[linux-2.6-block.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 <linux/smp_lock.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,
};

/*
 *	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>
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
14cc3e2b	57	mutex_lock(&phone_lock);
1da177e4 LT	58	p = phone_device[minor];
	59	if (p)
	60	new_fops = fops_get(p->f_op);
	61	if (!new_fops) {
14cc3e2b	62	mutex_unlock(&phone_lock);
1da177e4	63	request_module("char-major-%d-%d", PHONE_MAJOR, minor);
14cc3e2b	64	mutex_lock(&phone_lock);
1da177e4 LT	65	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);
	81	end:
14cc3e2b	82	mutex_unlock(&phone_lock);
1da177e4 LT	83	return err;
	84	}
	85
	86	/*
	87	* Telephony For Linux device drivers request registration here.
	88	*/
	89
	90	int 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
14cc3e2b	104	mutex_lock(&phone_lock);
1da177e4 LT	105	for (i = base; i < end; i++) {
	106	if (phone_device[i] == NULL) {
	107	phone_device[i] = p;
	108	p->minor = i;
14cc3e2b	109	mutex_unlock(&phone_lock);
1da177e4 LT	110	return 0;
	111	}
	112	}
14cc3e2b	113	mutex_unlock(&phone_lock);
1da177e4 LT	114	return -ENFILE;
	115	}
	116
	117	/*
	118	* Unregister an unused Telephony for linux device
	119	*/
	120
	121	void phone_unregister_device(struct phone_device *pfd)
	122	{
14cc3e2b	123	mutex_lock(&phone_lock);
01aae971 ML	124	if (likely(phone_device[pfd->minor] == pfd))
01aae971 ML	125	phone_device[pfd->minor] = NULL;
14cc3e2b	126	mutex_unlock(&phone_lock);
1da177e4 LT	127	}
	128
	129
00977a59	130	static const struct file_operations phone_fops =
1da177e4 LT	131	{
	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
	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);