[net-next-2.6.git] / drivers / telephony / phonedev.c

/*
 *            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@lxorguk.ukuu.org.uk>
 *
 * 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/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;
	const 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;
			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 (likely(phone_device[pfd->minor] == pfd))
		phone_device[pfd->minor] = NULL;
	mutex_unlock(&phone_lock);
}


static const struct file_operations phone_fops =
{
	.owner		= THIS_MODULE,
	.open		= phone_open,
	.llseek		= noop_llseek,
};

/*
 *	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);
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	*
0906dd9d	11	* Author: Alan Cox, <alan@lxorguk.ukuu.org.uk>
1da177e4 LT	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))
01aae971 ML	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,
6038f373	133	.llseek = noop_llseek,
1da177e4 LT	134	};
	135
	136	/*
	137	* Board init functions
	138	*/
	139
	140
	141	/*
	142	* Initialise Telephony for linux
	143	*/
	144
	145	static 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
	156	static void __exit telephony_exit(void)
	157	{
	158	unregister_chrdev(PHONE_MAJOR, "telephony");
	159	}
	160
	161	module_init(telephony_init);
	162	module_exit(telephony_exit);
	163
	164	MODULE_LICENSE("GPL");
	165
	166	EXPORT_SYMBOL(phone_register_device);
	167	EXPORT_SYMBOL(phone_unregister_device);