/*
* IT8712F "Smart Guardian" Watchdog support
*
* Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
*
* Based on info and code taken from:
*
* drivers/char/watchdog/scx200_wdt.c
* drivers/hwmon/it87.c
* IT8712F EC-LPC I/O Preliminary Specification 0.9.2.pdf
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* The author(s) of this software shall not be held liable for damages
* of any nature resulting due to the use of this software. This
* software is provided AS-IS with no warranties.
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/fs.h>
#include <linux/pci.h>
#include <linux/spinlock.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#define NAME "it8712f_wdt"
MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
MODULE_DESCRIPTION("IT8712F Watchdog Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
static int margin = 60; /* in seconds */
module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
static struct semaphore it8712f_wdt_sem;
static unsigned expect_close;
static spinlock_t io_lock;
/* Dog Food address - We use the game port address */
static unsigned short address;
#define REG 0x2e /* The register to read/write */
#define VAL 0x2f /* The value to read/write */
#define LDN 0x07 /* Register: Logical device select */
#define DEVID 0x20 /* Register: Device ID */
#define DEVREV 0x22 /* Register: Device Revision */
#define ACT_REG 0x30 /* LDN Register: Activation */
#define BASE_REG 0x60 /* LDN Register: Base address */
#define IT8712F_DEVID 0x8712
#define LDN_GPIO 0x07 /* GPIO and Watch Dog Timer */
#define LDN_GAME 0x09 /* Game Port */
#define WDT_CONTROL 0x71 /* WDT Register: Control */
#define WDT_CONFIG 0x72 /* WDT Register: Configuration */
#define WDT_TIMEOUT 0x73 /* WDT Register: Timeout Value */
#define WDT_RESET_GAME 0x10
#define WDT_RESET_KBD 0x20
#define WDT_RESET_MOUSE 0x40
#define WDT_RESET_CIR 0x80
#define WDT_UNIT_SEC 0x80 /* If 0 in MINUTES */
#define WDT_OUT_PWROK 0x10
#define WDT_OUT_KRST 0x40
static int
superio_inb(int reg)
{
outb(reg, REG);
return inb(VAL);
}
static void
superio_outb(int val, int reg)
{
outb(reg, REG);
outb(val, VAL);
}
static int
superio_inw(int reg)
{
int val;
outb(reg++, REG);
val = inb(VAL) << 8;
outb(reg, REG);
val |= inb(VAL);
return val;
}
static inline void
superio_select(int ldn)
{
outb(LDN, REG);
outb(ldn, VAL);
}
static inline void
superio_enter(void)
{
spin_lock(&io_lock);
outb(0x87, REG);
outb(0x01, REG);
outb(0x55, REG);
outb(0x55, REG);
}
static inline void
superio_exit(void)
{
outb(0x02, REG);
outb(0x02, VAL);
spin_unlock(&io_lock);
}
static inline void
it8712f_wdt_ping(void)
{
inb(address);
}
static void
it8712f_wdt_update_margin(void)
{
int config = WDT_OUT_KRST | WDT_OUT_PWROK;
printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
/* The timeout register only has 8bits wide */
if (margin < 256)
config |= WDT_UNIT_SEC; /* else UNIT are MINUTES */
superio_outb(config, WDT_CONFIG);
superio_outb((margin > 255) ? (margin / 60) : margin, WDT_TIMEOUT);
}
static void
it8712f_wdt_enable(void)
{
printk(KERN_DEBUG NAME ": enabling watchdog timer\n");
superio_enter();
superio_select(LDN_GPIO);
superio_outb(WDT_RESET_GAME, WDT_CONTROL);
it8712f_wdt_update_margin();
superio_exit();
it8712f_wdt_ping();
}
static void
it8712f_wdt_disable(void)
{
printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
superio_enter();
superio_select(LDN_GPIO);
superio_outb(0, WDT_CONFIG);
superio_outb(0, WDT_CONTROL);
superio_outb(0, WDT_TIMEOUT);
superio_exit();
}
static int
it8712f_wdt_notify(struct notifier_block *this,
unsigned long code, void *unused)
{
if (code == SYS_HALT || code == SYS_POWER_OFF)
if (!nowayout)
it8712f_wdt_disable();
return NOTIFY_DONE;
}
static struct notifier_block it8712f_wdt_notifier = {
.notifier_call = it8712f_wdt_notify,
};
static ssize_t
it8712f_wdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
/* check for a magic close character */
if (len) {
size_t i;
it8712f_wdt_ping();
expect_close = 0;
for (i = 0; i < len; ++i) {
char c;
if (get_user(c, data+i))
return -EFAULT;
if (c == 'V')
expect_close = 42;
}
}
return len;
}
static int
it8712f_wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
static struct watchdog_info ident = {
.identity = "IT8712F Watchdog",
.firmware_version = 1,
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
};
int new_margin;
switch (cmd) {
default:
return -ENOTTY;
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &ident, sizeof(ident)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_KEEPALIVE:
it8712f_wdt_ping();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_margin, p))
return -EFAULT;
if (new_margin < 1)
return -EINVAL;
margin = new_margin;
superio_enter();
superio_select(LDN_GPIO);
it8712f_wdt_update_margin();
superio_exit();
it8712f_wdt_ping();
case WDIOC_GETTIMEOUT:
if (put_user(margin, p))
return -EFAULT;
return 0;
}
}
static int
it8712f_wdt_open(struct inode *inode, struct file *file)
{
/* only allow one at a time */
if (down_trylock(&it8712f_wdt_sem))
return -EBUSY;
it8712f_wdt_enable();
return nonseekable_open(inode, file);
}
static int
it8712f_wdt_release(struct inode *inode, struct file *file)
{
if (expect_close != 42) {
printk(KERN_WARNING NAME
": watchdog device closed unexpectedly, will not"
" disable the watchdog timer\n");
} else if (!nowayout) {
it8712f_wdt_disable();
}
expect_close = 0;
up(&it8712f_wdt_sem);
return 0;
}
static const struct file_operations it8712f_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = it8712f_wdt_write,
.ioctl = it8712f_wdt_ioctl,
.open = it8712f_wdt_open,
.release = it8712f_wdt_release,
};
static struct miscdevice it8712f_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &it8712f_wdt_fops,
};
static int __init
it8712f_wdt_find(unsigned short *address)
{
int err = -ENODEV;
int chip_type;
superio_enter();
chip_type = superio_inw(DEVID);
if (chip_type != IT8712F_DEVID)
goto exit;
superio_select(LDN_GAME);
superio_outb(1, ACT_REG);
if (!(superio_inb(ACT_REG) & 0x01)) {
printk(KERN_ERR NAME ": Device not activated, skipping\n");
goto exit;
}
*address = superio_inw(BASE_REG);
if (*address == 0) {
printk(KERN_ERR NAME ": Base address not set, skipping\n");
goto exit;
}
err = 0;
printk(KERN_DEBUG NAME ": Found IT%04xF chip revision %d - "
"using DogFood address 0x%x\n",
chip_type, superio_inb(DEVREV) & 0x0f, *address);
exit:
superio_exit();
return err;
}
static int __init
it8712f_wdt_init(void)
{
int err = 0;
spin_lock_init(&io_lock);
if (it8712f_wdt_find(&address))
return -ENODEV;
if (!request_region(address, 1, "IT8712F Watchdog")) {
printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
return -EBUSY;
}
it8712f_wdt_disable();
sema_init(&it8712f_wdt_sem, 1);
err = register_reboot_notifier(&it8712f_wdt_notifier);
if (err) {
printk(KERN_ERR NAME ": unable to register reboot notifier\n");
goto out;
}
err = misc_register(&it8712f_wdt_miscdev);
if (err) {
printk(KERN_ERR NAME
": cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, err);
goto reboot_out;
}
return 0;
reboot_out:
unregister_reboot_notifier(&it8712f_wdt_notifier);
out:
release_region(address, 1);
return err;
}
static void __exit
it8712f_wdt_exit(void)
{
misc_deregister(&it8712f_wdt_miscdev);
unregister_reboot_notifier(&it8712f_wdt_notifier);
release_region(address, 1);
}
module_init(it8712f_wdt_init);
module_exit(it8712f_wdt_exit);
