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

 /*
  * Blackfin On-Chip Watchdog Driver
  *
  * Originally based on softdog.c
  * Copyright 2006-2010 Analog Devices Inc.
  * Copyright 2006-2007 Michele d'Amico
  * Copyright 1996 Alan Cox <[email protected]>
  *
  * Enter bugs at http://blackfin.uclinux.org/
  *
  * Licensed under the GPL-2 or later.
  */

 #include <linux/platform_device.h>
 #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/fs.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/uaccess.h>
 #include <asm/blackfin.h>
 #include <asm/bfin_watchdog.h>

 #define stamp(fmt, args...) \
 	pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
 #define stampit() stamp("here i am")
 #define pr_devinit(fmt, args...) \
 	({ static const __devinitconst char __fmt[] = fmt; \
 	printk(__fmt, ## args); })
 #define pr_init(fmt, args...) \
 	({ static const __initconst char __fmt[] = fmt; \
 	printk(__fmt, ## args); })

 #define WATCHDOG_NAME "bfin-wdt"
 #define PFX WATCHDOG_NAME ": "

 /* The BF561 has two watchdogs (one per core), but since Linux
  * only runs on core A, we'll just work with that one.
  */
 #ifdef BF561_FAMILY
 # define bfin_read_WDOG_CTL()    bfin_read_WDOGA_CTL()
 # define bfin_read_WDOG_CNT()    bfin_read_WDOGA_CNT()
 # define bfin_read_WDOG_STAT()   bfin_read_WDOGA_STAT()
 # define bfin_write_WDOG_CTL(x)  bfin_write_WDOGA_CTL(x)
 # define bfin_write_WDOG_CNT(x)  bfin_write_WDOGA_CNT(x)
 # define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x)
 #endif

 /* some defaults */
 #define WATCHDOG_TIMEOUT 20

 static unsigned int timeout = WATCHDOG_TIMEOUT;
 static int nowayout = WATCHDOG_NOWAYOUT;
 static const struct watchdog_info bfin_wdt_info;
 static unsigned long open_check;
 static char expect_close;
 static DEFINE_SPINLOCK(bfin_wdt_spinlock);

 /**
  *	bfin_wdt_keepalive - Keep the Userspace Watchdog Alive
  *
  * 	The Userspace watchdog got a KeepAlive: schedule the next timeout.
  */
 static int bfin_wdt_keepalive(void)
 {
 	stampit();
 	bfin_write_WDOG_STAT(0);
 	return 0;
 }

 /**
  *	bfin_wdt_stop - Stop the Watchdog
  *
  *	Stops the on-chip watchdog.
  */
 static int bfin_wdt_stop(void)
 {
 	stampit();
 	bfin_write_WDOG_CTL(WDEN_DISABLE);
 	return 0;
 }

 /**
  *	bfin_wdt_start - Start the Watchdog
  *
  *	Starts the on-chip watchdog.  Automatically loads WDOG_CNT
  *	into WDOG_STAT for us.
  */
 static int bfin_wdt_start(void)
 {
 	stampit();
 	bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET);
 	return 0;
 }

 /**
  *	bfin_wdt_running - Check Watchdog status
  *
  *	See if the watchdog is running.
  */
 static int bfin_wdt_running(void)
 {
 	stampit();
 	return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE);
 }

 /**
  *	bfin_wdt_set_timeout - Set the Userspace Watchdog timeout
  *	@t: new timeout value (in seconds)
  *
  *	Translate the specified timeout in seconds into System Clock
  *	terms which is what the on-chip Watchdog requires.
  */
 static int bfin_wdt_set_timeout(unsigned long t)
 {
 	u32 cnt, max_t, sclk;
 	unsigned long flags;

 	sclk = get_sclk();
 	max_t = -1 / sclk;
 	cnt = t * sclk;
 	stamp("maxtimeout=%us newtimeout=%lus (cnt=%#x)", max_t, t, cnt);

 	if (t > max_t) {
 		printk(KERN_WARNING PFX "timeout value is too large\n");
 		return -EINVAL;
 	}

 	spin_lock_irqsave(&bfin_wdt_spinlock, flags);
 	{
 		int run = bfin_wdt_running();
 		bfin_wdt_stop();
 		bfin_write_WDOG_CNT(cnt);
 		if (run)
 			bfin_wdt_start();
 	}
 	spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);

 	timeout = t;

 	return 0;
 }

 /**
  *	bfin_wdt_open - Open the Device
  *	@inode: inode of device
  *	@file: file handle of device
  *
  *	Watchdog device is opened and started.
  */
 static int bfin_wdt_open(struct inode *inode, struct file *file)
 {
 	stampit();

 	if (test_and_set_bit(0, &open_check))
 		return -EBUSY;

 	if (nowayout)
 		__module_get(THIS_MODULE);

 	bfin_wdt_keepalive();
 	bfin_wdt_start();

 	return nonseekable_open(inode, file);
 }

 /**
  *	bfin_wdt_close - Close the Device
  *	@inode: inode of device
  *	@file: file handle of device
  *
  *	Watchdog device is closed and stopped.
  */
 static int bfin_wdt_release(struct inode *inode, struct file *file)
 {
 	stampit();

 	if (expect_close == 42)
 		bfin_wdt_stop();
 	else {
 		printk(KERN_CRIT PFX
 			"Unexpected close, not stopping watchdog!\n");
 		bfin_wdt_keepalive();
 	}
 	expect_close = 0;
 	clear_bit(0, &open_check);
 	return 0;
 }

 /**
  *	bfin_wdt_write - Write to Device
  *	@file: file handle of device
  *	@buf: buffer to write
  *	@count: length of buffer
  *	@ppos: offset
  *
  *	Pings the watchdog on write.
  */
 static ssize_t bfin_wdt_write(struct file *file, const char __user *data,
 						size_t len, loff_t *ppos)
 {
 	stampit();

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

 			/* In case it was set long ago */
 			expect_close = 0;

 			for (i = 0; i != len; i++) {
 				char c;
 				if (get_user(c, data + i))
 					return -EFAULT;
 				if (c == 'V')
 					expect_close = 42;
 			}
 		}
 		bfin_wdt_keepalive();
 	}

 	return len;
 }

 /**
  *	bfin_wdt_ioctl - Query Device
  *	@file: file handle of device
  *	@cmd: watchdog command
  *	@arg: argument
  *
  *	Query basic information from the device or ping it, as outlined by the
  *	watchdog API.
  */
 static long bfin_wdt_ioctl(struct file *file,
 				unsigned int cmd, unsigned long arg)
 {
 	void __user *argp = (void __user *)arg;
 	int __user *p = argp;

 	stampit();

 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
 		if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info)))
 			return -EFAULT;
 		else
 			return 0;
 	case WDIOC_GETSTATUS:
 	case WDIOC_GETBOOTSTATUS:
 		return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p);
 	case WDIOC_SETOPTIONS: {
 		unsigned long flags;
 		int options, ret = -EINVAL;

 		if (get_user(options, p))
 			return -EFAULT;

 		spin_lock_irqsave(&bfin_wdt_spinlock, flags);
 		if (options & WDIOS_DISABLECARD) {
 			bfin_wdt_stop();
 			ret = 0;
 		}
 		if (options & WDIOS_ENABLECARD) {
 			bfin_wdt_start();
 			ret = 0;
 		}
 		spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
 		return ret;
 	}
 	case WDIOC_KEEPALIVE:
 		bfin_wdt_keepalive();
 		return 0;
 	case WDIOC_SETTIMEOUT: {
 		int new_timeout;

 		if (get_user(new_timeout, p))
 			return -EFAULT;
 		if (bfin_wdt_set_timeout(new_timeout))
 			return -EINVAL;
 	}
 	/* Fall */
 	case WDIOC_GETTIMEOUT:
 		return put_user(timeout, p);
 	default:
 		return -ENOTTY;
 	}
 }

 #ifdef CONFIG_PM
 static int state_before_suspend;

 /**
  *	bfin_wdt_suspend - suspend the watchdog
  *	@pdev: device being suspended
  *	@state: requested suspend state
  *
  *	Remember if the watchdog was running and stop it.
  *	TODO: is this even right?  Doesn't seem to be any
  *	      standard in the watchdog world ...
  */
 static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 {
 	stampit();

 	state_before_suspend = bfin_wdt_running();
 	bfin_wdt_stop();

 	return 0;
 }

 /**
  *	bfin_wdt_resume - resume the watchdog
  *	@pdev: device being resumed
  *
  *	If the watchdog was running, turn it back on.
  */
 static int bfin_wdt_resume(struct platform_device *pdev)
 {
 	stampit();

 	if (state_before_suspend) {
 		bfin_wdt_set_timeout(timeout);
 		bfin_wdt_start();
 	}

 	return 0;
 }
 #else
 # define bfin_wdt_suspend NULL
 # define bfin_wdt_resume NULL
 #endif

 static const struct file_operations bfin_wdt_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.write    	= bfin_wdt_write,
 	.unlocked_ioctl	= bfin_wdt_ioctl,
 	.open		= bfin_wdt_open,
 	.release	= bfin_wdt_release,
 };

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

 static const struct watchdog_info bfin_wdt_info = {
 	.identity = "Blackfin Watchdog",
 	.options  = WDIOF_SETTIMEOUT |
 		    WDIOF_KEEPALIVEPING |
 		    WDIOF_MAGICCLOSE,
 };

 /**
  *	bfin_wdt_probe - Initialize module
  *
  *	Registers the misc device.  Actual device
  *	initialization is handled by bfin_wdt_open().
  */
 static int __devinit bfin_wdt_probe(struct platform_device *pdev)
 {
 	int ret;

 	ret = misc_register(&bfin_wdt_miscdev);
 	if (ret) {
 		pr_devinit(KERN_ERR PFX
 			"cannot register miscdev on minor=%d (err=%d)\n",
 				WATCHDOG_MINOR, ret);
 		return ret;
 	}

 	pr_devinit(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n",
 	       timeout, nowayout);

 	return 0;
 }

 /**
  *	bfin_wdt_remove - Initialize module
  *
  *	Unregisters the misc device.  Actual device
  *	deinitialization is handled by bfin_wdt_close().
  */
 static int __devexit bfin_wdt_remove(struct platform_device *pdev)
 {
 	misc_deregister(&bfin_wdt_miscdev);
 	return 0;
 }

 /**
  *	bfin_wdt_shutdown - Soft Shutdown Handler
  *
  *	Handles the soft shutdown event.
  */
 static void bfin_wdt_shutdown(struct platform_device *pdev)
 {
 	stampit();

 	bfin_wdt_stop();
 }

 static struct platform_device *bfin_wdt_device;

 static struct platform_driver bfin_wdt_driver = {
 	.probe     = bfin_wdt_probe,
 	.remove    = __devexit_p(bfin_wdt_remove),
 	.shutdown  = bfin_wdt_shutdown,
 	.suspend   = bfin_wdt_suspend,
 	.resume    = bfin_wdt_resume,
 	.driver    = {
 		.name  = WATCHDOG_NAME,
 		.owner = THIS_MODULE,
 	},
 };

 /**
  *	bfin_wdt_init - Initialize module
  *
  *	Checks the module params and registers the platform device & driver.
  *	Real work is in the platform probe function.
  */
 static int __init bfin_wdt_init(void)
 {
 	int ret;

 	stampit();

 	/* Check that the timeout value is within range */
 	if (bfin_wdt_set_timeout(timeout))
 		return -EINVAL;

 	/* Since this is an on-chip device and needs no board-specific
 	 * resources, we'll handle all the platform device stuff here.
 	 */
 	ret = platform_driver_register(&bfin_wdt_driver);
 	if (ret) {
 		pr_init(KERN_ERR PFX "unable to register driver\n");
 		return ret;
 	}

 	bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME,
 								-1, NULL, 0);
 	if (IS_ERR(bfin_wdt_device)) {
 		pr_init(KERN_ERR PFX "unable to register device\n");
 		platform_driver_unregister(&bfin_wdt_driver);
 		return PTR_ERR(bfin_wdt_device);
 	}

 	return 0;
 }

 /**
  *	bfin_wdt_exit - Deinitialize module
  *
  *	Back out the platform device & driver steps.  Real work is in the
  *	platform remove function.
  */
 static void __exit bfin_wdt_exit(void)
 {
 	platform_device_unregister(bfin_wdt_device);
 	platform_driver_unregister(&bfin_wdt_driver);
 }

 module_init(bfin_wdt_init);
 module_exit(bfin_wdt_exit);

 MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <[email protected]>");
 MODULE_DESCRIPTION("Blackfin Watchdog Device Driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

 module_param(timeout, uint, 0);
 MODULE_PARM_DESC(timeout,
 	"Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default="
 		__MODULE_STRING(WATCHDOG_TIMEOUT) ")");

 module_param(nowayout, int, 0);
 MODULE_PARM_DESC(nowayout,
 	"Watchdog cannot be stopped once started (default="
 		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	/*
	* Blackfin On-Chip Watchdog Driver
	*
	* Originally based on softdog.c
	* Copyright 2006-2010 Analog Devices Inc.
	* Copyright 2006-2007 Michele d'Amico
	* Copyright 1996 Alan Cox <[email protected]>
	*
	* Enter bugs at http://blackfin.uclinux.org/
	*
	* Licensed under the GPL-2 or later.
	*/

	#include <linux/platform_device.h>
	#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/fs.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/uaccess.h>
	#include <asm/blackfin.h>
	#include <asm/bfin_watchdog.h>

	#define stamp(fmt, args...) \
	pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
	#define stampit() stamp("here i am")
	#define pr_devinit(fmt, args...) \
	({ static const __devinitconst char __fmt[] = fmt; \
	printk(__fmt, ## args); })
	#define pr_init(fmt, args...) \
	({ static const __initconst char __fmt[] = fmt; \
	printk(__fmt, ## args); })

	#define WATCHDOG_NAME "bfin-wdt"
	#define PFX WATCHDOG_NAME ": "

	/* The BF561 has two watchdogs (one per core), but since Linux
	* only runs on core A, we'll just work with that one.
	*/
	#ifdef BF561_FAMILY
	# define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL()
	# define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT()
	# define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT()
	# define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x)
	# define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x)
	# define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x)
	#endif

	/* some defaults */
	#define WATCHDOG_TIMEOUT 20

	static unsigned int timeout = WATCHDOG_TIMEOUT;
	static int nowayout = WATCHDOG_NOWAYOUT;
	static const struct watchdog_info bfin_wdt_info;
	static unsigned long open_check;
	static char expect_close;
	static DEFINE_SPINLOCK(bfin_wdt_spinlock);

	/**
	* bfin_wdt_keepalive - Keep the Userspace Watchdog Alive
	*
	* The Userspace watchdog got a KeepAlive: schedule the next timeout.
	*/
	static int bfin_wdt_keepalive(void)
	{
	stampit();
	bfin_write_WDOG_STAT(0);
	return 0;
	}

	/**
	* bfin_wdt_stop - Stop the Watchdog
	*
	* Stops the on-chip watchdog.
	*/
	static int bfin_wdt_stop(void)
	{
	stampit();
	bfin_write_WDOG_CTL(WDEN_DISABLE);
	return 0;
	}

	/**
	* bfin_wdt_start - Start the Watchdog
	*
	* Starts the on-chip watchdog. Automatically loads WDOG_CNT
	* into WDOG_STAT for us.
	*/
	static int bfin_wdt_start(void)
	{
	stampit();
	bfin_write_WDOG_CTL(WDEN_ENABLE \| ICTL_RESET);
	return 0;
	}

	/**
	* bfin_wdt_running - Check Watchdog status
	*
	* See if the watchdog is running.
	*/
	static int bfin_wdt_running(void)
	{
	stampit();
	return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE);
	}

	/**
	* bfin_wdt_set_timeout - Set the Userspace Watchdog timeout
	* @t: new timeout value (in seconds)
	*
	* Translate the specified timeout in seconds into System Clock
	* terms which is what the on-chip Watchdog requires.
	*/
	static int bfin_wdt_set_timeout(unsigned long t)
	{
	u32 cnt, max_t, sclk;
	unsigned long flags;

	sclk = get_sclk();
	max_t = -1 / sclk;
	cnt = t * sclk;
	stamp("maxtimeout=%us newtimeout=%lus (cnt=%#x)", max_t, t, cnt);

	if (t > max_t) {
	printk(KERN_WARNING PFX "timeout value is too large\n");
	return -EINVAL;
	}

	spin_lock_irqsave(&bfin_wdt_spinlock, flags);
	{
	int run = bfin_wdt_running();
	bfin_wdt_stop();
	bfin_write_WDOG_CNT(cnt);
	if (run)
	bfin_wdt_start();
	}
	spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);

	timeout = t;

	return 0;
	}

	/**
	* bfin_wdt_open - Open the Device
	* @inode: inode of device
	* @file: file handle of device
	*
	* Watchdog device is opened and started.
	*/
	static int bfin_wdt_open(struct inode inode, struct file file)
	{
	stampit();

	if (test_and_set_bit(0, &open_check))
	return -EBUSY;

	if (nowayout)
	__module_get(THIS_MODULE);

	bfin_wdt_keepalive();
	bfin_wdt_start();

	return nonseekable_open(inode, file);
	}

	/**
	* bfin_wdt_close - Close the Device
	* @inode: inode of device
	* @file: file handle of device
	*
	* Watchdog device is closed and stopped.
	*/
	static int bfin_wdt_release(struct inode inode, struct file file)
	{
	stampit();

	if (expect_close == 42)
	bfin_wdt_stop();
	else {
	printk(KERN_CRIT PFX
	"Unexpected close, not stopping watchdog!\n");
	bfin_wdt_keepalive();
	}
	expect_close = 0;
	clear_bit(0, &open_check);
	return 0;
	}

	/**
	* bfin_wdt_write - Write to Device
	* @file: file handle of device
	* @buf: buffer to write
	* @count: length of buffer
	* @ppos: offset
	*
	* Pings the watchdog on write.
	*/
	static ssize_t bfin_wdt_write(struct file file, const char __user data,
	size_t len, loff_t *ppos)
	{
	stampit();

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

	/* In case it was set long ago */
	expect_close = 0;

	for (i = 0; i != len; i++) {
	char c;
	if (get_user(c, data + i))
	return -EFAULT;
	if (c == 'V')
	expect_close = 42;
	}
	}
	bfin_wdt_keepalive();
	}

	return len;
	}

	/**
	* bfin_wdt_ioctl - Query Device
	* @file: file handle of device
	* @cmd: watchdog command
	* @arg: argument
	*
	* Query basic information from the device or ping it, as outlined by the
	* watchdog API.
	*/
	static long bfin_wdt_ioctl(struct file *file,
	unsigned int cmd, unsigned long arg)
	{
	void __user argp = (void __user )arg;
	int __user *p = argp;

	stampit();

	switch (cmd) {
	case WDIOC_GETSUPPORT:
	if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info)))
	return -EFAULT;
	else
	return 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p);
	case WDIOC_SETOPTIONS: {
	unsigned long flags;
	int options, ret = -EINVAL;

	if (get_user(options, p))
	return -EFAULT;

	spin_lock_irqsave(&bfin_wdt_spinlock, flags);
	if (options & WDIOS_DISABLECARD) {
	bfin_wdt_stop();
	ret = 0;
	}
	if (options & WDIOS_ENABLECARD) {
	bfin_wdt_start();
	ret = 0;
	}
	spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
	return ret;
	}
	case WDIOC_KEEPALIVE:
	bfin_wdt_keepalive();
	return 0;
	case WDIOC_SETTIMEOUT: {
	int new_timeout;

	if (get_user(new_timeout, p))
	return -EFAULT;
	if (bfin_wdt_set_timeout(new_timeout))
	return -EINVAL;
	}
	/* Fall */
	case WDIOC_GETTIMEOUT:
	return put_user(timeout, p);
	default:
	return -ENOTTY;
	}
	}

	#ifdef CONFIG_PM
	static int state_before_suspend;

	/**
	* bfin_wdt_suspend - suspend the watchdog
	* @pdev: device being suspended
	* @state: requested suspend state
	*
	* Remember if the watchdog was running and stop it.
	* TODO: is this even right? Doesn't seem to be any
	* standard in the watchdog world ...
	*/
	static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state)
	{
	stampit();

	state_before_suspend = bfin_wdt_running();
	bfin_wdt_stop();

	return 0;
	}

	/**
	* bfin_wdt_resume - resume the watchdog
	* @pdev: device being resumed
	*
	* If the watchdog was running, turn it back on.
	*/
	static int bfin_wdt_resume(struct platform_device *pdev)
	{
	stampit();

	if (state_before_suspend) {
	bfin_wdt_set_timeout(timeout);
	bfin_wdt_start();
	}

	return 0;
	}
	#else
	# define bfin_wdt_suspend NULL
	# define bfin_wdt_resume NULL
	#endif

	static const struct file_operations bfin_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = bfin_wdt_write,
	.unlocked_ioctl = bfin_wdt_ioctl,
	.open = bfin_wdt_open,
	.release = bfin_wdt_release,
	};

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

	static const struct watchdog_info bfin_wdt_info = {
	.identity = "Blackfin Watchdog",
	.options = WDIOF_SETTIMEOUT \|
	WDIOF_KEEPALIVEPING \|
	WDIOF_MAGICCLOSE,
	};

	/**
	* bfin_wdt_probe - Initialize module
	*
	* Registers the misc device. Actual device
	* initialization is handled by bfin_wdt_open().
	*/
	static int __devinit bfin_wdt_probe(struct platform_device *pdev)
	{
	int ret;

	ret = misc_register(&bfin_wdt_miscdev);
	if (ret) {
	pr_devinit(KERN_ERR PFX
	"cannot register miscdev on minor=%d (err=%d)\n",
	WATCHDOG_MINOR, ret);
	return ret;
	}

	pr_devinit(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n",
	timeout, nowayout);

	return 0;
	}

	/**
	* bfin_wdt_remove - Initialize module
	*
	* Unregisters the misc device. Actual device
	* deinitialization is handled by bfin_wdt_close().
	*/
	static int __devexit bfin_wdt_remove(struct platform_device *pdev)
	{
	misc_deregister(&bfin_wdt_miscdev);
	return 0;
	}

	/**
	* bfin_wdt_shutdown - Soft Shutdown Handler
	*
	* Handles the soft shutdown event.
	*/
	static void bfin_wdt_shutdown(struct platform_device *pdev)
	{
	stampit();

	bfin_wdt_stop();
	}

	static struct platform_device *bfin_wdt_device;

	static struct platform_driver bfin_wdt_driver = {
	.probe = bfin_wdt_probe,
	.remove = __devexit_p(bfin_wdt_remove),
	.shutdown = bfin_wdt_shutdown,
	.suspend = bfin_wdt_suspend,
	.resume = bfin_wdt_resume,
	.driver = {
	.name = WATCHDOG_NAME,
	.owner = THIS_MODULE,
	},
	};

	/**
	* bfin_wdt_init - Initialize module
	*
	* Checks the module params and registers the platform device & driver.
	* Real work is in the platform probe function.
	*/
	static int __init bfin_wdt_init(void)
	{
	int ret;

	stampit();

	/* Check that the timeout value is within range */
	if (bfin_wdt_set_timeout(timeout))
	return -EINVAL;

	/* Since this is an on-chip device and needs no board-specific
	* resources, we'll handle all the platform device stuff here.
	*/
	ret = platform_driver_register(&bfin_wdt_driver);
	if (ret) {
	pr_init(KERN_ERR PFX "unable to register driver\n");
	return ret;
	}

	bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME,
	-1, NULL, 0);
	if (IS_ERR(bfin_wdt_device)) {
	pr_init(KERN_ERR PFX "unable to register device\n");
	platform_driver_unregister(&bfin_wdt_driver);
	return PTR_ERR(bfin_wdt_device);
	}

	return 0;
	}

	/**
	* bfin_wdt_exit - Deinitialize module
	*
	* Back out the platform device & driver steps. Real work is in the
	* platform remove function.
	*/
	static void __exit bfin_wdt_exit(void)
	{
	platform_device_unregister(bfin_wdt_device);
	platform_driver_unregister(&bfin_wdt_driver);
	}

	module_init(bfin_wdt_init);
	module_exit(bfin_wdt_exit);

	MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <[email protected]>");
	MODULE_DESCRIPTION("Blackfin Watchdog Device Driver");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

	module_param(timeout, uint, 0);
	MODULE_PARM_DESC(timeout,
	"Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default="
	__MODULE_STRING(WATCHDOG_TIMEOUT) ")");

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