Commit ccb8f430 authored by Andrew Victor's avatar Andrew Victor Committed by Wim Van Sebroeck
Browse files

[WATCHDOG] ks8695_wdt.c - new KS8695 watchdog driver 



Watchdog driver for the Kendin/Micrel KS8695 processor.

Signed-off-by: default avatarAndrew Victor <andrew@sanpeople.com>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent 55b637c6

drivers/char/watchdog/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -115,6 +115,13 @@ config IXP4XX_WATCHDOG 


	  Say N if you are unsure.



config KS8695_WATCHDOG

	tristate "KS8695 watchdog"

	depends on ARCH_KS8695

	help

	  Watchdog timer embedded into KS8695 processor. This will reboot your

	  system when the timeout is reached.



config S3C2410_WATCHDOG

	tristate "S3C2410 Watchdog"

	depends on ARCH_S3C2410

drivers/char/watchdog/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ obj-$(CONFIG_21285_WATCHDOG) += wdt285.o 
obj-$(CONFIG_977_WATCHDOG) += wdt977.o

obj-$(CONFIG_IXP2000_WATCHDOG) += ixp2000_wdt.o

obj-$(CONFIG_IXP4XX_WATCHDOG) += ixp4xx_wdt.o

obj-$(CONFIG_KS8695_WATCHDOG) += ks8695_wdt.o

obj-$(CONFIG_S3C2410_WATCHDOG) += s3c2410_wdt.o

obj-$(CONFIG_SA1100_WATCHDOG) += sa1100_wdt.o

obj-$(CONFIG_MPCORE_WATCHDOG) += mpcore_wdt.o

drivers/char/watchdog/ks8695_wdt.c

0 → 100644
+308 −0
Original line number Diff line number Diff line 
/*

 * 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/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 <asm/bitops.h>

#include <asm/io.h>

#include <asm/uaccess.h>

#include <asm/arch/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;



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



/*

 * Disable the watchdog.

 */

static void inline ks8695_wdt_stop(void)

{

	unsigned long tmcon;



	/* disable timer0 */

	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);

	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);

}



/*

 * Enable and reset the watchdog.

 */

static void inline ks8695_wdt_start(void)

{

	unsigned long tmcon;

	unsigned long tval = wdt_time * CLOCK_TICK_RATE;



	/* 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);

}



/*

 * Reload the watchdog timer.  (ie, pat the watchdog)

 */

static void inline ks8695_wdt_reload(void)

{

	unsigned long tmcon;



	/* 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);

}



/*

 * 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)

{

	if (!nowayout)

		ks8695_wdt_stop();	/* Disable the watchdog when file is closed */



	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 int ks8695_wdt_ioctl(struct inode *inode, 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_KEEPALIVE:

			ks8695_wdt_reload();	/* pat the watchdog */

			return 0;



		case WDIOC_GETSUPPORT:

			return copy_to_user(argp, &ks8695_wdt_info, sizeof(ks8695_wdt_info)) ? -EFAULT : 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);



		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;



		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,

	.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("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)

{

	/* 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);