[deliverable/linux.git] / drivers / watchdog / sbc60xxwdt.c

/*
 *	60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x
 *
 *	Based on acquirewdt.c by Alan Cox.
 *
 *	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 author does 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 2000    Jakob Oestergaard <jakob@unthought.net>
 *
 *           12/4 - 2000      [Initial revision]
 *           25/4 - 2000      Added /dev/watchdog support
 *           09/5 - 2001      [smj@oro.net] fixed fop_write to "return 1"
 *					on success
 *           12/4 - 2002      [rob@osinvestor.com] eliminate fop_read
 *                            fix possible wdt_is_open race
 *                            add CONFIG_WATCHDOG_NOWAYOUT support
 *                            remove lock_kernel/unlock_kernel pairs
 *                            added KERN_* to printk's
 *                            got rid of extraneous comments
 *                            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
 *                            use module_param
 *                            made timeout (the emulated heartbeat) a
 *			      module_param
 *                            made the keepalive ping an internal subroutine
 *                            made wdt_stop and wdt_start module params
 *                            added extra printk's for startup problems
 *                            added MODULE_AUTHOR and MODULE_DESCRIPTION info
 *
 *
 *  This WDT driver is different from the other Linux WDT
 *  drivers in the following ways:
 *  *)  The driver will ping the watchdog by itself, because this
 *      particular WDT has a very short timeout (one second) and it
 *      would be insane to count on any userspace daemon always
 *      getting scheduled within that time frame.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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 <linux/io.h>
#include <linux/uaccess.h>

#include <asm/system.h>

#define OUR_NAME "sbc60xxwdt"
#define PFX OUR_NAME ": "

/*
 * You must set these - The driver cannot probe for the settings
 */

static int wdt_stop = 0x45;
module_param(wdt_stop, int, 0);
MODULE_PARM_DESC(wdt_stop, "SBC60xx WDT 'stop' io port (default 0x45)");

static int wdt_start = 0x443;
module_param(wdt_start, int, 0);
MODULE_PARM_DESC(wdt_start, "SBC60xx WDT 'start' io port (default 0x443)");

/*
 * The 60xx board can use watchdog timeout values from one second
 * to several minutes.  The default is one second, so 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.
 * If the daemon pulses us every 25 seconds, we can still afford
 * a 5 second scheduling delay on the (high priority) daemon. That
 * should be sufficient for a box under any load.
 */

#define WATCHDOG_TIMEOUT 30		/* 30 sec default timeout */
static int timeout = WATCHDOG_TIMEOUT;	/* in seconds, 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;

/*
 *	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 by reading from wdt_start */
		inb_p(wdt_start);
		/* Re-set the timer interval */
		mod_timer(&timer, jiffies + WDT_INTERVAL);
	} else
		pr_warn("Heartbeat lost! Will not ping the watchdog\n");
}

/*
 * Utility routines
 */

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

	/* Start the timer */
	mod_timer(&timer, jiffies + WDT_INTERVAL);
	pr_info("Watchdog timer is now enabled\n");
}

static void wdt_turnoff(void)
{
	/* Stop the timer */
	del_timer(&timer);
	inb_p(wdt_stop);
	pr_info("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;
			}
		}

		/* Well, anyhow someone wrote to us, we should
		   return that favour */
		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;

	if (nowayout)
		__module_get(THIS_MODULE);

	/* 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);
		pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
	}
	clear_bit(0, &wdt_is_open);
	wdt_expect_close = 0;
	return 0;
}

static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	static const struct watchdog_info ident = {
		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
							WDIOF_MAGICCLOSE,
		.firmware_version = 1,
		.identity = "SBC60xx",
	};

	switch (cmd) {
	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_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_KEEPALIVE:
		wdt_keepalive();
		return 0;
	case WDIOC_SETTIMEOUT:
	{
		int new_timeout;
		if (get_user(new_timeout, p))
			return -EFAULT;
		/* arbitrary upper limit */
		if (new_timeout < 1 || new_timeout > 3600)
			return -EINVAL;

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

static const struct file_operations wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= fop_write,
	.open		= fop_open,
	.release	= fop_close,
	.unlocked_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 sbc60xxwdt_unload(void)
{
	wdt_turnoff();

	/* Deregister */
	misc_deregister(&wdt_miscdev);

	unregister_reboot_notifier(&wdt_notifier);
	if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
		release_region(wdt_stop, 1);
	release_region(wdt_start, 1);
}

static int __init sbc60xxwdt_init(void)
{
	int rc = -EBUSY;

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

	if (!request_region(wdt_start, 1, "SBC 60XX WDT")) {
		pr_err("I/O address 0x%04x already in use\n", wdt_start);
		rc = -EIO;
		goto err_out;
	}

	/* We cannot reserve 0x45 - the kernel already has! */
	if (wdt_stop != 0x45 && wdt_stop != wdt_start) {
		if (!request_region(wdt_stop, 1, "SBC 60XX WDT")) {
			pr_err("I/O address 0x%04x already in use\n", wdt_stop);
			rc = -EIO;
			goto err_out_region1;
		}
	}

	rc = register_reboot_notifier(&wdt_notifier);
	if (rc) {
		pr_err("cannot register reboot notifier (err=%d)\n", rc);
		goto err_out_region2;
	}

	rc = misc_register(&wdt_miscdev);
	if (rc) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       wdt_miscdev.minor, rc);
		goto err_out_reboot;
	}
	pr_info("WDT driver for 60XX single board computer initialised. timeout=%d sec (nowayout=%d)\n",
		timeout, nowayout);

	return 0;

err_out_reboot:
	unregister_reboot_notifier(&wdt_notifier);
err_out_region2:
	if (wdt_stop != 0x45 && wdt_stop != wdt_start)
		release_region(wdt_stop, 1);
err_out_region1:
	release_region(wdt_start, 1);
err_out:
	return rc;
}

module_init(sbc60xxwdt_init);
module_exit(sbc60xxwdt_unload);

MODULE_AUTHOR("Jakob Oestergaard <jakob@unthought.net>");
MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* 60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x
	3	*
143a2e54	4	* Based on acquirewdt.c by Alan Cox.
1da177e4 LT	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	*
	11	* The author does NOT admit liability nor provide warranty for
	12	* any of this software. This material is provided "AS-IS" in
	13	* the hope that it may be useful for others.
	14	*
	15	* (c) Copyright 2000 Jakob Oestergaard <jakob@unthought.net>
	16	*
	17	* 12/4 - 2000 [Initial revision]
	18	* 25/4 - 2000 Added /dev/watchdog support
1780de41 AC	19	* 09/5 - 2001 [smj@oro.net] fixed fop_write to "return 1"
1780de41 AC	20	* on success
1da177e4 LT	21	* 12/4 - 2002 [rob@osinvestor.com] eliminate fop_read
	22	* fix possible wdt_is_open race
	23	* add CONFIG_WATCHDOG_NOWAYOUT support
	24	* remove lock_kernel/unlock_kernel pairs
	25	* added KERN_* to printk's
	26	* got rid of extraneous comments
1780de41 AC	27	* changed watchdog_info to correctly reflect what
	28	* the driver offers
	29	* added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS,
	30	* WDIOC_SETTIMEOUT, WDIOC_GETTIMEOUT, and
	31	* WDIOC_SETOPTIONS ioctls
1da177e4 LT	32	* 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces
1da177e4 LT	33	* use module_param
1780de41 AC	34	* made timeout (the emulated heartbeat) a
1780de41 AC	35	* module_param
1da177e4 LT	36	* made the keepalive ping an internal subroutine
	37	* made wdt_stop and wdt_start module params
	38	* added extra printk's for startup problems
	39	* added MODULE_AUTHOR and MODULE_DESCRIPTION info
	40	*
	41	*
	42	* This WDT driver is different from the other Linux WDT
	43	* drivers in the following ways:
	44	* *) The driver will ping the watchdog by itself, because this
	45	* particular WDT has a very short timeout (one second) and it
	46	* would be insane to count on any userspace daemon always
	47	* getting scheduled within that time frame.
	48	*
	49	*/
	50
27c766aa JP	51	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	52
1da177e4 LT	53	#include <linux/module.h>
	54	#include <linux/moduleparam.h>
	55	#include <linux/types.h>
	56	#include <linux/timer.h>
	57	#include <linux/jiffies.h>
	58	#include <linux/miscdevice.h>
	59	#include <linux/watchdog.h>
	60	#include <linux/fs.h>
	61	#include <linux/ioport.h>
	62	#include <linux/notifier.h>
	63	#include <linux/reboot.h>
	64	#include <linux/init.h>
1780de41 AC	65	#include <linux/io.h>
1780de41 AC	66	#include <linux/uaccess.h>
1da177e4	67
1da177e4 LT	68	#include <asm/system.h>
	69
	70	#define OUR_NAME "sbc60xxwdt"
	71	#define PFX OUR_NAME ": "
	72
	73	/*
	74	* You must set these - The driver cannot probe for the settings
	75	*/
	76
	77	static int wdt_stop = 0x45;
	78	module_param(wdt_stop, int, 0);
	79	MODULE_PARM_DESC(wdt_stop, "SBC60xx WDT 'stop' io port (default 0x45)");
	80
	81	static int wdt_start = 0x443;
	82	module_param(wdt_start, int, 0);
	83	MODULE_PARM_DESC(wdt_start, "SBC60xx WDT 'start' io port (default 0x443)");
	84
	85	/*
	86	* The 60xx board can use watchdog timeout values from one second
	87	* to several minutes. The default is one second, so if we reset
	88	* the watchdog every ~250ms we should be safe.
	89	*/
	90
	91	#define WDT_INTERVAL (HZ/4+1)
	92
	93	/*
	94	* We must not require too good response from the userspace daemon.
	95	* Here we require the userspace daemon to send us a heartbeat
	96	* char to /dev/watchdog every 30 seconds.
	97	* If the daemon pulses us every 25 seconds, we can still afford
	98	* a 5 second scheduling delay on the (high priority) daemon. That
	99	* should be sufficient for a box under any load.
	100	*/
	101
	102	#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
1780de41 AC	103	static int timeout = WATCHDOG_TIMEOUT; /* in seconds, multiplied by HZ to
1780de41 AC	104	get seconds to wait for a ping */
1da177e4	105	module_param(timeout, int, 0);
1780de41 AC	106	MODULE_PARM_DESC(timeout,
	107	"Watchdog timeout in seconds. (1<=timeout<=3600, default="
	108	__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
1da177e4	109
4bfdf378	110	static int nowayout = WATCHDOG_NOWAYOUT;
1da177e4	111	module_param(nowayout, int, 0);
1780de41 AC	112	MODULE_PARM_DESC(nowayout,
	113	"Watchdog cannot be stopped once started (default="
	114	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4 LT	115
1da177e4 LT	116	static void wdt_timer_ping(unsigned long);
82eb7c50	117	static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0);
1da177e4 LT	118	static unsigned long next_heartbeat;
	119	static unsigned long wdt_is_open;
	120	static char wdt_expect_close;
	121
	122	/*
	123	* Whack the dog
	124	*/
	125
	126	static void wdt_timer_ping(unsigned long data)
	127	{
	128	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
	129	* we agree to ping the WDT
	130	*/
1780de41	131	if (time_before(jiffies, next_heartbeat)) {
1da177e4 LT	132	/* Ping the WDT by reading from wdt_start */
	133	inb_p(wdt_start);
	134	/* Re-set the timer interval */
82eb7c50	135	mod_timer(&timer, jiffies + WDT_INTERVAL);
1780de41	136	} else
27c766aa	137	pr_warn("Heartbeat lost! Will not ping the watchdog\n");
1da177e4 LT	138	}
	139
	140	/*
	141	* Utility routines
	142	*/
	143
	144	static void wdt_startup(void)
	145	{
	146	next_heartbeat = jiffies + (timeout * HZ);
	147
	148	/* Start the timer */
82eb7c50	149	mod_timer(&timer, jiffies + WDT_INTERVAL);
27c766aa	150	pr_info("Watchdog timer is now enabled\n");
1da177e4 LT	151	}
	152
	153	static void wdt_turnoff(void)
	154	{
	155	/* Stop the timer */
	156	del_timer(&timer);
	157	inb_p(wdt_stop);
27c766aa	158	pr_info("Watchdog timer is now disabled...\n");
1da177e4 LT	159	}
	160
	161	static void wdt_keepalive(void)
	162	{
	163	/* user land ping */
	164	next_heartbeat = jiffies + (timeout * HZ);
	165	}
	166
	167	/*
	168	* /dev/watchdog handling
	169	*/
	170
1780de41 AC	171	static ssize_t fop_write(struct file file, const char __user buf,
1780de41 AC	172	size_t count, loff_t *ppos)
1da177e4 LT	173	{
1da177e4 LT	174	/* See if we got the magic character 'V' and reload the timer */
1780de41 AC	175	if (count) {
1780de41 AC	176	if (!nowayout) {
1da177e4 LT	177	size_t ofs;
1da177e4 LT	178
1780de41 AC	179	/* note: just in case someone wrote the
1780de41 AC	180	magic character five months ago... */
1da177e4 LT	181	wdt_expect_close = 0;
1da177e4 LT	182
1780de41 AC	183	/* scan to see whether or not we got the
	184	magic character */
	185	for (ofs = 0; ofs != count; ofs++) {
1da177e4	186	char c;
7944d3a5	187	if (get_user(c, buf + ofs))
1da177e4	188	return -EFAULT;
1780de41	189	if (c == 'V')
1da177e4 LT	190	wdt_expect_close = 42;
	191	}
	192	}
	193
1780de41 AC	194	/* Well, anyhow someone wrote to us, we should
1780de41 AC	195	return that favour */
1da177e4 LT	196	wdt_keepalive();
	197	}
	198	return count;
	199	}
	200
1780de41	201	static int fop_open(struct inode inode, struct file file)
1da177e4	202	{
1da177e4	203	/* Just in case we're already talking to someone... */
1780de41	204	if (test_and_set_bit(0, &wdt_is_open))
1da177e4 LT	205	return -EBUSY;
	206
	207	if (nowayout)
	208	__module_get(THIS_MODULE);
	209
	210	/* Good, fire up the show */
	211	wdt_startup();
6abe78bf	212	return nonseekable_open(inode, file);
1da177e4 LT	213	}
1da177e4 LT	214
1780de41	215	static int fop_close(struct inode inode, struct file file)
1da177e4	216	{
1780de41	217	if (wdt_expect_close == 42)
1da177e4 LT	218	wdt_turnoff();
	219	else {
	220	del_timer(&timer);
27c766aa	221	pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
1da177e4 LT	222	}
	223	clear_bit(0, &wdt_is_open);
	224	wdt_expect_close = 0;
	225	return 0;
	226	}
	227
1780de41	228	static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1da177e4 LT	229	{
	230	void __user argp = (void __user )arg;
	231	int __user *p = argp;
1780de41 AC	232	static const struct watchdog_info ident = {
	233	.options = WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT \|
	234	WDIOF_MAGICCLOSE,
1da177e4 LT	235	.firmware_version = 1,
	236	.identity = "SBC60xx",
	237	};
	238
1780de41	239	switch (cmd) {
1780de41	240	case WDIOC_GETSUPPORT:
7944d3a5	241	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
1780de41 AC	242	case WDIOC_GETSTATUS:
	243	case WDIOC_GETBOOTSTATUS:
	244	return put_user(0, p);
1780de41	245	case WDIOC_SETOPTIONS:
1da177e4	246	{
1780de41 AC	247	int new_options, retval = -EINVAL;
	248	if (get_user(new_options, p))
	249	return -EFAULT;
	250	if (new_options & WDIOS_DISABLECARD) {
	251	wdt_turnoff();
	252	retval = 0;
1da177e4	253	}
1780de41 AC	254	if (new_options & WDIOS_ENABLECARD) {
	255	wdt_startup();
	256	retval = 0;
1da177e4	257	}
1780de41 AC	258	return retval;
1780de41 AC	259	}
0c06090c WVS	260	case WDIOC_KEEPALIVE:
	261	wdt_keepalive();
	262	return 0;
1780de41 AC	263	case WDIOC_SETTIMEOUT:
	264	{
	265	int new_timeout;
	266	if (get_user(new_timeout, p))
	267	return -EFAULT;
	268	/* arbitrary upper limit */
	269	if (new_timeout < 1 \|\| new_timeout > 3600)
	270	return -EINVAL;
	271
	272	timeout = new_timeout;
	273	wdt_keepalive();
	274	/* Fall through */
	275	}
	276	case WDIOC_GETTIMEOUT:
	277	return put_user(timeout, p);
0c06090c WVS	278	default:
0c06090c WVS	279	return -ENOTTY;
1da177e4 LT	280	}
	281	}
	282
62322d25	283	static const struct file_operations wdt_fops = {
1da177e4 LT	284	.owner = THIS_MODULE,
	285	.llseek = no_llseek,
	286	.write = fop_write,
	287	.open = fop_open,
	288	.release = fop_close,
1780de41	289	.unlocked_ioctl = fop_ioctl,
1da177e4 LT	290	};
	291
	292	static struct miscdevice wdt_miscdev = {
	293	.minor = WATCHDOG_MINOR,
	294	.name = "watchdog",
	295	.fops = &wdt_fops,
	296	};
	297
	298	/*
	299	* Notifier for system down
	300	*/
	301
	302	static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
	303	void *unused)
	304	{
1780de41	305	if (code == SYS_DOWN \|\| code == SYS_HALT)
1da177e4 LT	306	wdt_turnoff();
	307	return NOTIFY_DONE;
	308	}
	309
	310	/*
	311	* The WDT needs to learn about soft shutdowns in order to
	312	* turn the timebomb registers off.
	313	*/
	314
1780de41	315	static struct notifier_block wdt_notifier = {
1da177e4 LT	316	.notifier_call = wdt_notify_sys,
	317	};
	318
	319	static void __exit sbc60xxwdt_unload(void)
	320	{
	321	wdt_turnoff();
	322
	323	/* Deregister */
	324	misc_deregister(&wdt_miscdev);
	325
	326	unregister_reboot_notifier(&wdt_notifier);
	327	if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
1780de41 AC	328	release_region(wdt_stop, 1);
1780de41 AC	329	release_region(wdt_start, 1);
1da177e4 LT	330	}
	331
	332	static int __init sbc60xxwdt_init(void)
	333	{
	334	int rc = -EBUSY;
	335
1780de41	336	if (timeout < 1 \|\| timeout > 3600) { /* arbitrary upper limit */
1da177e4	337	timeout = WATCHDOG_TIMEOUT;
27c766aa JP	338	pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
27c766aa JP	339	timeout);
1780de41	340	}
1da177e4	341
1780de41	342	if (!request_region(wdt_start, 1, "SBC 60XX WDT")) {
27c766aa	343	pr_err("I/O address 0x%04x already in use\n", wdt_start);
1da177e4 LT	344	rc = -EIO;
	345	goto err_out;
	346	}
	347
	348	/* We cannot reserve 0x45 - the kernel already has! */
1780de41 AC	349	if (wdt_stop != 0x45 && wdt_stop != wdt_start) {
1780de41 AC	350	if (!request_region(wdt_stop, 1, "SBC 60XX WDT")) {
27c766aa	351	pr_err("I/O address 0x%04x already in use\n", wdt_stop);
1da177e4 LT	352	rc = -EIO;
	353	goto err_out_region1;
	354	}
	355	}
	356
c6cb13ae	357	rc = register_reboot_notifier(&wdt_notifier);
1780de41	358	if (rc) {
27c766aa	359	pr_err("cannot register reboot notifier (err=%d)\n", rc);
1da177e4 LT	360	goto err_out_region2;
	361	}
	362
c6cb13ae	363	rc = misc_register(&wdt_miscdev);
1780de41	364	if (rc) {
27c766aa JP	365	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
27c766aa JP	366	wdt_miscdev.minor, rc);
c6cb13ae	367	goto err_out_reboot;
1da177e4	368	}
27c766aa JP	369	pr_info("WDT driver for 60XX single board computer initialised. timeout=%d sec (nowayout=%d)\n",
27c766aa JP	370	timeout, nowayout);
1da177e4 LT	371
	372	return 0;
	373
c6cb13ae WVS	374	err_out_reboot:
c6cb13ae WVS	375	unregister_reboot_notifier(&wdt_notifier);
1da177e4	376	err_out_region2:
1780de41 AC	377	if (wdt_stop != 0x45 && wdt_stop != wdt_start)
1780de41 AC	378	release_region(wdt_stop, 1);
1da177e4	379	err_out_region1:
1780de41	380	release_region(wdt_start, 1);
1da177e4 LT	381	err_out:
	382	return rc;
	383	}
	384
	385	module_init(sbc60xxwdt_init);
	386	module_exit(sbc60xxwdt_unload);
	387
	388	MODULE_AUTHOR("Jakob Oestergaard <jakob@unthought.net>");
	389	MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver");
	390	MODULE_LICENSE("GPL");
	391	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);