drivers/watchdog/shwdt.c - kernel/mindspeed - Git at Google

 /*
  * drivers/watchdog/shwdt.c
  *
  * Watchdog driver for integrated watchdog in the SuperH processors.
  *
  * Copyright (C) 2001 - 2010  Paul Mundt <lethal@linux-sh.org>
  *
  * 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.
  *
  * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  *     Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  *
  * 19-Apr-2002 Rob Radez <rob@osinvestor.com>
  *     Added expect close support, made emulated timeout runtime changeable
  *     general cleanups, add some ioctls
  */
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/platform_device.h>
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/miscdevice.h>
 #include <linux/watchdog.h>
 #include <linux/reboot.h>
 #include <linux/notifier.h>
 #include <linux/ioport.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/io.h>
 #include <linux/uaccess.h>
 #include <asm/watchdog.h>

 #define DRV_NAME "sh-wdt"

 /*
  * Default clock division ratio is 5.25 msecs. For an additional table of
  * values, consult the asm-sh/watchdog.h. Overload this at module load
  * time.
  *
  * In order for this to work reliably we need to have HZ set to 1000 or
  * something quite higher than 100 (or we need a proper high-res timer
  * implementation that will deal with this properly), otherwise the 10ms
  * resolution of a jiffy is enough to trigger the overflow. For things like
  * the SH-4 and SH-5, this isn't necessarily that big of a problem, though
  * for the SH-2 and SH-3, this isn't recommended unless the WDT is absolutely
  * necssary.
  *
  * As a result of this timing problem, the only modes that are particularly
  * feasible are the 4096 and the 2048 divisors, which yield 5.25 and 2.62ms
  * overflow periods respectively.
  *
  * Also, since we can't really expect userspace to be responsive enough
  * before the overflow happens, we maintain two separate timers .. One in
  * the kernel for clearing out WOVF every 2ms or so (again, this depends on
  * HZ == 1000), and another for monitoring userspace writes to the WDT device.
  *
  * As such, we currently use a configurable heartbeat interval which defaults
  * to 30s. In this case, the userspace daemon is only responsible for periodic
  * writes to the device before the next heartbeat is scheduled. If the daemon
  * misses its deadline, the kernel timer will allow the WDT to overflow.
  */
 static int clock_division_ratio = WTCSR_CKS_4096;
 #define next_ping_period(cks)	(jiffies + msecs_to_jiffies(cks - 4))

 static const struct watchdog_info sh_wdt_info;
 static struct platform_device *sh_wdt_dev;
 static DEFINE_SPINLOCK(shwdt_lock);

 #define WATCHDOG_HEARTBEAT 30			/* 30 sec default heartbeat */
 static int heartbeat = WATCHDOG_HEARTBEAT;	/* in seconds */
 static int nowayout = WATCHDOG_NOWAYOUT;
 static unsigned long next_heartbeat;

 struct sh_wdt {
 	void __iomem		*base;
 	struct device		*dev;

 	struct timer_list	timer;

 	unsigned long		enabled;
 	char			expect_close;
 };

 static void sh_wdt_start(struct sh_wdt *wdt)
 {
 	unsigned long flags;
 	u8 csr;

 	spin_lock_irqsave(&shwdt_lock, flags);

 	next_heartbeat = jiffies + (heartbeat * HZ);
 	mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));

 	csr = sh_wdt_read_csr();
 	csr |= WTCSR_WT | clock_division_ratio;
 	sh_wdt_write_csr(csr);

 	sh_wdt_write_cnt(0);

 	/*
 	 * These processors have a bit of an inconsistent initialization
 	 * process.. starting with SH-3, RSTS was moved to WTCSR, and the
 	 * RSTCSR register was removed.
 	 *
 	 * On the SH-2 however, in addition with bits being in different
 	 * locations, we must deal with RSTCSR outright..
 	 */
 	csr = sh_wdt_read_csr();
 	csr |= WTCSR_TME;
 	csr &= ~WTCSR_RSTS;
 	sh_wdt_write_csr(csr);

 #ifdef CONFIG_CPU_SH2
 	csr = sh_wdt_read_rstcsr();
 	csr &= ~RSTCSR_RSTS;
 	sh_wdt_write_rstcsr(csr);
 #endif
 	spin_unlock_irqrestore(&shwdt_lock, flags);
 }

 static void sh_wdt_stop(struct sh_wdt *wdt)
 {
 	unsigned long flags;
 	u8 csr;

 	spin_lock_irqsave(&shwdt_lock, flags);

 	del_timer(&wdt->timer);

 	csr = sh_wdt_read_csr();
 	csr &= ~WTCSR_TME;
 	sh_wdt_write_csr(csr);

 	spin_unlock_irqrestore(&shwdt_lock, flags);
 }

 static inline void sh_wdt_keepalive(struct sh_wdt *wdt)
 {
 	unsigned long flags;

 	spin_lock_irqsave(&shwdt_lock, flags);
 	next_heartbeat = jiffies + (heartbeat * HZ);
 	spin_unlock_irqrestore(&shwdt_lock, flags);
 }

 static int sh_wdt_set_heartbeat(int t)
 {
 	unsigned long flags;

 	if (unlikely(t < 1 || t > 3600)) /* arbitrary upper limit */
 		return -EINVAL;

 	spin_lock_irqsave(&shwdt_lock, flags);
 	heartbeat = t;
 	spin_unlock_irqrestore(&shwdt_lock, flags);
 	return 0;
 }

 static void sh_wdt_ping(unsigned long data)
 {
 	struct sh_wdt *wdt = (struct sh_wdt *)data;
 	unsigned long flags;

 	spin_lock_irqsave(&shwdt_lock, flags);
 	if (time_before(jiffies, next_heartbeat)) {
 		u8 csr;

 		csr = sh_wdt_read_csr();
 		csr &= ~WTCSR_IOVF;
 		sh_wdt_write_csr(csr);

 		sh_wdt_write_cnt(0);

 		mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));
 	} else
 		dev_warn(wdt->dev, "Heartbeat lost! Will not ping "
 		         "the watchdog\n");
 	spin_unlock_irqrestore(&shwdt_lock, flags);
 }

 static int sh_wdt_open(struct inode *inode, struct file *file)
 {
 	struct sh_wdt *wdt = platform_get_drvdata(sh_wdt_dev);

 	if (test_and_set_bit(0, &wdt->enabled))
 		return -EBUSY;
 	if (nowayout)
 		__module_get(THIS_MODULE);

 	file->private_data = wdt;

 	sh_wdt_start(wdt);

 	return nonseekable_open(inode, file);
 }

 static int sh_wdt_close(struct inode *inode, struct file *file)
 {
 	struct sh_wdt *wdt = file->private_data;

 	if (wdt->expect_close == 42) {
 		sh_wdt_stop(wdt);
 	} else {
 		dev_crit(wdt->dev, "Unexpected close, not "
 		         "stopping watchdog!\n");
 		sh_wdt_keepalive(wdt);
 	}

 	clear_bit(0, &wdt->enabled);
 	wdt->expect_close = 0;

 	return 0;
 }

 static ssize_t sh_wdt_write(struct file *file, const char *buf,
 			    size_t count, loff_t *ppos)
 {
 	struct sh_wdt *wdt = file->private_data;

 	if (count) {
 		if (!nowayout) {
 			size_t i;

 			wdt->expect_close = 0;

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

 	return count;
 }

 static long sh_wdt_ioctl(struct file *file, unsigned int cmd,
 							unsigned long arg)
 {
 	struct sh_wdt *wdt = file->private_data;
 	int new_heartbeat;
 	int options, retval = -EINVAL;

 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
 		return copy_to_user((struct watchdog_info *)arg,
 			  &sh_wdt_info, sizeof(sh_wdt_info)) ? -EFAULT : 0;
 	case WDIOC_GETSTATUS:
 	case WDIOC_GETBOOTSTATUS:
 		return put_user(0, (int *)arg);
 	case WDIOC_SETOPTIONS:
 		if (get_user(options, (int *)arg))
 			return -EFAULT;

 		if (options & WDIOS_DISABLECARD) {
 			sh_wdt_stop(wdt);
 			retval = 0;
 		}

 		if (options & WDIOS_ENABLECARD) {
 			sh_wdt_start(wdt);
 			retval = 0;
 		}

 		return retval;
 	case WDIOC_KEEPALIVE:
 		sh_wdt_keepalive(wdt);
 		return 0;
 	case WDIOC_SETTIMEOUT:
 		if (get_user(new_heartbeat, (int *)arg))
 			return -EFAULT;

 		if (sh_wdt_set_heartbeat(new_heartbeat))
 			return -EINVAL;

 		sh_wdt_keepalive(wdt);
 		/* Fall */
 	case WDIOC_GETTIMEOUT:
 		return put_user(heartbeat, (int *)arg);
 	default:
 		return -ENOTTY;
 	}
 	return 0;
 }

 static int sh_wdt_notify_sys(struct notifier_block *this,
 			     unsigned long code, void *unused)
 {
 	struct sh_wdt *wdt = platform_get_drvdata(sh_wdt_dev);

 	if (code == SYS_DOWN || code == SYS_HALT)
 		sh_wdt_stop(wdt);

 	return NOTIFY_DONE;
 }

 static const struct file_operations sh_wdt_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.write		= sh_wdt_write,
 	.unlocked_ioctl	= sh_wdt_ioctl,
 	.open		= sh_wdt_open,
 	.release	= sh_wdt_close,
 };

 static const struct watchdog_info sh_wdt_info = {
 	.options		= WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
 				  WDIOF_MAGICCLOSE,
 	.firmware_version	= 1,
 	.identity		= "SH WDT",
 };

 static struct notifier_block sh_wdt_notifier = {
 	.notifier_call		= sh_wdt_notify_sys,
 };

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

 static int __devinit sh_wdt_probe(struct platform_device *pdev)
 {
 	struct sh_wdt *wdt;
 	struct resource *res;
 	int rc;

 	/*
 	 * As this driver only covers the global watchdog case, reject
 	 * any attempts to register per-CPU watchdogs.
 	 */
 	if (pdev->id != -1)
 		return -EINVAL;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (unlikely(!res))
 		return -EINVAL;

 	if (!devm_request_mem_region(&pdev->dev, res->start,
 				     resource_size(res), DRV_NAME))
 		return -EBUSY;

 	wdt = devm_kzalloc(&pdev->dev, sizeof(struct sh_wdt), GFP_KERNEL);
 	if (unlikely(!wdt)) {
 		rc = -ENOMEM;
 		goto out_release;
 	}

 	wdt->dev = &pdev->dev;

 	wdt->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
 	if (unlikely(!wdt->base)) {
 		rc = -ENXIO;
 		goto out_err;
 	}

 	rc = register_reboot_notifier(&sh_wdt_notifier);
 	if (unlikely(rc)) {
 		dev_err(&pdev->dev,
 			"Can't register reboot notifier (err=%d)\n", rc);
 		goto out_unmap;
 	}

 	sh_wdt_miscdev.parent = wdt->dev;

 	rc = misc_register(&sh_wdt_miscdev);
 	if (unlikely(rc)) {
 		dev_err(&pdev->dev,
 			"Can't register miscdev on minor=%d (err=%d)\n",
 						sh_wdt_miscdev.minor, rc);
 		goto out_unreg;
 	}

 	init_timer(&wdt->timer);
 	wdt->timer.function	= sh_wdt_ping;
 	wdt->timer.data		= (unsigned long)wdt;
 	wdt->timer.expires	= next_ping_period(clock_division_ratio);

 	platform_set_drvdata(pdev, wdt);
 	sh_wdt_dev = pdev;

 	dev_info(&pdev->dev, "initialized.\n");

 	return 0;

 out_unreg:
 	unregister_reboot_notifier(&sh_wdt_notifier);
 out_unmap:
 	devm_iounmap(&pdev->dev, wdt->base);
 out_err:
 	devm_kfree(&pdev->dev, wdt);
 out_release:
 	devm_release_mem_region(&pdev->dev, res->start, resource_size(res));

 	return rc;
 }

 static int __devexit sh_wdt_remove(struct platform_device *pdev)
 {
 	struct sh_wdt *wdt = platform_get_drvdata(pdev);
 	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

 	platform_set_drvdata(pdev, NULL);

 	misc_deregister(&sh_wdt_miscdev);

 	sh_wdt_dev = NULL;

 	unregister_reboot_notifier(&sh_wdt_notifier);
 	devm_release_mem_region(&pdev->dev, res->start, resource_size(res));
 	devm_iounmap(&pdev->dev, wdt->base);
 	devm_kfree(&pdev->dev, wdt);

 	return 0;
 }

 static struct platform_driver sh_wdt_driver = {
 	.driver		= {
 		.name	= DRV_NAME,
 		.owner	= THIS_MODULE,
 	},

 	.probe	= sh_wdt_probe,
 	.remove	= __devexit_p(sh_wdt_remove),
 };

 static int __init sh_wdt_init(void)
 {
 	int rc;

 	if (unlikely(clock_division_ratio < 0x5 ||
 		     clock_division_ratio > 0x7)) {
 		clock_division_ratio = WTCSR_CKS_4096;

 		pr_info("%s: divisor must be 0x5<=x<=0x7, using %d\n",
 			 DRV_NAME, clock_division_ratio);
 	}

 	rc = sh_wdt_set_heartbeat(heartbeat);
 	if (unlikely(rc)) {
 		heartbeat = WATCHDOG_HEARTBEAT;

 		pr_info("%s: heartbeat value must be 1<=x<=3600, using %d\n",
 			DRV_NAME, heartbeat);
 	}

 	pr_info("%s: configured with heartbeat=%d sec (nowayout=%d)\n",
 		DRV_NAME, heartbeat, nowayout);

 	return platform_driver_register(&sh_wdt_driver);
 }

 static void __exit sh_wdt_exit(void)
 {
 	platform_driver_unregister(&sh_wdt_driver);
 }
 module_init(sh_wdt_init);
 module_exit(sh_wdt_exit);

 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
 MODULE_DESCRIPTION("SuperH watchdog driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:" DRV_NAME);
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

 module_param(clock_division_ratio, int, 0);
 MODULE_PARM_DESC(clock_division_ratio,
 	"Clock division ratio. Valid ranges are from 0x5 (1.31ms) "
 	"to 0x7 (5.25ms). (default=" __MODULE_STRING(WTCSR_CKS_4096) ")");

 module_param(heartbeat, int, 0);
 MODULE_PARM_DESC(heartbeat,
 	"Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default="
 				__MODULE_STRING(WATCHDOG_HEARTBEAT) ")");

 module_param(nowayout, int, 0);
 MODULE_PARM_DESC(nowayout,
 	"Watchdog cannot be stopped once started (default="
 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	/*
	* drivers/watchdog/shwdt.c
	*
	* Watchdog driver for integrated watchdog in the SuperH processors.
	*
	* Copyright (C) 2001 - 2010 Paul Mundt <lethal@linux-sh.org>
	*
	* 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.
	*
	* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
	* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
	*
	* 19-Apr-2002 Rob Radez <rob@osinvestor.com>
	* Added expect close support, made emulated timeout runtime changeable
	* general cleanups, add some ioctls
	*/
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/platform_device.h>
	#include <linux/init.h>
	#include <linux/types.h>
	#include <linux/miscdevice.h>
	#include <linux/watchdog.h>
	#include <linux/reboot.h>
	#include <linux/notifier.h>
	#include <linux/ioport.h>
	#include <linux/fs.h>
	#include <linux/mm.h>
	#include <linux/slab.h>
	#include <linux/io.h>
	#include <linux/uaccess.h>
	#include <asm/watchdog.h>

	#define DRV_NAME "sh-wdt"

	/*
	* Default clock division ratio is 5.25 msecs. For an additional table of
	* values, consult the asm-sh/watchdog.h. Overload this at module load
	* time.
	*
	* In order for this to work reliably we need to have HZ set to 1000 or
	* something quite higher than 100 (or we need a proper high-res timer
	* implementation that will deal with this properly), otherwise the 10ms
	* resolution of a jiffy is enough to trigger the overflow. For things like
	* the SH-4 and SH-5, this isn't necessarily that big of a problem, though
	* for the SH-2 and SH-3, this isn't recommended unless the WDT is absolutely
	* necssary.
	*
	* As a result of this timing problem, the only modes that are particularly
	* feasible are the 4096 and the 2048 divisors, which yield 5.25 and 2.62ms
	* overflow periods respectively.
	*
	* Also, since we can't really expect userspace to be responsive enough
	* before the overflow happens, we maintain two separate timers .. One in
	* the kernel for clearing out WOVF every 2ms or so (again, this depends on
	* HZ == 1000), and another for monitoring userspace writes to the WDT device.
	*
	* As such, we currently use a configurable heartbeat interval which defaults
	* to 30s. In this case, the userspace daemon is only responsible for periodic
	* writes to the device before the next heartbeat is scheduled. If the daemon
	* misses its deadline, the kernel timer will allow the WDT to overflow.
	*/
	static int clock_division_ratio = WTCSR_CKS_4096;
	#define next_ping_period(cks) (jiffies + msecs_to_jiffies(cks - 4))

	static const struct watchdog_info sh_wdt_info;
	static struct platform_device *sh_wdt_dev;
	static DEFINE_SPINLOCK(shwdt_lock);

	#define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat */
	static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
	static int nowayout = WATCHDOG_NOWAYOUT;
	static unsigned long next_heartbeat;

	struct sh_wdt {
	void __iomem *base;
	struct device *dev;

	struct timer_list timer;

	unsigned long enabled;
	char expect_close;
	};

	static void sh_wdt_start(struct sh_wdt *wdt)
	{
	unsigned long flags;
	u8 csr;

	spin_lock_irqsave(&shwdt_lock, flags);

	next_heartbeat = jiffies + (heartbeat * HZ);
	mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));

	csr = sh_wdt_read_csr();
	csr \|= WTCSR_WT \| clock_division_ratio;
	sh_wdt_write_csr(csr);

	sh_wdt_write_cnt(0);

	/*
	* These processors have a bit of an inconsistent initialization
	* process.. starting with SH-3, RSTS was moved to WTCSR, and the
	* RSTCSR register was removed.
	*
	* On the SH-2 however, in addition with bits being in different
	* locations, we must deal with RSTCSR outright..
	*/
	csr = sh_wdt_read_csr();
	csr \|= WTCSR_TME;
	csr &= ~WTCSR_RSTS;
	sh_wdt_write_csr(csr);

	#ifdef CONFIG_CPU_SH2
	csr = sh_wdt_read_rstcsr();
	csr &= ~RSTCSR_RSTS;
	sh_wdt_write_rstcsr(csr);
	#endif
	spin_unlock_irqrestore(&shwdt_lock, flags);
	}

	static void sh_wdt_stop(struct sh_wdt *wdt)
	{
	unsigned long flags;
	u8 csr;

	spin_lock_irqsave(&shwdt_lock, flags);

	del_timer(&wdt->timer);

	csr = sh_wdt_read_csr();
	csr &= ~WTCSR_TME;
	sh_wdt_write_csr(csr);

	spin_unlock_irqrestore(&shwdt_lock, flags);
	}

	static inline void sh_wdt_keepalive(struct sh_wdt *wdt)
	{
	unsigned long flags;

	spin_lock_irqsave(&shwdt_lock, flags);
	next_heartbeat = jiffies + (heartbeat * HZ);
	spin_unlock_irqrestore(&shwdt_lock, flags);
	}

	static int sh_wdt_set_heartbeat(int t)
	{
	unsigned long flags;

	if (unlikely(t < 1 \|\| t > 3600)) /* arbitrary upper limit */
	return -EINVAL;

	spin_lock_irqsave(&shwdt_lock, flags);
	heartbeat = t;
	spin_unlock_irqrestore(&shwdt_lock, flags);
	return 0;
	}

	static void sh_wdt_ping(unsigned long data)
	{
	struct sh_wdt wdt = (struct sh_wdt )data;
	unsigned long flags;

	spin_lock_irqsave(&shwdt_lock, flags);
	if (time_before(jiffies, next_heartbeat)) {
	u8 csr;

	csr = sh_wdt_read_csr();
	csr &= ~WTCSR_IOVF;
	sh_wdt_write_csr(csr);

	sh_wdt_write_cnt(0);

	mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));
	} else
	dev_warn(wdt->dev, "Heartbeat lost! Will not ping "
	"the watchdog\n");
	spin_unlock_irqrestore(&shwdt_lock, flags);
	}

	static int sh_wdt_open(struct inode inode, struct file file)
	{
	struct sh_wdt *wdt = platform_get_drvdata(sh_wdt_dev);

	if (test_and_set_bit(0, &wdt->enabled))
	return -EBUSY;
	if (nowayout)
	__module_get(THIS_MODULE);

	file->private_data = wdt;

	sh_wdt_start(wdt);

	return nonseekable_open(inode, file);
	}

	static int sh_wdt_close(struct inode inode, struct file file)
	{
	struct sh_wdt *wdt = file->private_data;

	if (wdt->expect_close == 42) {
	sh_wdt_stop(wdt);
	} else {
	dev_crit(wdt->dev, "Unexpected close, not "
	"stopping watchdog!\n");
	sh_wdt_keepalive(wdt);
	}

	clear_bit(0, &wdt->enabled);
	wdt->expect_close = 0;

	return 0;
	}

	static ssize_t sh_wdt_write(struct file file, const char buf,
	size_t count, loff_t *ppos)
	{
	struct sh_wdt *wdt = file->private_data;

	if (count) {
	if (!nowayout) {
	size_t i;

	wdt->expect_close = 0;

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

	return count;
	}

	static long sh_wdt_ioctl(struct file *file, unsigned int cmd,
	unsigned long arg)
	{
	struct sh_wdt *wdt = file->private_data;
	int new_heartbeat;
	int options, retval = -EINVAL;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
	return copy_to_user((struct watchdog_info *)arg,
	&sh_wdt_info, sizeof(sh_wdt_info)) ? -EFAULT : 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	return put_user(0, (int *)arg);
	case WDIOC_SETOPTIONS:
	if (get_user(options, (int *)arg))
	return -EFAULT;

	if (options & WDIOS_DISABLECARD) {
	sh_wdt_stop(wdt);
	retval = 0;
	}

	if (options & WDIOS_ENABLECARD) {
	sh_wdt_start(wdt);
	retval = 0;
	}

	return retval;
	case WDIOC_KEEPALIVE:
	sh_wdt_keepalive(wdt);
	return 0;
	case WDIOC_SETTIMEOUT:
	if (get_user(new_heartbeat, (int *)arg))
	return -EFAULT;

	if (sh_wdt_set_heartbeat(new_heartbeat))
	return -EINVAL;

	sh_wdt_keepalive(wdt);
	/* Fall */
	case WDIOC_GETTIMEOUT:
	return put_user(heartbeat, (int *)arg);
	default:
	return -ENOTTY;
	}
	return 0;
	}

	static int sh_wdt_notify_sys(struct notifier_block *this,
	unsigned long code, void *unused)
	{
	struct sh_wdt *wdt = platform_get_drvdata(sh_wdt_dev);

	if (code == SYS_DOWN \|\| code == SYS_HALT)
	sh_wdt_stop(wdt);

	return NOTIFY_DONE;
	}

	static const struct file_operations sh_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = sh_wdt_write,
	.unlocked_ioctl = sh_wdt_ioctl,
	.open = sh_wdt_open,
	.release = sh_wdt_close,
	};

	static const struct watchdog_info sh_wdt_info = {
	.options = WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT \|
	WDIOF_MAGICCLOSE,
	.firmware_version = 1,
	.identity = "SH WDT",
	};

	static struct notifier_block sh_wdt_notifier = {
	.notifier_call = sh_wdt_notify_sys,
	};

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

	static int __devinit sh_wdt_probe(struct platform_device *pdev)
	{
	struct sh_wdt *wdt;
	struct resource *res;
	int rc;

	/*
	* As this driver only covers the global watchdog case, reject
	* any attempts to register per-CPU watchdogs.
	*/
	if (pdev->id != -1)
	return -EINVAL;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (unlikely(!res))
	return -EINVAL;

	if (!devm_request_mem_region(&pdev->dev, res->start,
	resource_size(res), DRV_NAME))
	return -EBUSY;

	wdt = devm_kzalloc(&pdev->dev, sizeof(struct sh_wdt), GFP_KERNEL);
	if (unlikely(!wdt)) {
	rc = -ENOMEM;
	goto out_release;
	}

	wdt->dev = &pdev->dev;

	wdt->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
	if (unlikely(!wdt->base)) {
	rc = -ENXIO;
	goto out_err;
	}

	rc = register_reboot_notifier(&sh_wdt_notifier);
	if (unlikely(rc)) {
	dev_err(&pdev->dev,
	"Can't register reboot notifier (err=%d)\n", rc);
	goto out_unmap;
	}

	sh_wdt_miscdev.parent = wdt->dev;

	rc = misc_register(&sh_wdt_miscdev);
	if (unlikely(rc)) {
	dev_err(&pdev->dev,
	"Can't register miscdev on minor=%d (err=%d)\n",
	sh_wdt_miscdev.minor, rc);
	goto out_unreg;
	}

	init_timer(&wdt->timer);
	wdt->timer.function = sh_wdt_ping;
	wdt->timer.data = (unsigned long)wdt;
	wdt->timer.expires = next_ping_period(clock_division_ratio);

	platform_set_drvdata(pdev, wdt);
	sh_wdt_dev = pdev;

	dev_info(&pdev->dev, "initialized.\n");

	return 0;

	out_unreg:
	unregister_reboot_notifier(&sh_wdt_notifier);
	out_unmap:
	devm_iounmap(&pdev->dev, wdt->base);
	out_err:
	devm_kfree(&pdev->dev, wdt);
	out_release:
	devm_release_mem_region(&pdev->dev, res->start, resource_size(res));

	return rc;
	}

	static int __devexit sh_wdt_remove(struct platform_device *pdev)
	{
	struct sh_wdt *wdt = platform_get_drvdata(pdev);
	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	platform_set_drvdata(pdev, NULL);

	misc_deregister(&sh_wdt_miscdev);

	sh_wdt_dev = NULL;

	unregister_reboot_notifier(&sh_wdt_notifier);
	devm_release_mem_region(&pdev->dev, res->start, resource_size(res));
	devm_iounmap(&pdev->dev, wdt->base);
	devm_kfree(&pdev->dev, wdt);

	return 0;
	}

	static struct platform_driver sh_wdt_driver = {
	.driver = {
	.name = DRV_NAME,
	.owner = THIS_MODULE,
	},

	.probe = sh_wdt_probe,
	.remove = __devexit_p(sh_wdt_remove),
	};

	static int __init sh_wdt_init(void)
	{
	int rc;

	if (unlikely(clock_division_ratio < 0x5 \|\|
	clock_division_ratio > 0x7)) {
	clock_division_ratio = WTCSR_CKS_4096;

	pr_info("%s: divisor must be 0x5<=x<=0x7, using %d\n",
	DRV_NAME, clock_division_ratio);
	}

	rc = sh_wdt_set_heartbeat(heartbeat);
	if (unlikely(rc)) {
	heartbeat = WATCHDOG_HEARTBEAT;

	pr_info("%s: heartbeat value must be 1<=x<=3600, using %d\n",
	DRV_NAME, heartbeat);
	}

	pr_info("%s: configured with heartbeat=%d sec (nowayout=%d)\n",
	DRV_NAME, heartbeat, nowayout);

	return platform_driver_register(&sh_wdt_driver);
	}

	static void __exit sh_wdt_exit(void)
	{
	platform_driver_unregister(&sh_wdt_driver);
	}
	module_init(sh_wdt_init);
	module_exit(sh_wdt_exit);

	MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
	MODULE_DESCRIPTION("SuperH watchdog driver");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:" DRV_NAME);
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

	module_param(clock_division_ratio, int, 0);
	MODULE_PARM_DESC(clock_division_ratio,
	"Clock division ratio. Valid ranges are from 0x5 (1.31ms) "
	"to 0x7 (5.25ms). (default=" __MODULE_STRING(WTCSR_CKS_4096) ")");

	module_param(heartbeat, int, 0);
	MODULE_PARM_DESC(heartbeat,
	"Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default="
	__MODULE_STRING(WATCHDOG_HEARTBEAT) ")");

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