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/* UML hardware watchdog, shamelessly stolen from:
*
* SoftDog 0.05: A Software Watchdog Device
*
* (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
* http://www.redhat.com
*
* 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.
*
* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
* warranty for any of this software. This material is provided
* "AS-IS" and at no charge.
*
* (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
*
* Software only watchdog driver. Unlike its big brother the WDT501P
* driver this won't always recover a failed machine.
*
* 03/96: Angelo Haritsis <ah@doc.ic.ac.uk> :
* Modularised.
* Added soft_margin; use upon insmod to change the timer delay.
* NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate
* minors.
*
* 19980911 Alan Cox
* Made SMP safe for 2.3.x
*
* 20011127 Joel Becker (jlbec@evilplan.org>
* Added soft_noboot; Allows testing the softdog trigger without
* requiring a recompile.
* Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT.
*/
#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/mutex.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <asm/uaccess.h>
#include "mconsole.h"
MODULE_LICENSE("GPL");
static DEFINE_MUTEX(harddog_mutex);
static DEFINE_SPINLOCK(lock);
static int timer_alive;
static int harddog_in_fd = -1;
static int harddog_out_fd = -1;
/*
* Allow only one person to hold it open
*/
extern int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock);
static int harddog_open(struct inode *inode, struct file *file)
{
int err = -EBUSY;
char *sock = NULL;
mutex_lock(&harddog_mutex);
spin_lock(&lock);
if(timer_alive)
goto err;
#ifdef CONFIG_WATCHDOG_NOWAYOUT
__module_get(THIS_MODULE);
#endif
#ifdef CONFIG_MCONSOLE
sock = mconsole_notify_socket();
#endif
err = start_watchdog(&harddog_in_fd, &harddog_out_fd, sock);
if(err)
goto err;
timer_alive = 1;
spin_unlock(&lock);
mutex_unlock(&harddog_mutex);
return nonseekable_open(inode, file);
err:
spin_unlock(&lock);
mutex_unlock(&harddog_mutex);
return err;
}
extern void stop_watchdog(int in_fd, int out_fd);
static int harddog_release(struct inode *inode, struct file *file)
{
/*
* Shut off the timer.
*/
spin_lock(&lock);
stop_watchdog(harddog_in_fd, harddog_out_fd);
harddog_in_fd = -1;
harddog_out_fd = -1;
timer_alive=0;
spin_unlock(&lock);
return 0;
}
extern int ping_watchdog(int fd);
static ssize_t harddog_write(struct file *file, const char __user *data, size_t len,
loff_t *ppos)
{
/*
* Refresh the timer.
*/
if(len)
return ping_watchdog(harddog_out_fd);
return 0;
}
static int harddog_ioctl_unlocked(struct file *file,
unsigned int cmd, unsigned long arg)
{
void __user *argp= (void __user *)arg;
static struct watchdog_info ident = {
WDIOC_SETTIMEOUT,
0,
"UML Hardware Watchdog"
};
switch (cmd) {
default:
return -ENOTTY;
case WDIOC_GETSUPPORT:
if(copy_to_user(argp, &ident, sizeof(ident)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0,(int __user *)argp);
case WDIOC_KEEPALIVE:
return ping_watchdog(harddog_out_fd);
}
}
static long harddog_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
long ret;
mutex_lock(&harddog_mutex);
ret = harddog_ioctl_unlocked(file, cmd, arg);
mutex_unlock(&harddog_mutex);
return ret;
}
static const struct file_operations harddog_fops = {
.owner = THIS_MODULE,
.write = harddog_write,
.unlocked_ioctl = harddog_ioctl,
.open = harddog_open,
.release = harddog_release,
.llseek = no_llseek,
};
static struct miscdevice harddog_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &harddog_fops,
};
static char banner[] __initdata = KERN_INFO "UML Watchdog Timer\n";
static int __init harddog_init(void)
{
int ret;
ret = misc_register(&harddog_miscdev);
if (ret)
return ret;
printk(banner);
return 0;
}
static void __exit harddog_exit(void)
{
misc_deregister(&harddog_miscdev);
}
module_init(harddog_init);
module_exit(harddog_exit);
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