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![Jean Delvare](/assets/img/avatar_default.png)
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR) and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements. Either the device is enumerated and the driver already has a module alias (e.g. PCI, USB etc.) that will get the right driver loaded automatically. Or the device is not enumerated and loading its driver will lead to more or less intrusive hardware poking. Such hardware poking should be limited to a bare minimum, so the user should really decide which drivers should be tried and in what order. Trying them all in arbitrary order can't do any good. On top of that, loading that many drivers at once bloats the kernel log. Also many drivers will stay loaded afterward, bloating the output of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets loaded as a dependency) can't even be unloaded! If defining char-major-10-130 is needed then it should happen in user-space. Signed-off-by: Jean Delvare <jdelvare@suse.de> Acked-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: Mike Frysinger <vapier.adi@gmail.com> Cc: Wan ZongShun <mcuos.com@gmail.com> Cc: Ben Dooks <ben-linux@fluff.org> Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk> Cc: Jim Cromie <jim.cromie@gmail.com>
216 lines
4.7 KiB
C
216 lines
4.7 KiB
C
/*
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* IndyDog 0.3 A Hardware Watchdog Device for SGI IP22
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*
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* (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>,
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* 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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* based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/moduleparam.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/notifier.h>
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#include <linux/reboot.h>
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#include <linux/init.h>
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#include <linux/uaccess.h>
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#include <asm/sgi/mc.h>
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static unsigned long indydog_alive;
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static DEFINE_SPINLOCK(indydog_lock);
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#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 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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static void indydog_start(void)
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{
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u32 mc_ctrl0;
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spin_lock(&indydog_lock);
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mc_ctrl0 = sgimc->cpuctrl0;
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mc_ctrl0 = sgimc->cpuctrl0 | SGIMC_CCTRL0_WDOG;
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sgimc->cpuctrl0 = mc_ctrl0;
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spin_unlock(&indydog_lock);
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}
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static void indydog_stop(void)
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{
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u32 mc_ctrl0;
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spin_lock(&indydog_lock);
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mc_ctrl0 = sgimc->cpuctrl0;
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mc_ctrl0 &= ~SGIMC_CCTRL0_WDOG;
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sgimc->cpuctrl0 = mc_ctrl0;
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spin_unlock(&indydog_lock);
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pr_info("Stopped watchdog timer\n");
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}
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static void indydog_ping(void)
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{
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sgimc->watchdogt = 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 indydog_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(0, &indydog_alive))
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return -EBUSY;
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if (nowayout)
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__module_get(THIS_MODULE);
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/* Activate timer */
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indydog_start();
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indydog_ping();
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pr_info("Started watchdog timer\n");
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return nonseekable_open(inode, file);
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}
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static int indydog_release(struct inode *inode, struct file *file)
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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 defined ...NOWAYOUT */
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if (!nowayout)
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indydog_stop(); /* Turn the WDT off */
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clear_bit(0, &indydog_alive);
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return 0;
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}
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static ssize_t indydog_write(struct file *file, const char *data,
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size_t len, loff_t *ppos)
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{
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/* Refresh the timer. */
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if (len)
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indydog_ping();
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return len;
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}
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static long indydog_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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int options, retval = -EINVAL;
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static const struct watchdog_info ident = {
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.options = WDIOF_KEEPALIVEPING,
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.firmware_version = 0,
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.identity = "Hardware Watchdog for SGI IP22",
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};
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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if (copy_to_user((struct watchdog_info *)arg,
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&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_SETOPTIONS:
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{
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if (get_user(options, (int *)arg))
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return -EFAULT;
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if (options & WDIOS_DISABLECARD) {
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indydog_stop();
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retval = 0;
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}
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if (options & WDIOS_ENABLECARD) {
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indydog_start();
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retval = 0;
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}
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return retval;
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}
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case WDIOC_KEEPALIVE:
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indydog_ping();
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return 0;
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case WDIOC_GETTIMEOUT:
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return put_user(WATCHDOG_TIMEOUT, (int *)arg);
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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 indydog_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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indydog_stop(); /* Turn the WDT off */
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return NOTIFY_DONE;
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}
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static const struct file_operations indydog_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = indydog_write,
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.unlocked_ioctl = indydog_ioctl,
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.open = indydog_open,
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.release = indydog_release,
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};
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static struct miscdevice indydog_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &indydog_fops,
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};
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static struct notifier_block indydog_notifier = {
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.notifier_call = indydog_notify_sys,
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};
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static int __init watchdog_init(void)
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{
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int ret;
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ret = register_reboot_notifier(&indydog_notifier);
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if (ret) {
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pr_err("cannot register reboot notifier (err=%d)\n", ret);
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return ret;
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}
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ret = misc_register(&indydog_miscdev);
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if (ret) {
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pr_err("cannot register miscdev on minor=%d (err=%d)\n",
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WATCHDOG_MINOR, ret);
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unregister_reboot_notifier(&indydog_notifier);
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return ret;
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}
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pr_info("Hardware Watchdog Timer for SGI IP22: 0.3\n");
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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(&indydog_miscdev);
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unregister_reboot_notifier(&indydog_notifier);
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}
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module_init(watchdog_init);
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module_exit(watchdog_exit);
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MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>");
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MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22");
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MODULE_LICENSE("GPL");
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