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/*
* Advantech Single Board Computer WDT driver for Linux 2.4.x
*
* (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
*
* Based on acquirewdt.c which is based on wdt.c.
* Original copyright messages:
*
* (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@redhat.com>
*
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/version.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/smp_lock.h>
static int advwdt_is_open;
static spinlock_t advwdt_lock;
/*
* You must set these - there is no sane way to probe for this board.
*
* To enable or restart, write the timeout value in seconds (1 to 63)
* to I/O port WDT_START. To disable, read I/O port WDT_STOP.
* Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
* check your manual (at least the PCA-6159 seems to be different -
* the manual says WDT_STOP is 0x43, not 0x443).
* (0x43 is also a write-only control register for the 8254 timer!)
*
* TODO: module parameters to set the I/O port addresses and NOWAYOUT
* option at load time.
*/
#define WDT_STOP 0x443
#define WDT_START 0x443
#define WD_TIMO 60 /* 1 minute */
/*
* Kernel methods.
*/
static void
advwdt_ping(void)
{
/* Write a watchdog value */
outb_p(WD_TIMO, WDT_START);
}
static ssize_t
advwdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
/* Can't seek (pwrite) on this device */
if (ppos != &file->f_pos)
return -ESPIPE;
if (count) {
advwdt_ping();
return 1;
}
return 0;
}
static ssize_t
advwdt_read(struct file *file, char *buf, size_t count, loff_t *ppos)
{
return -EINVAL;
}
static int
advwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
static struct watchdog_info ident = {
WDIOF_KEEPALIVEPING, 1, "Advantech WDT"
};
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)))
return -EFAULT;
break;
case WDIOC_GETSTATUS:
if (copy_to_user((int *)arg, &advwdt_is_open, sizeof(int)))
return -EFAULT;
break;
case WDIOC_KEEPALIVE:
advwdt_ping();
break;
default:
return -ENOIOCTLCMD;
}
return 0;
}
static int
advwdt_open(struct inode *inode, struct file *file)
{
switch (MINOR(inode->i_rdev)) {
case WATCHDOG_MINOR:
spin_lock(&advwdt_lock);
if (advwdt_is_open) {
spin_unlock(&advwdt_lock);
return -EBUSY;
}
/*
* Activate
*/
advwdt_is_open = 1;
advwdt_ping();
spin_unlock(&advwdt_lock);
return 0;
default:
return -ENODEV;
}
}
static int
advwdt_close(struct inode *inode, struct file *file)
{
lock_kernel();
if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
spin_lock(&advwdt_lock);
#ifndef CONFIG_WATCHDOG_NOWAYOUT
inb_p(WDT_STOP);
#endif
advwdt_is_open = 0;
spin_unlock(&advwdt_lock);
}
unlock_kernel();
return 0;
}
/*
* Notifier for system down
*/
static int
advwdt_notify_sys(struct notifier_block *this, unsigned long code,
void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT) {
/* Turn the WDT off */
inb_p(WDT_STOP);
}
return NOTIFY_DONE;
}
/*
* Kernel Interfaces
*/
static struct file_operations advwdt_fops = {
owner: THIS_MODULE,
read: advwdt_read,
write: advwdt_write,
ioctl: advwdt_ioctl,
open: advwdt_open,
release: advwdt_close,
};
static struct miscdevice advwdt_miscdev = {
WATCHDOG_MINOR,
"watchdog",
&advwdt_fops
};
/*
* The WDT needs to learn about soft shutdowns in order to
* turn the timebomb registers off.
*/
static struct notifier_block advwdt_notifier = {
advwdt_notify_sys,
NULL,
0
};
static int __init
advwdt_init(void)
{
printk("WDT driver for Advantech single board computer initialising.\n");
spin_lock_init(&advwdt_lock);
misc_register(&advwdt_miscdev);
#if WDT_START != WDT_STOP
request_region(WDT_STOP, 1, "Advantech WDT");
#endif
request_region(WDT_START, 1, "Advantech WDT");
register_reboot_notifier(&advwdt_notifier);
return 0;
}
static void __exit
advwdt_exit(void)
{
misc_deregister(&advwdt_miscdev);
unregister_reboot_notifier(&advwdt_notifier);
#if WDT_START != WDT_STOP
release_region(WDT_STOP,1);
#endif
release_region(WDT_START,1);
}
module_init(advwdt_init);
module_exit(advwdt_exit);
/* end of advantechwdt.c */
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