aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/media/video/v4l2-int-device.c
blob: a935bae538ef26f4455cea5f58e0bf1da2b7c159 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
/*
 * 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");