LXR linux/drivers/media/v4l2-core/v4l2-fh.c

   1/*
   2 * v4l2-fh.c
   3 *
   4 * V4L2 file handles.
   5 *
   6 * Copyright (C) 2009--2010 Nokia Corporation.
   7 *
   8 * Contact: Sakari Ailus <sakari.ailus@iki.fi>
   9 *
  10 * This program is free software; you can redistribute it and/or
  11 * modify it under the terms of the GNU General Public License
  12 * version 2 as published by the Free Software Foundation.
  13 *
  14 * This program is distributed in the hope that it will be useful, but
  15 * WITHOUT ANY WARRANTY; without even the implied warranty of
  16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17 * General Public License for more details.
  18 */
  19
  20#include <linux/bitops.h>
  21#include <linux/slab.h>
  22#include <linux/export.h>
  23#include <media/v4l2-dev.h>
  24#include <media/v4l2-fh.h>
  25#include <media/v4l2-event.h>
  26#include <media/v4l2-ioctl.h>
  27#include <media/v4l2-mc.h>
  28
  29void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
  30{
  31        fh->vdev = vdev;
  32        /* Inherit from video_device. May be overridden by the driver. */
  33        fh->ctrl_handler = vdev->ctrl_handler;
  34        INIT_LIST_HEAD(&fh->list);
  35        set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags);
  36        /*
  37         * determine_valid_ioctls() does not know if struct v4l2_fh
  38         * is used by this driver, but here we do. So enable the
  39         * prio ioctls here.
  40         */
  41        set_bit(_IOC_NR(VIDIOC_G_PRIORITY), vdev->valid_ioctls);
  42        set_bit(_IOC_NR(VIDIOC_S_PRIORITY), vdev->valid_ioctls);
  43        fh->prio = V4L2_PRIORITY_UNSET;
  44        init_waitqueue_head(&fh->wait);
  45        INIT_LIST_HEAD(&fh->available);
  46        INIT_LIST_HEAD(&fh->subscribed);
  47        fh->sequence = -1;
  48        mutex_init(&fh->subscribe_lock);
  49}
  50EXPORT_SYMBOL_GPL(v4l2_fh_init);
  51
  52void v4l2_fh_add(struct v4l2_fh *fh)
  53{
  54        unsigned long flags;
  55
  56        v4l2_prio_open(fh->vdev->prio, &fh->prio);
  57        spin_lock_irqsave(&fh->vdev->fh_lock, flags);
  58        list_add(&fh->list, &fh->vdev->fh_list);
  59        spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
  60}
  61EXPORT_SYMBOL_GPL(v4l2_fh_add);
  62
  63int v4l2_fh_open(struct file *filp)
  64{
  65        struct video_device *vdev = video_devdata(filp);
  66        struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
  67
  68        filp->private_data = fh;
  69        if (fh == NULL)
  70                return -ENOMEM;
  71        v4l2_fh_init(fh, vdev);
  72        v4l2_fh_add(fh);
  73        return 0;
  74}
  75EXPORT_SYMBOL_GPL(v4l2_fh_open);
  76
  77void v4l2_fh_del(struct v4l2_fh *fh)
  78{
  79        unsigned long flags;
  80
  81        spin_lock_irqsave(&fh->vdev->fh_lock, flags);
  82        list_del_init(&fh->list);
  83        spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
  84        v4l2_prio_close(fh->vdev->prio, fh->prio);
  85}
  86EXPORT_SYMBOL_GPL(v4l2_fh_del);
  87
  88void v4l2_fh_exit(struct v4l2_fh *fh)
  89{
  90        if (fh->vdev == NULL)
  91                return;
  92        v4l_disable_media_source(fh->vdev);
  93        v4l2_event_unsubscribe_all(fh);
  94        mutex_destroy(&fh->subscribe_lock);
  95        fh->vdev = NULL;
  96}
  97EXPORT_SYMBOL_GPL(v4l2_fh_exit);
  98
  99int v4l2_fh_release(struct file *filp)
 100{
 101        struct v4l2_fh *fh = filp->private_data;
 102
 103        if (fh) {
 104                v4l2_fh_del(fh);
 105                v4l2_fh_exit(fh);
 106                kfree(fh);
 107        }
 108        return 0;
 109}
 110EXPORT_SYMBOL_GPL(v4l2_fh_release);
 111
 112int v4l2_fh_is_singular(struct v4l2_fh *fh)
 113{
 114        unsigned long flags;
 115        int is_singular;
 116
 117        if (fh == NULL || fh->vdev == NULL)
 118                return 0;
 119        spin_lock_irqsave(&fh->vdev->fh_lock, flags);
 120        is_singular = list_is_singular(&fh->list);
 121        spin_unlock_irqrestore(&fh->vdev->fh_lock, flags);
 122        return is_singular;
 123}
 124EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);
 125