287 lines
6.1 KiB
C
287 lines
6.1 KiB
C
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/*
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* Watchdog driver for Broadcom BCM47XX
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*
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* Copyright (C) 2008 Aleksandar Radovanovic <biblbroks@sezampro.rs>
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* Copyright (C) 2009 Matthieu CASTET <castet.matthieu@free.fr>
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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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#include <linux/bitops.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/reboot.h>
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#include <linux/types.h>
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#include <linux/uaccess.h>
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#include <linux/watchdog.h>
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#include <linux/timer.h>
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#include <linux/jiffies.h>
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#include <linux/ssb/ssb_embedded.h>
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#include <asm/mach-bcm47xx/bcm47xx.h>
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#define DRV_NAME "bcm47xx_wdt"
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#define WDT_DEFAULT_TIME 30 /* seconds */
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#define WDT_MAX_TIME 255 /* seconds */
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static int wdt_time = WDT_DEFAULT_TIME;
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static int nowayout = WATCHDOG_NOWAYOUT;
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module_param(wdt_time, int, 0);
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MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
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__MODULE_STRING(WDT_DEFAULT_TIME) ")");
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#ifdef CONFIG_WATCHDOG_NOWAYOUT
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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#endif
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static unsigned long bcm47xx_wdt_busy;
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static char expect_release;
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static struct timer_list wdt_timer;
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static atomic_t ticks;
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static inline void bcm47xx_wdt_hw_start(void)
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{
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/* this is 2,5s on 100Mhz clock and 2s on 133 Mhz */
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ssb_watchdog_timer_set(&ssb_bcm47xx, 0xfffffff);
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}
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static inline int bcm47xx_wdt_hw_stop(void)
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{
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return ssb_watchdog_timer_set(&ssb_bcm47xx, 0);
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}
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static void bcm47xx_timer_tick(unsigned long unused)
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{
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if (!atomic_dec_and_test(&ticks)) {
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bcm47xx_wdt_hw_start();
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mod_timer(&wdt_timer, jiffies + HZ);
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} else {
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printk(KERN_CRIT DRV_NAME "Watchdog will fire soon!!!\n");
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}
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}
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static inline void bcm47xx_wdt_pet(void)
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{
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atomic_set(&ticks, wdt_time);
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}
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static void bcm47xx_wdt_start(void)
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{
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bcm47xx_wdt_pet();
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bcm47xx_timer_tick(0);
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}
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static void bcm47xx_wdt_pause(void)
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{
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del_timer_sync(&wdt_timer);
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bcm47xx_wdt_hw_stop();
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}
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static void bcm47xx_wdt_stop(void)
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{
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bcm47xx_wdt_pause();
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}
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static int bcm47xx_wdt_settimeout(int new_time)
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{
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if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
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return -EINVAL;
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wdt_time = new_time;
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return 0;
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}
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static int bcm47xx_wdt_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(0, &bcm47xx_wdt_busy))
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return -EBUSY;
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bcm47xx_wdt_start();
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return nonseekable_open(inode, file);
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}
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static int bcm47xx_wdt_release(struct inode *inode, struct file *file)
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{
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if (expect_release == 42) {
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bcm47xx_wdt_stop();
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} else {
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printk(KERN_CRIT DRV_NAME
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": Unexpected close, not stopping watchdog!\n");
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bcm47xx_wdt_start();
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}
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clear_bit(0, &bcm47xx_wdt_busy);
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expect_release = 0;
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return 0;
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}
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static ssize_t bcm47xx_wdt_write(struct file *file, const char __user *data,
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size_t len, loff_t *ppos)
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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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expect_release = 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_release = 42;
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}
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}
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bcm47xx_wdt_pet();
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}
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return len;
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}
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static struct watchdog_info bcm47xx_wdt_info = {
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.identity = DRV_NAME,
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.options = WDIOF_SETTIMEOUT |
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WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE,
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};
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static long bcm47xx_wdt_ioctl(struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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int new_value, retval = -EINVAL;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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return copy_to_user(argp, &bcm47xx_wdt_info,
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sizeof(bcm47xx_wdt_info)) ? -EFAULT : 0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(0, p);
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case WDIOC_SETOPTIONS:
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if (get_user(new_value, p))
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return -EFAULT;
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if (new_value & WDIOS_DISABLECARD) {
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bcm47xx_wdt_stop();
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retval = 0;
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}
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if (new_value & WDIOS_ENABLECARD) {
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bcm47xx_wdt_start();
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retval = 0;
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}
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return retval;
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case WDIOC_KEEPALIVE:
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bcm47xx_wdt_pet();
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return 0;
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case WDIOC_SETTIMEOUT:
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if (get_user(new_value, p))
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return -EFAULT;
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if (bcm47xx_wdt_settimeout(new_value))
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return -EINVAL;
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bcm47xx_wdt_pet();
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case WDIOC_GETTIMEOUT:
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return put_user(wdt_time, p);
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default:
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return -ENOTTY;
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}
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}
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static int bcm47xx_wdt_notify_sys(struct notifier_block *this,
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unsigned long code, void *unused)
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{
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if (code == SYS_DOWN || code == SYS_HALT)
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bcm47xx_wdt_stop();
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return NOTIFY_DONE;
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}
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static const struct file_operations bcm47xx_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.unlocked_ioctl = bcm47xx_wdt_ioctl,
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.open = bcm47xx_wdt_open,
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.release = bcm47xx_wdt_release,
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.write = bcm47xx_wdt_write,
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};
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static struct miscdevice bcm47xx_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &bcm47xx_wdt_fops,
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};
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static struct notifier_block bcm47xx_wdt_notifier = {
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.notifier_call = bcm47xx_wdt_notify_sys,
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};
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static int __init bcm47xx_wdt_init(void)
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{
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int ret;
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if (bcm47xx_wdt_hw_stop() < 0)
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return -ENODEV;
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setup_timer(&wdt_timer, bcm47xx_timer_tick, 0L);
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if (bcm47xx_wdt_settimeout(wdt_time)) {
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bcm47xx_wdt_settimeout(WDT_DEFAULT_TIME);
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printk(KERN_INFO DRV_NAME ": "
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"wdt_time value must be 0 < wdt_time < %d, using %d\n",
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(WDT_MAX_TIME + 1), wdt_time);
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}
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ret = register_reboot_notifier(&bcm47xx_wdt_notifier);
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if (ret)
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return ret;
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ret = misc_register(&bcm47xx_wdt_miscdev);
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if (ret) {
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unregister_reboot_notifier(&bcm47xx_wdt_notifier);
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return ret;
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}
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printk(KERN_INFO "BCM47xx Watchdog Timer enabled (%d seconds%s)\n",
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wdt_time, nowayout ? ", nowayout" : "");
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return 0;
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}
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static void __exit bcm47xx_wdt_exit(void)
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{
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if (!nowayout)
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bcm47xx_wdt_stop();
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misc_deregister(&bcm47xx_wdt_miscdev);
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unregister_reboot_notifier(&bcm47xx_wdt_notifier);
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}
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module_init(bcm47xx_wdt_init);
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module_exit(bcm47xx_wdt_exit);
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MODULE_AUTHOR("Aleksandar Radovanovic");
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MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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