V4L/DVB (8489): add dvb-t support for terratec cinergy hybrid T usb xs
[linux-2.6] / drivers / media / video / v4l2-int-device.c
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
35 static 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
70 static int ioctl_sort_cmp(const void *a, const void *b)
71 {
72         const struct v4l2_int_ioctl_desc *d1 = a, *d2 = b;
73
74         if (d1->num > d2->num)
75                 return 1;
76
77         if (d1->num < d2->num)
78                 return -1;
79
80         return 0;
81 }
82
83 int v4l2_int_device_register(struct v4l2_int_device *d)
84 {
85         if (d->type == v4l2_int_type_slave)
86                 sort(d->u.slave->ioctls, d->u.slave->num_ioctls,
87                      sizeof(struct v4l2_int_ioctl_desc),
88                      &ioctl_sort_cmp, NULL);
89         mutex_lock(&mutex);
90         list_add(&d->head, &int_list);
91         v4l2_int_device_try_attach_all();
92         mutex_unlock(&mutex);
93
94         return 0;
95 }
96 EXPORT_SYMBOL_GPL(v4l2_int_device_register);
97
98 void v4l2_int_device_unregister(struct v4l2_int_device *d)
99 {
100         mutex_lock(&mutex);
101         list_del(&d->head);
102         if (d->type == v4l2_int_type_slave
103             && d->u.slave->master != NULL) {
104                 d->u.slave->master->u.master->detach(d);
105                 module_put(d->u.slave->master->module);
106                 d->u.slave->master = NULL;
107         }
108         mutex_unlock(&mutex);
109 }
110 EXPORT_SYMBOL_GPL(v4l2_int_device_unregister);
111
112 /* Adapted from search_extable in extable.c. */
113 static v4l2_int_ioctl_func *find_ioctl(struct v4l2_int_slave *slave, int cmd,
114                                        v4l2_int_ioctl_func *no_such_ioctl)
115 {
116         const struct v4l2_int_ioctl_desc *first = slave->ioctls;
117         const struct v4l2_int_ioctl_desc *last =
118                 first + slave->num_ioctls - 1;
119
120         while (first <= last) {
121                 const struct v4l2_int_ioctl_desc *mid;
122
123                 mid = (last - first) / 2 + first;
124
125                 if (mid->num < cmd)
126                         first = mid + 1;
127                 else if (mid->num > cmd)
128                         last = mid - 1;
129                 else
130                         return mid->func;
131         }
132
133         return no_such_ioctl;
134 }
135
136 static int no_such_ioctl_0(struct v4l2_int_device *d)
137 {
138         return -ENOIOCTLCMD;
139 }
140
141 int v4l2_int_ioctl_0(struct v4l2_int_device *d, int cmd)
142 {
143         return ((v4l2_int_ioctl_func_0 *)
144                 find_ioctl(d->u.slave, cmd,
145                            (v4l2_int_ioctl_func *)no_such_ioctl_0))(d);
146 }
147
148 static int no_such_ioctl_1(struct v4l2_int_device *d, void *arg)
149 {
150         return -ENOIOCTLCMD;
151 }
152
153 int v4l2_int_ioctl_1(struct v4l2_int_device *d, int cmd, void *arg)
154 {
155         return ((v4l2_int_ioctl_func_1 *)
156                 find_ioctl(d->u.slave, cmd,
157                            (v4l2_int_ioctl_func *)no_such_ioctl_1))(d, arg);
158 }
159
160 MODULE_LICENSE("GPL");