Commit 853807fb authored by Andrew Victor's avatar Andrew Victor Committed by Wim Van Sebroeck
Browse files

[WATCHDOG] at91_wdt.c - Atmel AT91RM9200 watchdog driver 



Watchdog driver for the Atmel AT91RM9200 processor.

Signed-off-by: default avatarAndrew Victor <andrew@sanpeople.com>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
parent c9d1a0b8

drivers/char/watchdog/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -60,6 +60,13 @@ config SOFT_WATCHDOG 


# ARM Architecture



config AT91_WATCHDOG

	tristate "AT91RM9200 watchdog"

	depends on WATCHDOG && ARCH_AT91RM9200

	help

	  Watchdog timer embedded into AT91RM9200 chips. This will reboot your

	  system when the timeout is reached.



config 21285_WATCHDOG

	tristate "DC21285 watchdog"

	depends on WATCHDOG && FOOTBRIDGE

drivers/char/watchdog/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ obj-$(CONFIG_WDTPCI) += wdt_pci.o 
obj-$(CONFIG_USBPCWATCHDOG) += pcwd_usb.o



# ARM Architecture

obj-$(CONFIG_AT91_WATCHDOG) += at91_wdt.o

obj-$(CONFIG_21285_WATCHDOG) += wdt285.o

obj-$(CONFIG_977_WATCHDOG) += wdt977.o

obj-$(CONFIG_IXP2000_WATCHDOG) += ixp2000_wdt.o

drivers/char/watchdog/at91_wdt.c

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+228 −0
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/*

 * Watchdog driver for Atmel AT91RM9200 (Thunder)

 *

 *  Copyright (C) 2003 SAN People (Pty) Ltd

 *

 * 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.

 */



#include <linux/config.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/types.h>

#include <linux/watchdog.h>

#include <asm/bitops.h>

#include <asm/uaccess.h>





#define WDT_DEFAULT_TIME	5	/* 5 seconds */

#define WDT_MAX_TIME		256	/* 256 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) ")");



module_param(nowayout, int, 0);

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





static unsigned long at91wdt_busy;



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



/*

 * Disable the watchdog.

 */

static void inline at91_wdt_stop(void)

{

	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN);

}



/*

 * Enable and reset the watchdog.

 */

static void inline at91_wdt_start(void)

{

	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN | (((65536 * wdt_time) >> 8) & AT91_ST_WDV));

	at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);

}



/*

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

 */

static void inline at91_wdt_reload(void)

{

	at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);

}



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



/*

 * Watchdog device is opened, and watchdog starts running.

 */

static int at91_wdt_open(struct inode *inode, struct file *file)

{

	if (test_and_set_bit(0, &at91wdt_busy))

		return -EBUSY;



	at91_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 at91_wdt_close(struct inode *inode, struct file *file)

{

	if (!nowayout)

		at91_wdt_stop();	/* Disable the watchdog when file is closed */



	clear_bit(0, &at91wdt_busy);

	return 0;

}



/*

 * Change the watchdog time interval.

 */

static int at91_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 at91_wdt_start() is called. */

	wdt_time = new_time;

	return 0;

}



static struct watchdog_info at91_wdt_info = {

	.identity	= "at91 watchdog",

	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,

};



/*

 * Handle commands from user-space.

 */

static int at91_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:

			at91_wdt_reload();	/* pat the watchdog */

			return 0;



		case WDIOC_GETSUPPORT:

			return copy_to_user(argp, &at91_wdt_info, sizeof(at91_wdt_info)) ? -EFAULT : 0;



		case WDIOC_SETTIMEOUT:

			if (get_user(new_value, p))

				return -EFAULT;

				

			if (at91_wdt_settimeout(new_value))

				return -EINVAL;



			/* Enable new time value */

			at91_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)

				at91_wdt_stop();

			if (new_value & WDIOS_ENABLECARD)

				at91_wdt_start();

			return 0;



		default:

			return -ENOIOCTLCMD;

	}

}



/*

 * Pat the watchdog whenever device is written to.

 */

static ssize_t at91_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)

{

	at91_wdt_reload();		/* pat the watchdog */

	return len;

}



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



static struct file_operations at91wdt_fops = {

	.owner		= THIS_MODULE,

	.llseek		= no_llseek,

	.ioctl		= at91_wdt_ioctl,

	.open		= at91_wdt_open,

	.release	= at91_wdt_close,

	.write		= at91_wdt_write,

};



static struct miscdevice at91wdt_miscdev = {

	.minor		= WATCHDOG_MINOR,

	.name		= "watchdog",

	.fops		= &at91wdt_fops,

};



static int __init at91_wdt_init(void)

{

	int res;



	/* Check that the heartbeat value is within range; if not reset to the default */

	if (at91_wdt_settimeout(wdt_time)) {

		at91_wdt_settimeout(WDT_DEFAULT_TIME);

		printk(KERN_INFO "at91_wdt: wdt_time value must be 1 <= wdt_time <= 256, using %d\n", wdt_time);

	}



	res = misc_register(&at91wdt_miscdev);

	if (res)

		return res;



	printk("AT91 Watchdog Timer enabled (%d seconds, nowayout=%d)\n", wdt_time, nowayout);

	return 0;

}



static void __exit at91_wdt_exit(void)

{

	misc_deregister(&at91wdt_miscdev);

}



module_init(at91_wdt_init);

module_exit(at91_wdt_exit);



MODULE_AUTHOR("Andrew Victor");

MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");

MODULE_LICENSE("GPL");

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);