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/*

 *      Driver for the MTX-1 Watchdog.

 *

 *      (C) Copyright 2005 4G Systems <info@4g-systems.biz>, All Rights Reserved.

 *                              http://www.4g-systems.biz

 *

 *      (C) Copyright 2007 OpenWrt.org, Florian Fainelli <florian@openwrt.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.

 *

 *      Neither Michael Stickel nor 4G Systems admit liability nor provide

 *      warranty for any of this software. This material is provided

 *      "AS-IS" and at no charge.

 *

 *      (c) Copyright 2005    4G Systems <info@4g-systems.biz>

 *

 *      Release 0.01.

 *      Author: Michael Stickel  michael.stickel@4g-systems.biz

 *

 *      Release 0.02.

 *      Author: Florian Fainelli florian@openwrt.org

 *              use the Linux watchdog/timer APIs

 *

 *      The Watchdog is configured to reset the MTX-1

 *      if it is not triggered for 100 seconds.

 *      It should not be triggered more often than 1.6 seconds.

 *

 *      A timer triggers the watchdog every 5 seconds, until

 *      it is opened for the first time. After the first open

 *      it MUST be triggered every 2..95 seconds.

 */

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/types.h>

#include <linux/errno.h>

#include <linux/miscdevice.h>

#include <linux/fs.h>

#include <linux/init.h>

#include <linux/ioport.h>

#include <linux/timer.h>

#include <linux/completion.h>

#include <linux/jiffies.h>

#include <linux/watchdog.h>

#include <asm/io.h>

#include <asm/uaccess.h>

#include <asm/mach-au1x00/au1000.h>

#define MTX1_WDT_INTERVAL       (5 * HZ)

static int ticks = 100 * HZ;

static struct {

        struct completion stop;

        volatile int running;

        struct timer_list timer;

        volatile int queue;

        int default_ticks;

        unsigned long inuse;

} mtx1_wdt_device;

static void mtx1_wdt_trigger(unsigned long unused)

{

        u32 tmp;

        if (mtx1_wdt_device.running)

                ticks--;

        /*

         * toggle GPIO2_15

         */

        tmp = au_readl(GPIO2_DIR);

        tmp = (tmp & ~(1<<15)) | ((~tmp) & (1<<15));

        au_writel (tmp, GPIO2_DIR);

        if (mtx1_wdt_device.queue && ticks)

                mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);

        else {

                complete(&mtx1_wdt_device.stop);

        }

}

static void mtx1_wdt_reset(void)

{

        ticks = mtx1_wdt_device.default_ticks;

}

static void mtx1_wdt_start(void)

{

        if (!mtx1_wdt_device.queue) {

                mtx1_wdt_device.queue = 1;

                au_writel (au_readl(GPIO2_DIR) | (u32)(1<<15), GPIO2_DIR);

                mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);

        }

        mtx1_wdt_device.running++;

}

static int mtx1_wdt_stop(void)

{

        if (mtx1_wdt_device.queue) {

                mtx1_wdt_device.queue = 0;

                au_writel (au_readl(GPIO2_DIR) & ~((u32)(1<<15)), GPIO2_DIR);

        }

        ticks = mtx1_wdt_device.default_ticks;

        return 0;

}

/* Filesystem functions */

static int mtx1_wdt_open(struct inode *inode, struct file *file)

{

        if (test_and_set_bit(0, &mtx1_wdt_device.inuse))

                return -EBUSY;

        return nonseekable_open(inode, file);

}

static int mtx1_wdt_release(struct inode *inode, struct file *file)

{

        clear_bit(0, &mtx1_wdt_device.inuse);

        return 0;

}

static int mtx1_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)

{

        void __user *argp = (void __user *)arg;

        unsigned int value;

        static struct watchdog_info ident =

        {

                .options = WDIOF_CARDRESET,

                .identity = "MTX-1 WDT",

        };

        switch(cmd) {

                case WDIOC_KEEPALIVE:

                        mtx1_wdt_reset();

                        break;

                case WDIOC_GETSTATUS:

                case WDIOC_GETBOOTSTATUS:

                        if ( copy_to_user(argp, &value, sizeof(int)) )

                                return -EFAULT;

                        break;

                case WDIOC_GETSUPPORT:

                        if ( copy_to_user(argp, &ident, sizeof(ident)) )

                                return -EFAULT;

                        break;

                case WDIOC_SETOPTIONS:

                        if ( copy_from_user(&value, argp, sizeof(int)) )

                                return -EFAULT;

                        switch(value) {

                                case WDIOS_ENABLECARD:

                                        mtx1_wdt_start();

                                        break;

                                case WDIOS_DISABLECARD:

                                        return mtx1_wdt_stop();

                                default:

                                        return -EINVAL;

                        }

                        break;

                default:

                        return -ENOTTY;

        }

        return 0;

}

static ssize_t mtx1_wdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos)

{

        if (!count)

                return -EIO;

        mtx1_wdt_reset();

        return count;

}

static struct file_operations mtx1_wdt_fops = {

        .owner          = THIS_MODULE,

        .llseek         = no_llseek,

        .ioctl          = mtx1_wdt_ioctl,

        .open           = mtx1_wdt_open,

        .write          = mtx1_wdt_write,

        .release        = mtx1_wdt_release

};

static struct miscdevice mtx1_wdt_misc = {

        .minor  = WATCHDOG_MINOR,

        .name   = "watchdog",

        .fops   = &mtx1_wdt_fops

};

static int __init mtx1_wdt_init(void)

{

        int ret;

        if ((ret = misc_register(&mtx1_wdt_misc)) < 0) {

                printk(KERN_ERR " mtx-1_wdt : failed to register\n");

                return ret;

        }

        init_completion(&mtx1_wdt_device.stop);

        mtx1_wdt_device.queue = 0;

        clear_bit(0, &mtx1_wdt_device.inuse);

        setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);

        mtx1_wdt_device.default_ticks = ticks;

        mtx1_wdt_start();

        printk(KERN_INFO "MTX-1 Watchdog driver\n");

        return 0;

}

static void __exit mtx1_wdt_exit(void)

{

        if (mtx1_wdt_device.queue) {

                mtx1_wdt_device.queue = 0;

                wait_for_completion(&mtx1_wdt_device.stop);

        }

        misc_deregister(&mtx1_wdt_misc);

}

module_init(mtx1_wdt_init);

module_exit(mtx1_wdt_exit);

MODULE_AUTHOR("Michael Stickel, Florian Fainelli");

MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");

MODULE_LICENSE("GPL");