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