1/*
2 * drivers/media/video/v4l2-int-device.c
3 *
4 * V4L2 internal ioctl interface.
5 *
6 * Copyright (C) 2007 Nokia Corporation.
7 *
8 * Contact: Sakari Ailus <sakari.ailus@nokia.com>
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 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22 * 02110-1301 USA
23 */
24
25#include <linux/kernel.h>
26#include <linux/list.h>
27#include <linux/sort.h>
28#include <linux/string.h>
29#include <linux/module.h>
30
31#include <media/v4l2-int-device.h>
32
33static DEFINE_MUTEX(mutex);
34static LIST_HEAD(int_list);
35
36void v4l2_int_device_try_attach_all(void)
37{
38	struct v4l2_int_device *m, *s;
39
40	list_for_each_entry(m, &int_list, head) {
41		if (m->type != v4l2_int_type_master)
42			continue;
43
44		list_for_each_entry(s, &int_list, head) {
45			if (s->type != v4l2_int_type_slave)
46				continue;
47
48			/* Slave is connected? */
49			if (s->u.slave->master)
50				continue;
51
52			/* Slave wants to attach to master? */
53			if (s->u.slave->attach_to[0] != 0
54			    && strncmp(m->name, s->u.slave->attach_to,
55				       V4L2NAMESIZE))
56				continue;
57
58			if (!try_module_get(m->module))
59				continue;
60
61			s->u.slave->master = m;
62			if (m->u.master->attach(s)) {
63				s->u.slave->master = NULL;
64				module_put(m->module);
65				continue;
66			}
67		}
68	}
69}
70EXPORT_SYMBOL_GPL(v4l2_int_device_try_attach_all);
71
72static int ioctl_sort_cmp(const void *a, const void *b)
73{
74	const struct v4l2_int_ioctl_desc *d1 = a, *d2 = b;
75
76	if (d1->num > d2->num)
77		return 1;
78
79	if (d1->num < d2->num)
80		return -1;
81
82	return 0;
83}
84
85int v4l2_int_device_register(struct v4l2_int_device *d)
86{
87	if (d->type == v4l2_int_type_slave)
88		sort(d->u.slave->ioctls, d->u.slave->num_ioctls,
89		     sizeof(struct v4l2_int_ioctl_desc),
90		     &ioctl_sort_cmp, NULL);
91	mutex_lock(&mutex);
92	list_add(&d->head, &int_list);
93	v4l2_int_device_try_attach_all();
94	mutex_unlock(&mutex);
95
96	return 0;
97}
98EXPORT_SYMBOL_GPL(v4l2_int_device_register);
99
100void v4l2_int_device_unregister(struct v4l2_int_device *d)
101{
102	mutex_lock(&mutex);
103	list_del(&d->head);
104	if (d->type == v4l2_int_type_slave
105	    && d->u.slave->master != NULL) {
106		d->u.slave->master->u.master->detach(d);
107		module_put(d->u.slave->master->module);
108		d->u.slave->master = NULL;
109	}
110	mutex_unlock(&mutex);
111}
112EXPORT_SYMBOL_GPL(v4l2_int_device_unregister);
113
114/* Adapted from search_extable in extable.c. */
115static v4l2_int_ioctl_func *find_ioctl(struct v4l2_int_slave *slave, int cmd,
116				       v4l2_int_ioctl_func *no_such_ioctl)
117{
118	const struct v4l2_int_ioctl_desc *first = slave->ioctls;
119	const struct v4l2_int_ioctl_desc *last =
120		first + slave->num_ioctls - 1;
121
122	while (first <= last) {
123		const struct v4l2_int_ioctl_desc *mid;
124
125		mid = (last - first) / 2 + first;
126
127		if (mid->num < cmd)
128			first = mid + 1;
129		else if (mid->num > cmd)
130			last = mid - 1;
131		else
132			return mid->func;
133	}
134
135	return no_such_ioctl;
136}
137
138static int no_such_ioctl_0(struct v4l2_int_device *d)
139{
140	return -ENOIOCTLCMD;
141}
142
143int v4l2_int_ioctl_0(struct v4l2_int_device *d, int cmd)
144{
145	return ((v4l2_int_ioctl_func_0 *)
146		find_ioctl(d->u.slave, cmd,
147			   (v4l2_int_ioctl_func *)no_such_ioctl_0))(d);
148}
149EXPORT_SYMBOL_GPL(v4l2_int_ioctl_0);
150
151static int no_such_ioctl_1(struct v4l2_int_device *d, void *arg)
152{
153	return -ENOIOCTLCMD;
154}
155
156int v4l2_int_ioctl_1(struct v4l2_int_device *d, int cmd, void *arg)
157{
158	return ((v4l2_int_ioctl_func_1 *)
159		find_ioctl(d->u.slave, cmd,
160			   (v4l2_int_ioctl_func *)no_such_ioctl_1))(d, arg);
161}
162EXPORT_SYMBOL_GPL(v4l2_int_ioctl_1);
163
164MODULE_LICENSE("GPL");
165