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
30 #include <media/v4l2-int-device.h>
31
32 static DEFINE_MUTEX(mutex);
33 static LIST_HEAD(int_list);
34
v4l2_int_device_try_attach_all(void)35 void v4l2_int_device_try_attach_all(void)
36 {
37 struct v4l2_int_device *m, *s;
38
39 list_for_each_entry(m, &int_list, head) {
40 if (m->type != v4l2_int_type_master)
41 continue;
42
43 list_for_each_entry(s, &int_list, head) {
44 if (s->type != v4l2_int_type_slave)
45 continue;
46
47 /* Slave is connected? */
48 if (s->u.slave->master)
49 continue;
50
51 /* Slave wants to attach to master? */
52 if (s->u.slave->attach_to[0] != 0
53 && strncmp(m->name, s->u.slave->attach_to,
54 V4L2NAMESIZE))
55 continue;
56
57 if (!try_module_get(m->module))
58 continue;
59
60 s->u.slave->master = m;
61 if (m->u.master->attach(s)) {
62 s->u.slave->master = NULL;
63 module_put(m->module);
64 continue;
65 }
66 }
67 }
68 }
69 EXPORT_SYMBOL_GPL(v4l2_int_device_try_attach_all);
70
ioctl_sort_cmp(const void * a,const void * b)71 static int ioctl_sort_cmp(const void *a, const void *b)
72 {
73 const struct v4l2_int_ioctl_desc *d1 = a, *d2 = b;
74
75 if (d1->num > d2->num)
76 return 1;
77
78 if (d1->num < d2->num)
79 return -1;
80
81 return 0;
82 }
83
v4l2_int_device_register(struct v4l2_int_device * d)84 int v4l2_int_device_register(struct v4l2_int_device *d)
85 {
86 if (d->type == v4l2_int_type_slave)
87 sort(d->u.slave->ioctls, d->u.slave->num_ioctls,
88 sizeof(struct v4l2_int_ioctl_desc),
89 &ioctl_sort_cmp, NULL);
90 mutex_lock(&mutex);
91 list_add(&d->head, &int_list);
92 v4l2_int_device_try_attach_all();
93 mutex_unlock(&mutex);
94
95 return 0;
96 }
97 EXPORT_SYMBOL_GPL(v4l2_int_device_register);
98
v4l2_int_device_unregister(struct v4l2_int_device * d)99 void v4l2_int_device_unregister(struct v4l2_int_device *d)
100 {
101 mutex_lock(&mutex);
102 list_del(&d->head);
103 if (d->type == v4l2_int_type_slave
104 && d->u.slave->master != NULL) {
105 d->u.slave->master->u.master->detach(d);
106 module_put(d->u.slave->master->module);
107 d->u.slave->master = NULL;
108 }
109 mutex_unlock(&mutex);
110 }
111 EXPORT_SYMBOL_GPL(v4l2_int_device_unregister);
112
113 /* Adapted from search_extable in extable.c. */
find_ioctl(struct v4l2_int_slave * slave,int cmd,v4l2_int_ioctl_func * no_such_ioctl)114 static v4l2_int_ioctl_func *find_ioctl(struct v4l2_int_slave *slave, int cmd,
115 v4l2_int_ioctl_func *no_such_ioctl)
116 {
117 const struct v4l2_int_ioctl_desc *first = slave->ioctls;
118 const struct v4l2_int_ioctl_desc *last =
119 first + slave->num_ioctls - 1;
120
121 while (first <= last) {
122 const struct v4l2_int_ioctl_desc *mid;
123
124 mid = (last - first) / 2 + first;
125
126 if (mid->num < cmd)
127 first = mid + 1;
128 else if (mid->num > cmd)
129 last = mid - 1;
130 else
131 return mid->func;
132 }
133
134 return no_such_ioctl;
135 }
136
no_such_ioctl_0(struct v4l2_int_device * d)137 static int no_such_ioctl_0(struct v4l2_int_device *d)
138 {
139 return -ENOIOCTLCMD;
140 }
141
v4l2_int_ioctl_0(struct v4l2_int_device * d,int cmd)142 int v4l2_int_ioctl_0(struct v4l2_int_device *d, int cmd)
143 {
144 return ((v4l2_int_ioctl_func_0 *)
145 find_ioctl(d->u.slave, cmd,
146 (v4l2_int_ioctl_func *)no_such_ioctl_0))(d);
147 }
148 EXPORT_SYMBOL_GPL(v4l2_int_ioctl_0);
149
no_such_ioctl_1(struct v4l2_int_device * d,void * arg)150 static int no_such_ioctl_1(struct v4l2_int_device *d, void *arg)
151 {
152 return -ENOIOCTLCMD;
153 }
154
v4l2_int_ioctl_1(struct v4l2_int_device * d,int cmd,void * arg)155 int v4l2_int_ioctl_1(struct v4l2_int_device *d, int cmd, void *arg)
156 {
157 return ((v4l2_int_ioctl_func_1 *)
158 find_ioctl(d->u.slave, cmd,
159 (v4l2_int_ioctl_func *)no_such_ioctl_1))(d, arg);
160 }
161 EXPORT_SYMBOL_GPL(v4l2_int_ioctl_1);
162
163 MODULE_LICENSE("GPL");
164