[net-next-2.6.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.
 *
 */

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

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

		/* 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);
		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 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;
		printk(KERN_INFO PFX
			"timeout value must be 1 <= x <= 3600, using %d\n",
								timeout);
	}

	if (!request_region(wdt_start, 1, "SBC 60XX WDT")) {
		printk(KERN_ERR PFX "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")) {
			printk(KERN_ERR PFX
				"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) {
		printk(KERN_ERR PFX
			"cannot register reboot notifier (err=%d)\n", rc);
		goto err_out_region2;
	}

	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_reboot;
	}
	printk(KERN_INFO PFX
		"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
	51	#include <linux/module.h>
	52	#include <linux/moduleparam.h>
	53	#include <linux/types.h>
	54	#include <linux/timer.h>
	55	#include <linux/jiffies.h>
	56	#include <linux/miscdevice.h>
	57	#include <linux/watchdog.h>
	58	#include <linux/fs.h>
	59	#include <linux/ioport.h>
	60	#include <linux/notifier.h>
	61	#include <linux/reboot.h>
	62	#include <linux/init.h>
1780de41 AC	63	#include <linux/io.h>
1780de41 AC	64	#include <linux/uaccess.h>
1da177e4	65
1da177e4 LT	66	#include <asm/system.h>
	67
	68	#define OUR_NAME "sbc60xxwdt"
	69	#define PFX OUR_NAME ": "
	70
	71	/*
	72	* You must set these - The driver cannot probe for the settings
	73	*/
	74
	75	static int wdt_stop = 0x45;
	76	module_param(wdt_stop, int, 0);
	77	MODULE_PARM_DESC(wdt_stop, "SBC60xx WDT 'stop' io port (default 0x45)");
	78
	79	static int wdt_start = 0x443;
	80	module_param(wdt_start, int, 0);
	81	MODULE_PARM_DESC(wdt_start, "SBC60xx WDT 'start' io port (default 0x443)");
	82
	83	/*
	84	* The 60xx board can use watchdog timeout values from one second
	85	* to several minutes. The default is one second, so if we reset
	86	* the watchdog every ~250ms we should be safe.
	87	*/
	88
	89	#define WDT_INTERVAL (HZ/4+1)
	90
	91	/*
	92	* We must not require too good response from the userspace daemon.
	93	* Here we require the userspace daemon to send us a heartbeat
	94	* char to /dev/watchdog every 30 seconds.
	95	* If the daemon pulses us every 25 seconds, we can still afford
	96	* a 5 second scheduling delay on the (high priority) daemon. That
	97	* should be sufficient for a box under any load.
	98	*/
	99
	100	#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
1780de41 AC	101	static int timeout = WATCHDOG_TIMEOUT; /* in seconds, multiplied by HZ to
1780de41 AC	102	get seconds to wait for a ping */
1da177e4	103	module_param(timeout, int, 0);
1780de41 AC	104	MODULE_PARM_DESC(timeout,
	105	"Watchdog timeout in seconds. (1<=timeout<=3600, default="
	106	__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
1da177e4	107
4bfdf378	108	static int nowayout = WATCHDOG_NOWAYOUT;
1da177e4	109	module_param(nowayout, int, 0);
1780de41 AC	110	MODULE_PARM_DESC(nowayout,
	111	"Watchdog cannot be stopped once started (default="
	112	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4 LT	113
1da177e4 LT	114	static void wdt_timer_ping(unsigned long);
82eb7c50	115	static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0);
1da177e4 LT	116	static unsigned long next_heartbeat;
	117	static unsigned long wdt_is_open;
	118	static char wdt_expect_close;
	119
	120	/*
	121	* Whack the dog
	122	*/
	123
	124	static void wdt_timer_ping(unsigned long data)
	125	{
	126	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
	127	* we agree to ping the WDT
	128	*/
1780de41	129	if (time_before(jiffies, next_heartbeat)) {
1da177e4 LT	130	/* Ping the WDT by reading from wdt_start */
	131	inb_p(wdt_start);
	132	/* Re-set the timer interval */
82eb7c50	133	mod_timer(&timer, jiffies + WDT_INTERVAL);
1780de41 AC	134	} else
	135	printk(KERN_WARNING PFX
	136	"Heartbeat lost! Will not ping the watchdog\n");
1da177e4 LT	137	}
	138
	139	/*
	140	* Utility routines
	141	*/
	142
	143	static void wdt_startup(void)
	144	{
	145	next_heartbeat = jiffies + (timeout * HZ);
	146
	147	/* Start the timer */
82eb7c50	148	mod_timer(&timer, jiffies + WDT_INTERVAL);
1da177e4 LT	149	printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
	150	}
	151
	152	static void wdt_turnoff(void)
	153	{
	154	/* Stop the timer */
	155	del_timer(&timer);
	156	inb_p(wdt_stop);
	157	printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
	158	}
	159
	160	static void wdt_keepalive(void)
	161	{
	162	/* user land ping */
	163	next_heartbeat = jiffies + (timeout * HZ);
	164	}
	165
	166	/*
	167	* /dev/watchdog handling
	168	*/
	169
1780de41 AC	170	static ssize_t fop_write(struct file file, const char __user buf,
1780de41 AC	171	size_t count, loff_t *ppos)
1da177e4 LT	172	{
1da177e4 LT	173	/* See if we got the magic character 'V' and reload the timer */
1780de41 AC	174	if (count) {
1780de41 AC	175	if (!nowayout) {
1da177e4 LT	176	size_t ofs;
1da177e4 LT	177
1780de41 AC	178	/* note: just in case someone wrote the
1780de41 AC	179	magic character five months ago... */
1da177e4 LT	180	wdt_expect_close = 0;
1da177e4 LT	181
1780de41 AC	182	/* scan to see whether or not we got the
	183	magic character */
	184	for (ofs = 0; ofs != count; ofs++) {
1da177e4	185	char c;
7944d3a5	186	if (get_user(c, buf + ofs))
1da177e4	187	return -EFAULT;
1780de41	188	if (c == 'V')
1da177e4 LT	189	wdt_expect_close = 42;
	190	}
	191	}
	192
1780de41 AC	193	/* Well, anyhow someone wrote to us, we should
1780de41 AC	194	return that favour */
1da177e4 LT	195	wdt_keepalive();
	196	}
	197	return count;
	198	}
	199
1780de41	200	static int fop_open(struct inode inode, struct file file)
1da177e4	201	{
1da177e4	202	/* Just in case we're already talking to someone... */
1780de41	203	if (test_and_set_bit(0, &wdt_is_open))
1da177e4 LT	204	return -EBUSY;
	205
	206	if (nowayout)
	207	__module_get(THIS_MODULE);
	208
	209	/* Good, fire up the show */
	210	wdt_startup();
6abe78bf	211	return nonseekable_open(inode, file);
1da177e4 LT	212	}
1da177e4 LT	213
1780de41	214	static int fop_close(struct inode inode, struct file file)
1da177e4	215	{
1780de41	216	if (wdt_expect_close == 42)
1da177e4 LT	217	wdt_turnoff();
	218	else {
	219	del_timer(&timer);
1780de41 AC	220	printk(KERN_CRIT PFX
1780de41 AC	221	"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;
1780de41 AC	338	printk(KERN_INFO PFX
	339	"timeout value must be 1 <= x <= 3600, using %d\n",
	340	timeout);
	341	}
1da177e4	342
1780de41	343	if (!request_region(wdt_start, 1, "SBC 60XX WDT")) {
1da177e4 LT	344	printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
	345	wdt_start);
	346	rc = -EIO;
	347	goto err_out;
	348	}
	349
	350	/* We cannot reserve 0x45 - the kernel already has! */
1780de41 AC	351	if (wdt_stop != 0x45 && wdt_stop != wdt_start) {
	352	if (!request_region(wdt_stop, 1, "SBC 60XX WDT")) {
	353	printk(KERN_ERR PFX
	354	"I/O address 0x%04x already in use\n",
	355	wdt_stop);
1da177e4 LT	356	rc = -EIO;
	357	goto err_out_region1;
	358	}
	359	}
	360
c6cb13ae	361	rc = register_reboot_notifier(&wdt_notifier);
1780de41 AC	362	if (rc) {
	363	printk(KERN_ERR PFX
	364	"cannot register reboot notifier (err=%d)\n", rc);
1da177e4 LT	365	goto err_out_region2;
	366	}
	367
c6cb13ae	368	rc = misc_register(&wdt_miscdev);
1780de41 AC	369	if (rc) {
	370	printk(KERN_ERR PFX
	371	"cannot register miscdev on minor=%d (err=%d)\n",
	372	wdt_miscdev.minor, rc);
c6cb13ae	373	goto err_out_reboot;
1da177e4	374	}
a77dba7e WVS	375	printk(KERN_INFO PFX
	376	"WDT driver for 60XX single board computer initialised. "
	377	"timeout=%d sec (nowayout=%d)\n", timeout, nowayout);
1da177e4 LT	378
	379	return 0;
	380
c6cb13ae WVS	381	err_out_reboot:
c6cb13ae WVS	382	unregister_reboot_notifier(&wdt_notifier);
1da177e4	383	err_out_region2:
1780de41 AC	384	if (wdt_stop != 0x45 && wdt_stop != wdt_start)
1780de41 AC	385	release_region(wdt_stop, 1);
1da177e4	386	err_out_region1:
1780de41	387	release_region(wdt_start, 1);
1da177e4 LT	388	err_out:
	389	return rc;
	390	}
	391
	392	module_init(sbc60xxwdt_init);
	393	module_exit(sbc60xxwdt_unload);
	394
	395	MODULE_AUTHOR("Jakob Oestergaard <jakob@unthought.net>");
	396	MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver");
	397	MODULE_LICENSE("GPL");
	398	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);