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/*

 *      Intel 21285 watchdog driver

 *      Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998

 *

 *      based on

 *

 *      SoftDog 0.05:   A Software Watchdog Device

 *

 *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, 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.

 *

 */

#include <linux/module.h>

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/fs.h>

#include <linux/mm.h>

#include <linux/miscdevice.h>

#include <linux/watchdog.h>

#include <linux/reboot.h>

#include <linux/init.h>

#include <linux/interrupt.h>

#include <linux/smp_lock.h>

#include <asm/irq.h>

#include <asm/uaccess.h>

#include <asm/hardware.h>

#include <asm/mach-types.h>

#include <asm/hardware/dec21285.h>

/*

 * Define this to stop the watchdog actually rebooting the machine.

 */

#undef ONLY_TESTING

#define TIMER_MARGIN    60              /* (secs) Default is 1 minute */

#define FCLK    (50*1000*1000)          /* 50MHz */

static int soft_margin = TIMER_MARGIN;  /* in seconds */

static int timer_alive;

#ifdef ONLY_TESTING

/*

 *      If the timer expires..

 */

static void watchdog_fire(int irq, void *dev_id, struct pt_regs *regs)

{

        printk(KERN_CRIT "Watchdog: Would Reboot.\n");

        *CSR_TIMER4_CNTL = 0;

        *CSR_TIMER4_CLR = 0;

}

#endif

static void watchdog_ping(void)

{

        /*

         *      Refresh the timer.

         */

        *CSR_TIMER4_LOAD = soft_margin * (FCLK / 256);

}

/*

 *      Allow only one person to hold it open

 */

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

{

        if(timer_alive)

                return -EBUSY;

        /*

         *      Ahead watchdog factor ten, Mr Sulu

         */

        *CSR_TIMER4_CLR = 0;

        watchdog_ping();

        *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD

                | TIMER_CNTL_DIV256;

#ifdef ONLY_TESTING

        request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);

#else

        *CSR_SA110_CNTL |= 1 << 13;

        MOD_INC_USE_COUNT;

#endif

        timer_alive = 1;

        return 0;

}

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

{

#ifdef ONLY_TESTING

        lock_kernel();

        free_irq(IRQ_TIMER4, NULL);

        timer_alive = 0;

        unlock_kernel();

#else

        /*

         *      It's irreversible!

         */

#endif

        return 0;

}

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

{

        /*  Can't seek (pwrite) on this device  */

        if (ppos != &file->f_pos)

                return -ESPIPE;

        /*

         *      Refresh the timer.

         */

        if(len)

        {

                watchdog_ping();

                return 1;

        }

        return 0;

}

static int watchdog_ioctl(struct inode *inode, struct file *file,

        unsigned int cmd, unsigned long arg)

{

        int i, new_margin;

        static struct watchdog_info ident=

        {

                WDIOF_SETTIMEOUT,

                0,

                "Footbridge Watchdog"

        };

        switch(cmd)

        {

                default:

                        return -ENOTTY;

                case WDIOC_GETSUPPORT:

                        if(copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)))

                                return -EFAULT;

                        return 0;

                case WDIOC_GETSTATUS:

                case WDIOC_GETBOOTSTATUS:

                        return put_user(0,(int *)arg);

                case WDIOC_KEEPALIVE:

                        watchdog_ping();

                        return 0;

                case WDIOC_SETTIMEOUT:

                        if (get_user(new_margin, (int *)arg))

                                return -EFAULT;

                        /* Arbitrary, can't find the card's limits */

                        if ((new_marg < 0) || (new_margin > 60))

                                return -EINVAL;

                        soft_margin = new_margin;

                        watchdog_ping();

                        /* Fall */

                case WDIOC_GETTIMEOUT:

                        return put_user(soft_margin, (int *)arg);

        }

}

static struct file_operations watchdog_fops=

{

        owner:          THIS_MODULE,

        write:          watchdog_write,

        ioctl:          watchdog_ioctl,

        open:           watchdog_open,

        release:        watchdog_release,

};

static struct miscdevice watchdog_miscdev=

{

        WATCHDOG_MINOR,

        "watchdog",

        &watchdog_fops

};

static int __init footbridge_watchdog_init(void)

{

        int retval;

        if (machine_is_netwinder())

                return -ENODEV;

        retval = misc_register(&watchdog_miscdev);

        if(retval < 0)

                return retval;

        printk("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",

               soft_margin);

        if (machine_is_cats())

                printk("Warning: Watchdog reset may not work on this machine.\n");

        return 0;

}

static void __exit footbridge_watchdog_exit(void)

{

        misc_deregister(&watchdog_miscdev);

}

EXPORT_NO_SYMBOLS;

MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");

MODULE_DESCRIPTION("21285 watchdog driver");

MODULE_LICENSE("GPL");

MODULE_PARM(soft_margin,"i");

MODULE_PARM_DESC(soft_margin,"Watchdog timeout in seconds");

module_init(footbridge_watchdog_init);

module_exit(footbridge_watchdog_exit);