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/*
* Intel 21285 watchdog driver
* Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998
*
* based on
*
* SoftDog 0.05: A Software Watchdog Device
*
* (c) Copyright 1996 Alan Cox <alan@cymru.net>, All Rights Reserved.
* http://www.cymru.net
*
* 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/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/smp_lock.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/hardware.h>
#include <asm/system.h>
#include <asm/dec21285.h>
/*
* Define this to stop the watchdog actually rebooting the machine.
*/
#undef ONLY_TESTING
#define TIMER_MARGIN 60 /* (secs) Default is 1 minute */
#define FCLK (50*1000*1000) /* 50MHz */
static int soft_margin = TIMER_MARGIN; /* in seconds */
static int timer_alive = 0;
#ifdef ONLY_TESTING
/*
* If the timer expires..
*/
static void watchdog_fire(int irq, void *dev_id, struct pt_regs *regs)
{
printk(KERN_CRIT "Watchdog: Would Reboot.\n");
*CSR_TIMER4_CNTL = 0;
*CSR_TIMER4_CLR = 0;
}
#endif
static void watchdog_ping(void)
{
/*
* Refresh the timer.
*/
*CSR_TIMER4_LOAD = soft_margin * (FCLK / 256);
}
/*
* Allow only one person to hold it open
*/
static int watchdog_open(struct inode *inode, struct file *file)
{
if(timer_alive)
return -EBUSY;
/*
* Ahead watchdog factor ten, Mr Sulu
*/
*CSR_TIMER4_CLR = 0;
watchdog_ping();
*CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD
| TIMER_CNTL_DIV256;
#ifdef ONLY_TESTING
request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
#else
*CSR_SA110_CNTL |= 1 << 13;
MOD_INC_USE_COUNT;
#endif
timer_alive = 1;
return 0;
}
static int watchdog_release(struct inode *inode, struct file *file)
{
#ifdef ONLY_TESTING
lock_kernel();
free_irq(IRQ_TIMER4, NULL);
timer_alive = 0;
unlock_kernel();
#else
/*
* It's irreversible!
*/
#endif
return 0;
}
static ssize_t watchdog_write(struct file *file, const char *data, size_t len, loff_t *ppos)
{
/* Can't seek (pwrite) on this device */
if (ppos != &file->f_pos)
return -ESPIPE;
/*
* Refresh the timer.
*/
if(len)
{
watchdog_ping();
return 1;
}
return 0;
}
static int watchdog_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int i;
static struct watchdog_info ident=
{
0,
0,
"Footbridge Watchdog"
};
switch(cmd)
{
default:
return -ENOIOCTLCMD;
case WDIOC_GETSUPPORT:
i = verify_area(VERIFY_WRITE, (void*) arg, sizeof(struct watchdog_info));
if (i)
return i;
else
return copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident));
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0,(int *)arg);
case WDIOC_KEEPALIVE:
watchdog_ping();
return 0;
}
}
static struct file_operations watchdog_fops=
{
owner: THIS_MODULE,
write: watchdog_write,
ioctl: watchdog_ioctl,
open: watchdog_open,
release: watchdog_release,
};
static struct miscdevice watchdog_miscdev=
{
WATCHDOG_MINOR,
"watchdog",
&watchdog_fops
};
static int __init footbridge_watchdog_init(void)
{
if (machine_is_netwinder())
return -ENODEV;
misc_register(&watchdog_miscdev);
printk("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
soft_margin);
if (machine_is_cats())
printk("Warning: Watchdog reset may not work on this machine.\n");
return 0;
}
static void __exit footbridge_watchdog_exit(void)
{
misc_deregister(&watchdog_miscdev);
}
EXPORT_NO_SYMBOLS;
MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");
MODULE_DESCRIPTION("21285 watchdog driver");
MODULE_PARM(soft_margin,"i");
MODULE_PARM_DESC(soft_margin,"Watchdog timeout in seconds");
module_init(footbridge_watchdog_init);
module_exit(footbridge_watchdog_exit);
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