Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Telephony registration for Linux | |
3 | * | |
4 | * (c) Copyright 1999 Red Hat Software Inc. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * Author: Alan Cox, <alan@redhat.com> | |
12 | * | |
13 | * Fixes: Mar 01 2000 Thomas Sparr, <thomas.l.sparr@telia.com> | |
14 | * phone_register_device now works with unit!=PHONE_UNIT_ANY | |
15 | */ | |
16 | ||
17 | #include <linux/module.h> | |
18 | #include <linux/types.h> | |
19 | #include <linux/kernel.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/mm.h> | |
22 | #include <linux/string.h> | |
23 | #include <linux/errno.h> | |
24 | #include <linux/phonedev.h> | |
25 | #include <linux/init.h> | |
26 | #include <asm/uaccess.h> | |
27 | #include <asm/system.h> | |
28 | ||
29 | #include <linux/kmod.h> | |
30 | #include <linux/sem.h> | |
14cc3e2b | 31 | #include <linux/mutex.h> |
1da177e4 LT |
32 | |
33 | #define PHONE_NUM_DEVICES 256 | |
34 | ||
35 | /* | |
36 | * Active devices | |
37 | */ | |
38 | ||
39 | static struct phone_device *phone_device[PHONE_NUM_DEVICES]; | |
14cc3e2b | 40 | static DEFINE_MUTEX(phone_lock); |
1da177e4 LT |
41 | |
42 | /* | |
43 | * Open a phone device. | |
44 | */ | |
45 | ||
46 | static int phone_open(struct inode *inode, struct file *file) | |
47 | { | |
48 | unsigned int minor = iminor(inode); | |
49 | int err = 0; | |
50 | struct phone_device *p; | |
99ac48f5 | 51 | const struct file_operations *old_fops, *new_fops = NULL; |
1da177e4 LT |
52 | |
53 | if (minor >= PHONE_NUM_DEVICES) | |
54 | return -ENODEV; | |
55 | ||
14cc3e2b | 56 | mutex_lock(&phone_lock); |
1da177e4 LT |
57 | p = phone_device[minor]; |
58 | if (p) | |
59 | new_fops = fops_get(p->f_op); | |
60 | if (!new_fops) { | |
14cc3e2b | 61 | mutex_unlock(&phone_lock); |
1da177e4 | 62 | request_module("char-major-%d-%d", PHONE_MAJOR, minor); |
14cc3e2b | 63 | mutex_lock(&phone_lock); |
1da177e4 LT |
64 | p = phone_device[minor]; |
65 | if (p == NULL || (new_fops = fops_get(p->f_op)) == NULL) | |
66 | { | |
67 | err=-ENODEV; | |
68 | goto end; | |
69 | } | |
70 | } | |
71 | old_fops = file->f_op; | |
72 | file->f_op = new_fops; | |
73 | if (p->open) | |
74 | err = p->open(p, file); /* Tell the device it is open */ | |
75 | if (err) { | |
76 | fops_put(file->f_op); | |
77 | file->f_op = fops_get(old_fops); | |
78 | } | |
79 | fops_put(old_fops); | |
80 | end: | |
14cc3e2b | 81 | mutex_unlock(&phone_lock); |
1da177e4 LT |
82 | return err; |
83 | } | |
84 | ||
85 | /* | |
86 | * Telephony For Linux device drivers request registration here. | |
87 | */ | |
88 | ||
89 | int phone_register_device(struct phone_device *p, int unit) | |
90 | { | |
91 | int base; | |
92 | int end; | |
93 | int i; | |
94 | ||
95 | base = 0; | |
96 | end = PHONE_NUM_DEVICES - 1; | |
97 | ||
98 | if (unit != PHONE_UNIT_ANY) { | |
99 | base = unit; | |
100 | end = unit + 1; /* enter the loop at least one time */ | |
101 | } | |
102 | ||
14cc3e2b | 103 | mutex_lock(&phone_lock); |
1da177e4 LT |
104 | for (i = base; i < end; i++) { |
105 | if (phone_device[i] == NULL) { | |
106 | phone_device[i] = p; | |
107 | p->minor = i; | |
14cc3e2b | 108 | mutex_unlock(&phone_lock); |
1da177e4 LT |
109 | return 0; |
110 | } | |
111 | } | |
14cc3e2b | 112 | mutex_unlock(&phone_lock); |
1da177e4 LT |
113 | return -ENFILE; |
114 | } | |
115 | ||
116 | /* | |
117 | * Unregister an unused Telephony for linux device | |
118 | */ | |
119 | ||
120 | void phone_unregister_device(struct phone_device *pfd) | |
121 | { | |
14cc3e2b | 122 | mutex_lock(&phone_lock); |
01aae971 ML |
123 | if (likely(phone_device[pfd->minor] == pfd)) |
124 | phone_device[pfd->minor] = NULL; | |
14cc3e2b | 125 | mutex_unlock(&phone_lock); |
1da177e4 LT |
126 | } |
127 | ||
128 | ||
00977a59 | 129 | static const struct file_operations phone_fops = |
1da177e4 LT |
130 | { |
131 | .owner = THIS_MODULE, | |
132 | .open = phone_open, | |
133 | }; | |
134 | ||
135 | /* | |
136 | * Board init functions | |
137 | */ | |
138 | ||
139 | ||
140 | /* | |
141 | * Initialise Telephony for linux | |
142 | */ | |
143 | ||
144 | static int __init telephony_init(void) | |
145 | { | |
146 | printk(KERN_INFO "Linux telephony interface: v1.00\n"); | |
147 | if (register_chrdev(PHONE_MAJOR, "telephony", &phone_fops)) { | |
148 | printk("phonedev: unable to get major %d\n", PHONE_MAJOR); | |
149 | return -EIO; | |
150 | } | |
151 | ||
152 | return 0; | |
153 | } | |
154 | ||
155 | static void __exit telephony_exit(void) | |
156 | { | |
157 | unregister_chrdev(PHONE_MAJOR, "telephony"); | |
158 | } | |
159 | ||
160 | module_init(telephony_init); | |
161 | module_exit(telephony_exit); | |
162 | ||
163 | MODULE_LICENSE("GPL"); | |
164 | ||
165 | EXPORT_SYMBOL(phone_register_device); | |
166 | EXPORT_SYMBOL(phone_unregister_device); |