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
164
165
166
167
168
169
170
171
|
/*
* Telephony registration for Linux
*
* (c) Copyright 1999 Red Hat Software Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Author: Alan Cox, <alan@redhat.com>
*
* Fixes: Mar 01 2000 Thomas Sparr, <thomas.l.sparr@telia.com>
* phone_register_device now works with unit!=PHONE_UNIT_ANY
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/phonedev.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/kmod.h>
#include <linux/sem.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/mutex.h>
#define PHONE_NUM_DEVICES 256
/*
* Active devices
*/
static struct phone_device *phone_device[PHONE_NUM_DEVICES];
static DEFINE_MUTEX(phone_lock);
/*
* Open a phone device.
*/
static int phone_open(struct inode *inode, struct file *file)
{
unsigned int minor = iminor(inode);
int err = 0;
struct phone_device *p;
struct file_operations *old_fops, *new_fops = NULL;
if (minor >= PHONE_NUM_DEVICES)
return -ENODEV;
mutex_lock(&phone_lock);
p = phone_device[minor];
if (p)
new_fops = fops_get(p->f_op);
if (!new_fops) {
mutex_unlock(&phone_lock);
request_module("char-major-%d-%d", PHONE_MAJOR, minor);
mutex_lock(&phone_lock);
p = phone_device[minor];
if (p == NULL || (new_fops = fops_get(p->f_op)) == NULL)
{
err=-ENODEV;
goto end;
}
}
old_fops = file->f_op;
file->f_op = new_fops;
if (p->open)
err = p->open(p, file); /* Tell the device it is open */
if (err) {
fops_put(file->f_op);
file->f_op = fops_get(old_fops);
}
fops_put(old_fops);
end:
mutex_unlock(&phone_lock);
return err;
}
/*
* Telephony For Linux device drivers request registration here.
*/
int phone_register_device(struct phone_device *p, int unit)
{
int base;
int end;
int i;
base = 0;
end = PHONE_NUM_DEVICES - 1;
if (unit != PHONE_UNIT_ANY) {
base = unit;
end = unit + 1; /* enter the loop at least one time */
}
mutex_lock(&phone_lock);
for (i = base; i < end; i++) {
if (phone_device[i] == NULL) {
phone_device[i] = p;
p->minor = i;
devfs_mk_cdev(MKDEV(PHONE_MAJOR,i),
S_IFCHR|S_IRUSR|S_IWUSR, "phone/%d", i);
mutex_unlock(&phone_lock);
return 0;
}
}
mutex_unlock(&phone_lock);
return -ENFILE;
}
/*
* Unregister an unused Telephony for linux device
*/
void phone_unregister_device(struct phone_device *pfd)
{
mutex_lock(&phone_lock);
if (phone_device[pfd->minor] != pfd)
panic("phone: bad unregister");
devfs_remove("phone/%d", pfd->minor);
phone_device[pfd->minor] = NULL;
mutex_unlock(&phone_lock);
}
static struct file_operations phone_fops =
{
.owner = THIS_MODULE,
.open = phone_open,
};
/*
* Board init functions
*/
/*
* Initialise Telephony for linux
*/
static int __init telephony_init(void)
{
printk(KERN_INFO "Linux telephony interface: v1.00\n");
if (register_chrdev(PHONE_MAJOR, "telephony", &phone_fops)) {
printk("phonedev: unable to get major %d\n", PHONE_MAJOR);
return -EIO;
}
return 0;
}
static void __exit telephony_exit(void)
{
unregister_chrdev(PHONE_MAJOR, "telephony");
}
module_init(telephony_init);
module_exit(telephony_exit);
MODULE_LICENSE("GPL");
EXPORT_SYMBOL(phone_register_device);
EXPORT_SYMBOL(phone_unregister_device);
|
