linux-imx

/*

 *  ICP Wafer 5823 Single Board Computer WDT driver

 *  http://www.icpamerica.com/wafer_5823.php

 *  May also work on other similar models

 *

 *  (c) Copyright 2002 Justin Cormack <justin@street-vision.com>

 *

 *  Release 0.02

 *

 *  Based on advantechwdt.c which is based on wdt.c.

 *  Original copyright messages:

 *

 *  (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,

 *                      All Rights Reserved.

 *

 *  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@lxorguk.ukuu.org.uk>

 *

 */

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/module.h>

#include <linux/moduleparam.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 "Wafer 5823 WDT"

#define PFX WATCHDOG_NAME ": "

#define WD_TIMO 60          /* 60 sec default timeout */

​

static unsigned long wafwdt_is_open;

static char expect_close;

static DEFINE_SPINLOCK(wafwdt_lock);

​

/*

 *  You must set these - there is no sane way to probe for this board.

 *

 *  To enable, write the timeout value in seconds (1 to 255) to I/O

 *  port WDT_START, then read the port to start the watchdog. To pat

 *  the dog, read port WDT_STOP to stop the timer, then read WDT_START

 *  to restart it again.

 */

​

static int wdt_stop = 0x843;

static int wdt_start = 0x443;

​

static int timeout = WD_TIMO;  /* in seconds */

module_param(timeout, int, 0);

MODULE_PARM_DESC(timeout,

        "Watchdog timeout in seconds. 1 <= timeout <= 255, default="

                __MODULE_STRING(WD_TIMO) ".");

​

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) ")");

​

static void wafwdt_ping(void)

{

    /* pat watchdog */

    spin_lock(&wafwdt_lock);

    inb_p(wdt_stop);

    inb_p(wdt_start);

    spin_unlock(&wafwdt_lock);

}

​

static void wafwdt_start(void)

{

    /* start up watchdog */

    outb_p(timeout, wdt_start);

    inb_p(wdt_start);

}

​

static void wafwdt_stop(void)