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/*
* Driver for the Atheros AR71xx SoC's built-in hardware watchdog timer.
*
* Copyright (C) 2008 Gabor Juhos <juhosg@openwrt.org>
* Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
*
* This driver was based on: drivers/watchdog/ixp4xx_wdt.c
* Author: Deepak Saxena <dsaxena@plexity.net>
* Copyright 2004 (c) MontaVista, Software, Inc.
*
* which again was based on sa1100 driver,
* Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
*/
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <asm/mach-ar71xx/ar71xx.h>
#define DRV_NAME "ar71xx-wdt"
#define DRV_DESC "Atheros AR71xx hardware watchdog driver"
#define DRV_VERSION "0.1.0"
#define WDT_TIMEOUT 15 /* seconds */
static int nowayout = WATCHDOG_NOWAYOUT;
#ifdef CONFIG_WATCHDOG_NOWAYOUT
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
#endif
static unsigned long wdt_flags;
#define WDT_FLAGS_BUSY 0
#define WDT_FLAGS_EXPECT_CLOSE 1
static int wdt_timeout = WDT_TIMEOUT;
static int boot_status;
static int max_timeout;
static void inline ar71xx_wdt_keepalive(void)
{
ar71xx_reset_wr(AR71XX_RESET_REG_WDOG, ar71xx_ahb_freq * wdt_timeout);
}
static void inline ar71xx_wdt_enable(void)
{
printk(KERN_DEBUG DRV_NAME ": enabling watchdog timer\n");
ar71xx_wdt_keepalive();
ar71xx_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR);
}
static void inline ar71xx_wdt_disable(void)
{
printk(KERN_DEBUG DRV_NAME ": disabling watchdog timer\n");
ar71xx_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE);
}
static int ar71xx_wdt_set_timeout(int val)
{
if (val < 1 || val > max_timeout)
return -EINVAL;
wdt_timeout = val;
ar71xx_wdt_keepalive();
printk(KERN_DEBUG DRV_NAME ": timeout=%d secs\n", wdt_timeout);
return 0;
}
static int ar71xx_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
return -EBUSY;
clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
ar71xx_wdt_enable();
return nonseekable_open(inode, file);
}
static int ar71xx_wdt_release(struct inode *inode, struct file *file)
{
if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags)) {
ar71xx_wdt_disable();
} else {
printk(KERN_CRIT DRV_NAME ": device closed unexpectedly, "
"watchdog timer will not stop!\n");
}
clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
return 0;
}
static ssize_t ar71xx_wdt_write(struct file *file, const char *data,
size_t len, loff_t *ppos)
{
if (len) {
if (!nowayout) {
size_t i;
clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
set_bit(WDT_FLAGS_EXPECT_CLOSE,
&wdt_flags);
}
}
ar71xx_wdt_keepalive();
}
return len;
}
static struct watchdog_info ar71xx_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
.firmware_version = 0,
.identity = "AR71XX watchdog",
};
static int ar71xx_wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int t;
int ret;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user((struct watchdog_info *)arg,
&ar71xx_wdt_info,
sizeof(&ar71xx_wdt_info)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, (int *)arg) ? -EFAULT : 0;
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(boot_status, (int *)arg) ? -EFAULT : 0;
break;
case WDIOC_KEEPALIVE:
ar71xx_wdt_keepalive();
ret = 0;
break;
case WDIOC_SETTIMEOUT:
ret = get_user(t, (int *)arg) ? -EFAULT : 0;
if (ret)
break;
ret = ar71xx_wdt_set_timeout(t);
if (ret)
break;
/* fallthrough */
case WDIOC_GETTIMEOUT:
ret = put_user(wdt_timeout, (int *)arg) ? -EFAULT : 0;
break;
default:
ret = -ENOTTY;
break;
}
return ret;
}
static const struct file_operations ar71xx_wdt_fops = {
.owner = THIS_MODULE,
.write = ar71xx_wdt_write,
.ioctl = ar71xx_wdt_ioctl,
.open = ar71xx_wdt_open,
.release = ar71xx_wdt_release,
};
static struct miscdevice ar71xx_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &ar71xx_wdt_fops,
};
static int __devinit ar71xx_wdt_probe(struct platform_device *pdev)
{
int ret;
max_timeout = (0xfffffffful / ar71xx_ahb_freq);
wdt_timeout = (max_timeout < WDT_TIMEOUT) ? max_timeout : WDT_TIMEOUT;
boot_status =
(ar71xx_reset_rr(AR71XX_RESET_REG_WDOG_CTRL) & WDOG_CTRL_LAST_RESET) ?
WDIOF_CARDRESET : 0;
ret = misc_register(&ar71xx_wdt_miscdev);
if (ret)
goto err_out;
printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
printk(KERN_DEBUG DRV_NAME ": timeout=%d secs (max=%d)\n",
wdt_timeout, max_timeout);
return 0;
err_out:
return ret;
}
static int __devexit ar71xx_wdt_remove(struct platform_device *pdev)
{
misc_deregister(&ar71xx_wdt_miscdev);
return 0;
}
static struct platform_driver ar71xx_wdt_driver = {
.probe = ar71xx_wdt_probe,
.remove = __devexit_p(ar71xx_wdt_remove),
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
},
};
static int __init ar71xx_wdt_init(void)
{
return platform_driver_register(&ar71xx_wdt_driver);
}
module_init(ar71xx_wdt_init);
static void __exit ar71xx_wdt_exit(void)
{
platform_driver_unregister(&ar71xx_wdt_driver);
}
module_exit(ar71xx_wdt_exit);
MODULE_DESCRIPTION(DRV_DESC);
MODULE_VERSION(DRV_VERSION);
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRV_NAME);
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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