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kernel/linux-rt-4.4.41/drivers/media/v4l2-core/v4l2-fh.c 3.19 KB
5113f6f70   김현기   kernel add
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  /*
   * v4l2-fh.c
   *
   * V4L2 file handles.
   *
   * Copyright (C) 2009--2010 Nokia Corporation.
   *
   * Contact: 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., 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);
  	/*
  	 * determine_valid_ioctls() does not know if struct v4l2_fh
  	 * is used by this driver, but here we do. So enable the
  	 * prio ioctls here.
  	 */
  	set_bit(_IOC_NR(VIDIOC_G_PRIORITY), vdev->valid_ioctls);
  	set_bit(_IOC_NR(VIDIOC_S_PRIORITY), vdev->valid_ioctls);
  	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;
  
  	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);
  	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);