[linux-2.6-block.git] / drivers / watchdog / sbc60xxwdt.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x
 *
 *	Based on acquirewdt.c by Alan Cox.
 *
 *	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>


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

static void wdt_timer_ping(struct timer_list *);
static DEFINE_TIMER(timer, wdt_timer_ping);
static unsigned long next_heartbeat;
static unsigned long wdt_is_open;
static char wdt_expect_close;

/*
 *	Whack the dog
 */

static void wdt_timer_ping(struct timer_list *unused)
{
	/* 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 stream_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");
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* 60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x
	4	*
143a2e54	5	* Based on acquirewdt.c by Alan Cox.
1da177e4	6	*
1da177e4 LT	7	* The author does NOT admit liability nor provide warranty for
	8	* any of this software. This material is provided "AS-IS" in
	9	* the hope that it may be useful for others.
	10	*
	11	* (c) Copyright 2000 Jakob Oestergaard <jakob@unthought.net>
	12	*
	13	* 12/4 - 2000 [Initial revision]
	14	* 25/4 - 2000 Added /dev/watchdog support
1780de41 AC	15	* 09/5 - 2001 [smj@oro.net] fixed fop_write to "return 1"
1780de41 AC	16	* on success
1da177e4 LT	17	* 12/4 - 2002 [rob@osinvestor.com] eliminate fop_read
	18	* fix possible wdt_is_open race
	19	* add CONFIG_WATCHDOG_NOWAYOUT support
	20	* remove lock_kernel/unlock_kernel pairs
	21	* added KERN_* to printk's
	22	* got rid of extraneous comments
1780de41 AC	23	* changed watchdog_info to correctly reflect what
	24	* the driver offers
	25	* added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS,
	26	* WDIOC_SETTIMEOUT, WDIOC_GETTIMEOUT, and
	27	* WDIOC_SETOPTIONS ioctls
1da177e4 LT	28	* 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces
1da177e4 LT	29	* use module_param
1780de41 AC	30	* made timeout (the emulated heartbeat) a
1780de41 AC	31	* module_param
1da177e4 LT	32	* made the keepalive ping an internal subroutine
	33	* made wdt_stop and wdt_start module params
	34	* added extra printk's for startup problems
	35	* added MODULE_AUTHOR and MODULE_DESCRIPTION info
	36	*
1da177e4 LT	37	* This WDT driver is different from the other Linux WDT
	38	* drivers in the following ways:
	39	* *) The driver will ping the watchdog by itself, because this
	40	* particular WDT has a very short timeout (one second) and it
	41	* would be insane to count on any userspace daemon always
	42	* getting scheduled within that time frame.
1da177e4 LT	43	*/
1da177e4 LT	44
27c766aa JP	45	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	46
1da177e4 LT	47	#include <linux/module.h>
	48	#include <linux/moduleparam.h>
	49	#include <linux/types.h>
	50	#include <linux/timer.h>
	51	#include <linux/jiffies.h>
	52	#include <linux/miscdevice.h>
	53	#include <linux/watchdog.h>
	54	#include <linux/fs.h>
	55	#include <linux/ioport.h>
	56	#include <linux/notifier.h>
	57	#include <linux/reboot.h>
	58	#include <linux/init.h>
1780de41 AC	59	#include <linux/io.h>
1780de41 AC	60	#include <linux/uaccess.h>
1da177e4	61
1da177e4 LT	62
	63	#define OUR_NAME "sbc60xxwdt"
	64	#define PFX OUR_NAME ": "
	65
	66	/*
	67	* You must set these - The driver cannot probe for the settings
	68	*/
	69
	70	static int wdt_stop = 0x45;
	71	module_param(wdt_stop, int, 0);
	72	MODULE_PARM_DESC(wdt_stop, "SBC60xx WDT 'stop' io port (default 0x45)");
	73
	74	static int wdt_start = 0x443;
	75	module_param(wdt_start, int, 0);
	76	MODULE_PARM_DESC(wdt_start, "SBC60xx WDT 'start' io port (default 0x443)");
	77
	78	/*
	79	* The 60xx board can use watchdog timeout values from one second
	80	* to several minutes. The default is one second, so if we reset
	81	* the watchdog every ~250ms we should be safe.
	82	*/
	83
	84	#define WDT_INTERVAL (HZ/4+1)
	85
	86	/*
	87	* We must not require too good response from the userspace daemon.
	88	* Here we require the userspace daemon to send us a heartbeat
	89	* char to /dev/watchdog every 30 seconds.
	90	* If the daemon pulses us every 25 seconds, we can still afford
	91	* a 5 second scheduling delay on the (high priority) daemon. That
	92	* should be sufficient for a box under any load.
	93	*/
	94
	95	#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
1780de41 AC	96	static int timeout = WATCHDOG_TIMEOUT; /* in seconds, multiplied by HZ to
1780de41 AC	97	get seconds to wait for a ping */
1da177e4	98	module_param(timeout, int, 0);
1780de41 AC	99	MODULE_PARM_DESC(timeout,
	100	"Watchdog timeout in seconds. (1<=timeout<=3600, default="
	101	__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
1da177e4	102
86a1e189 WVS	103	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	104	module_param(nowayout, bool, 0);
1780de41 AC	105	MODULE_PARM_DESC(nowayout,
	106	"Watchdog cannot be stopped once started (default="
	107	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4	108
24ed960a	109	static void wdt_timer_ping(struct timer_list *);
1d27e3e2	110	static DEFINE_TIMER(timer, wdt_timer_ping);
1da177e4 LT	111	static unsigned long next_heartbeat;
	112	static unsigned long wdt_is_open;
	113	static char wdt_expect_close;
	114
	115	/*
	116	* Whack the dog
	117	*/
	118
24ed960a	119	static void wdt_timer_ping(struct timer_list *unused)
1da177e4 LT	120	{
	121	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
	122	* we agree to ping the WDT
	123	*/
1780de41	124	if (time_before(jiffies, next_heartbeat)) {
1da177e4 LT	125	/* Ping the WDT by reading from wdt_start */
	126	inb_p(wdt_start);
	127	/* Re-set the timer interval */
82eb7c50	128	mod_timer(&timer, jiffies + WDT_INTERVAL);
1780de41	129	} else
27c766aa	130	pr_warn("Heartbeat lost! Will not ping the watchdog\n");
1da177e4 LT	131	}
	132
	133	/*
	134	* Utility routines
	135	*/
	136
	137	static void wdt_startup(void)
	138	{
	139	next_heartbeat = jiffies + (timeout * HZ);
	140
	141	/* Start the timer */
82eb7c50	142	mod_timer(&timer, jiffies + WDT_INTERVAL);
27c766aa	143	pr_info("Watchdog timer is now enabled\n");
1da177e4 LT	144	}
	145
	146	static void wdt_turnoff(void)
	147	{
	148	/* Stop the timer */
	149	del_timer(&timer);
	150	inb_p(wdt_stop);
27c766aa	151	pr_info("Watchdog timer is now disabled...\n");
1da177e4 LT	152	}
	153
	154	static void wdt_keepalive(void)
	155	{
	156	/* user land ping */
	157	next_heartbeat = jiffies + (timeout * HZ);
	158	}
	159
	160	/*
	161	* /dev/watchdog handling
	162	*/
	163
1780de41 AC	164	static ssize_t fop_write(struct file file, const char __user buf,
1780de41 AC	165	size_t count, loff_t *ppos)
1da177e4 LT	166	{
1da177e4 LT	167	/* See if we got the magic character 'V' and reload the timer */
1780de41 AC	168	if (count) {
1780de41 AC	169	if (!nowayout) {
1da177e4 LT	170	size_t ofs;
1da177e4 LT	171
1780de41 AC	172	/* note: just in case someone wrote the
1780de41 AC	173	magic character five months ago... */
1da177e4 LT	174	wdt_expect_close = 0;
1da177e4 LT	175
1780de41 AC	176	/* scan to see whether or not we got the
	177	magic character */
	178	for (ofs = 0; ofs != count; ofs++) {
1da177e4	179	char c;
7944d3a5	180	if (get_user(c, buf + ofs))
1da177e4	181	return -EFAULT;
1780de41	182	if (c == 'V')
1da177e4 LT	183	wdt_expect_close = 42;
	184	}
	185	}
	186
1780de41 AC	187	/* Well, anyhow someone wrote to us, we should
1780de41 AC	188	return that favour */
1da177e4 LT	189	wdt_keepalive();
	190	}
	191	return count;
	192	}
	193
1780de41	194	static int fop_open(struct inode inode, struct file file)
1da177e4	195	{
1da177e4	196	/* Just in case we're already talking to someone... */
1780de41	197	if (test_and_set_bit(0, &wdt_is_open))
1da177e4 LT	198	return -EBUSY;
	199
	200	if (nowayout)
	201	__module_get(THIS_MODULE);
	202
	203	/* Good, fire up the show */
	204	wdt_startup();
c5bf68fe	205	return stream_open(inode, file);
1da177e4 LT	206	}
1da177e4 LT	207
1780de41	208	static int fop_close(struct inode inode, struct file file)
1da177e4	209	{
1780de41	210	if (wdt_expect_close == 42)
1da177e4 LT	211	wdt_turnoff();
	212	else {
	213	del_timer(&timer);
27c766aa	214	pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
1da177e4 LT	215	}
	216	clear_bit(0, &wdt_is_open);
	217	wdt_expect_close = 0;
	218	return 0;
	219	}
	220
1780de41	221	static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1da177e4 LT	222	{
	223	void __user argp = (void __user )arg;
	224	int __user *p = argp;
1780de41 AC	225	static const struct watchdog_info ident = {
	226	.options = WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT \|
	227	WDIOF_MAGICCLOSE,
1da177e4 LT	228	.firmware_version = 1,
	229	.identity = "SBC60xx",
	230	};
	231
1780de41	232	switch (cmd) {
1780de41	233	case WDIOC_GETSUPPORT:
7944d3a5	234	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
1780de41 AC	235	case WDIOC_GETSTATUS:
	236	case WDIOC_GETBOOTSTATUS:
	237	return put_user(0, p);
1780de41	238	case WDIOC_SETOPTIONS:
1da177e4	239	{
1780de41 AC	240	int new_options, retval = -EINVAL;
	241	if (get_user(new_options, p))
	242	return -EFAULT;
	243	if (new_options & WDIOS_DISABLECARD) {
	244	wdt_turnoff();
	245	retval = 0;
1da177e4	246	}
1780de41 AC	247	if (new_options & WDIOS_ENABLECARD) {
	248	wdt_startup();
	249	retval = 0;
1da177e4	250	}
1780de41 AC	251	return retval;
1780de41 AC	252	}
0c06090c WVS	253	case WDIOC_KEEPALIVE:
	254	wdt_keepalive();
	255	return 0;
1780de41 AC	256	case WDIOC_SETTIMEOUT:
	257	{
	258	int new_timeout;
	259	if (get_user(new_timeout, p))
	260	return -EFAULT;
	261	/* arbitrary upper limit */
	262	if (new_timeout < 1 \|\| new_timeout > 3600)
	263	return -EINVAL;
	264
	265	timeout = new_timeout;
	266	wdt_keepalive();
1780de41	267	}
3612b87d	268	/* Fall through */
1780de41 AC	269	case WDIOC_GETTIMEOUT:
1780de41 AC	270	return put_user(timeout, p);
0c06090c WVS	271	default:
0c06090c WVS	272	return -ENOTTY;
1da177e4 LT	273	}
	274	}
	275
62322d25	276	static const struct file_operations wdt_fops = {
1da177e4 LT	277	.owner = THIS_MODULE,
	278	.llseek = no_llseek,
	279	.write = fop_write,
	280	.open = fop_open,
	281	.release = fop_close,
1780de41	282	.unlocked_ioctl = fop_ioctl,
1da177e4 LT	283	};
	284
	285	static struct miscdevice wdt_miscdev = {
	286	.minor = WATCHDOG_MINOR,
	287	.name = "watchdog",
	288	.fops = &wdt_fops,
	289	};
	290
	291	/*
	292	* Notifier for system down
	293	*/
	294
	295	static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
	296	void *unused)
	297	{
1780de41	298	if (code == SYS_DOWN \|\| code == SYS_HALT)
1da177e4 LT	299	wdt_turnoff();
	300	return NOTIFY_DONE;
	301	}
	302
	303	/*
	304	* The WDT needs to learn about soft shutdowns in order to
	305	* turn the timebomb registers off.
	306	*/
	307
1780de41	308	static struct notifier_block wdt_notifier = {
1da177e4 LT	309	.notifier_call = wdt_notify_sys,
	310	};
	311
	312	static void __exit sbc60xxwdt_unload(void)
	313	{
	314	wdt_turnoff();
	315
	316	/* Deregister */
	317	misc_deregister(&wdt_miscdev);
	318
	319	unregister_reboot_notifier(&wdt_notifier);
	320	if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
1780de41 AC	321	release_region(wdt_stop, 1);
1780de41 AC	322	release_region(wdt_start, 1);
1da177e4 LT	323	}
	324
	325	static int __init sbc60xxwdt_init(void)
	326	{
	327	int rc = -EBUSY;
	328
1780de41	329	if (timeout < 1 \|\| timeout > 3600) { /* arbitrary upper limit */
1da177e4	330	timeout = WATCHDOG_TIMEOUT;
27c766aa JP	331	pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
27c766aa JP	332	timeout);
1780de41	333	}
1da177e4	334
1780de41	335	if (!request_region(wdt_start, 1, "SBC 60XX WDT")) {
27c766aa	336	pr_err("I/O address 0x%04x already in use\n", wdt_start);
1da177e4 LT	337	rc = -EIO;
	338	goto err_out;
	339	}
	340
	341	/* We cannot reserve 0x45 - the kernel already has! */
1780de41 AC	342	if (wdt_stop != 0x45 && wdt_stop != wdt_start) {
1780de41 AC	343	if (!request_region(wdt_stop, 1, "SBC 60XX WDT")) {
27c766aa	344	pr_err("I/O address 0x%04x already in use\n", wdt_stop);
1da177e4 LT	345	rc = -EIO;
	346	goto err_out_region1;
	347	}
	348	}
	349
c6cb13ae	350	rc = register_reboot_notifier(&wdt_notifier);
1780de41	351	if (rc) {
27c766aa	352	pr_err("cannot register reboot notifier (err=%d)\n", rc);
1da177e4 LT	353	goto err_out_region2;
	354	}
	355
c6cb13ae	356	rc = misc_register(&wdt_miscdev);
1780de41	357	if (rc) {
27c766aa JP	358	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
27c766aa JP	359	wdt_miscdev.minor, rc);
c6cb13ae	360	goto err_out_reboot;
1da177e4	361	}
27c766aa JP	362	pr_info("WDT driver for 60XX single board computer initialised. timeout=%d sec (nowayout=%d)\n",
27c766aa JP	363	timeout, nowayout);
1da177e4 LT	364
	365	return 0;
	366
c6cb13ae WVS	367	err_out_reboot:
c6cb13ae WVS	368	unregister_reboot_notifier(&wdt_notifier);
1da177e4	369	err_out_region2:
1780de41 AC	370	if (wdt_stop != 0x45 && wdt_stop != wdt_start)
1780de41 AC	371	release_region(wdt_stop, 1);
1da177e4	372	err_out_region1:
1780de41	373	release_region(wdt_start, 1);
1da177e4 LT	374	err_out:
	375	return rc;
	376	}
	377
	378	module_init(sbc60xxwdt_init);
	379	module_exit(sbc60xxwdt_unload);
	380
	381	MODULE_AUTHOR("Jakob Oestergaard <jakob@unthought.net>");
	382	MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver");
	383	MODULE_LICENSE("GPL");