/*
   * drivers/media/video/v4l2-int-device.c
   *
   * V4L2 internal ioctl interface.
   *
   * Copyright (C) 2007 Nokia Corporation.
   *
   * Contact: Sakari Ailus <sakari.ailus@nokia.com>
   *
   * 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/kernel.h>
  #include <linux/list.h>
  #include <linux/sort.h>
  #include <linux/string.h>
  
  #include <media/v4l2-int-device.h>
  
  static DEFINE_MUTEX(mutex);
  static LIST_HEAD(int_list);

  void v4l2_int_device_try_attach_all(void)

  {

  	struct v4l2_int_device *m, *s;

  	list_for_each_entry(m, &int_list, head) {

  		if (m->type != v4l2_int_type_master)
  			continue;

  		list_for_each_entry(s, &int_list, head) {

  			if (s->type != v4l2_int_type_slave)
  				continue;
  
  			/* Slave is connected? */
  			if (s->u.slave->master)
  				continue;
  
  			/* Slave wants to attach to master? */
  			if (s->u.slave->attach_to[0] != 0
  			    && strncmp(m->name, s->u.slave->attach_to,
  				       V4L2NAMESIZE))
  				continue;
  
  			if (!try_module_get(m->module))
  				continue;

  			s->u.slave->master = m;
  			if (m->u.master->attach(s)) {
  				s->u.slave->master = NULL;

  				module_put(m->module);
  				continue;
  			}

  		}
  	}
  }

  EXPORT_SYMBOL_GPL(v4l2_int_device_try_attach_all);

  
  static int ioctl_sort_cmp(const void *a, const void *b)
  {
  	const struct v4l2_int_ioctl_desc *d1 = a, *d2 = b;
  
  	if (d1->num > d2->num)
  		return 1;
  
  	if (d1->num < d2->num)
  		return -1;
  
  	return 0;
  }
  
  int v4l2_int_device_register(struct v4l2_int_device *d)
  {
  	if (d->type == v4l2_int_type_slave)
  		sort(d->u.slave->ioctls, d->u.slave->num_ioctls,
  		     sizeof(struct v4l2_int_ioctl_desc),
  		     &ioctl_sort_cmp, NULL);
  	mutex_lock(&mutex);
  	list_add(&d->head, &int_list);
  	v4l2_int_device_try_attach_all();
  	mutex_unlock(&mutex);
  
  	return 0;
  }

  EXPORT_SYMBOL_GPL(v4l2_int_device_register);

  
  void v4l2_int_device_unregister(struct v4l2_int_device *d)
  {
  	mutex_lock(&mutex);
  	list_del(&d->head);
  	if (d->type == v4l2_int_type_slave
  	    && d->u.slave->master != NULL) {
  		d->u.slave->master->u.master->detach(d);
  		module_put(d->u.slave->master->module);
  		d->u.slave->master = NULL;
  	}
  	mutex_unlock(&mutex);
  }

  EXPORT_SYMBOL_GPL(v4l2_int_device_unregister);

  /* Adapted from search_extable in extable.c. */

  static v4l2_int_ioctl_func *find_ioctl(struct v4l2_int_slave *slave, int cmd,
  				       v4l2_int_ioctl_func *no_such_ioctl)

  {
  	const struct v4l2_int_ioctl_desc *first = slave->ioctls;
  	const struct v4l2_int_ioctl_desc *last =
  		first + slave->num_ioctls - 1;
  
  	while (first <= last) {
  		const struct v4l2_int_ioctl_desc *mid;
  
  		mid = (last - first) / 2 + first;
  
  		if (mid->num < cmd)
  			first = mid + 1;
  		else if (mid->num > cmd)
  			last = mid - 1;
  		else
  			return mid->func;
  	}

  	return no_such_ioctl;
  }
  
  static int no_such_ioctl_0(struct v4l2_int_device *d)
  {

  	return -ENOIOCTLCMD;

  }
  
  int v4l2_int_ioctl_0(struct v4l2_int_device *d, int cmd)
  {

  	return ((v4l2_int_ioctl_func_0 *)
  		find_ioctl(d->u.slave, cmd,

  			   (v4l2_int_ioctl_func *)no_such_ioctl_0))(d);

  }

  EXPORT_SYMBOL_GPL(v4l2_int_ioctl_0);

  
  static int no_such_ioctl_1(struct v4l2_int_device *d, void *arg)
  {

  	return -ENOIOCTLCMD;

  }
  
  int v4l2_int_ioctl_1(struct v4l2_int_device *d, int cmd, void *arg)
  {

  	return ((v4l2_int_ioctl_func_1 *)
  		find_ioctl(d->u.slave, cmd,

  			   (v4l2_int_ioctl_func *)no_such_ioctl_1))(d, arg);

  }

  EXPORT_SYMBOL_GPL(v4l2_int_ioctl_1);

  
  MODULE_LICENSE("GPL");