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
33 static DEFINE_MUTEX(mutex);
34 static LIST_HEAD(int_list);
35
v4l2_int_device_try_attach_all(void)36 void 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 }
70 EXPORT_SYMBOL_GPL(v4l2_int_device_try_attach_all);
71
ioctl_sort_cmp(const void * a,const void * b)72 static 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
v4l2_int_device_register(struct v4l2_int_device * d)85 int 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 }
98 EXPORT_SYMBOL_GPL(v4l2_int_device_register);
99
v4l2_int_device_unregister(struct v4l2_int_device * d)100 void 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 }
112 EXPORT_SYMBOL_GPL(v4l2_int_device_unregister);
113
114 /* Adapted from search_extable in extable.c. */
find_ioctl(struct v4l2_int_slave * slave,int cmd,v4l2_int_ioctl_func * no_such_ioctl)115 static 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
no_such_ioctl_0(struct v4l2_int_device * d)138 static int no_such_ioctl_0(struct v4l2_int_device *d)
139 {
140 return -ENOIOCTLCMD;
141 }
142
v4l2_int_ioctl_0(struct v4l2_int_device * d,int cmd)143 int 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 }
149 EXPORT_SYMBOL_GPL(v4l2_int_ioctl_0);
150
no_such_ioctl_1(struct v4l2_int_device * d,void * arg)151 static int no_such_ioctl_1(struct v4l2_int_device *d, void *arg)
152 {
153 return -ENOIOCTLCMD;
154 }
155
v4l2_int_ioctl_1(struct v4l2_int_device * d,int cmd,void * arg)156 int 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 }
162 EXPORT_SYMBOL_GPL(v4l2_int_ioctl_1);
163
164 MODULE_LICENSE("GPL");
165