// SPDX-License-Identifier: GPL-2.0+
/*
* ICP Wafer 5823 Single Board Computer WDT driver
* http://www.icpamerica.com/wafer_5823.php
* May also work on other similar models
*
* (c) Copyright 2002 Justin Cormack <[email protected]>
*
* Release 0.02
*
* Based on advantechwdt.c which is based on wdt.c.
* Original copyright messages:
*
* (c) Copyright 1996-1997 Alan Cox <[email protected]>,
* All Rights Reserved.
*
* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
* warranty for any of this software. This material is provided
* "AS-IS" and at no charge.
*
* (c) Copyright 1995 Alan Cox <[email protected]>
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/fs.h>
#include <linux/ioport.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#define WATCHDOG_NAME "Wafer 5823 WDT"
#define PFX WATCHDOG_NAME ": "
#define WD_TIMO 60 /* 60 sec default timeout */
static unsigned long wafwdt_is_open;
static char expect_close;
static DEFINE_SPINLOCK(wafwdt_lock);
/*
* You must set these - there is no sane way to probe for this board.
*
* To enable, write the timeout value in seconds (1 to 255) to I/O
* port WDT_START, then read the port to start the watchdog. To pat
* the dog, read port WDT_STOP to stop the timer, then read WDT_START
* to restart it again.
*/
static int wdt_stop = 0x843;
static int wdt_start = 0x443;
static int timeout = WD_TIMO; /* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. 1 <= timeout <= 255, default="
__MODULE_STRING(WD_TIMO) ".");
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 wafwdt_ping(void)
{
/* pat watchdog */
spin_lock(&wafwdt_lock);
inb_p(wdt_stop);
inb_p(wdt_start);
spin_unlock(&wafwdt_lock);
}
static void wafwdt_start(void)
{
/* start up watchdog */
outb_p(timeout, wdt_start);
inb_p(wdt_start);
}
static void wafwdt_stop(void)
{
/* stop watchdog */
inb_p(wdt_stop);
}
static ssize_t wafwdt_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
/* See if we got the magic character 'V' and reload the timer */
if (count) {
if (!nowayout) {
size_t i;
/* In case it was set long ago */
expect_close = 0;
/* scan to see whether or not we got the magic
character */
for (i = 0; i != count; i++) {
char c;
if (get_user(c, buf + i))
return -EFAULT;
if (c == 'V')
expect_close = 42;
}
}
/* Well, anyhow someone wrote to us, we should
return that favour */
wafwdt_ping();
}
return count;
}
static long wafwdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int new_timeout;
void __user *argp = (void __user *)arg;
int __user *p = argp;
static const struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE,
.firmware_version = 1,
.identity = "Wafer 5823 WDT",
};
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &ident, sizeof(ident)))
return -EFAULT;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_SETOPTIONS:
{
int options, retval = -EINVAL;
if (get_user(options, p))
return -EFAULT;
if (options & WDIOS_DISABLECARD) {
wafwdt_stop();
retval = 0;
}
if (options & WDIOS_ENABLECARD) {
wafwdt_start();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
wafwdt_ping();
break;
case WDIOC_SETTIMEOUT:
if (get_user(new_timeout, p))
return -EFAULT;
if ((new_timeout < 1) || (new_timeout > 255))
return -EINVAL;
timeout = new_timeout;
wafwdt_stop();
wafwdt_start();
fallthrough;
case WDIOC_GETTIMEOUT:
return put_user(timeout, p);
default:
return -ENOTTY;
}
return 0;
}
static int wafwdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &wafwdt_is_open))
return -EBUSY;
/*
* Activate
*/
wafwdt_start();
return stream_open(inode, file);
}
static int wafwdt_close(struct inode *inode, struct file *file)
{
if (expect_close == 42)
wafwdt_stop();
else {
pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
wafwdt_ping();
}
clear_bit(0, &wafwdt_is_open);
expect_close = 0;
return 0;
}
/*
* Notifier for system down
*/
static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code,
void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
wafwdt_stop();
return NOTIFY_DONE;
}
/*
* Kernel Interfaces
*/
static const struct file_operations wafwdt_fops = {
.owner = THIS_MODULE,
.write = wafwdt_write,
.unlocked_ioctl = wafwdt_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = wafwdt_open,
.release = wafwdt_close,
};
static struct miscdevice wafwdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &wafwdt_fops,
};
/*
* The WDT needs to learn about soft shutdowns in order to
* turn the timebomb registers off.
*/
static struct notifier_block wafwdt_notifier = {
.notifier_call = wafwdt_notify_sys,
};
static int __init wafwdt_init(void)
{
int ret;
pr_info("WDT driver for Wafer 5823 single board computer initialising\n");
if (timeout < 1 || timeout > 255) {
timeout = WD_TIMO;
pr_info("timeout value must be 1 <= x <= 255, using %d\n",
timeout);
}
if (wdt_stop != wdt_start) {
if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
pr_err("I/O address 0x%04x already in use\n", wdt_stop);
ret = -EIO;
goto error;
}
}
if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
pr_err("I/O address 0x%04x already in use\n", wdt_start);
ret = -EIO;
goto error2;
}
ret = register_reboot_notifier(&wafwdt_notifier);
if (ret != 0) {
pr_err("cannot register reboot notifier (err=%d)\n", ret);
goto error3;
}
ret = misc_register(&wafwdt_miscdev);
if (ret != 0) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto error4;
}
pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
timeout, nowayout);
return ret;
error4:
unregister_reboot_notifier(&wafwdt_notifier);
error3:
release_region(wdt_start, 1);
error2:
if (wdt_stop != wdt_start)
release_region(wdt_stop, 1);
error:
return ret;
}
static void __exit wafwdt_exit(void)
{
misc_deregister(&wafwdt_miscdev);
unregister_reboot_notifier(&wafwdt_notifier);
if (wdt_stop != wdt_start)
release_region(wdt_stop, 1);
release_region(wdt_start, 1);
}
module_init(wafwdt_init);
module_exit(wafwdt_exit);
MODULE_AUTHOR("Justin Cormack");
MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
MODULE_LICENSE("GPL");
/* end of wafer5823wdt.c */
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