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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* IndyDog 0.3 A Hardware Watchdog Device for SGI IP22
*
* (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>,
* All Rights Reserved.
*
* based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.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/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/uaccess.h>
#include <asm/sgi/mc.h>
static unsigned long indydog_alive;
static DEFINE_SPINLOCK(indydog_lock);
#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static void indydog_start(void)
{
spin_lock(&indydog_lock);
sgimc->cpuctrl0 |= SGIMC_CCTRL0_WDOG;
spin_unlock(&indydog_lock);
}
static void indydog_stop(void)
{
spin_lock(&indydog_lock);
sgimc->cpuctrl0 &= ~SGIMC_CCTRL0_WDOG;
spin_unlock(&indydog_lock);
pr_info("Stopped watchdog timer\n");
}
static void indydog_ping(void)
{
sgimc->watchdogt = 0;
}
/*
* Allow only one person to hold it open
*/
static int indydog_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &indydog_alive))
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
/* Activate timer */
indydog_start();
indydog_ping();
pr_info("Started watchdog timer\n");
return stream_open(inode, file);
}
static int indydog_release(struct inode *inode, struct file *file)
{
/* Shut off the timer.
* Lock it in if it's a module and we defined ...NOWAYOUT */
if (!nowayout)
indydog_stop(); /* Turn the WDT off */
clear_bit(0, &indydog_alive);
return 0;
}
static ssize_t indydog_write(struct file *file, const char *data,
size_t len, loff_t *ppos)
{
/* Refresh the timer. */
if (len)
indydog_ping();
return len;
}
static long indydog_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int options, retval = -EINVAL;
static const struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING,
.firmware_version = 0,
.identity = "Hardware Watchdog for SGI IP22",
};
switch (cmd) {
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_SETOPTIONS:
{
if (get_user(options, (int *)arg))
return -EFAULT;
if (options & WDIOS_DISABLECARD) {
indydog_stop();
retval = 0;
}
if (options & WDIOS_ENABLECARD) {
indydog_start();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
indydog_ping();
return 0;
case WDIOC_GETTIMEOUT:
return put_user(WATCHDOG_TIMEOUT, (int *)arg);
default:
return -ENOTTY;
}
}
static int indydog_notify_sys(struct notifier_block *this,
unsigned long code, void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
indydog_stop(); /* Turn the WDT off */
return NOTIFY_DONE;
}
static const struct file_operations indydog_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = indydog_write,
.unlocked_ioctl = indydog_ioctl,
.open = indydog_open,
.release = indydog_release,
};
static struct miscdevice indydog_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &indydog_fops,
};
static struct notifier_block indydog_notifier = {
.notifier_call = indydog_notify_sys,
};
static int __init watchdog_init(void)
{
int ret;
ret = register_reboot_notifier(&indydog_notifier);
if (ret) {
pr_err("cannot register reboot notifier (err=%d)\n", ret);
return ret;
}
ret = misc_register(&indydog_miscdev);
if (ret) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
unregister_reboot_notifier(&indydog_notifier);
return ret;
}
pr_info("Hardware Watchdog Timer for SGI IP22: 0.3\n");
return 0;
}
static void __exit watchdog_exit(void)
{
misc_deregister(&indydog_miscdev);
unregister_reboot_notifier(&indydog_notifier);
}
module_init(watchdog_init);
module_exit(watchdog_exit);
MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>");
MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22");
MODULE_LICENSE("GPL");
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