media-device.c

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/*
 * Media device
 *
 * Copyright (C) 2010 Nokia Corporation
 *
 * Contacts: Laurent Pinchart <[email protected]>
 *       Sakari Ailus <[email protected]>
 *
 * 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/types.h>
#include <linux/ioctl.h>
#include <linux/media.h>
#include <linux/export.h>

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

/* -----------------------------------------------------------------------------
 * 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 ((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.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 = 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_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;
}

static const struct media_file_operations media_device_fops = {
    .owner = THIS_MODULE,
    .open = media_device_open,
    .ioctl = media_device_ioctl,
    .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)
{
}

int __must_check media_device_register(struct media_device *mdev)
{
    int ret;

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

    mdev->entity_id = 1;
    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);
    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);

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);

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);
    if (entity->id == 0)
        entity->id = mdev->entity_id++;
    else
        mdev->entity_id = max(entity->id + 1, mdev->entity_id);
    list_add_tail(&entity->list, &mdev->entities);
    spin_unlock(&mdev->lock);

    return 0;
}
EXPORT_SYMBOL_GPL(media_device_register_entity);

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

    if (mdev == NULL)
        return;

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