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/*

 * 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);

}