blob: a5b601923a54db643ab32855974e8bdff7bfcd98 [file] [log] [blame]
/*
* 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/version.h>
#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>
#define PHONE_NUM_DEVICES 256
/*
* Active devices
*/
static struct phone_device *phone_device[PHONE_NUM_DEVICES];
static DECLARE_MUTEX(phone_lock);
/*
* Open a phone device.
*/
static int phone_open(struct inode *inode, struct file *file)
{
unsigned int minor = minor(inode->i_rdev);
int err = 0;
struct phone_device *p;
struct file_operations *old_fops, *new_fops = NULL;
if (minor >= PHONE_NUM_DEVICES)
return -ENODEV;
down(&phone_lock);
p = phone_device[minor];
if (p)
new_fops = fops_get(p->f_op);
if (!new_fops) {
char modname[32];
up(&phone_lock);
sprintf(modname, "char-major-%d-%d", PHONE_MAJOR, minor);
request_module(modname);
down(&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:
up(&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 */
}
down(&phone_lock);
for (i = base; i < end; i++) {
if (phone_device[i] == NULL) {
phone_device[i] = p;
p->minor = i;
MOD_INC_USE_COUNT;
up(&phone_lock);
return 0;
}
}
up(&phone_lock);
return -ENFILE;
}
/*
* Unregister an unused Telephony for linux device
*/
void phone_unregister_device(struct phone_device *pfd)
{
down(&phone_lock);
if (phone_device[pfd->minor] != pfd)
panic("phone: bad unregister");
phone_device[pfd->minor] = NULL;
up(&phone_lock);
MOD_DEC_USE_COUNT;
}
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);