v4l2-fh.c

Go to the documentation of this file.

/*
 * v4l2-fh.c
 *
 * V4L2 file handles.
 *
 * Copyright (C) 2009--2010 Nokia Corporation.
 *
 * Contact: 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., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <media/v4l2-dev.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-event.h>
#include <media/v4l2-ioctl.h>

void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
{
    fh->vdev = vdev;
    /* Inherit from video_device. May be overridden by the driver. */
    fh->ctrl_handler = vdev->ctrl_handler;
    INIT_LIST_HEAD(&fh->list);
    set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
    fh->prio = V4L2_PRIORITY_UNSET;
    init_waitqueue_head(&fh->wait);
    INIT_LIST_HEAD(&fh->available);
    INIT_LIST_HEAD(&fh->subscribed);
    fh->sequence = -1;
}
EXPORT_SYMBOL_GPL(v4l2_fh_init);

void v4l2_fh_add(struct v4l2_fh *fh)
{
    unsigned long flags;

    if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
        v4l2_prio_open(fh->vdev->prio, &fh->prio);
    spin_lock_irqsave(&fh->vdev->fh_lock, flags);
    list_add(&fh->list, &fh->vdev->fh_list);
    spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
}
EXPORT_SYMBOL_GPL(v4l2_fh_add);

int v4l2_fh_open(struct file *filp)
{
    struct video_device *vdev = video_devdata(filp);
    struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);

    filp->private_data = fh;
    if (fh == NULL)
        return -ENOMEM;
    v4l2_fh_init(fh, vdev);
    v4l2_fh_add(fh);
    return 0;
}
EXPORT_SYMBOL_GPL(v4l2_fh_open);

void v4l2_fh_del(struct v4l2_fh *fh)
{
    unsigned long flags;

    spin_lock_irqsave(&fh->vdev->fh_lock, flags);
    list_del_init(&fh->list);
    spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
    if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags))
        v4l2_prio_close(fh->vdev->prio, fh->prio);
}
EXPORT_SYMBOL_GPL(v4l2_fh_del);

void v4l2_fh_exit(struct v4l2_fh *fh)
{
    if (fh->vdev == NULL)
        return;
    v4l2_event_unsubscribe_all(fh);
    fh->vdev = NULL;
}
EXPORT_SYMBOL_GPL(v4l2_fh_exit);

int v4l2_fh_release(struct file *filp)
{
    struct v4l2_fh *fh = filp->private_data;

    if (fh) {
        v4l2_fh_del(fh);
        v4l2_fh_exit(fh);
        kfree(fh);
    }
    return 0;
}
EXPORT_SYMBOL_GPL(v4l2_fh_release);

int v4l2_fh_is_singular(struct v4l2_fh *fh)
{
    unsigned long flags;
    int is_singular;

    if (fh == NULL || fh->vdev == NULL)
        return 0;
    spin_lock_irqsave(&fh->vdev->fh_lock, flags);
    is_singular = list_is_singular(&fh->list);
    spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
    return is_singular;
}
EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);