// SPDX-License-Identifier: GPL-2.0+
/*
* SBC8360 Watchdog driver
*
* (c) Copyright 2005 Webcon, Inc.
*
* Based on ib700wdt.c, which is based on advantechwdt.c which is based
* on acquirewdt.c which is based on wdt.c.
*
* (c) Copyright 2001 Charles Howes <chowes@vsol.net>
*
* Based on advantechwdt.c which is based on acquirewdt.c which
* is based on wdt.c.
*
* (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
*
* Based on acquirewdt.c which is based on wdt.c.
* Original copyright messages:
*
* (c) Copyright 1996 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>
*
* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
* Added timeout module option to override default
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/notifier.h>
#include <linux/fs.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/moduleparam.h>
#include <linux/io.h>
#include <linux/uaccess.h>
static unsigned long sbc8360_is_open;
static char expect_close;
/*
*
* Watchdog Timer Configuration
*
* The function of the watchdog timer is to reset the system automatically
* and is defined at I/O port 0120H and 0121H. To enable the watchdog timer
* and allow the system to reset, write appropriate values from the table
* below to I/O port 0120H and 0121H. To disable the timer, write a zero
* value to I/O port 0121H for the system to stop the watchdog function.
*
* The following describes how the timer should be programmed (according to
* the vendor documentation)
*
* Enabling Watchdog:
* MOV AX,000AH (enable, phase I)
* MOV DX,0120H
* OUT DX,AX
* MOV AX,000BH (enable, phase II)
* MOV DX,0120H
* OUT DX,AX
* MOV AX,000nH (set multiplier n, from 1-4)
* MOV DX,0120H
* OUT DX,AX
* MOV AX,000mH (set base timer m, from 0-F)
* MOV DX,0121H
* OUT DX,AX
*
* Reset timer:
* MOV AX,000mH (same as set base timer, above)
* MOV DX,0121H
* OUT DX,AX
*
* Disabling Watchdog:
* MOV AX,0000H (a zero value)
* MOV DX,0120H
* OUT DX,AX
*
* Watchdog timeout configuration values:
* N
* M | 1 2 3 4
* --|----------------------------------
* 0 | 0.5s 5s 50s 100s
* 1 | 1s 10s 100s 200s
* 2 | 1.5s 15s 150s 300s
* 3 | 2s 20s 200s 400s
* 4 | 2.5s 25s 250s 500s
* 5 | 3s 30s 300s 600s
* 6 | 3.5s 35s 350s 700s
* 7 | 4s 40s 400s 800s
* 8 | 4.5s 45s 450s 900s
* 9 | 5s 50s 500s 1000s
* A | 5.5s 55s 550s 1100s
* B | 6s 60s 600s 1200s
* C | 6.5s 65s 650s 1300s
* D | 7s 70s 700s 1400s
* E | 7.5s 75s 750s 1500s
* F | 8s 80s 800s 1600s
*
* Another way to say the same things is:
* For N=1, Timeout = (M+1) * 0.5s
* For N=2, Timeout = (M+1) * 5s
* For N=3, Timeout = (M+1) * 50s
* For N=4, Timeout = (M+1) * 100s
*
*/
static int wd_times[64][2] = {
{0, 1}, /* 0 = 0.5s */
{1, 1}, /* 1 = 1s */
{2, 1}, /* 2 = 1.5s */
{3, 1}, /* 3 = 2s */
{4, 1}, /* 4 = 2.5s */
{5, 1}, /* 5 = 3s */
{6, 1}, /* 6 = 3.5s */
{7, 1}, /* 7 = 4s */
{8, 1}, /* 8 = 4.5s */
{9, 1}, /* 9 = 5s */
{0xA, 1}, /* 10 = 5.5s */
{0xB, 1}, /* 11 = 6s */
{0xC, 1}, /* 12 = 6.5s */
{0xD, 1}, /* 13 = 7s */
{0xE, 1}, /* 14 = 7.5s */
{0xF, 1}, /* 15 = 8s */
{0, 2}, /* 16 = 5s */
{1, 2}, /* 17 = 10s */
{2, 2}, /* 18 = 15s */
{3, 2}, /* 19 = 20s */
{4, 2}, /* 20 = 25s */
{5, 2}, /* 21 = 30s */
{6, 2}, /* 22 = 35s */
{7, 2}, /* 23 = 40s */
{8, 2}, /* 24 = 45s */
{9, 2}, /* 25 = 50s */
{0xA, 2}, /* 26 = 55s */
{0xB, 2}, /* 27 = 60s */
{0xC, 2}, /* 28 = 65s */
{0xD, 2}, /* 29 = 70s */
{0xE, 2}, /* 30 = 75s */
{0xF, 2}, /* 31 = 80s */
{0, 3}, /* 32 = 50s */
{1, 3}, /* 33 = 100s */
{2, 3}, /* 34 = 150s */
{3, 3}, /* 35 = 200s */
{4, 3}, /* 36 = 250s */
{5, 3}, /* 37 = 300s */
{6, 3}, /* 38 = 350s */
{7, 3}, /* 39 = 400s */
{8, 3}, /* 40 = 450s */
{9, 3}, /* 41 = 500s */
{0xA, 3}, /* 42 = 550s */
{0xB, 3}, /* 43 = 600s */
{0xC, 3}, /* 44 = 650s */
{0xD, 3}, /* 45 = 700s */
{0xE, 3}, /* 46 = 750s */
{0xF, 3}, /* 47 = 800s */
{0, 4}, /* 48 = 100s */
{1, 4}, /* 49 = 200s */
{2, 4}, /* 50 = 300s */
{3, 4}, /* 51 = 400s */
{4, 4}, /* 52 = 500s */
{5, 4}, /* 53 = 600s */
{6, 4}, /* 54 = 700s */
{7, 4}, /* 55 = 800s */
{8, 4}, /* 56 = 900s */
{9, 4}, /* 57 = 1000s */
{0xA, 4}, /* 58 = 1100s */
{0xB, 4}, /* 59 = 1200s */
{0xC, 4}, /* 60 = 1300s */
{0xD, 4}, /* 61 = 1400s */
{0xE, 4}, /* 62 = 1500s */
{0xF, 4} /* 63 = 1600s */
};
#define SBC8360_ENABLE 0x120
#define SBC8360_BASETIME 0x121
static int timeout = 27;
static int wd_margin = 0xB;
static int wd_multiplier = 2;
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
/*
* Kernel methods.
*/
/* Activate and pre-configure watchdog */
static void sbc8360_activate(void)
{
/* Enable the watchdog */
outb(0x0A, SBC8360_ENABLE);
msleep_interruptible(100);
outb(0x0B, SBC8360_ENABLE);
msleep_interruptible(100);
/* Set timeout multiplier */
outb(wd_multiplier, SBC8360_ENABLE);
msleep_interruptible(100);
/* Nothing happens until first sbc8360_ping() */
}
/* Kernel pings watchdog */
static void sbc8360_ping(void)
{
/* Write the base timer register */
outb(wd_margin, SBC8360_BASETIME);
}
/* stop watchdog */
static void sbc8360_stop(void)
{
/* De-activate the watchdog */
outb(0, SBC8360_ENABLE);
}
/* Userspace pings kernel driver, or requests clean close */
static ssize_t sbc8360_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;
}
}
sbc8360_ping();
}
return count;
}
static int sbc8360_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &sbc8360_is_open))
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
/* Activate and ping once to start the countdown */
sbc8360_activate();
sbc8360_ping();
return stream_open(inode, file);
}
static int sbc8360_close(struct inode *inode, struct file *file)
{
if (expect_close == 42)
sbc8360_stop();
else
pr_crit("SBC8360 device closed unexpectedly. SBC8360 will not stop!\n");
clear_bit(0, &sbc8360_is_open);
expect_close = 0;
return 0;
}
/*
* Notifier for system down
*/
static int sbc8360_notify_sys(struct notifier_block *this, unsigned long code,
void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
sbc8360_stop(); /* Disable the SBC8360 Watchdog */
return NOTIFY_DONE;
}
/*
* Kernel Interfaces
*/
static const struct file_operations sbc8360_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = sbc8360_write,
.open = sbc8360_open,
.release = sbc8360_close,
};
static struct miscdevice sbc8360_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &sbc8360_fops,
};
/*
* The SBC8360 needs to learn about soft shutdowns in order to
* turn the timebomb registers off.
*/
static struct notifier_block sbc8360_notifier = {
.notifier_call = sbc8360_notify_sys,
};
static int __init sbc8360_init(void)
{
int res;
unsigned long int mseconds = 60000;
if (timeout < 0 || timeout > 63) {
pr_err("Invalid timeout index (must be 0-63)\n");
res = -EINVAL;
goto out;
}
if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) {
pr_err("ENABLE method I/O %X is not available\n",
SBC8360_ENABLE);
res = -EIO;
goto out;
}
if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) {
pr_err("BASETIME method I/O %X is not available\n",
SBC8360_BASETIME);
res = -EIO;
goto out_nobasetimereg;
}
res = register_reboot_notifier(&sbc8360_notifier);
if (res) {
pr_err("Failed to register reboot notifier\n");
goto out_noreboot;
}
res = misc_register(&sbc8360_miscdev);
if (res) {
pr_err("failed to register misc device\n");
goto out_nomisc;
}
wd_margin = wd_times[timeout][0];
wd_multiplier = wd_times[timeout][1];
if (wd_multiplier == 1)
mseconds = (wd_margin + 1) * 500;
else if (wd_multiplier == 2)
mseconds = (wd_margin + 1) * 5000;
else if (wd_multiplier == 3)
mseconds = (wd_margin + 1) * 50000;
else if (wd_multiplier == 4)
mseconds = (wd_margin + 1) * 100000;
/* My kingdom for the ability to print "0.5 seconds" in the kernel! */
pr_info("Timeout set at %ld ms\n", mseconds);
return 0;
out_nomisc:
unregister_reboot_notifier(&sbc8360_notifier);
out_noreboot:
release_region(SBC8360_BASETIME, 1);
out_nobasetimereg:
release_region(SBC8360_ENABLE, 1);
out:
return res;
}
static void __exit sbc8360_exit(void)
{
misc_deregister(&sbc8360_miscdev);
unregister_reboot_notifier(&sbc8360_notifier);
release_region(SBC8360_ENABLE, 1);
release_region(SBC8360_BASETIME, 1);
}
module_init(sbc8360_init);
module_exit(sbc8360_exit);
MODULE_AUTHOR("Ian E. Morgan <imorgan@webcon.ca>");
MODULE_DESCRIPTION("SBC8360 watchdog driver");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.01");
/* end of sbc8360.c */