drivers/watchdog/w83877f_wdt.c - kernel/msm - Gitiles

 /*
  *	W83877F Computer Watchdog Timer driver
  *
  *      Based on acquirewdt.c by Alan Cox,
  *           and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
  *
  *	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.
  *
  *	The authors do NOT admit liability nor provide warranty for
  *	any of this software. This material is provided "AS-IS" in
  *      the hope that it may be useful for others.
  *
  *	(c) Copyright 2001    Scott Jennings <linuxdrivers@oro.net>
  *
  *           4/19 - 2001      [Initial revision]
  *           9/27 - 2001      Added spinlocking
  *           4/12 - 2002      [rob@osinvestor.com] Eliminate extra comments
  *                            Eliminate fop_read
  *                            Eliminate extra spin_unlock
  *                            Added KERN_* tags to printks
  *                            add CONFIG_WATCHDOG_NOWAYOUT support
  *                            fix possible wdt_is_open race
  *                            changed watchdog_info to correctly reflect what the driver offers
  *                            added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, WDIOC_SETTIMEOUT,
  *                            WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls
  *           09/8 - 2003      [wim@iguana.be] cleanup of trailing spaces
  *                            added extra printk's for startup problems
  *                            use module_param
  *                            made timeout (the emulated heartbeat) a module_param
  *                            made the keepalive ping an internal subroutine
  *
  *  This WDT driver is different from most other Linux WDT
  *  drivers in that the driver will ping the watchdog by itself,
  *  because this particular WDT has a very short timeout (1.6
  *  seconds) and it would be insane to count on any userspace
  *  daemon always getting scheduled within that time frame.
  */

 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/types.h>
 #include <linux/timer.h>
 #include <linux/jiffies.h>
 #include <linux/miscdevice.h>
 #include <linux/watchdog.h>
 #include <linux/fs.h>
 #include <linux/ioport.h>
 #include <linux/notifier.h>
 #include <linux/reboot.h>
 #include <linux/init.h>
 #include <asm/io.h>
 #include <asm/uaccess.h>
 #include <asm/system.h>

 #define OUR_NAME "w83877f_wdt"
 #define PFX OUR_NAME ": "

 #define ENABLE_W83877F_PORT 0x3F0
 #define ENABLE_W83877F 0x87
 #define DISABLE_W83877F 0xAA
 #define WDT_PING 0x443
 #define WDT_REGISTER 0x14
 #define WDT_ENABLE 0x9C
 #define WDT_DISABLE 0x8C

 /*
  * The W83877F seems to be fixed at 1.6s timeout (at least on the
  * EMACS PC-104 board I'm using). If we reset the watchdog every
  * ~250ms we should be safe.  */

 #define WDT_INTERVAL (HZ/4+1)

 /*
  * We must not require too good response from the userspace daemon.
  * Here we require the userspace daemon to send us a heartbeat
  * char to /dev/watchdog every 30 seconds.
  */

 #define WATCHDOG_TIMEOUT 30            /* 30 sec default timeout */
 static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
 module_param(timeout, int, 0);
 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");


 static int nowayout = WATCHDOG_NOWAYOUT;
 module_param(nowayout, int, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

 static void wdt_timer_ping(unsigned long);
 static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0);
 static unsigned long next_heartbeat;
 static unsigned long wdt_is_open;
 static char wdt_expect_close;
 static DEFINE_SPINLOCK(wdt_spinlock);

 /*
  *	Whack the dog
  */

 static void wdt_timer_ping(unsigned long data)
 {
 	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
 	 * we agree to ping the WDT
 	 */
 	if(time_before(jiffies, next_heartbeat))
 	{
 		/* Ping the WDT */
 		spin_lock(&wdt_spinlock);

 		/* Ping the WDT by reading from WDT_PING */
 		inb_p(WDT_PING);

 		/* Re-set the timer interval */
 		mod_timer(&timer, jiffies + WDT_INTERVAL);

 		spin_unlock(&wdt_spinlock);

 	} else {
 		printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
 	}
 }

 /*
  * Utility routines
  */

 static void wdt_change(int writeval)
 {
 	unsigned long flags;
 	spin_lock_irqsave(&wdt_spinlock, flags);

 	/* buy some time */
 	inb_p(WDT_PING);

 	/* make W83877F available */
 	outb_p(ENABLE_W83877F,  ENABLE_W83877F_PORT);
 	outb_p(ENABLE_W83877F,  ENABLE_W83877F_PORT);

 	/* enable watchdog */
 	outb_p(WDT_REGISTER,    ENABLE_W83877F_PORT);
 	outb_p(writeval,        ENABLE_W83877F_PORT+1);

 	/* lock the W8387FF away */
 	outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT);

 	spin_unlock_irqrestore(&wdt_spinlock, flags);
 }

 static void wdt_startup(void)
 {
 	next_heartbeat = jiffies + (timeout * HZ);

 	/* Start the timer */
 	mod_timer(&timer, jiffies + WDT_INTERVAL);

 	wdt_change(WDT_ENABLE);

 	printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
 }

 static void wdt_turnoff(void)
 {
 	/* Stop the timer */
 	del_timer(&timer);

 	wdt_change(WDT_DISABLE);

 	printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
 }

 static void wdt_keepalive(void)
 {
 	/* user land ping */
 	next_heartbeat = jiffies + (timeout * HZ);
 }

 /*
  * /dev/watchdog handling
  */

 static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
 {
 	/* See if we got the magic character 'V' and reload the timer */
 	if(count)
 	{
 		if (!nowayout)
 		{
 			size_t ofs;

 			/* note: just in case someone wrote the magic character
 			 * five months ago... */
 			wdt_expect_close = 0;

 			/* scan to see whether or not we got the magic character */
 			for(ofs = 0; ofs != count; ofs++)
 			{
 				char c;
 				if (get_user(c, buf + ofs))
 					return -EFAULT;
 				if (c == 'V')
 					wdt_expect_close = 42;
 			}
 		}

 		/* someone wrote to us, we should restart timer */
 		wdt_keepalive();
 	}
 	return count;
 }

 static int fop_open(struct inode * inode, struct file * file)
 {
 	/* Just in case we're already talking to someone... */
 	if(test_and_set_bit(0, &wdt_is_open))
 		return -EBUSY;

 	/* Good, fire up the show */
 	wdt_startup();
 	return nonseekable_open(inode, file);
 }

 static int fop_close(struct inode * inode, struct file * file)
 {
 	if(wdt_expect_close == 42)
 		wdt_turnoff();
 	else {
 		del_timer(&timer);
 		printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
 	}
 	clear_bit(0, &wdt_is_open);
 	wdt_expect_close = 0;
 	return 0;
 }

 static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 	unsigned long arg)
 {
 	void __user *argp = (void __user *)arg;
 	int __user *p = argp;
 	static struct watchdog_info ident=
 	{
 		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 		.firmware_version = 1,
 		.identity = "W83877F",
 	};

 	switch(cmd)
 	{
 		default:
 			return -ENOTTY;
 		case WDIOC_GETSUPPORT:
 			return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
 		case WDIOC_GETSTATUS:
 		case WDIOC_GETBOOTSTATUS:
 			return put_user(0, p);
 		case WDIOC_KEEPALIVE:
 			wdt_keepalive();
 			return 0;
 		case WDIOC_SETOPTIONS:
 		{
 			int new_options, retval = -EINVAL;

 			if(get_user(new_options, p))
 				return -EFAULT;

 			if(new_options & WDIOS_DISABLECARD) {
 				wdt_turnoff();
 				retval = 0;
 			}

 			if(new_options & WDIOS_ENABLECARD) {
 				wdt_startup();
 				retval = 0;
 			}

 			return retval;
 		}
 		case WDIOC_SETTIMEOUT:
 		{
 			int new_timeout;

 			if(get_user(new_timeout, p))
 				return -EFAULT;

 			if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
 				return -EINVAL;

 			timeout = new_timeout;
 			wdt_keepalive();
 			/* Fall through */
 		}
 		case WDIOC_GETTIMEOUT:
 			return put_user(timeout, p);
 	}
 }

 static const struct file_operations wdt_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.write		= fop_write,
 	.open		= fop_open,
 	.release	= fop_close,
 	.ioctl		= fop_ioctl,
 };

 static struct miscdevice wdt_miscdev = {
 	.minor	= WATCHDOG_MINOR,
 	.name	= "watchdog",
 	.fops	= &wdt_fops,
 };

 /*
  *	Notifier for system down
  */

 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 	void *unused)
 {
 	if(code==SYS_DOWN || code==SYS_HALT)
 		wdt_turnoff();
 	return NOTIFY_DONE;
 }

 /*
  *	The WDT needs to learn about soft shutdowns in order to
  *	turn the timebomb registers off.
  */

 static struct notifier_block wdt_notifier=
 {
 	.notifier_call = wdt_notify_sys,
 };

 static void __exit w83877f_wdt_unload(void)
 {
 	wdt_turnoff();

 	/* Deregister */
 	misc_deregister(&wdt_miscdev);

 	unregister_reboot_notifier(&wdt_notifier);
 	release_region(WDT_PING,1);
 	release_region(ENABLE_W83877F_PORT,2);
 }

 static int __init w83877f_wdt_init(void)
 {
 	int rc = -EBUSY;

 	if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
 	{
 		timeout = WATCHDOG_TIMEOUT;
 		printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
 			timeout);
 	}

 	if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT"))
 	{
 		printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 			ENABLE_W83877F_PORT);
 		rc = -EIO;
 		goto err_out;
 	}

 	if (!request_region(WDT_PING, 1, "W8387FF WDT"))
 	{
 		printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 			WDT_PING);
 		rc = -EIO;
 		goto err_out_region1;
 	}

 	rc = misc_register(&wdt_miscdev);
 	if (rc)
 	{
 		printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 			wdt_miscdev.minor, rc);
 		goto err_out_region2;
 	}

 	rc = register_reboot_notifier(&wdt_notifier);
 	if (rc)
 	{
 		printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 			rc);
 		goto err_out_miscdev;
 	}

 	printk(KERN_INFO PFX "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
 		timeout, nowayout);

 	return 0;

 err_out_miscdev:
 	misc_deregister(&wdt_miscdev);
 err_out_region2:
 	release_region(WDT_PING,1);
 err_out_region1:
 	release_region(ENABLE_W83877F_PORT,2);
 err_out:
 	return rc;
 }

 module_init(w83877f_wdt_init);
 module_exit(w83877f_wdt_unload);

 MODULE_AUTHOR("Scott and Bill Jennings");
 MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	/*
	* W83877F Computer Watchdog Timer driver
	*
	* Based on acquirewdt.c by Alan Cox,
	* and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
	*
	* 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.
	*
	* The authors do NOT admit liability nor provide warranty for
	* any of this software. This material is provided "AS-IS" in
	* the hope that it may be useful for others.
	*
	* (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net>
	*
	* 4/19 - 2001 [Initial revision]
	* 9/27 - 2001 Added spinlocking
	* 4/12 - 2002 [rob@osinvestor.com] Eliminate extra comments
	* Eliminate fop_read
	* Eliminate extra spin_unlock
	* Added KERN_* tags to printks
	* add CONFIG_WATCHDOG_NOWAYOUT support
	* fix possible wdt_is_open race
	* changed watchdog_info to correctly reflect what the driver offers
	* added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, WDIOC_SETTIMEOUT,
	* WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls
	* 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces
	* added extra printk's for startup problems
	* use module_param
	* made timeout (the emulated heartbeat) a module_param
	* made the keepalive ping an internal subroutine
	*
	* This WDT driver is different from most other Linux WDT
	* drivers in that the driver will ping the watchdog by itself,
	* because this particular WDT has a very short timeout (1.6
	* seconds) and it would be insane to count on any userspace
	* daemon always getting scheduled within that time frame.
	*/

	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/types.h>
	#include <linux/timer.h>
	#include <linux/jiffies.h>
	#include <linux/miscdevice.h>
	#include <linux/watchdog.h>
	#include <linux/fs.h>
	#include <linux/ioport.h>
	#include <linux/notifier.h>
	#include <linux/reboot.h>
	#include <linux/init.h>
	#include <asm/io.h>
	#include <asm/uaccess.h>
	#include <asm/system.h>

	#define OUR_NAME "w83877f_wdt"
	#define PFX OUR_NAME ": "

	#define ENABLE_W83877F_PORT 0x3F0
	#define ENABLE_W83877F 0x87
	#define DISABLE_W83877F 0xAA
	#define WDT_PING 0x443
	#define WDT_REGISTER 0x14
	#define WDT_ENABLE 0x9C
	#define WDT_DISABLE 0x8C

	/*
	* The W83877F seems to be fixed at 1.6s timeout (at least on the
	* EMACS PC-104 board I'm using). If we reset the watchdog every
	* ~250ms we should be safe. */

	#define WDT_INTERVAL (HZ/4+1)

	/*
	* We must not require too good response from the userspace daemon.
	* Here we require the userspace daemon to send us a heartbeat
	* char to /dev/watchdog every 30 seconds.
	*/

	#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
	static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
	module_param(timeout, int, 0);
	MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");


	static int nowayout = WATCHDOG_NOWAYOUT;
	module_param(nowayout, int, 0);
	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

	static void wdt_timer_ping(unsigned long);
	static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0);
	static unsigned long next_heartbeat;
	static unsigned long wdt_is_open;
	static char wdt_expect_close;
	static DEFINE_SPINLOCK(wdt_spinlock);

	/*
	* Whack the dog
	*/

	static void wdt_timer_ping(unsigned long data)
	{
	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
	* we agree to ping the WDT
	*/
	if(time_before(jiffies, next_heartbeat))
	{
	/* Ping the WDT */
	spin_lock(&wdt_spinlock);

	/* Ping the WDT by reading from WDT_PING */
	inb_p(WDT_PING);

	/* Re-set the timer interval */
	mod_timer(&timer, jiffies + WDT_INTERVAL);

	spin_unlock(&wdt_spinlock);

	} else {
	printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
	}
	}

	/*
	* Utility routines
	*/

	static void wdt_change(int writeval)
	{
	unsigned long flags;
	spin_lock_irqsave(&wdt_spinlock, flags);

	/* buy some time */
	inb_p(WDT_PING);

	/* make W83877F available */
	outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
	outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);

	/* enable watchdog */
	outb_p(WDT_REGISTER, ENABLE_W83877F_PORT);
	outb_p(writeval, ENABLE_W83877F_PORT+1);

	/* lock the W8387FF away */
	outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT);

	spin_unlock_irqrestore(&wdt_spinlock, flags);
	}

	static void wdt_startup(void)
	{
	next_heartbeat = jiffies + (timeout * HZ);

	/* Start the timer */
	mod_timer(&timer, jiffies + WDT_INTERVAL);

	wdt_change(WDT_ENABLE);

	printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
	}

	static void wdt_turnoff(void)
	{
	/* Stop the timer */
	del_timer(&timer);

	wdt_change(WDT_DISABLE);

	printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
	}

	static void wdt_keepalive(void)
	{
	/* user land ping */
	next_heartbeat = jiffies + (timeout * HZ);
	}

	/*
	* /dev/watchdog handling
	*/

	static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
	{
	/* See if we got the magic character 'V' and reload the timer */
	if(count)
	{
	if (!nowayout)
	{
	size_t ofs;

	/* note: just in case someone wrote the magic character
	* five months ago... */
	wdt_expect_close = 0;

	/* scan to see whether or not we got the magic character */
	for(ofs = 0; ofs != count; ofs++)
	{
	char c;
	if (get_user(c, buf + ofs))
	return -EFAULT;
	if (c == 'V')
	wdt_expect_close = 42;
	}
	}

	/* someone wrote to us, we should restart timer */
	wdt_keepalive();
	}
	return count;
	}

	static int fop_open(struct inode * inode, struct file * file)
	{
	/* Just in case we're already talking to someone... */
	if(test_and_set_bit(0, &wdt_is_open))
	return -EBUSY;

	/* Good, fire up the show */
	wdt_startup();
	return nonseekable_open(inode, file);
	}

	static int fop_close(struct inode * inode, struct file * file)
	{
	if(wdt_expect_close == 42)
	wdt_turnoff();
	else {
	del_timer(&timer);
	printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
	}
	clear_bit(0, &wdt_is_open);
	wdt_expect_close = 0;
	return 0;
	}

	static int fop_ioctl(struct inode inode, struct file file, unsigned int cmd,
	unsigned long arg)
	{
	void __user argp = (void __user )arg;
	int __user *p = argp;
	static struct watchdog_info ident=
	{
	.options = WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT \| WDIOF_MAGICCLOSE,
	.firmware_version = 1,
	.identity = "W83877F",
	};

	switch(cmd)
	{
	default:
	return -ENOTTY;
	case WDIOC_GETSUPPORT:
	return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	return put_user(0, p);
	case WDIOC_KEEPALIVE:
	wdt_keepalive();
	return 0;
	case WDIOC_SETOPTIONS:
	{
	int new_options, retval = -EINVAL;

	if(get_user(new_options, p))
	return -EFAULT;

	if(new_options & WDIOS_DISABLECARD) {
	wdt_turnoff();
	retval = 0;
	}

	if(new_options & WDIOS_ENABLECARD) {
	wdt_startup();
	retval = 0;
	}

	return retval;
	}
	case WDIOC_SETTIMEOUT:
	{
	int new_timeout;

	if(get_user(new_timeout, p))
	return -EFAULT;

	if(new_timeout < 1 \|\| new_timeout > 3600) /* arbitrary upper limit */
	return -EINVAL;

	timeout = new_timeout;
	wdt_keepalive();
	/* Fall through */
	}
	case WDIOC_GETTIMEOUT:
	return put_user(timeout, p);
	}
	}

	static const struct file_operations wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = fop_write,
	.open = fop_open,
	.release = fop_close,
	.ioctl = fop_ioctl,
	};

	static struct miscdevice wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &wdt_fops,
	};

	/*
	* Notifier for system down
	*/

	static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
	void *unused)
	{
	if(code==SYS_DOWN \|\| code==SYS_HALT)
	wdt_turnoff();
	return NOTIFY_DONE;
	}

	/*
	* The WDT needs to learn about soft shutdowns in order to
	* turn the timebomb registers off.
	*/

	static struct notifier_block wdt_notifier=
	{
	.notifier_call = wdt_notify_sys,
	};

	static void __exit w83877f_wdt_unload(void)
	{
	wdt_turnoff();

	/* Deregister */
	misc_deregister(&wdt_miscdev);

	unregister_reboot_notifier(&wdt_notifier);
	release_region(WDT_PING,1);
	release_region(ENABLE_W83877F_PORT,2);
	}

	static int __init w83877f_wdt_init(void)
	{
	int rc = -EBUSY;

	if(timeout < 1 \|\| timeout > 3600) /* arbitrary upper limit */
	{
	timeout = WATCHDOG_TIMEOUT;
	printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
	timeout);
	}

	if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT"))
	{
	printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
	ENABLE_W83877F_PORT);
	rc = -EIO;
	goto err_out;
	}

	if (!request_region(WDT_PING, 1, "W8387FF WDT"))
	{
	printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
	WDT_PING);
	rc = -EIO;
	goto err_out_region1;
	}

	rc = misc_register(&wdt_miscdev);
	if (rc)
	{
	printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
	wdt_miscdev.minor, rc);
	goto err_out_region2;
	}

	rc = register_reboot_notifier(&wdt_notifier);
	if (rc)
	{
	printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
	rc);
	goto err_out_miscdev;
	}

	printk(KERN_INFO PFX "WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
	timeout, nowayout);

	return 0;

	err_out_miscdev:
	misc_deregister(&wdt_miscdev);
	err_out_region2:
	release_region(WDT_PING,1);
	err_out_region1:
	release_region(ENABLE_W83877F_PORT,2);
	err_out:
	return rc;
	}

	module_init(w83877f_wdt_init);
	module_exit(w83877f_wdt_unload);

	MODULE_AUTHOR("Scott and Bill Jennings");
	MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);