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/*
* RC32434_WDT 0.01: IDT Interprise 79RC32434 watchdog driver
* Copyright (c) Ondrej Zajicek <santiago@crfreenet.org>, 2006
*
* based on
*
* SoftDog 0.05: A Software Watchdog Device
*
* (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
*
* 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/smp_lock.h>
#include <linux/init.h>
#include <asm/bootinfo.h>
#include <asm/time.h>
#include <asm/uaccess.h>
#include <asm/rc32434/integ.h>
#define DEFAULT_TIMEOUT 15 /* (secs) Default is 15 seconds */
#define MAX_TIMEOUT 20
/*
* (secs) Max is 20 seconds
* (max frequency of counter is ~200 MHz, counter is 32-bit unsigned int)
*/
#define NAME "rc32434_wdt"
#define VERSION "0.1"
static INTEG_t rc_wdt = (INTEG_t) INTEG_VirtualAddress;
static int expect_close = 0;
static int access = 0;
static int timeout = 0;
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_LICENSE("GPL");
static inline void start_wdt(void)
{
rc_wdt -> wtcount = 0;
rc_wdt -> errcs |= ERRCS_wre_m;
rc_wdt -> wtc |= WTC_en_m;
}
static inline void stop_wdt(void)
{
rc_wdt -> wtc &= ~WTC_en_m;
rc_wdt -> errcs &= ~ERRCS_wre_m;
}
static inline void set_wdt(int new_timeout)
{
u32 cmp = new_timeout * mips_hpt_frequency;
u32 state;
timeout = new_timeout;
/*
* store and disable WTC
*/
state = rc_wdt -> wtc & WTC_en_m;
rc_wdt -> wtc &= ~WTC_en_m;
rc_wdt -> wtcount = 0;
rc_wdt -> wtcompare = cmp;
/*
* restore WTC
*/
rc_wdt -> wtc |= state;
}
static inline void update_wdt(void)
{
rc_wdt -> wtcount = 0;
}
/*
* Allow only one person to hold it open
*/
static int wdt_open(struct inode *inode, struct file *file)
{
if (access)
return -EBUSY;
if (nowayout) {
__module_get(THIS_MODULE);
}
/*
* Activate timer
*/
start_wdt();
printk(KERN_INFO NAME ": enabling watchdog timer\n");
access = 1;
return 0;
}
static int wdt_release(struct inode *inode, struct file *file)
{
/*
* Shut off the timer.
* Lock it in if it's a module and we set nowayout
*/
if (expect_close && nowayout == 0) {
stop_wdt ();
printk(KERN_INFO NAME ": disabling watchdog timer\n");
module_put(THIS_MODULE);
} else {
printk (KERN_CRIT NAME ": device closed unexpectedly. WDT will not stop!\n");
}
access = 0;
return 0;
}
static ssize_t wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
{
/*
* Refresh the timer.
*/
if (len) {
if (!nowayout) {
size_t i;
/* In case it was set long ago */
expect_close = 0;
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
expect_close = 1;
}
}
update_wdt ();
return len;
}
return 0;
}
static int wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int new_timeout;
static struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
.firmware_version = 0,
.identity = "RC32434_WDT Watchdog",
};
switch (cmd) {
default:
return -ENOTTY;
case WDIOC_GETSUPPORT:
if(copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0,(int *)arg);
case WDIOC_KEEPALIVE:
update_wdt();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_timeout, (int *)arg))
return -EFAULT;
if (new_timeout < 1)
return -EINVAL;
if (new_timeout > MAX_TIMEOUT)
return -EINVAL;
set_wdt(new_timeout);
/* Fall */
case WDIOC_GETTIMEOUT:
return put_user(timeout, (int *)arg);
}
}
static struct file_operations wdt_fops = {
owner: THIS_MODULE,
llseek: no_llseek,
write: wdt_write,
ioctl: wdt_ioctl,
open: wdt_open,
release: wdt_release,
};
static struct miscdevice wdt_miscdev = {
minor: WATCHDOG_MINOR,
name: "watchdog",
fops: &wdt_fops,
};
static char banner[] __initdata = KERN_INFO NAME ": Watchdog Timer version " VERSION ", timer margin: %d sec\n";
static int __init watchdog_init(void)
{
int ret;
/*
* There should be check for RC32434 SoC
*/
if (mips_machgroup != MACH_GROUP_MIKROTIK) return -1;
ret = misc_register(&wdt_miscdev);
if (ret)
return ret;
stop_wdt();
set_wdt(DEFAULT_TIMEOUT);
printk(banner, timeout);
return 0;
}
static void __exit watchdog_exit(void)
{
misc_deregister(&wdt_miscdev);
}
module_init(watchdog_init);
module_exit(watchdog_exit);
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