// SPDX-License-Identifier: GPL-2.0+
/*
* Industrial Computer Source WDT501 driver
*
* (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
* 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 <alan@lxorguk.ukuu.org.uk>
*
* Release 0.10.
*
* Fixes
* Dave Gregorich : Modularisation and minor bugs
* Alan Cox : Added the watchdog ioctl() stuff
* Alan Cox : Fixed the reboot problem (as noted by
* Matt Crocker).
* Alan Cox : Added wdt= boot option
* Alan Cox : Cleaned up copy/user stuff
* Tim Hockin : Added insmod parameters, comment
* cleanup, parameterized timeout
* Tigran Aivazian : Restructured wdt_init() to handle
* failures
* Joel Becker : Added WDIOC_GET/SETTIMEOUT
* Matt Domsch : Added nowayout module option
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.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/io.h>
#include <linux/uaccess.h>
#include "wd501p.h"
static unsigned long wdt_is_open;
static char expect_close;
/*
* Module parameters
*/
#define WD_TIMO 60 /* Default heartbeat = 60 seconds */
static int heartbeat = WD_TIMO;
static int wd_heartbeat;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat in seconds. (0 < heartbeat < 65536, 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) ")");
/* You must set these - there is no sane way to probe for this board. */
static int io = 0x240;
static int irq = 11;
static DEFINE_SPINLOCK(wdt_lock);
module_param_hw(io, int, ioport, 0);
MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
module_param_hw(irq, int, irq, 0);
MODULE_PARM_DESC(irq, "WDT irq (default=11)");
/* Support for the Fan Tachometer on the WDT501-P */
static int tachometer;
module_param(tachometer, int, 0);
MODULE_PARM_DESC(tachometer,
"WDT501-P Fan Tachometer support (0=disable, default=0)");
static int type = 500;
module_param(type, int, 0);
MODULE_PARM_DESC(type,
"WDT501-P Card type (500 or 501, default=500)");
/*
* Programming support
*/
static void wdt_ctr_mode(int ctr, int mode)
{
ctr <<= 6;
ctr |= 0x30;
ctr |= (mode << 1);
outb_p(ctr, WDT_CR);
}
static void wdt_ctr_load(int ctr, int val)
{
outb_p(val&0xFF, WDT_COUNT0+ctr);
outb_p(val>>8, WDT_COUNT0+ctr);
}
/**
* wdt_start:
*
* Start the watchdog driver.
*/
static int wdt_start(void)
{
unsigned long flags;
spin_lock_irqsave(&wdt_lock, flags);
inb_p(WDT_DC); /* Disable watchdog */
wdt_ctr_mode(0, 3); /* Program CTR0 for Mode 3:
Square Wave Generator */
wdt_ctr_mode(1, 2); /* Program CTR1 for Mode 2:
Rate Generator */
wdt_ctr_mode(2, 0); /* Program CTR2 for Mode 0:
Pulse on Terminal Count */
wdt_ctr_load(0, 8948); /* Count at 100Hz */
wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */
wdt_ctr_load(2, 65535); /* Length of reset pulse */
outb_p(0, WDT_DC); /* Enable watchdog */
spin_unlock_irqrestore(&wdt_lock, flags);
return 0;
}
/**
* wdt_stop:
*
* Stop the watchdog driver.
*/
static int wdt_stop(void)
{
unsigned long flags;
spin_lock_irqsave(&wdt_lock, flags);
/* Turn the card off */
inb_p(WDT_DC); /* Disable watchdog */
wdt_ctr_load(2, 0); /* 0 length reset pulses now */
spin_unlock_irqrestore(&wdt_lock, flags);
return 0;
}
/**
* wdt_ping:
*
* Reload counter one with the watchdog heartbeat. We don't bother
* reloading the cascade counter.
*/
static void wdt_ping(void)
{
unsigned long flags;
spin_lock_irqsave(&wdt_lock, flags);
/* Write a watchdog value */
inb_p(WDT_DC); /* Disable watchdog */
wdt_ctr_mode(1, 2); /* Re-Program CTR1 for Mode 2:
Rate Generator */
wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */
outb_p(0, WDT_DC); /* Enable watchdog */
spin_unlock_irqrestore(&wdt_lock, flags);
}
/**
* wdt_set_heartbeat:
* @t: the new heartbeat value that needs to be set.
*
* Set a new heartbeat value for the watchdog device. If the heartbeat
* value is incorrect we keep the old value and return -EINVAL. If
* successful we return 0.
*/
static int wdt_set_heartbeat(int t)
{
if (t < 1 || t > 65535)
return -EINVAL;
heartbeat = t;
wd_heartbeat = t * 100;
return 0;
}
/**
* wdt_get_status:
*
* Extract the status information from a WDT watchdog device. There are
* several board variants so we have to know which bits are valid. Some
* bits default to one and some to zero in order to be maximally painful.
*
* we then map the bits onto the status ioctl flags.
*/
static int wdt_get_status(void)
{
unsigned char new_status;
int status = 0;
unsigned long flags;
spin_lock_irqsave(&wdt_lock, flags);
new_status = inb_p(WDT_SR);
spin_unlock_irqrestore(&wdt_lock, flags);
if (new_status & WDC_SR_ISOI0)
status |= WDIOF_EXTERN1;
if (new_status & WDC_SR_ISII1)
status |= WDIOF_EXTERN2;
if (type == 501) {
if (!(new_status & WDC_SR_TGOOD))
status |= WDIOF_OVERHEAT;
if (!(new_status & WDC_SR_PSUOVER))
status |= WDIOF_POWEROVER;
if (!(new_status & WDC_SR_PSUUNDR))
status |= WDIOF_POWERUNDER;
if (tachometer) {
if (!(new_status & WDC_SR_FANGOOD))
status |= WDIOF_FANFAULT;
}
}
return status;
}
/**
* wdt_get_temperature:
*
* Reports the temperature in degrees Fahrenheit. The API is in
* farenheit. It was designed by an imperial measurement luddite.
*/
static int wdt_get_temperature(void)
{
unsigned short c;
unsigned long flags;
spin_lock_irqsave(&wdt_lock, flags);
c = inb_p(WDT_RT);
spin_unlock_irqrestore(&wdt_lock, flags);
return (c * 11 / 15) + 7;
}
static void wdt_decode_501(int status)
{
if (!(status & WDC_SR_TGOOD))
pr_crit("Overheat alarm (%d)\n", inb_p(WDT_RT));
if (!(status & WDC_SR_PSUOVER))
pr_crit("PSU over voltage\n");
if (!(status & WDC_SR_PSUUNDR))
pr_crit("PSU under voltage\n");
}
/**
* wdt_interrupt:
* @irq: Interrupt number
* @dev_id: Unused as we don't allow multiple devices.
*
* Handle an interrupt from the board. These are raised when the status
* map changes in what the board considers an interesting way. That means
* a failure condition occurring.
*/
static irqreturn_t wdt_interrupt(int irq, void *dev_id)
{
/*
* Read the status register see what is up and
* then printk it.
*/
unsigned char status;
spin_lock(&wdt_lock);
status = inb_p(WDT_SR);
pr_crit("WDT status %d\n", status);
if (type == 501) {
wdt_decode_501(status);
if (tachometer) {
if (!(status & WDC_SR_FANGOOD))
pr_crit("Possible fan fault\n");
}
}
if (!(status & WDC_SR_WCCR)) {
#ifdef SOFTWARE_REBOOT
#ifdef ONLY_TESTING
pr_crit("Would Reboot\n");
#else
pr_crit("Initiating system reboot\n");
emergency_restart();
#endif
#else
pr_crit("Reset in 5ms\n");
#endif
}
spin_unlock(&wdt_lock);
return IRQ_HANDLED;
}
/**
* wdt_write:
* @file: file handle to the watchdog
* @buf: buffer to write (unused as data does not matter here
* @count: count of bytes
* @ppos: pointer to the position to write. No seeks allowed
*
* A write to a watchdog device is defined as a keepalive signal. Any
* write of data will do, as we we don't define content meaning.
*/
static ssize_t wdt_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
if (count) {
if (!nowayout) {
size_t i;
/* In case it was set long ago */
expect_close = 0;
for (i = 0; i != count; i++) {
char c;
if (get_user(c, buf + i))
return -EFAULT;
if (c == 'V')
expect_close = 42;
}
}
wdt_ping();
}
return count;
}
/**
* wdt_ioctl:
* @file: file handle to the device
* @cmd: watchdog command
* @arg: argument pointer
*
* The watchdog API defines a common set of functions for all watchdogs
* according to their available features. We only actually usefully support
* querying capabilities and current status.
*/
static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
int new_heartbeat;
int status;
struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT|
WDIOF_MAGICCLOSE|
WDIOF_KEEPALIVEPING,
.firmware_version = 1,
.identity = "WDT500/501",
};
/* Add options according to the card we have */
ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
if (type == 501) {
ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|
WDIOF_POWEROVER);
if (tachometer)
ident.options |= WDIOF_FANFAULT;
}
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
status = wdt_get_status();
return put_user(status, p);
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_KEEPALIVE:
wdt_ping();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_heartbeat, p))
return -EFAULT;
if (wdt_set_heartbeat(new_heartbeat))
return -EINVAL;
wdt_ping();
fallthrough;
case WDIOC_GETTIMEOUT:
return put_user(heartbeat, p);
default:
return -ENOTTY;
}
}
/**
* wdt_open:
* @inode: inode of device
* @file: file handle to device
*
* The watchdog device has been opened. The watchdog device is single
* open and on opening we load the counters. Counter zero is a 100Hz
* cascade, into counter 1 which downcounts to reboot. When the counter
* triggers counter 2 downcounts the length of the reset pulse which
* set set to be as long as possible.
*/
static int wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &wdt_is_open))
return -EBUSY;
/*
* Activate
*/
wdt_start();
return stream_open(inode, file);
}
/**
* wdt_release:
* @inode: inode to board
* @file: file handle to board
*
* The watchdog has a configurable API. There is a religious dispute
* between people who want their watchdog to be able to shut down and
* those who want to be sure if the watchdog manager dies the machine
* reboots. In the former case we disable the counters, in the latter
* case you have to open it again very soon.
*/
static int wdt_release(struct inode *inode, struct file *file)
{
if (expect_close == 42) {
wdt_stop();
clear_bit(0, &wdt_is_open);
} else {
pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
wdt_ping();
}
expect_close = 0;
return 0;
}
/**
* wdt_temp_read:
* @file: file handle to the watchdog board
* @buf: buffer to write 1 byte into
* @count: length of buffer
* @ptr: offset (no seek allowed)
*
* Temp_read reports the temperature in degrees Fahrenheit. The API is in
* farenheit. It was designed by an imperial measurement luddite.
*/
static ssize_t wdt_temp_read(struct file *file, char __user *buf,
size_t count, loff_t *ptr)
{
int temperature = wdt_get_temperature();
if (copy_to_user(buf, &temperature, 1))
return -EFAULT;
return 1;
}
/**
* wdt_temp_open:
* @inode: inode of device
* @file: file handle to device
*
* The temperature device has been opened.
*/
static int wdt_temp_open(struct inode *inode, struct file *file)
{
return stream_open(inode, file);
}
/**
* wdt_temp_release:
* @inode: inode to board
* @file: file handle to board
*
* The temperature device has been closed.
*/
static int wdt_temp_release(struct inode *inode, struct file *file)
{
return 0;
}
/**
* wdt_notify_sys:
* @this: our notifier block
* @code: the event being reported
* @unused: unused
*
* Our notifier is called on system shutdowns. We want to turn the card
* off at reboot otherwise the machine will reboot again during memory
* test or worse yet during the following fsck. This would suck, in fact
* trust me - if it happens it does suck.
*/
static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
wdt_stop();
return NOTIFY_DONE;
}
/*
* Kernel Interfaces
*/
static const struct file_operations wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = wdt_write,
.unlocked_ioctl = wdt_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = wdt_open,
.release = wdt_release,
};
static struct miscdevice wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &wdt_fops,
};
static const struct file_operations wdt_temp_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read = wdt_temp_read,
.open = wdt_temp_open,
.release = wdt_temp_release,
};
static struct miscdevice temp_miscdev = {
.minor = TEMP_MINOR,
.name = "temperature",
.fops = &wdt_temp_fops,
};
/*
* The WDT card needs to learn about soft shutdowns in order to
* turn the timebomb registers off.
*/
static struct notifier_block wdt_notifier = {
.notifier_call = wdt_notify_sys,
};
/**
* wdt_exit:
*
* Unload the watchdog. You cannot do this with any file handles open.
* If your watchdog is set to continue ticking on close and you unload
* it, well it keeps ticking. We won't get the interrupt but the board
* will not touch PC memory so all is fine. You just have to load a new
* module in 60 seconds or reboot.
*/
static void __exit wdt_exit(void)
{
misc_deregister(&wdt_miscdev);
if (type == 501)
misc_deregister(&temp_miscdev);
unregister_reboot_notifier(&wdt_notifier);
free_irq(irq, NULL);
release_region(io, 8);
}
/**
* wdt_init:
*
* Set up the WDT watchdog board. All we have to do is grab the
* resources we require and bitch if anyone beat us to them.
* The open() function will actually kick the board off.
*/
static int __init wdt_init(void)
{
int ret;
if (type != 500 && type != 501) {
pr_err("unknown card type '%d'\n", type);
return -ENODEV;
}
/* Check that the heartbeat value is within it's range;
if not reset to the default */
if (wdt_set_heartbeat(heartbeat)) {
wdt_set_heartbeat(WD_TIMO);
pr_info("heartbeat value must be 0 < heartbeat < 65536, using %d\n",
WD_TIMO);
}
if (!request_region(io, 8, "wdt501p")) {
pr_err("I/O address 0x%04x already in use\n", io);
ret = -EBUSY;
goto out;
}
ret = request_irq(irq, wdt_interrupt, 0, "wdt501p", NULL);
if (ret) {
pr_err("IRQ %d is not free\n", irq);
goto outreg;
}
ret = register_reboot_notifier(&wdt_notifier);
if (ret) {
pr_err("cannot register reboot notifier (err=%d)\n", ret);
goto outirq;
}
if (type == 501) {
ret = misc_register(&temp_miscdev);
if (ret) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
TEMP_MINOR, ret);
goto outrbt;
}
}
ret = misc_register(&wdt_miscdev);
if (ret) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto outmisc;
}
pr_info("WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
io, irq, heartbeat, nowayout);
if (type == 501)
pr_info("Fan Tachometer is %s\n",
tachometer ? "Enabled" : "Disabled");
return 0;
outmisc:
if (type == 501)
misc_deregister(&temp_miscdev);
outrbt:
unregister_reboot_notifier(&wdt_notifier);
outirq:
free_irq(irq, NULL);
outreg:
release_region(io, 8);
out:
return ret;
}
module_init(wdt_init);
module_exit(wdt_exit);
MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
MODULE_LICENSE("GPL");