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/*
* drivers/char/watchdog/ixp2000_wdt.c
*
* Watchdog driver for Intel IXP2000 network processors
*
* Adapted from the IXP4xx watchdog driver by Lennert Buytenhek.
* The original version carries these notices:
*
* Author: Deepak Saxena <dsaxena@plexity.net>
*
* Copyright 2004 (c) MontaVista, Software, Inc.
* Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <mach/hardware.h>
static bool nowayout = WATCHDOG_NOWAYOUT;
static unsigned int heartbeat = 60; /* (secs) Default is 1 minute */
static unsigned long wdt_status;
static DEFINE_SPINLOCK(wdt_lock);
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
static unsigned long wdt_tick_rate;
static void wdt_enable(void)
{
spin_lock(&wdt_lock);
ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) | WDT_RESET_ENABLE);
ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 | TIMER_ENABLE);
spin_unlock(&wdt_lock);
}
static void wdt_disable(void)
{
spin_lock(&wdt_lock);
ixp2000_reg_write(IXP2000_T4_CTL, 0);
spin_unlock(&wdt_lock);
}
static void wdt_keepalive(void)
{
spin_lock(&wdt_lock);
ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
spin_unlock(&wdt_lock);
}
static int ixp2000_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();
return nonseekable_open(inode, file);
}
static ssize_t ixp2000_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_keepalive();
}
return len;
}
static const struct watchdog_info ident = {
.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING,
.identity = "IXP2000 Watchdog",
};
static long ixp2000_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int ret = -ENOTTY;
int time;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user((struct watchdog_info *)arg, &ident,
sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_KEEPALIVE:
wdt_enable();
ret = 0;
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, (int *)arg);
if (ret)
break;
if (time <= 0 || time > 60) {
ret = -EINVAL;
break;
}
heartbeat = time;
wdt_keepalive();
/* Fall through */
case WDIOC_GETTIMEOUT:
ret = put_user(heartbeat, (int *)arg);
break;
}
return ret;
}
static int ixp2000_wdt_release(struct inode *inode, struct file *file)
{
if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
wdt_disable();
else
pr_crit("Device closed unexpectedly - timer will not stop\n");
clear_bit(WDT_IN_USE, &wdt_status);
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
return 0;
}
static const struct file_operations ixp2000_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = ixp2000_wdt_write,
.unlocked_ioctl = ixp2000_wdt_ioctl,
.open = ixp2000_wdt_open,
.release = ixp2000_wdt_release,
};
static struct miscdevice ixp2000_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &ixp2000_wdt_fops,
};
static int __init ixp2000_wdt_init(void)
{
if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
pr_info("Unable to use IXP2000 watchdog due to IXP2800 erratum #25\n");
return -EIO;
}
wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256;
return misc_register(&ixp2000_wdt_miscdev);
}
static void __exit ixp2000_wdt_exit(void)
{
misc_deregister(&ixp2000_wdt_miscdev);
}
module_init(ixp2000_wdt_init);
module_exit(ixp2000_wdt_exit);
MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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