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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> | |
16750c2f | 26 | #include <linux/smp_lock.h> |
1da177e4 LT |
27 | #include <asm/uaccess.h> |
28 | #include <asm/system.h> | |
29 | ||
30 | #include <linux/kmod.h> | |
31 | #include <linux/sem.h> | |
14cc3e2b | 32 | #include <linux/mutex.h> |
1da177e4 LT |
33 | |
34 | #define PHONE_NUM_DEVICES 256 | |
35 | ||
36 | /* | |
37 | * Active devices | |
38 | */ | |
39 | ||
40 | static struct phone_device *phone_device[PHONE_NUM_DEVICES]; | |
14cc3e2b | 41 | static DEFINE_MUTEX(phone_lock); |
1da177e4 LT |
42 | |
43 | /* | |
44 | * Open a phone device. | |
45 | */ | |
46 | ||
47 | static int phone_open(struct inode *inode, struct file *file) | |
48 | { | |
49 | unsigned int minor = iminor(inode); | |
50 | int err = 0; | |
51 | struct phone_device *p; | |
99ac48f5 | 52 | const struct file_operations *old_fops, *new_fops = NULL; |
1da177e4 LT |
53 | |
54 | if (minor >= PHONE_NUM_DEVICES) | |
55 | return -ENODEV; | |
56 | ||
16750c2f | 57 | lock_kernel(); |
14cc3e2b | 58 | mutex_lock(&phone_lock); |
1da177e4 LT |
59 | p = phone_device[minor]; |
60 | if (p) | |
61 | new_fops = fops_get(p->f_op); | |
62 | if (!new_fops) { | |
14cc3e2b | 63 | mutex_unlock(&phone_lock); |
1da177e4 | 64 | request_module("char-major-%d-%d", PHONE_MAJOR, minor); |
14cc3e2b | 65 | mutex_lock(&phone_lock); |
1da177e4 LT |
66 | p = phone_device[minor]; |
67 | if (p == NULL || (new_fops = fops_get(p->f_op)) == NULL) | |
68 | { | |
69 | err=-ENODEV; | |
70 | goto end; | |
71 | } | |
72 | } | |
73 | old_fops = file->f_op; | |
74 | file->f_op = new_fops; | |
75 | if (p->open) | |
76 | err = p->open(p, file); /* Tell the device it is open */ | |
77 | if (err) { | |
78 | fops_put(file->f_op); | |
79 | file->f_op = fops_get(old_fops); | |
80 | } | |
81 | fops_put(old_fops); | |
82 | end: | |
14cc3e2b | 83 | mutex_unlock(&phone_lock); |
16750c2f | 84 | unlock_kernel(); |
1da177e4 LT |
85 | return err; |
86 | } | |
87 | ||
88 | /* | |
89 | * Telephony For Linux device drivers request registration here. | |
90 | */ | |
91 | ||
92 | int phone_register_device(struct phone_device *p, int unit) | |
93 | { | |
94 | int base; | |
95 | int end; | |
96 | int i; | |
97 | ||
98 | base = 0; | |
99 | end = PHONE_NUM_DEVICES - 1; | |
100 | ||
101 | if (unit != PHONE_UNIT_ANY) { | |
102 | base = unit; | |
103 | end = unit + 1; /* enter the loop at least one time */ | |
104 | } | |
105 | ||
14cc3e2b | 106 | mutex_lock(&phone_lock); |
1da177e4 LT |
107 | for (i = base; i < end; i++) { |
108 | if (phone_device[i] == NULL) { | |
109 | phone_device[i] = p; | |
110 | p->minor = i; | |
14cc3e2b | 111 | mutex_unlock(&phone_lock); |
1da177e4 LT |
112 | return 0; |
113 | } | |
114 | } | |
14cc3e2b | 115 | mutex_unlock(&phone_lock); |
1da177e4 LT |
116 | return -ENFILE; |
117 | } | |
118 | ||
119 | /* | |
120 | * Unregister an unused Telephony for linux device | |
121 | */ | |
122 | ||
123 | void phone_unregister_device(struct phone_device *pfd) | |
124 | { | |
14cc3e2b | 125 | mutex_lock(&phone_lock); |
01aae971 ML |
126 | if (likely(phone_device[pfd->minor] == pfd)) |
127 | phone_device[pfd->minor] = NULL; | |
14cc3e2b | 128 | mutex_unlock(&phone_lock); |
1da177e4 LT |
129 | } |
130 | ||
131 | ||
00977a59 | 132 | static const struct file_operations phone_fops = |
1da177e4 LT |
133 | { |
134 | .owner = THIS_MODULE, | |
135 | .open = phone_open, | |
136 | }; | |
137 | ||
138 | /* | |
139 | * Board init functions | |
140 | */ | |
141 | ||
142 | ||
143 | /* | |
144 | * Initialise Telephony for linux | |
145 | */ | |
146 | ||
147 | static int __init telephony_init(void) | |
148 | { | |
149 | printk(KERN_INFO "Linux telephony interface: v1.00\n"); | |
150 | if (register_chrdev(PHONE_MAJOR, "telephony", &phone_fops)) { | |
151 | printk("phonedev: unable to get major %d\n", PHONE_MAJOR); | |
152 | return -EIO; | |
153 | } | |
154 | ||
155 | return 0; | |
156 | } | |
157 | ||
158 | static void __exit telephony_exit(void) | |
159 | { | |
160 | unregister_chrdev(PHONE_MAJOR, "telephony"); | |
161 | } | |
162 | ||
163 | module_init(telephony_init); | |
164 | module_exit(telephony_exit); | |
165 | ||
166 | MODULE_LICENSE("GPL"); | |
167 | ||
168 | EXPORT_SYMBOL(phone_register_device); | |
169 | EXPORT_SYMBOL(phone_unregister_device); |