drivers/char/watchdog/sbc8360.c - linux - Git at Google

 /*
  *	SBC8360 Watchdog driver
  *
  *	(c) Copyright 2005 Webcon, Inc.
  *
  *	Based on ib700wdt.c, which is based on advantechwdt.c which is based
  *      on acquirewdt.c which is based on wdt.c.
  *
  *	(c) Copyright 2001 Charles Howes <chowes@vsol.net>
  *
  *      Based on advantechwdt.c which is based on acquirewdt.c which
  *       is based on wdt.c.
  *
  *	(c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  *
  *	Based on acquirewdt.c which is based on wdt.c.
  *	Original copyright messages:
  *
  *	(c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  *				http://www.redhat.com
  *
  *	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.
  *
  *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  *	warranty for any of this software. This material is provided
  *	"AS-IS" and at no charge.
  *
  *	(c) Copyright 1995    Alan Cox <alan@redhat.com>
  *
  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  *           Added timeout module option to override default
  *
  */

 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/miscdevice.h>
 #include <linux/watchdog.h>
 #include <linux/ioport.h>
 #include <linux/delay.h>
 #include <linux/notifier.h>
 #include <linux/fs.h>
 #include <linux/reboot.h>
 #include <linux/init.h>
 #include <linux/spinlock.h>
 #include <linux/moduleparam.h>

 #include <asm/io.h>
 #include <asm/uaccess.h>
 #include <asm/system.h>

 static unsigned long sbc8360_is_open;
 static spinlock_t sbc8360_lock;
 static char expect_close;

 #define PFX "sbc8360: "

 /*
  *
  * Watchdog Timer Configuration
  *
  * The function of the watchdog timer is to reset the system automatically
  * and is defined at I/O port 0120H and 0121H.  To enable the watchdog timer
  * and allow the system to reset, write appropriate values from the table
  * below to I/O port 0120H and 0121H.  To disable the timer, write a zero
  * value to I/O port 0121H for the system to stop the watchdog function.
  *
  * The following describes how the timer should be programmed (according to
  * the vendor documentation)
  *
  * Enabling Watchdog:
  * MOV AX,000AH (enable, phase I)
  * MOV DX,0120H
  * OUT DX,AX
  * MOV AX,000BH (enable, phase II)
  * MOV DX,0120H
  * OUT DX,AX
  * MOV AX,000nH (set multiplier n, from 1-4)
  * MOV DX,0120H
  * OUT DX,AX
  * MOV AX,000mH (set base timer m, from 0-F)
  * MOV DX,0121H
  * OUT DX,AX
  *
  * Reset timer:
  * MOV AX,000mH (same as set base timer, above)
  * MOV DX,0121H
  * OUT DX,AX
  *
  * Disabling Watchdog:
  * MOV AX,0000H (a zero value)
  * MOV DX,0120H
  * OUT DX,AX
  *
  * Watchdog timeout configuration values:
  *		N
  *	M |	1	2	3	4
  *	--|----------------------------------
  *	0 |	0.5s	5s	50s	100s
  *	1 |	1s	10s	100s	200s
  *	2 |	1.5s	15s	150s	300s
  *	3 |	2s	20s	200s	400s
  *	4 |	2.5s	25s	250s	500s
  *	5 |	3s	30s	300s	600s
  *	6 |	3.5s	35s	350s	700s
  *	7 |	4s	40s	400s	800s
  *	8 |	4.5s	45s	450s	900s
  *	9 |	5s	50s	500s	1000s
  *	A |	5.5s	55s	550s	1100s
  *	B |	6s	60s	600s	1200s
  *	C |	6.5s	65s	650s	1300s
  *	D |	7s	70s	700s	1400s
  *	E |	7.5s	75s	750s	1500s
  *	F |	8s	80s 	800s 	1600s
  *
  * Another way to say the same things is:
  *  For N=1, Timeout = (M+1) * 0.5s
  *  For N=2, Timeout = (M+1) * 5s
  *  For N=3, Timeout = (M+1) * 50s
  *  For N=4, Timeout = (M+1) * 100s
  *
  */

 static int wd_times[64][2] = {
 	{0, 1},			/* 0  = 0.5s */
 	{1, 1},			/* 1  = 1s   */
 	{2, 1},			/* 2  = 1.5s */
 	{3, 1},			/* 3  = 2s   */
 	{4, 1},			/* 4  = 2.5s */
 	{5, 1},			/* 5  = 3s   */
 	{6, 1},			/* 6  = 3.5s */
 	{7, 1},			/* 7  = 4s   */
 	{8, 1},			/* 8  = 4.5s */
 	{9, 1},			/* 9  = 5s   */
 	{0xA, 1},		/* 10 = 5.5s */
 	{0xB, 1},		/* 11 = 6s   */
 	{0xC, 1},		/* 12 = 6.5s */
 	{0xD, 1},		/* 13 = 7s   */
 	{0xE, 1},		/* 14 = 7.5s */
 	{0xF, 1},		/* 15 = 8s   */
 	{0, 2},			/* 16 = 5s  */
 	{1, 2},			/* 17 = 10s */
 	{2, 2},			/* 18 = 15s */
 	{3, 2},			/* 19 = 20s */
 	{4, 2},			/* 20 = 25s */
 	{5, 2},			/* 21 = 30s */
 	{6, 2},			/* 22 = 35s */
 	{7, 2},			/* 23 = 40s */
 	{8, 2},			/* 24 = 45s */
 	{9, 2},			/* 25 = 50s */
 	{0xA, 2},		/* 26 = 55s */
 	{0xB, 2},		/* 27 = 60s */
 	{0xC, 2},		/* 28 = 65s */
 	{0xD, 2},		/* 29 = 70s */
 	{0xE, 2},		/* 30 = 75s */
 	{0xF, 2},		/* 31 = 80s */
 	{0, 3},			/* 32 = 50s  */
 	{1, 3},			/* 33 = 100s */
 	{2, 3},			/* 34 = 150s */
 	{3, 3},			/* 35 = 200s */
 	{4, 3},			/* 36 = 250s */
 	{5, 3},			/* 37 = 300s */
 	{6, 3},			/* 38 = 350s */
 	{7, 3},			/* 39 = 400s */
 	{8, 3},			/* 40 = 450s */
 	{9, 3},			/* 41 = 500s */
 	{0xA, 3},		/* 42 = 550s */
 	{0xB, 3},		/* 43 = 600s */
 	{0xC, 3},		/* 44 = 650s */
 	{0xD, 3},		/* 45 = 700s */
 	{0xE, 3},		/* 46 = 750s */
 	{0xF, 3},		/* 47 = 800s */
 	{0, 4},			/* 48 = 100s */
 	{1, 4},			/* 49 = 200s */
 	{2, 4},			/* 50 = 300s */
 	{3, 4},			/* 51 = 400s */
 	{4, 4},			/* 52 = 500s */
 	{5, 4},			/* 53 = 600s */
 	{6, 4},			/* 54 = 700s */
 	{7, 4},			/* 55 = 800s */
 	{8, 4},			/* 56 = 900s */
 	{9, 4},			/* 57 = 1000s */
 	{0xA, 4},		/* 58 = 1100s */
 	{0xB, 4},		/* 59 = 1200s */
 	{0xC, 4},		/* 60 = 1300s */
 	{0xD, 4},		/* 61 = 1400s */
 	{0xE, 4},		/* 62 = 1500s */
 	{0xF, 4}		/* 63 = 1600s */
 };

 #define SBC8360_ENABLE 0x120
 #define SBC8360_BASETIME 0x121

 static int timeout = 27;
 static int wd_margin = 0xB;
 static int wd_multiplier = 2;
 static int nowayout = WATCHDOG_NOWAYOUT;

 module_param(timeout, int, 27);
 MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))");
 module_param(nowayout, int, 0);
 MODULE_PARM_DESC(nowayout,
 		 "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");

 /*
  *	Kernel methods.
  */

 /* Activate and pre-configure watchdog */
 static void sbc8360_activate(void)
 {
 	/* Enable the watchdog */
 	outb(0x0A, SBC8360_ENABLE);
 	msleep_interruptible(100);
 	outb(0x0B, SBC8360_ENABLE);
 	msleep_interruptible(100);
 	/* Set timeout multiplier */
 	outb(wd_multiplier, SBC8360_ENABLE);
 	msleep_interruptible(100);
 	/* Nothing happens until first sbc8360_ping() */
 }

 /* Kernel pings watchdog */
 static void sbc8360_ping(void)
 {
 	/* Write the base timer register */
 	outb(wd_margin, SBC8360_BASETIME);
 }

 /* Userspace pings kernel driver, or requests clean close */
 static ssize_t sbc8360_write(struct file *file, const char __user * buf,
 			     size_t count, loff_t * ppos)
 {
 	if (count) {
 		if (!nowayout) {
 			size_t i;

 			/* In case it was set long ago */
 			expect_close = 0;

 			for (i = 0; i != count; i++) {
 				char c;
 				if (get_user(c, buf + i))
 					return -EFAULT;
 				if (c == 'V')
 					expect_close = 42;
 			}
 		}
 		sbc8360_ping();
 	}
 	return count;
 }

 static int sbc8360_open(struct inode *inode, struct file *file)
 {
 	spin_lock(&sbc8360_lock);
 	if (test_and_set_bit(0, &sbc8360_is_open)) {
 		spin_unlock(&sbc8360_lock);
 		return -EBUSY;
 	}
 	if (nowayout)
 		__module_get(THIS_MODULE);

 	/* Activate and ping once to start the countdown */
 	spin_unlock(&sbc8360_lock);
 	sbc8360_activate();
 	sbc8360_ping();
 	return nonseekable_open(inode, file);
 }

 static int sbc8360_close(struct inode *inode, struct file *file)
 {
 	spin_lock(&sbc8360_lock);
 	if (expect_close == 42)
 		outb(0, SBC8360_ENABLE);
 	else
 		printk(KERN_CRIT PFX
 		       "SBC8360 device closed unexpectedly.  SBC8360 will not stop!\n");

 	clear_bit(0, &sbc8360_is_open);
 	expect_close = 0;
 	spin_unlock(&sbc8360_lock);
 	return 0;
 }

 /*
  *	Notifier for system down
  */

 static int sbc8360_notify_sys(struct notifier_block *this, unsigned long code,
 			      void *unused)
 {
 	if (code == SYS_DOWN || code == SYS_HALT) {
 		/* Disable the SBC8360 Watchdog */
 		outb(0, SBC8360_ENABLE);
 	}
 	return NOTIFY_DONE;
 }

 /*
  *	Kernel Interfaces
  */

 static const struct file_operations sbc8360_fops = {
 	.owner = THIS_MODULE,
 	.llseek = no_llseek,
 	.write = sbc8360_write,
 	.open = sbc8360_open,
 	.release = sbc8360_close,
 };

 static struct miscdevice sbc8360_miscdev = {
 	.minor = WATCHDOG_MINOR,
 	.name = "watchdog",
 	.fops = &sbc8360_fops,
 };

 /*
  *	The SBC8360 needs to learn about soft shutdowns in order to
  *	turn the timebomb registers off.
  */

 static struct notifier_block sbc8360_notifier = {
 	.notifier_call = sbc8360_notify_sys,
 };

 static int __init sbc8360_init(void)
 {
 	int res;
 	unsigned long int mseconds = 60000;

 	spin_lock_init(&sbc8360_lock);
 	res = misc_register(&sbc8360_miscdev);
 	if (res) {
 		printk(KERN_ERR PFX "failed to register misc device\n");
 		goto out_nomisc;
 	}

 	if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) {
 		printk(KERN_ERR PFX "ENABLE method I/O %X is not available.\n",
 		       SBC8360_ENABLE);
 		res = -EIO;
 		goto out_noenablereg;
 	}
 	if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) {
 		printk(KERN_ERR PFX
 		       "BASETIME method I/O %X is not available.\n",
 		       SBC8360_BASETIME);
 		res = -EIO;
 		goto out_nobasetimereg;
 	}

 	res = register_reboot_notifier(&sbc8360_notifier);
 	if (res) {
 		printk(KERN_ERR PFX "Failed to register reboot notifier.\n");
 		goto out_noreboot;
 	}

 	if (timeout < 0 || timeout > 63) {
 		printk(KERN_ERR PFX "Invalid timeout index (must be 0-63).\n");
 		res = -EINVAL;
 		goto out_noreboot;
 	}

 	wd_margin = wd_times[timeout][0];
 	wd_multiplier = wd_times[timeout][1];

 	if (wd_multiplier == 1)
 		mseconds = (wd_margin + 1) * 500;
 	else if (wd_multiplier == 2)
 		mseconds = (wd_margin + 1) * 5000;
 	else if (wd_multiplier == 3)
 		mseconds = (wd_margin + 1) * 50000;
 	else if (wd_multiplier == 4)
 		mseconds = (wd_margin + 1) * 100000;

 	/* My kingdom for the ability to print "0.5 seconds" in the kernel! */
 	printk(KERN_INFO PFX "Timeout set at %ld ms.\n", mseconds);

 	return 0;

       out_noreboot:
 	release_region(SBC8360_ENABLE, 1);
 	release_region(SBC8360_BASETIME, 1);
       out_noenablereg:
       out_nobasetimereg:
 	misc_deregister(&sbc8360_miscdev);
       out_nomisc:
 	return res;
 }

 static void __exit sbc8360_exit(void)
 {
 	misc_deregister(&sbc8360_miscdev);
 	unregister_reboot_notifier(&sbc8360_notifier);
 	release_region(SBC8360_ENABLE, 1);
 	release_region(SBC8360_BASETIME, 1);
 }

 module_init(sbc8360_init);
 module_exit(sbc8360_exit);

 MODULE_AUTHOR("Ian E. Morgan <imorgan@webcon.ca>");
 MODULE_DESCRIPTION("SBC8360 watchdog driver");
 MODULE_LICENSE("GPL");
 MODULE_VERSION("1.0");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

 /* end of sbc8360.c */
	/*
	* SBC8360 Watchdog driver
	*
	* (c) Copyright 2005 Webcon, Inc.
	*
	* Based on ib700wdt.c, which is based on advantechwdt.c which is based
	* on acquirewdt.c which is based on wdt.c.
	*
	* (c) Copyright 2001 Charles Howes <chowes@vsol.net>
	*
	* Based on advantechwdt.c which is based on acquirewdt.c which
	* is based on wdt.c.
	*
	* (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
	*
	* Based on acquirewdt.c which is based on wdt.c.
	* Original copyright messages:
	*
	* (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
	* http://www.redhat.com
	*
	* 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.
	*
	* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
	* warranty for any of this software. This material is provided
	* "AS-IS" and at no charge.
	*
	* (c) Copyright 1995 Alan Cox <alan@redhat.com>
	*
	* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
	* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
	* Added timeout module option to override default
	*
	*/

	#include <linux/module.h>
	#include <linux/types.h>
	#include <linux/miscdevice.h>
	#include <linux/watchdog.h>
	#include <linux/ioport.h>
	#include <linux/delay.h>
	#include <linux/notifier.h>
	#include <linux/fs.h>
	#include <linux/reboot.h>
	#include <linux/init.h>
	#include <linux/spinlock.h>
	#include <linux/moduleparam.h>

	#include <asm/io.h>
	#include <asm/uaccess.h>
	#include <asm/system.h>

	static unsigned long sbc8360_is_open;
	static spinlock_t sbc8360_lock;
	static char expect_close;

	#define PFX "sbc8360: "

	/*
	*
	* Watchdog Timer Configuration
	*
	* The function of the watchdog timer is to reset the system automatically
	* and is defined at I/O port 0120H and 0121H. To enable the watchdog timer
	* and allow the system to reset, write appropriate values from the table
	* below to I/O port 0120H and 0121H. To disable the timer, write a zero
	* value to I/O port 0121H for the system to stop the watchdog function.
	*
	* The following describes how the timer should be programmed (according to
	* the vendor documentation)
	*
	* Enabling Watchdog:
	* MOV AX,000AH (enable, phase I)
	* MOV DX,0120H
	* OUT DX,AX
	* MOV AX,000BH (enable, phase II)
	* MOV DX,0120H
	* OUT DX,AX
	* MOV AX,000nH (set multiplier n, from 1-4)
	* MOV DX,0120H
	* OUT DX,AX
	* MOV AX,000mH (set base timer m, from 0-F)
	* MOV DX,0121H
	* OUT DX,AX
	*
	* Reset timer:
	* MOV AX,000mH (same as set base timer, above)
	* MOV DX,0121H
	* OUT DX,AX
	*
	* Disabling Watchdog:
	* MOV AX,0000H (a zero value)
	* MOV DX,0120H
	* OUT DX,AX
	*
	* Watchdog timeout configuration values:
	* N
	* M \| 1 2 3 4
	* --\|----------------------------------
	* 0 \| 0.5s 5s 50s 100s
	* 1 \| 1s 10s 100s 200s
	* 2 \| 1.5s 15s 150s 300s
	* 3 \| 2s 20s 200s 400s
	* 4 \| 2.5s 25s 250s 500s
	* 5 \| 3s 30s 300s 600s
	* 6 \| 3.5s 35s 350s 700s
	* 7 \| 4s 40s 400s 800s
	* 8 \| 4.5s 45s 450s 900s
	* 9 \| 5s 50s 500s 1000s
	* A \| 5.5s 55s 550s 1100s
	* B \| 6s 60s 600s 1200s
	* C \| 6.5s 65s 650s 1300s
	* D \| 7s 70s 700s 1400s
	* E \| 7.5s 75s 750s 1500s
	* F \| 8s 80s 800s 1600s
	*
	* Another way to say the same things is:
	* For N=1, Timeout = (M+1) * 0.5s
	* For N=2, Timeout = (M+1) * 5s
	* For N=3, Timeout = (M+1) * 50s
	* For N=4, Timeout = (M+1) * 100s
	*
	*/

	static int wd_times[64][2] = {
	{0, 1}, /* 0 = 0.5s */
	{1, 1}, /* 1 = 1s */
	{2, 1}, /* 2 = 1.5s */
	{3, 1}, /* 3 = 2s */
	{4, 1}, /* 4 = 2.5s */
	{5, 1}, /* 5 = 3s */
	{6, 1}, /* 6 = 3.5s */
	{7, 1}, /* 7 = 4s */
	{8, 1}, /* 8 = 4.5s */
	{9, 1}, /* 9 = 5s */
	{0xA, 1}, /* 10 = 5.5s */
	{0xB, 1}, /* 11 = 6s */
	{0xC, 1}, /* 12 = 6.5s */
	{0xD, 1}, /* 13 = 7s */
	{0xE, 1}, /* 14 = 7.5s */
	{0xF, 1}, /* 15 = 8s */
	{0, 2}, /* 16 = 5s */
	{1, 2}, /* 17 = 10s */
	{2, 2}, /* 18 = 15s */
	{3, 2}, /* 19 = 20s */
	{4, 2}, /* 20 = 25s */
	{5, 2}, /* 21 = 30s */
	{6, 2}, /* 22 = 35s */
	{7, 2}, /* 23 = 40s */
	{8, 2}, /* 24 = 45s */
	{9, 2}, /* 25 = 50s */
	{0xA, 2}, /* 26 = 55s */
	{0xB, 2}, /* 27 = 60s */
	{0xC, 2}, /* 28 = 65s */
	{0xD, 2}, /* 29 = 70s */
	{0xE, 2}, /* 30 = 75s */
	{0xF, 2}, /* 31 = 80s */
	{0, 3}, /* 32 = 50s */
	{1, 3}, /* 33 = 100s */
	{2, 3}, /* 34 = 150s */
	{3, 3}, /* 35 = 200s */
	{4, 3}, /* 36 = 250s */
	{5, 3}, /* 37 = 300s */
	{6, 3}, /* 38 = 350s */
	{7, 3}, /* 39 = 400s */
	{8, 3}, /* 40 = 450s */
	{9, 3}, /* 41 = 500s */
	{0xA, 3}, /* 42 = 550s */
	{0xB, 3}, /* 43 = 600s */
	{0xC, 3}, /* 44 = 650s */
	{0xD, 3}, /* 45 = 700s */
	{0xE, 3}, /* 46 = 750s */
	{0xF, 3}, /* 47 = 800s */
	{0, 4}, /* 48 = 100s */
	{1, 4}, /* 49 = 200s */
	{2, 4}, /* 50 = 300s */
	{3, 4}, /* 51 = 400s */
	{4, 4}, /* 52 = 500s */
	{5, 4}, /* 53 = 600s */
	{6, 4}, /* 54 = 700s */
	{7, 4}, /* 55 = 800s */
	{8, 4}, /* 56 = 900s */
	{9, 4}, /* 57 = 1000s */
	{0xA, 4}, /* 58 = 1100s */
	{0xB, 4}, /* 59 = 1200s */
	{0xC, 4}, /* 60 = 1300s */
	{0xD, 4}, /* 61 = 1400s */
	{0xE, 4}, /* 62 = 1500s */
	{0xF, 4} /* 63 = 1600s */
	};

	#define SBC8360_ENABLE 0x120
	#define SBC8360_BASETIME 0x121

	static int timeout = 27;
	static int wd_margin = 0xB;
	static int wd_multiplier = 2;
	static int nowayout = WATCHDOG_NOWAYOUT;

	module_param(timeout, int, 27);
	MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))");
	module_param(nowayout, int, 0);
	MODULE_PARM_DESC(nowayout,
	"Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");

	/*
	* Kernel methods.
	*/

	/* Activate and pre-configure watchdog */
	static void sbc8360_activate(void)
	{
	/* Enable the watchdog */
	outb(0x0A, SBC8360_ENABLE);
	msleep_interruptible(100);
	outb(0x0B, SBC8360_ENABLE);
	msleep_interruptible(100);
	/* Set timeout multiplier */
	outb(wd_multiplier, SBC8360_ENABLE);
	msleep_interruptible(100);
	/* Nothing happens until first sbc8360_ping() */
	}

	/* Kernel pings watchdog */
	static void sbc8360_ping(void)
	{
	/* Write the base timer register */
	outb(wd_margin, SBC8360_BASETIME);
	}

	/* Userspace pings kernel driver, or requests clean close */
	static ssize_t sbc8360_write(struct file file, const char __user buf,
	size_t count, loff_t * ppos)
	{
	if (count) {
	if (!nowayout) {
	size_t i;

	/* In case it was set long ago */
	expect_close = 0;

	for (i = 0; i != count; i++) {
	char c;
	if (get_user(c, buf + i))
	return -EFAULT;
	if (c == 'V')
	expect_close = 42;
	}
	}
	sbc8360_ping();
	}
	return count;
	}

	static int sbc8360_open(struct inode inode, struct file file)
	{
	spin_lock(&sbc8360_lock);
	if (test_and_set_bit(0, &sbc8360_is_open)) {
	spin_unlock(&sbc8360_lock);
	return -EBUSY;
	}
	if (nowayout)
	__module_get(THIS_MODULE);

	/* Activate and ping once to start the countdown */
	spin_unlock(&sbc8360_lock);
	sbc8360_activate();
	sbc8360_ping();
	return nonseekable_open(inode, file);
	}

	static int sbc8360_close(struct inode inode, struct file file)
	{
	spin_lock(&sbc8360_lock);
	if (expect_close == 42)
	outb(0, SBC8360_ENABLE);
	else
	printk(KERN_CRIT PFX
	"SBC8360 device closed unexpectedly. SBC8360 will not stop!\n");

	clear_bit(0, &sbc8360_is_open);
	expect_close = 0;
	spin_unlock(&sbc8360_lock);
	return 0;
	}

	/*
	* Notifier for system down
	*/

	static int sbc8360_notify_sys(struct notifier_block *this, unsigned long code,
	void *unused)
	{
	if (code == SYS_DOWN \|\| code == SYS_HALT) {
	/* Disable the SBC8360 Watchdog */
	outb(0, SBC8360_ENABLE);
	}
	return NOTIFY_DONE;
	}

	/*
	* Kernel Interfaces
	*/

	static const struct file_operations sbc8360_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = sbc8360_write,
	.open = sbc8360_open,
	.release = sbc8360_close,
	};

	static struct miscdevice sbc8360_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &sbc8360_fops,
	};

	/*
	* The SBC8360 needs to learn about soft shutdowns in order to
	* turn the timebomb registers off.
	*/

	static struct notifier_block sbc8360_notifier = {
	.notifier_call = sbc8360_notify_sys,
	};

	static int __init sbc8360_init(void)
	{
	int res;
	unsigned long int mseconds = 60000;

	spin_lock_init(&sbc8360_lock);
	res = misc_register(&sbc8360_miscdev);
	if (res) {
	printk(KERN_ERR PFX "failed to register misc device\n");
	goto out_nomisc;
	}

	if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) {
	printk(KERN_ERR PFX "ENABLE method I/O %X is not available.\n",
	SBC8360_ENABLE);
	res = -EIO;
	goto out_noenablereg;
	}
	if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) {
	printk(KERN_ERR PFX
	"BASETIME method I/O %X is not available.\n",
	SBC8360_BASETIME);
	res = -EIO;
	goto out_nobasetimereg;
	}

	res = register_reboot_notifier(&sbc8360_notifier);
	if (res) {
	printk(KERN_ERR PFX "Failed to register reboot notifier.\n");
	goto out_noreboot;
	}

	if (timeout < 0 \|\| timeout > 63) {
	printk(KERN_ERR PFX "Invalid timeout index (must be 0-63).\n");
	res = -EINVAL;
	goto out_noreboot;
	}

	wd_margin = wd_times[timeout][0];
	wd_multiplier = wd_times[timeout][1];

	if (wd_multiplier == 1)
	mseconds = (wd_margin + 1) * 500;
	else if (wd_multiplier == 2)
	mseconds = (wd_margin + 1) * 5000;
	else if (wd_multiplier == 3)
	mseconds = (wd_margin + 1) * 50000;
	else if (wd_multiplier == 4)
	mseconds = (wd_margin + 1) * 100000;

	/* My kingdom for the ability to print "0.5 seconds" in the kernel! */
	printk(KERN_INFO PFX "Timeout set at %ld ms.\n", mseconds);

	return 0;

	out_noreboot:
	release_region(SBC8360_ENABLE, 1);
	release_region(SBC8360_BASETIME, 1);
	out_noenablereg:
	out_nobasetimereg:
	misc_deregister(&sbc8360_miscdev);
	out_nomisc:
	return res;
	}

	static void __exit sbc8360_exit(void)
	{
	misc_deregister(&sbc8360_miscdev);
	unregister_reboot_notifier(&sbc8360_notifier);
	release_region(SBC8360_ENABLE, 1);
	release_region(SBC8360_BASETIME, 1);
	}

	module_init(sbc8360_init);
	module_exit(sbc8360_exit);

	MODULE_AUTHOR("Ian E. Morgan <imorgan@webcon.ca>");
	MODULE_DESCRIPTION("SBC8360 watchdog driver");
	MODULE_LICENSE("GPL");
	MODULE_VERSION("1.0");
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

	/* end of sbc8360.c */