blob: 37caf4d690370489cd7dcbd880f035c67c0c4bd2 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Jonathan Corbet16750c22008-05-15 11:58:31 -060026#include <linux/smp_lock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <asm/uaccess.h>
28#include <asm/system.h>
29
30#include <linux/kmod.h>
31#include <linux/sem.h>
Ingo Molnar14cc3e22006-03-26 01:37:14 -080032#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34#define PHONE_NUM_DEVICES 256
35
36/*
37 * Active devices
38 */
39
40static struct phone_device *phone_device[PHONE_NUM_DEVICES];
Ingo Molnar14cc3e22006-03-26 01:37:14 -080041static DEFINE_MUTEX(phone_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
43/*
44 * Open a phone device.
45 */
46
47static 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;
Arjan van de Ven99ac48f2006-03-28 01:56:41 -080052 const struct file_operations *old_fops, *new_fops = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
54 if (minor >= PHONE_NUM_DEVICES)
55 return -ENODEV;
56
Ingo Molnar14cc3e22006-03-26 01:37:14 -080057 mutex_lock(&phone_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 p = phone_device[minor];
59 if (p)
60 new_fops = fops_get(p->f_op);
61 if (!new_fops) {
Ingo Molnar14cc3e22006-03-26 01:37:14 -080062 mutex_unlock(&phone_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 request_module("char-major-%d-%d", PHONE_MAJOR, minor);
Ingo Molnar14cc3e22006-03-26 01:37:14 -080064 mutex_lock(&phone_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 p = phone_device[minor];
66 if (p == NULL || (new_fops = fops_get(p->f_op)) == NULL)
67 {
68 err=-ENODEV;
69 goto end;
70 }
71 }
72 old_fops = file->f_op;
73 file->f_op = new_fops;
74 if (p->open)
75 err = p->open(p, file); /* Tell the device it is open */
76 if (err) {
77 fops_put(file->f_op);
78 file->f_op = fops_get(old_fops);
79 }
80 fops_put(old_fops);
81end:
Ingo Molnar14cc3e22006-03-26 01:37:14 -080082 mutex_unlock(&phone_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 return err;
84}
85
86/*
87 * Telephony For Linux device drivers request registration here.
88 */
89
90int phone_register_device(struct phone_device *p, int unit)
91{
92 int base;
93 int end;
94 int i;
95
96 base = 0;
97 end = PHONE_NUM_DEVICES - 1;
98
99 if (unit != PHONE_UNIT_ANY) {
100 base = unit;
101 end = unit + 1; /* enter the loop at least one time */
102 }
103
Ingo Molnar14cc3e22006-03-26 01:37:14 -0800104 mutex_lock(&phone_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 for (i = base; i < end; i++) {
106 if (phone_device[i] == NULL) {
107 phone_device[i] = p;
108 p->minor = i;
Ingo Molnar14cc3e22006-03-26 01:37:14 -0800109 mutex_unlock(&phone_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 return 0;
111 }
112 }
Ingo Molnar14cc3e22006-03-26 01:37:14 -0800113 mutex_unlock(&phone_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 return -ENFILE;
115}
116
117/*
118 * Unregister an unused Telephony for linux device
119 */
120
121void phone_unregister_device(struct phone_device *pfd)
122{
Ingo Molnar14cc3e22006-03-26 01:37:14 -0800123 mutex_lock(&phone_lock);
Matti Linnanvuori01aae972007-11-05 14:51:02 -0800124 if (likely(phone_device[pfd->minor] == pfd))
125 phone_device[pfd->minor] = NULL;
Ingo Molnar14cc3e22006-03-26 01:37:14 -0800126 mutex_unlock(&phone_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127}
128
129
Arjan van de Ven00977a52007-02-12 00:55:34 -0800130static const struct file_operations phone_fops =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131{
132 .owner = THIS_MODULE,
133 .open = phone_open,
134};
135
136/*
137 * Board init functions
138 */
139
140
141/*
142 * Initialise Telephony for linux
143 */
144
145static int __init telephony_init(void)
146{
147 printk(KERN_INFO "Linux telephony interface: v1.00\n");
148 if (register_chrdev(PHONE_MAJOR, "telephony", &phone_fops)) {
149 printk("phonedev: unable to get major %d\n", PHONE_MAJOR);
150 return -EIO;
151 }
152
153 return 0;
154}
155
156static void __exit telephony_exit(void)
157{
158 unregister_chrdev(PHONE_MAJOR, "telephony");
159}
160
161module_init(telephony_init);
162module_exit(telephony_exit);
163
164MODULE_LICENSE("GPL");
165
166EXPORT_SYMBOL(phone_register_device);
167EXPORT_SYMBOL(phone_unregister_device);