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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/moduleparam.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 <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

static unsigned int soft_margin = 60;           /* in seconds */

static unsigned int reload;

static unsigned long timer_alive;

#ifdef ONLY_TESTING

/*

 *      If the timer expires..

 */

static void watchdog_fire(int irq, void *dev_id)

{

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

        *CSR_TIMER4_CNTL = 0;

        *CSR_TIMER4_CLR = 0;

}

#endif

/*

 *      Refresh the timer.

 */

static void watchdog_ping(void)

{

        *CSR_TIMER4_LOAD = reload;

}

/*

 *      Allow only one person to hold it open

 */

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

{

        int ret;

        if (*CSR_SA110_CNTL & (1 << 13))

                return -EBUSY;

        if (test_and_set_bit(1, &timer_alive))

                return -EBUSY;

        reload = soft_margin * (mem_fclk_21285 / 256);

        *CSR_TIMER4_CLR = 0;

        watchdog_ping();

        *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD

                | TIMER_CNTL_DIV256;

#ifdef ONLY_TESTING

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

        if (ret) {

                *CSR_TIMER4_CNTL = 0;

                clear_bit(1, &timer_alive);

        }

#else

        /*

         * Setting this bit is irreversible; once enabled, there is

         * no way to disable the watchdog.

         */

        *CSR_SA110_CNTL |= 1 << 13;

        ret = 0;

#endif

        nonseekable_open(inode, file);

        return ret;

}

/*

 *      Shut off the timer.

 *      Note: if we really have enabled the watchdog, there

 *      is no way to turn off.

 */

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

{

#ifdef ONLY_TESTING

        free_irq(IRQ_TIMER4, NULL);

        clear_bit(1, &timer_alive);

#endif

        return 0;

}

static ssize_t

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

{

        /*

         *      Refresh the timer.

         */

        if (len)

                watchdog_ping();

        return len;

}

static struct watchdog_info ident = {

        .options        = WDIOF_SETTIMEOUT,

        .identity       = "Footbridge Watchdog",

};

static int

watchdog_ioctl(struct inode *inode, struct file *file, unsigned int cmd,

               unsigned long arg)

{

        unsigned int new_margin;

        int ret = -ENOTTY;

        switch(cmd) {

        case WDIOC_GETSUPPORT:

                ret = 0;

                if (copy_to_user((void *)arg, &ident, sizeof(ident)))

                        ret = -EFAULT;

                break;

        case WDIOC_GETSTATUS:

        case WDIOC_GETBOOTSTATUS:

                ret = put_user(0,(int *)arg);

                break;

        case WDIOC_KEEPALIVE:

                watchdog_ping();

                ret = 0;

                break;

        case WDIOC_SETTIMEOUT:

                ret = get_user(new_margin, (int *)arg);

                if (ret)

                        break;

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

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

                        ret = -EINVAL;

                        break;

                }

                soft_margin = new_margin;

                reload = soft_margin * (mem_fclk_21285 / 256);

                watchdog_ping();

                /* Fall */

        case WDIOC_GETTIMEOUT:

                ret = put_user(soft_margin, (int *)arg);

                break;

        }

        return ret;

}

static const struct file_operations watchdog_fops = {

        .owner          = THIS_MODULE,

        .llseek         = no_llseek,

        .write          = watchdog_write,

        .ioctl          = watchdog_ioctl,

        .open           = watchdog_open,

        .release        = watchdog_release,

};

static struct miscdevice watchdog_miscdev = {

        .minor          = WATCHDOG_MINOR,

        .name           = "watchdog",

        .fops           = &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);

}

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

MODULE_DESCRIPTION("Footbridge watchdog driver");

MODULE_LICENSE("GPL");

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

module_param(soft_margin, int, 0);

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

module_init(footbridge_watchdog_init);

module_exit(footbridge_watchdog_exit);