/*
* w83697ug/uf WDT driver
*
* (c) Copyright 2008 Flemming Fransen <ff@nrvissing.net>
* reused original code to support w83697ug/uf.
*
* Based on w83627hf_wdt.c which is based on advantechwdt.c
* which is based on wdt.c.
* Original copyright messages:
*
* (c) Copyright 2007 Vlad Drukker <vlad@storewiz.com>
* added support for W83627THF.
*
* (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
*
* (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
*
* (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
* http://www.redhat.com
*
* 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.
*
* 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@redhat.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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/spinlock.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#define WATCHDOG_NAME "w83697ug/uf WDT"
#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
static unsigned long wdt_is_open;
static char expect_close;
static DEFINE_SPINLOCK(io_lock);
static int wdt_io = 0x2e;
module_param(wdt_io, int, 0);
MODULE_PARM_DESC(wdt_io, "w83697ug/uf WDT io port (default 0x2e)");
static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. 1<= timeout <=255 (default="
__MODULE_STRING(WATCHDOG_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) ")");
/*
* Kernel methods.
*/
#define WDT_EFER (wdt_io+0) /* Extended Function Enable Registers */
#define WDT_EFIR (wdt_io+0) /* Extended Function Index Register
(same as EFER) */
#define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
static int w83697ug_select_wd_register(void)
{
unsigned char c;
unsigned char version;
outb_p(0x87, WDT_EFER); /* Enter extended function mode */
outb_p(0x87, WDT_EFER); /* Again according to manual */
outb(0x20, WDT_EFER); /* check chip version */
version = inb(WDT_EFDR);
if (version == 0x68) { /* W83697UG */
pr_info("Watchdog chip version 0x%02x = W83697UG/UF found at 0x%04x\n",
version, wdt_io);
outb_p(0x2b, WDT_EFER);
c = inb_p(WDT_EFDR); /* select WDT0 */
c &= ~0x04;
outb_p(0x2b, WDT_EFER);
outb_p(c, WDT_EFDR); /* set pin118 to WDT0 */
} else {
pr_err("No W83697UG/UF could be found\n");
return -ENODEV;
}
outb_p(0x07, WDT_EFER); /* point to logical device number reg */
outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
outb_p(0x30, WDT_EFER); /* select CR30 */
c = inb_p(WDT_EFDR);
outb_p(c | 0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
return 0;
}
static void w83697ug_unselect_wd_register(void)
{
outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
}
static int w83697ug_init(void)
{
int ret;
unsigned char t;
ret = w83697ug_select_wd_register();
if (ret != 0)
return ret;
outb_p(0xF6, WDT_EFER); /* Select CRF6 */
t = inb_p(WDT_EFDR); /* read CRF6 */
if (t != 0) {
pr_info("Watchdog already running. Resetting timeout to %d sec\n",
timeout);
outb_p(timeout, WDT_EFDR); /* Write back to CRF6 */
}
outb_p(0xF5, WDT_EFER); /* Select CRF5 */
t = inb_p(WDT_EFDR); /* read CRF5 */
t &= ~0x0C; /* set second mode &
disable keyboard turning off watchdog */
outb_p(t, WDT_EFDR); /* Write back to CRF5 */
w83697ug_unselect_wd_register();
return 0;
}
static void wdt_ctrl(int timeout)
{
spin_lock(&io_lock);
if (w83697ug_select_wd_register() < 0) {
spin_unlock(&io_lock);
return;
}
outb_p(0xF4, WDT_EFER); /* Select CRF4 */
outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF4 */
w83697ug_unselect_wd_register();
spin_unlock(&io_lock);
}
static int wdt_ping(void)
{
wdt_ctrl(timeout);
return 0;
}
static int wdt_disable(void)
{
wdt_ctrl(0);
return 0;
}
static int wdt_set_heartbeat(int t)
{
if (t < 1 || t > 255)
return -EINVAL;
timeout = t;
return 0;
}
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;
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;
}
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_timeout;
static const struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING |
WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE,
.firmware_version = 1,
.identity = "W83697UG 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) {
wdt_disable();
retval = 0;
}
if (options & WDIOS_ENABLECARD) {
wdt_ping();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
wdt_ping();
break;
case WDIOC_SETTIMEOUT:
if (get_user(new_timeout, p))
return -EFAULT;
if (wdt_set_heartbeat(new_timeout))
return -EINVAL;
wdt_ping();
/* Fall */
case WDIOC_GETTIMEOUT:
return put_user(timeout, p);
default:
return -ENOTTY;
}
return 0;
}
static int wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &wdt_is_open))
return -EBUSY;
/*
* Activate
*/
wdt_ping();
return nonseekable_open(inode, file);
}
static int wdt_close(struct inode *inode, struct file *file)
{
if (expect_close == 42)
wdt_disable();
else {
pr_crit("Unexpected close, not stopping watchdog!\n");
wdt_ping();
}
expect_close = 0;
clear_bit(0, &wdt_is_open);
return 0;
}
/*
* Notifier for system down
*/
static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
wdt_disable(); /* Turn the WDT off */
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,
.open = wdt_open,
.release = wdt_close,
};
static struct miscdevice wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &wdt_fops,
};
/*
* The WDT 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,
};
static int __init wdt_init(void)
{
int ret;
pr_info("WDT driver for the Winbond(TM) W83697UG/UF Super I/O chip initialising\n");
if (wdt_set_heartbeat(timeout)) {
wdt_set_heartbeat(WATCHDOG_TIMEOUT);
pr_info("timeout value must be 1<=timeout<=255, using %d\n",
WATCHDOG_TIMEOUT);
}
if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
pr_err("I/O address 0x%04x already in use\n", wdt_io);
ret = -EIO;
goto out;
}
ret = w83697ug_init();
if (ret != 0)
goto unreg_regions;
ret = register_reboot_notifier(&wdt_notifier);
if (ret != 0) {
pr_err("cannot register reboot notifier (err=%d)\n", ret);
goto unreg_regions;
}
ret = misc_register(&wdt_miscdev);
if (ret != 0) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto unreg_reboot;
}
pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
timeout, nowayout);
out:
return ret;
unreg_reboot:
unregister_reboot_notifier(&wdt_notifier);
unreg_regions:
release_region(wdt_io, 1);
goto out;
}
static void __exit wdt_exit(void)
{
misc_deregister(&wdt_miscdev);
unregister_reboot_notifier(&wdt_notifier);
release_region(wdt_io, 1);
}
module_init(wdt_init);
module_exit(wdt_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Flemming Frandsen <ff@nrvissing.net>");
MODULE_DESCRIPTION("w83697ug/uf WDT driver");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
