, graph_obj.list)
                __media_device_unregister_entity(entity);

        /* Remove all entity_notify callbacks from the media device */
        list_for_each_entry_safe(notify, nextp, &mdev->entity_notify, list)
                __media_device_unregister_entity_notify(mdev, notify);

        /* Remove all interfaces from the media device */
        list_for_each_entry_safe(intf, tmp_intf, &mdev->interfaces,
                                 graph_obj.list) {
                /*
                 * Unlink the interface, but don't free it here; the
                 * module which created it is responsible for freeing
                 * it
                 */
                __media_remove_intf_links(intf);
                media_gobj_destroy(&intf->graph_obj);
        }

        mutex_unlock(&mdev->graph_mutex);

        dev_dbg(mdev->dev, "Media device unregistered\n");

        debugfs_remove_recursive(mdev->media_dir);
        device_remove_file(&mdev->devnode->dev, &dev_attr_model);
        media_devnode_unregister(mdev->devnode);
        /* devnode free is handled in media_devnode_*() */
        mdev->devnode = NULL;
}
EXPORT_SYMBOL_GPL(media_device_unregister);

#if IS_ENABLED(CONFIG_PCI)
void media_device_pci_init(struct media_device *mdev,
                           struct pci_dev *pci_dev,
                           const char *name)
{
        mdev->dev = &pci_dev->dev;

        if (name)
                strscpy(mdev->model, name, sizeof(mdev->model));
        else
                strscpy(mdev->model, pci_name(pci_dev), sizeof(mdev->model));

        sprintf(mdev->bus_info, "PCI:%s", pci_name(pci_dev));

        mdev->hw_revision = (pci_dev->subsystem_vendor << 16)
                            | pci_dev->subsystem_device;

        media_device_init(mdev);
}
EXPORT_SYMBOL_GPL(media_device_pci_init);
#endif

#if IS_ENABLED(CONFIG_USB)
void __media_device_usb_init(struct media_device *mdev,
                             struct usb_device *udev,
                             const char *board_name,
                             const char *driver_name)
{
        mdev->dev = &udev->dev;

        if (driver_name)
                strscpy(mdev->driver_name, driver_name,
                        sizeof(mdev->driver_name));

        if (board_name)
                strscpy(mdev->model, board_name, sizeof(mdev->model));
        else if (udev->product)
                strscpy(mdev->model, udev->product, sizeof(mdev->model));
        else
                strscpy(mdev->model, "unknown model", sizeof(mdev->model));
        if (udev->serial)
                strscpy(mdev->serial, udev->serial, sizeof(mdev->serial));
        usb_make_path(udev, mdev->bus_info, sizeof(mdev->bus_info));
        mdev->hw_revision = le16_to_cpu(udev->descriptor.bcdDevice);

        media_device_init(mdev);
}
EXPORT_SYMBOL_GPL(__media_device_usb_init);
#endif


#endif /* CONFIG_MEDIA_CONTROLLER */