drivers/watchdog/alim7101_wdt.c - kernel/common - Git at Google

 /*
  *	ALi M7101 PMU Computer Watchdog Timer driver
  *
  *	Based on w83877f_wdt.c by Scott Jennings <[email protected]>
  *	and the Cobalt kernel WDT timer driver by Tim Hockin
  *	                                      <[email protected]>
  *
  *	(c)2002 Steve Hill <[email protected]>
  *
  *  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.
  *
  *  Additions:
  *   Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs
  *                  found on very old cobalt hardware.
  *                  -- Mike Waychison <[email protected]>
  */

 #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/miscdevice.h>
 #include <linux/watchdog.h>
 #include <linux/ioport.h>
 #include <linux/notifier.h>
 #include <linux/reboot.h>
 #include <linux/init.h>
 #include <linux/fs.h>
 #include <linux/pci.h>
 #include <linux/io.h>
 #include <linux/uaccess.h>


 #define WDT_ENABLE 0x9C
 #define WDT_DISABLE 0x8C

 #define ALI_7101_WDT    0x92
 #define ALI_7101_GPIO   0x7D
 #define ALI_7101_GPIO_O 0x7E
 #define ALI_WDT_ARM     0x01

 /*
  * We're going to use a 1 second timeout.
  * 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 */
 /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
 static int timeout = WATCHDOG_TIMEOUT;
 module_param(timeout, int, 0);
 MODULE_PARM_DESC(timeout,
 		"Watchdog timeout in seconds. (1<=timeout<=3600, default="
 				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");

 static int use_gpio; /* Use the pic (for a1d revision alim7101) */
 module_param(use_gpio, int, 0);
 MODULE_PARM_DESC(use_gpio,
 		"Use the gpio watchdog (required by old cobalt boards).");

 static void wdt_timer_ping(unsigned long);
 static DEFINE_TIMER(timer, wdt_timer_ping, 0, 1);
 static unsigned long next_heartbeat;
 static unsigned long wdt_is_open;
 static char wdt_expect_close;
 static struct pci_dev *alim7101_pmu;

 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) ")");

 /*
  *	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
 	 */
 	char tmp;

 	if (time_before(jiffies, next_heartbeat)) {
 		/* Ping the WDT (this is actually a disarm/arm sequence) */
 		pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
 		pci_write_config_byte(alim7101_pmu,
 					ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
 		pci_write_config_byte(alim7101_pmu,
 					ALI_7101_WDT, (tmp | ALI_WDT_ARM));
 		if (use_gpio) {
 			pci_read_config_byte(alim7101_pmu,
 					ALI_7101_GPIO_O, &tmp);
 			pci_write_config_byte(alim7101_pmu,
 					ALI_7101_GPIO_O, tmp | 0x20);
 			pci_write_config_byte(alim7101_pmu,
 					ALI_7101_GPIO_O, tmp & ~0x20);
 		}
 	} else {
 		pr_warn("Heartbeat lost! Will not ping the watchdog\n");
 	}
 	/* Re-set the timer interval */
 	mod_timer(&timer, jiffies + WDT_INTERVAL);
 }

 /*
  * Utility routines
  */

 static void wdt_change(int writeval)
 {
 	char tmp;

 	pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);
 	if (writeval == WDT_ENABLE) {
 		pci_write_config_byte(alim7101_pmu,
 					ALI_7101_WDT, (tmp | ALI_WDT_ARM));
 		if (use_gpio) {
 			pci_read_config_byte(alim7101_pmu,
 					ALI_7101_GPIO_O, &tmp);
 			pci_write_config_byte(alim7101_pmu,
 					ALI_7101_GPIO_O, tmp & ~0x20);
 		}

 	} else {
 		pci_write_config_byte(alim7101_pmu,
 					ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
 		if (use_gpio) {
 			pci_read_config_byte(alim7101_pmu,
 					ALI_7101_GPIO_O, &tmp);
 			pci_write_config_byte(alim7101_pmu,
 					ALI_7101_GPIO_O, tmp | 0x20);
 		}
 	}
 }

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

 	/* We must enable before we kick off the timer in case the timer
 	   occurs as we ping it */

 	wdt_change(WDT_ENABLE);

 	/* 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_sync(&timer);
 	wdt_change(WDT_DISABLE);
 	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;

 			/* now scan */
 			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 {
 		/* wim: shouldn't there be a: 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 = "ALiM7101",
 	};

 	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,
 };

 static int wdt_restart_handle(struct notifier_block *this, unsigned long mode,
 			      void *cmd)
 {
 	/*
 	 * Cobalt devices have no way of rebooting themselves other
 	 * than getting the watchdog to pull reset, so we restart the
 	 * watchdog on reboot with no heartbeat.
 	 */
 	wdt_change(WDT_ENABLE);

 	/* loop until the watchdog fires */
 	while (true)
 		;

 	return NOTIFY_DONE;
 }

 static struct notifier_block wdt_restart_handler = {
 	.notifier_call = wdt_restart_handle,
 	.priority = 128,
 };

 /*
  *	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 alim7101_wdt_unload(void)
 {
 	wdt_turnoff();
 	/* Deregister */
 	misc_deregister(&wdt_miscdev);
 	unregister_reboot_notifier(&wdt_notifier);
 	unregister_restart_handler(&wdt_restart_handler);
 	pci_dev_put(alim7101_pmu);
 }

 static int __init alim7101_wdt_init(void)
 {
 	int rc = -EBUSY;
 	struct pci_dev *ali1543_south;
 	char tmp;

 	pr_info("Steve Hill <[email protected]>\n");
 	alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
 		NULL);
 	if (!alim7101_pmu) {
 		pr_info("ALi M7101 PMU not present - WDT not set\n");
 		return -EBUSY;
 	}

 	/* Set the WDT in the PMU to 1 second */
 	pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);

 	ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
 		NULL);
 	if (!ali1543_south) {
 		pr_info("ALi 1543 South-Bridge not present - WDT not set\n");
 		goto err_out;
 	}
 	pci_read_config_byte(ali1543_south, 0x5e, &tmp);
 	pci_dev_put(ali1543_south);
 	if ((tmp & 0x1e) == 0x00) {
 		if (!use_gpio) {
 			pr_info("Detected old alim7101 revision 'a1d'.  If this is a cobalt board, set the 'use_gpio' module parameter.\n");
 			goto err_out;
 		}
 		nowayout = 1;
 	} else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
 		pr_info("ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
 		goto err_out;
 	}

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

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

 	rc = register_restart_handler(&wdt_restart_handler);
 	if (rc) {
 		pr_err("cannot register restart handler (err=%d)\n", rc);
 		goto err_out_reboot;
 	}

 	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_restart;
 	}

 	if (nowayout)
 		__module_get(THIS_MODULE);

 	pr_info("WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
 		timeout, nowayout);
 	return 0;

 err_out_restart:
 	unregister_restart_handler(&wdt_restart_handler);
 err_out_reboot:
 	unregister_reboot_notifier(&wdt_notifier);
 err_out:
 	pci_dev_put(alim7101_pmu);
 	return rc;
 }

 module_init(alim7101_wdt_init);
 module_exit(alim7101_wdt_unload);

 static const struct pci_device_id alim7101_pci_tbl[] __used = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
 	{ }
 };

 MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);

 MODULE_AUTHOR("Steve Hill");
 MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
 MODULE_LICENSE("GPL");
	/*
	* ALi M7101 PMU Computer Watchdog Timer driver
	*
	* Based on w83877f_wdt.c by Scott Jennings <[email protected]>
	* and the Cobalt kernel WDT timer driver by Tim Hockin
	* <[email protected]>
	*
	* (c)2002 Steve Hill <[email protected]>
	*
	* 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.
	*
	* Additions:
	* Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs
	* found on very old cobalt hardware.
	* -- Mike Waychison <[email protected]>
	*/

	#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/miscdevice.h>
	#include <linux/watchdog.h>
	#include <linux/ioport.h>
	#include <linux/notifier.h>
	#include <linux/reboot.h>
	#include <linux/init.h>
	#include <linux/fs.h>
	#include <linux/pci.h>
	#include <linux/io.h>
	#include <linux/uaccess.h>


	#define WDT_ENABLE 0x9C
	#define WDT_DISABLE 0x8C

	#define ALI_7101_WDT 0x92
	#define ALI_7101_GPIO 0x7D
	#define ALI_7101_GPIO_O 0x7E
	#define ALI_WDT_ARM 0x01

	/*
	* We're going to use a 1 second timeout.
	* 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 */
	/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
	static int timeout = WATCHDOG_TIMEOUT;
	module_param(timeout, int, 0);
	MODULE_PARM_DESC(timeout,
	"Watchdog timeout in seconds. (1<=timeout<=3600, default="
	__MODULE_STRING(WATCHDOG_TIMEOUT) ")");

	static int use_gpio; /* Use the pic (for a1d revision alim7101) */
	module_param(use_gpio, int, 0);
	MODULE_PARM_DESC(use_gpio,
	"Use the gpio watchdog (required by old cobalt boards).");

	static void wdt_timer_ping(unsigned long);
	static DEFINE_TIMER(timer, wdt_timer_ping, 0, 1);
	static unsigned long next_heartbeat;
	static unsigned long wdt_is_open;
	static char wdt_expect_close;
	static struct pci_dev *alim7101_pmu;

	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) ")");

	/*
	* 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
	*/
	char tmp;

	if (time_before(jiffies, next_heartbeat)) {
	/* Ping the WDT (this is actually a disarm/arm sequence) */
	pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
	pci_write_config_byte(alim7101_pmu,
	ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
	pci_write_config_byte(alim7101_pmu,
	ALI_7101_WDT, (tmp \| ALI_WDT_ARM));
	if (use_gpio) {
	pci_read_config_byte(alim7101_pmu,
	ALI_7101_GPIO_O, &tmp);
	pci_write_config_byte(alim7101_pmu,
	ALI_7101_GPIO_O, tmp \| 0x20);
	pci_write_config_byte(alim7101_pmu,
	ALI_7101_GPIO_O, tmp & ~0x20);
	}
	} else {
	pr_warn("Heartbeat lost! Will not ping the watchdog\n");
	}
	/* Re-set the timer interval */
	mod_timer(&timer, jiffies + WDT_INTERVAL);
	}

	/*
	* Utility routines
	*/

	static void wdt_change(int writeval)
	{
	char tmp;

	pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);
	if (writeval == WDT_ENABLE) {
	pci_write_config_byte(alim7101_pmu,
	ALI_7101_WDT, (tmp \| ALI_WDT_ARM));
	if (use_gpio) {
	pci_read_config_byte(alim7101_pmu,
	ALI_7101_GPIO_O, &tmp);
	pci_write_config_byte(alim7101_pmu,
	ALI_7101_GPIO_O, tmp & ~0x20);
	}

	} else {
	pci_write_config_byte(alim7101_pmu,
	ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
	if (use_gpio) {
	pci_read_config_byte(alim7101_pmu,
	ALI_7101_GPIO_O, &tmp);
	pci_write_config_byte(alim7101_pmu,
	ALI_7101_GPIO_O, tmp \| 0x20);
	}
	}
	}

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

	/* We must enable before we kick off the timer in case the timer
	occurs as we ping it */

	wdt_change(WDT_ENABLE);

	/* 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_sync(&timer);
	wdt_change(WDT_DISABLE);
	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;

	/* now scan */
	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 {
	/* wim: shouldn't there be a: 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 = "ALiM7101",
	};

	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,
	};

	static int wdt_restart_handle(struct notifier_block *this, unsigned long mode,
	void *cmd)
	{
	/*
	* Cobalt devices have no way of rebooting themselves other
	* than getting the watchdog to pull reset, so we restart the
	* watchdog on reboot with no heartbeat.
	*/
	wdt_change(WDT_ENABLE);

	/* loop until the watchdog fires */
	while (true)
	;

	return NOTIFY_DONE;
	}

	static struct notifier_block wdt_restart_handler = {
	.notifier_call = wdt_restart_handle,
	.priority = 128,
	};

	/*
	* 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 alim7101_wdt_unload(void)
	{
	wdt_turnoff();
	/* Deregister */
	misc_deregister(&wdt_miscdev);
	unregister_reboot_notifier(&wdt_notifier);
	unregister_restart_handler(&wdt_restart_handler);
	pci_dev_put(alim7101_pmu);
	}

	static int __init alim7101_wdt_init(void)
	{
	int rc = -EBUSY;
	struct pci_dev *ali1543_south;
	char tmp;

	pr_info("Steve Hill <[email protected]>\n");
	alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
	NULL);
	if (!alim7101_pmu) {
	pr_info("ALi M7101 PMU not present - WDT not set\n");
	return -EBUSY;
	}

	/* Set the WDT in the PMU to 1 second */
	pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);

	ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
	NULL);
	if (!ali1543_south) {
	pr_info("ALi 1543 South-Bridge not present - WDT not set\n");
	goto err_out;
	}
	pci_read_config_byte(ali1543_south, 0x5e, &tmp);
	pci_dev_put(ali1543_south);
	if ((tmp & 0x1e) == 0x00) {
	if (!use_gpio) {
	pr_info("Detected old alim7101 revision 'a1d'. If this is a cobalt board, set the 'use_gpio' module parameter.\n");
	goto err_out;
	}
	nowayout = 1;
	} else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
	pr_info("ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
	goto err_out;
	}

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

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

	rc = register_restart_handler(&wdt_restart_handler);
	if (rc) {
	pr_err("cannot register restart handler (err=%d)\n", rc);
	goto err_out_reboot;
	}

	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_restart;
	}

	if (nowayout)
	__module_get(THIS_MODULE);

	pr_info("WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
	timeout, nowayout);
	return 0;

	err_out_restart:
	unregister_restart_handler(&wdt_restart_handler);
	err_out_reboot:
	unregister_reboot_notifier(&wdt_notifier);
	err_out:
	pci_dev_put(alim7101_pmu);
	return rc;
	}

	module_init(alim7101_wdt_init);
	module_exit(alim7101_wdt_unload);

	static const struct pci_device_id alim7101_pci_tbl[] __used = {
	{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
	{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
	{ }
	};

	MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);

	MODULE_AUTHOR("Steve Hill");
	MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
	MODULE_LICENSE("GPL");