/* * 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);static 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;			if (m->u.master->attach(m, s)) {				module_put(m->module);				continue;			}			s->u.slave->master = m;		}	}}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);}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);}