/*
* drivers/char/watchdog/iop_wdt.c
*
* WDT driver for Intel I/O Processors
* Copyright (C) 2005, Intel Corporation.
*
* Based on ixp4xx driver, Copyright 2004 (c) MontaVista, Software, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place - Suite 330, Boston, MA 02111-1307 USA.
*
* Curt E Bruns <curt.e.bruns@intel.com>
* Peter Milne <peter.milne@d-tacq.com>
* Dan Williams <dan.j.williams@intel.com>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <mach/hardware.h>
static int nowayout = WATCHDOG_NOWAYOUT;
static unsigned long wdt_status;
static unsigned long boot_status;
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
#define WDT_ENABLED 2
static unsigned long iop_watchdog_timeout(void)
{
return (0xffffffffUL / get_iop_tick_rate());
}
/**
* wdt_supports_disable - determine if we are accessing a iop13xx watchdog
* or iop3xx by whether it has a disable command
*/
static int wdt_supports_disable(void)
{
int can_disable;
if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM)
can_disable = 1;
else
can_disable = 0;
return can_disable;
}
static void wdt_enable(void)
{
/* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF
* Takes approx. 10.7s to timeout
*/
write_wdtcr(IOP_WDTCR_EN_ARM);
write_wdtcr(IOP_WDTCR_EN);
}
/* returns 0 if the timer was successfully disabled */
static int wdt_disable(void)
{
/* Stop Counting */
if (wdt_supports_disable()) {
write_wdtcr(IOP_WDTCR_DIS_ARM);
write_wdtcr(IOP_WDTCR_DIS);
clear_bit(WDT_ENABLED, &wdt_status);
printk(KERN_INFO "WATCHDOG: Disabled\n");
return 0;
} else
return 1;
}
static int iop_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(WDT_IN_USE, &wdt_status))
return -EBUSY;
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
wdt_enable();
set_bit(WDT_ENABLED, &wdt_status);
return nonseekable_open(inode, file);
}
static ssize_t
iop_wdt_write(struct file *file, const char *data, size_t len,
loff_t *ppos)
{
if (len) {
if (!nowayout) {
size_t i;
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
set_bit(WDT_OK_TO_CLOSE, &wdt_status);
}
}
wdt_enable();
}
return len;
}
static struct watchdog_info ident = {
.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
.identity = "iop watchdog",
};
static int
iop_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
int options;
int ret = -ENOTTY;
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user
((struct watchdog_info *)arg, &ident, sizeof ident))
ret = -EFAULT;
else
ret = 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(boot_status, (int *)arg);
break;
case WDIOC_GETTIMEOUT:
ret = put_user(iop_watchdog_timeout(), (int *)arg);
break;
case WDIOC_KEEPALIVE:
wdt_enable();
ret = 0;
break;
case WDIOC_SETOPTIONS:
if (get_user(options, (int *)arg))
return -EFAULT;
if (options & WDIOS_DISABLECARD) {
if (!nowayout) {
if (wdt_disable() == 0) {
set_bit(WDT_OK_TO_CLOSE, &wdt_status);
ret = 0;
} else
ret = -ENXIO;
} else
ret = 0;
}
if (options & WDIOS_ENABLECARD) {
wdt_enable();
ret = 0;
}
break;
}
return ret;
}
static int iop_wdt_release(struct inode *inode, struct file *file)
{
int state = 1;
if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
if (test_bit(WDT_ENABLED, &wdt_status))
state = wdt_disable();
/* if the timer is not disbaled reload and notify that we are still
* going down
*/
if (state != 0) {
wdt_enable();
printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
"reset in %lu seconds\n", iop_watchdog_timeout());
}
clear_bit(WDT_IN_USE, &wdt_status);
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
return 0;
}
static const struct file_operations iop_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = iop_wdt_write,
.ioctl = iop_wdt_ioctl,
.open = iop_wdt_open,
.release = iop_wdt_release,
};
static struct miscdevice iop_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &iop_wdt_fops,
};
static int __init iop_wdt_init(void)
{
int ret;
ret = misc_register(&iop_wdt_miscdev);
if (ret == 0)
printk("iop watchdog timer: timeout %lu sec\n",
iop_watchdog_timeout());
/* check if the reset was caused by the watchdog timer */
boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0;
/* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset
* NOTE: An IB Reset will Reset both cores in the IOP342
*/
write_wdtsr(IOP13XX_WDTCR_IB_RESET);
return ret;
}
static void __exit iop_wdt_exit(void)
{
misc_deregister(&iop_wdt_miscdev);
}
module_init(iop_wdt_init);
module_exit(iop_wdt_exit);
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>");
MODULE_DESCRIPTION("iop watchdog timer driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
