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/*

 *      Wdt977  0.02:   A Watchdog Device for Netwinder W83977AF chip

 *

 *      (c) Copyright 1998 Rebel.com (Woody Suwalski <woody@netwinder.org>)

 *

 *                      -----------------------

 *

 *      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.

 *

 *                      -----------------------

 *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>

 *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT

 */

#include <linux/module.h>

#include <linux/config.h>

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/fs.h>

#include <linux/miscdevice.h>

#include <linux/init.h>

#include <linux/smp_lock.h>

#include <asm/io.h>

#include <asm/system.h>

#include <asm/mach-types.h>

#define WATCHDOG_MINOR  130

static  int timeout = 3;

static  int timer_alive;

static  int testmode;

static  int expect_close = 0;

#ifdef CONFIG_WATCHDOG_NOWAYOUT

static int nowayout = 1;

#else

static int nowayout = 0;

#endif

MODULE_PARM(nowayout,"i");

MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");

/*

 *      Allow only one person to hold it open

 */

static int wdt977_open(struct inode *inode, struct file *file)

{

        if(timer_alive)

                return -EBUSY;

        if (nowayout) {

                MOD_INC_USE_COUNT;

        }

        timer_alive++;

        //max timeout value = 255 minutes (0xFF). Write 0 to disable WatchDog.

        if (timeout>255)

            timeout = 255;

        printk(KERN_INFO "Watchdog: active, current timeout %d min.\n",timeout);

        // unlock the SuperIO chip

        outb(0x87,0x370);

        outb(0x87,0x370);

        //select device Aux2 (device=8) and set watchdog regs F2, F3 and F4

        //F2 has the timeout in minutes

        //F3 could be set to the POWER LED blink (with GP17 set to PowerLed)

        //   at timeout, and to reset timer on kbd/mouse activity (not now)

        //F4 is used to just clear the TIMEOUT'ed state (bit 0)

        outb(0x07,0x370);

        outb(0x08,0x371);

        outb(0xF2,0x370);

        outb(timeout,0x371);

        outb(0xF3,0x370);

        outb(0x00,0x371);       //another setting is 0E for kbd/mouse/LED

        outb(0xF4,0x370);

        outb(0x00,0x371);

        //at last select device Aux1 (dev=7) and set GP16 as a watchdog output

        if (!testmode)

        {

                outb(0x07,0x370);

                outb(0x07,0x371);

                outb(0xE6,0x370);

                outb(0x08,0x371);

        }

        // lock the SuperIO chip

        outb(0xAA,0x370);

        return 0;

}

static int wdt977_release(struct inode *inode, struct file *file)

{

        /*

         *      Shut off the timer.

         *      Lock it in if it's a module and we set nowayout

         */

        lock_kernel();

        if (expect_close) {

                // unlock the SuperIO chip

                outb(0x87,0x370);

                outb(0x87,0x370);

                //select device Aux2 (device=8) and set watchdog regs F2,F3 and F4

                //F3 is reset to its default state

                //F4 can clear the TIMEOUT'ed state (bit 0) - back to default

                //We can not use GP17 as a PowerLed, as we use its usage as a RedLed

                outb(0x07,0x370);

                outb(0x08,0x371);

                outb(0xF2,0x370);

                outb(0xFF,0x371);

                outb(0xF3,0x370);

                outb(0x00,0x371);

                outb(0xF4,0x370);

                outb(0x00,0x371);

                outb(0xF2,0x370);

                outb(0x00,0x371);

                //at last select device Aux1 (dev=7) and set GP16 as a watchdog output

                outb(0x07,0x370);

                outb(0x07,0x371);

                outb(0xE6,0x370);

                outb(0x08,0x371);

                // lock the SuperIO chip

                outb(0xAA,0x370);

                printk(KERN_INFO "Watchdog: shutdown.\n");

        } else {

                printk(KERN_CRIT "WDT device closed unexpectedly.  WDT will not stop!\n");

        }

        timer_alive=0;

        unlock_kernel();

        return 0;

}

static ssize_t wdt977_write(struct file *file, const char *data, size_t len, loff_t *ppos)

{

        if (!nowayout) {

                size_t i;

                /* In case it was set long ago */

                expect_close = 0;

                for (i = 0; i != len; i++) {

                        char c;

                        if (get_user(c, data + i))

                                return -EFAULT;

                        if (c == 'V')

                                expect_close = 1;

                }

        }

        //max timeout value = 255 minutes (0xFF). Write 0 to disable WatchDog.

        if (timeout>255)

            timeout = 255;

        /*

         *      Refresh the timer.

         */

        //we have a hw bug somewhere, so each 977 minute is actually only 30sec

        //as such limit the max timeout to half of max of 255 minutes...

//      if (timeout>126)

//          timeout = 126;

        // unlock the SuperIO chip

        outb(0x87,0x370);

        outb(0x87,0x370);

        //select device Aux2 (device=8) and kicks watchdog reg F2

        //F2 has the timeout in minutes

        outb(0x07,0x370);

        outb(0x08,0x371);

        outb(0xF2,0x370);

        outb(timeout,0x371);

        // lock the SuperIO chip

        outb(0xAA,0x370);

        return 1;

}

static struct file_operations wdt977_fops=

{

        owner:          THIS_MODULE,

        write:          wdt977_write,

        open:           wdt977_open,

        release:        wdt977_release,

};

static struct miscdevice wdt977_miscdev=

{

        WATCHDOG_MINOR,

        "watchdog",

        &wdt977_fops

};

static int __init nwwatchdog_init(void)

{

        if (!machine_is_netwinder())

                return -ENODEV;

        misc_register(&wdt977_miscdev);

        printk(KERN_INFO "NetWinder Watchdog sleeping.\n");

        return 0;

}

static void __exit nwwatchdog_exit(void)

{

        misc_deregister(&wdt977_miscdev);

}

EXPORT_NO_SYMBOLS;

module_init(nwwatchdog_init);

module_exit(nwwatchdog_exit);

MODULE_LICENSE("GPL");