drivers/watchdog/ks8695_wdt.c - linux - Git at Google

 /*
  * Watchdog driver for Kendin/Micrel KS8695.
  *
  * (C) 2007 Andrew Victor
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <linux/bitops.h>
 #include <linux/errno.h>
 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
 #include <linux/watchdog.h>
 #include <linux/io.h>
 #include <linux/uaccess.h>
 #include <mach/regs-timer.h>

 #define WDT_DEFAULT_TIME	5	/* seconds */
 #define WDT_MAX_TIME		171	/* seconds */

 static int wdt_time = WDT_DEFAULT_TIME;
 static int nowayout = WATCHDOG_NOWAYOUT;

 module_param(wdt_time, int, 0);
 MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
 					__MODULE_STRING(WDT_DEFAULT_TIME) ")");

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


 static unsigned long ks8695wdt_busy;
 static spinlock_t ks8695_lock;

 /* ......................................................................... */

 /*
  * Disable the watchdog.
  */
 static inline void ks8695_wdt_stop(void)
 {
 	unsigned long tmcon;

 	spin_lock(&ks8695_lock);
 	/* disable timer0 */
 	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
 	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
 	spin_unlock(&ks8695_lock);
 }

 /*
  * Enable and reset the watchdog.
  */
 static inline void ks8695_wdt_start(void)
 {
 	unsigned long tmcon;
 	unsigned long tval = wdt_time * CLOCK_TICK_RATE;

 	spin_lock(&ks8695_lock);
 	/* disable timer0 */
 	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
 	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);

 	/* program timer0 */
 	__raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);

 	/* re-enable timer0 */
 	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
 	__raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
 	spin_unlock(&ks8695_lock);
 }

 /*
  * Reload the watchdog timer.  (ie, pat the watchdog)
  */
 static inline void ks8695_wdt_reload(void)
 {
 	unsigned long tmcon;

 	spin_lock(&ks8695_lock);
 	/* disable, then re-enable timer0 */
 	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
 	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
 	__raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
 	spin_unlock(&ks8695_lock);
 }

 /*
  * Change the watchdog time interval.
  */
 static int ks8695_wdt_settimeout(int new_time)
 {
 	/*
 	 * All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz
 	 *
 	 * Since WDV is a 16-bit counter, the maximum period is
 	 * 65536 / 0.256 = 256 seconds.
 	 */
 	if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
 		return -EINVAL;

 	/* Set new watchdog time. It will be used when
 	   ks8695_wdt_start() is called. */
 	wdt_time = new_time;
 	return 0;
 }

 /* ......................................................................... */

 /*
  * Watchdog device is opened, and watchdog starts running.
  */
 static int ks8695_wdt_open(struct inode *inode, struct file *file)
 {
 	if (test_and_set_bit(0, &ks8695wdt_busy))
 		return -EBUSY;

 	ks8695_wdt_start();
 	return nonseekable_open(inode, file);
 }

 /*
  * Close the watchdog device.
  * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
  *  disabled.
  */
 static int ks8695_wdt_close(struct inode *inode, struct file *file)
 {
 	/* Disable the watchdog when file is closed */
 	if (!nowayout)
 		ks8695_wdt_stop();
 	clear_bit(0, &ks8695wdt_busy);
 	return 0;
 }

 static struct watchdog_info ks8695_wdt_info = {
 	.identity	= "ks8695 watchdog",
 	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 };

 /*
  * Handle commands from user-space.
  */
 static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd,
 							unsigned long arg)
 {
 	void __user *argp = (void __user *)arg;
 	int __user *p = argp;
 	int new_value;

 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
 		return copy_to_user(argp, &ks8695_wdt_info,
 					sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
 	case WDIOC_GETSTATUS:
 	case WDIOC_GETBOOTSTATUS:
 		return put_user(0, p);
 	case WDIOC_SETOPTIONS:
 		if (get_user(new_value, p))
 			return -EFAULT;
 		if (new_value & WDIOS_DISABLECARD)
 			ks8695_wdt_stop();
 		if (new_value & WDIOS_ENABLECARD)
 			ks8695_wdt_start();
 		return 0;
 	case WDIOC_KEEPALIVE:
 		ks8695_wdt_reload();	/* pat the watchdog */
 		return 0;
 	case WDIOC_SETTIMEOUT:
 		if (get_user(new_value, p))
 			return -EFAULT;
 		if (ks8695_wdt_settimeout(new_value))
 			return -EINVAL;
 		/* Enable new time value */
 		ks8695_wdt_start();
 		/* Return current value */
 		return put_user(wdt_time, p);
 	case WDIOC_GETTIMEOUT:
 		return put_user(wdt_time, p);
 	default:
 		return -ENOTTY;
 	}
 }

 /*
  * Pat the watchdog whenever device is written to.
  */
 static ssize_t ks8695_wdt_write(struct file *file, const char *data,
 						size_t len, loff_t *ppos)
 {
 	ks8695_wdt_reload();		/* pat the watchdog */
 	return len;
 }

 /* ......................................................................... */

 static const struct file_operations ks8695wdt_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.unlocked_ioctl	= ks8695_wdt_ioctl,
 	.open		= ks8695_wdt_open,
 	.release	= ks8695_wdt_close,
 	.write		= ks8695_wdt_write,
 };

 static struct miscdevice ks8695wdt_miscdev = {
 	.minor		= WATCHDOG_MINOR,
 	.name		= "watchdog",
 	.fops		= &ks8695wdt_fops,
 };

 static int __init ks8695wdt_probe(struct platform_device *pdev)
 {
 	int res;

 	if (ks8695wdt_miscdev.parent)
 		return -EBUSY;
 	ks8695wdt_miscdev.parent = &pdev->dev;

 	res = misc_register(&ks8695wdt_miscdev);
 	if (res)
 		return res;

 	printk(KERN_INFO "KS8695 Watchdog Timer enabled (%d seconds%s)\n",
 				wdt_time, nowayout ? ", nowayout" : "");
 	return 0;
 }

 static int __exit ks8695wdt_remove(struct platform_device *pdev)
 {
 	int res;

 	res = misc_deregister(&ks8695wdt_miscdev);
 	if (!res)
 		ks8695wdt_miscdev.parent = NULL;

 	return res;
 }

 static void ks8695wdt_shutdown(struct platform_device *pdev)
 {
 	ks8695_wdt_stop();
 }

 #ifdef CONFIG_PM

 static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
 {
 	ks8695_wdt_stop();
 	return 0;
 }

 static int ks8695wdt_resume(struct platform_device *pdev)
 {
 	if (ks8695wdt_busy)
 		ks8695_wdt_start();
 	return 0;
 }

 #else
 #define ks8695wdt_suspend NULL
 #define ks8695wdt_resume	NULL
 #endif

 static struct platform_driver ks8695wdt_driver = {
 	.probe		= ks8695wdt_probe,
 	.remove		= __exit_p(ks8695wdt_remove),
 	.shutdown	= ks8695wdt_shutdown,
 	.suspend	= ks8695wdt_suspend,
 	.resume		= ks8695wdt_resume,
 	.driver		= {
 		.name	= "ks8695_wdt",
 		.owner	= THIS_MODULE,
 	},
 };

 static int __init ks8695_wdt_init(void)
 {
 	spin_lock_init(&ks8695_lock);
 	/* Check that the heartbeat value is within range;
 	   if not reset to the default */
 	if (ks8695_wdt_settimeout(wdt_time)) {
 		ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
 		pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i, using %d\n",
 							wdt_time, WDT_MAX_TIME);
 	}
 	return platform_driver_register(&ks8695wdt_driver);
 }

 static void __exit ks8695_wdt_exit(void)
 {
 	platform_driver_unregister(&ks8695wdt_driver);
 }

 module_init(ks8695_wdt_init);
 module_exit(ks8695_wdt_exit);

 MODULE_AUTHOR("Andrew Victor");
 MODULE_DESCRIPTION("Watchdog driver for KS8695");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 MODULE_ALIAS("platform:ks8695_wdt");
	/*
	* Watchdog driver for Kendin/Micrel KS8695.
	*
	* (C) 2007 Andrew Victor
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/bitops.h>
	#include <linux/errno.h>
	#include <linux/fs.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/miscdevice.h>
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/platform_device.h>
	#include <linux/types.h>
	#include <linux/watchdog.h>
	#include <linux/io.h>
	#include <linux/uaccess.h>
	#include <mach/regs-timer.h>

	#define WDT_DEFAULT_TIME 5 /* seconds */
	#define WDT_MAX_TIME 171 /* seconds */

	static int wdt_time = WDT_DEFAULT_TIME;
	static int nowayout = WATCHDOG_NOWAYOUT;

	module_param(wdt_time, int, 0);
	MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
	__MODULE_STRING(WDT_DEFAULT_TIME) ")");

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


	static unsigned long ks8695wdt_busy;
	static spinlock_t ks8695_lock;

	/* ......................................................................... */

	/*
	* Disable the watchdog.
	*/
	static inline void ks8695_wdt_stop(void)
	{
	unsigned long tmcon;

	spin_lock(&ks8695_lock);
	/* disable timer0 */
	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	spin_unlock(&ks8695_lock);
	}

	/*
	* Enable and reset the watchdog.
	*/
	static inline void ks8695_wdt_start(void)
	{
	unsigned long tmcon;
	unsigned long tval = wdt_time * CLOCK_TICK_RATE;

	spin_lock(&ks8695_lock);
	/* disable timer0 */
	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);

	/* program timer0 */
	__raw_writel(tval \| T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);

	/* re-enable timer0 */
	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	__raw_writel(tmcon \| TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	spin_unlock(&ks8695_lock);
	}

	/*
	* Reload the watchdog timer. (ie, pat the watchdog)
	*/
	static inline void ks8695_wdt_reload(void)
	{
	unsigned long tmcon;

	spin_lock(&ks8695_lock);
	/* disable, then re-enable timer0 */
	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	__raw_writel(tmcon \| TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	spin_unlock(&ks8695_lock);
	}

	/*
	* Change the watchdog time interval.
	*/
	static int ks8695_wdt_settimeout(int new_time)
	{
	/*
	* All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz
	*
	* Since WDV is a 16-bit counter, the maximum period is
	* 65536 / 0.256 = 256 seconds.
	*/
	if ((new_time <= 0) \|\| (new_time > WDT_MAX_TIME))
	return -EINVAL;

	/* Set new watchdog time. It will be used when
	ks8695_wdt_start() is called. */
	wdt_time = new_time;
	return 0;
	}

	/* ......................................................................... */

	/*
	* Watchdog device is opened, and watchdog starts running.
	*/
	static int ks8695_wdt_open(struct inode inode, struct file file)
	{
	if (test_and_set_bit(0, &ks8695wdt_busy))
	return -EBUSY;

	ks8695_wdt_start();
	return nonseekable_open(inode, file);
	}

	/*
	* Close the watchdog device.
	* If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
	* disabled.
	*/
	static int ks8695_wdt_close(struct inode inode, struct file file)
	{
	/* Disable the watchdog when file is closed */
	if (!nowayout)
	ks8695_wdt_stop();
	clear_bit(0, &ks8695wdt_busy);
	return 0;
	}

	static struct watchdog_info ks8695_wdt_info = {
	.identity = "ks8695 watchdog",
	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	};

	/*
	* Handle commands from user-space.
	*/
	static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd,
	unsigned long arg)
	{
	void __user argp = (void __user )arg;
	int __user *p = argp;
	int new_value;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
	return copy_to_user(argp, &ks8695_wdt_info,
	sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	return put_user(0, p);
	case WDIOC_SETOPTIONS:
	if (get_user(new_value, p))
	return -EFAULT;
	if (new_value & WDIOS_DISABLECARD)
	ks8695_wdt_stop();
	if (new_value & WDIOS_ENABLECARD)
	ks8695_wdt_start();
	return 0;
	case WDIOC_KEEPALIVE:
	ks8695_wdt_reload(); /* pat the watchdog */
	return 0;
	case WDIOC_SETTIMEOUT:
	if (get_user(new_value, p))
	return -EFAULT;
	if (ks8695_wdt_settimeout(new_value))
	return -EINVAL;
	/* Enable new time value */
	ks8695_wdt_start();
	/* Return current value */
	return put_user(wdt_time, p);
	case WDIOC_GETTIMEOUT:
	return put_user(wdt_time, p);
	default:
	return -ENOTTY;
	}
	}

	/*
	* Pat the watchdog whenever device is written to.
	*/
	static ssize_t ks8695_wdt_write(struct file file, const char data,
	size_t len, loff_t *ppos)
	{
	ks8695_wdt_reload(); /* pat the watchdog */
	return len;
	}

	/* ......................................................................... */

	static const struct file_operations ks8695wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.unlocked_ioctl = ks8695_wdt_ioctl,
	.open = ks8695_wdt_open,
	.release = ks8695_wdt_close,
	.write = ks8695_wdt_write,
	};

	static struct miscdevice ks8695wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &ks8695wdt_fops,
	};

	static int __init ks8695wdt_probe(struct platform_device *pdev)
	{
	int res;

	if (ks8695wdt_miscdev.parent)
	return -EBUSY;
	ks8695wdt_miscdev.parent = &pdev->dev;

	res = misc_register(&ks8695wdt_miscdev);
	if (res)
	return res;

	printk(KERN_INFO "KS8695 Watchdog Timer enabled (%d seconds%s)\n",
	wdt_time, nowayout ? ", nowayout" : "");
	return 0;
	}

	static int __exit ks8695wdt_remove(struct platform_device *pdev)
	{
	int res;

	res = misc_deregister(&ks8695wdt_miscdev);
	if (!res)
	ks8695wdt_miscdev.parent = NULL;

	return res;
	}

	static void ks8695wdt_shutdown(struct platform_device *pdev)
	{
	ks8695_wdt_stop();
	}

	#ifdef CONFIG_PM

	static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
	{
	ks8695_wdt_stop();
	return 0;
	}

	static int ks8695wdt_resume(struct platform_device *pdev)
	{
	if (ks8695wdt_busy)
	ks8695_wdt_start();
	return 0;
	}

	#else
	#define ks8695wdt_suspend NULL
	#define ks8695wdt_resume NULL
	#endif

	static struct platform_driver ks8695wdt_driver = {
	.probe = ks8695wdt_probe,
	.remove = __exit_p(ks8695wdt_remove),
	.shutdown = ks8695wdt_shutdown,
	.suspend = ks8695wdt_suspend,
	.resume = ks8695wdt_resume,
	.driver = {
	.name = "ks8695_wdt",
	.owner = THIS_MODULE,
	},
	};

	static int __init ks8695_wdt_init(void)
	{
	spin_lock_init(&ks8695_lock);
	/* Check that the heartbeat value is within range;
	if not reset to the default */
	if (ks8695_wdt_settimeout(wdt_time)) {
	ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
	pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i, using %d\n",
	wdt_time, WDT_MAX_TIME);
	}
	return platform_driver_register(&ks8695wdt_driver);
	}

	static void __exit ks8695_wdt_exit(void)
	{
	platform_driver_unregister(&ks8695wdt_driver);
	}

	module_init(ks8695_wdt_init);
	module_exit(ks8695_wdt_exit);

	MODULE_AUTHOR("Andrew Victor");
	MODULE_DESCRIPTION("Watchdog driver for KS8695");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	MODULE_ALIAS("platform:ks8695_wdt");