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/*

 *      Advantech Single Board Computer WDT driver

 *

 *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>

 *

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

 *      Original copyright messages:

 *

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

 *                              http://www.redhat.com

 *

 *      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@redhat.com>

 *

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

 *          Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT

 *

 *      16-Oct-2002 Rob Radez <rob@osinvestor.com>

 *          Clean up ioctls, clean up init + exit, add expect close support,

 *          add wdt_start and wdt_stop as parameters.

 */

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/types.h>

#include <linux/miscdevice.h>

#include <linux/watchdog.h>

#include <linux/fs.h>

#include <linux/ioport.h>

#include <linux/platform_device.h>

#include <linux/init.h>

#include <asm/io.h>

#include <asm/uaccess.h>

#include <asm/system.h>

#define DRV_NAME "advantechwdt"

#define PFX DRV_NAME ": "

#define WATCHDOG_NAME "Advantech WDT"

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

static struct platform_device *advwdt_platform_device;  /* the watchdog platform device */

static unsigned long advwdt_is_open;

static char adv_expect_close;

/*

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

 *

 *      To enable or restart, write the timeout value in seconds (1 to 63)

 *      to I/O port wdt_start.  To disable, read I/O port wdt_stop.

 *      Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but

 *      check your manual (at least the PCA-6159 seems to be different -

 *      the manual says wdt_stop is 0x43, not 0x443).

 *      (0x43 is also a write-only control register for the 8254 timer!)

 */

static int wdt_stop = 0x443;

module_param(wdt_stop, int, 0);

MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");

static int wdt_start = 0x443;

module_param(wdt_start, int, 0);

MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");

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

module_param(timeout, int, 0);

MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=63, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");

static int nowayout = WATCHDOG_NOWAYOUT;

module_param(nowayout, int, 0);

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

/*

 *      Watchdog Operations

 */

static void

advwdt_ping(void)

{

        /* Write a watchdog value */

        outb_p(timeout, wdt_start);

}

static void

advwdt_disable(void)

{

        inb_p(wdt_stop);

}

static int

advwdt_set_heartbeat(int t)

{

        if ((t < 1) || (t > 63))

                return -EINVAL;

        timeout = t;

        return 0;

}

/*

 *      /dev/watchdog handling

 */

static ssize_t

advwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)

{

        if (count) {

                if (!nowayout) {

                        size_t i;

                        adv_expect_close = 0;

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

                                char c;

                                if (get_user(c, buf+i))

                                        return -EFAULT;

                                if (c == 'V')

                                        adv_expect_close = 42;

                        }

                }

                advwdt_ping();

        }

        return count;

}

static int

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

          unsigned long arg)

{

        int new_timeout;

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

        int __user *p = argp;

        static struct watchdog_info ident = {

                .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,

                .firmware_version = 1,

                .identity = WATCHDOG_NAME,

        };

        switch (cmd) {

        case WDIOC_GETSUPPORT:

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

            return -EFAULT;

          break;

        case WDIOC_GETSTATUS:

        case WDIOC_GETBOOTSTATUS:

          return put_user(0, p);

        case WDIOC_KEEPALIVE:

          advwdt_ping();

          break;

        case WDIOC_SETTIMEOUT:

          if (get_user(new_timeout, p))

                  return -EFAULT;

          if (advwdt_set_heartbeat(new_timeout))

                  return -EINVAL;

          advwdt_ping();

          /* Fall */

        case WDIOC_GETTIMEOUT:

          return put_user(timeout, p);

        case WDIOC_SETOPTIONS:

        {

          int options, retval = -EINVAL;

          if (get_user(options, p))

            return -EFAULT;

          if (options & WDIOS_DISABLECARD) {

            advwdt_disable();

            retval = 0;

          }

          if (options & WDIOS_ENABLECARD) {

            advwdt_ping();

            retval = 0;

          }

          return retval;

        }

        default:

          return -ENOTTY;

        }

        return 0;

}

static int

advwdt_open(struct inode *inode, struct file *file)

{

        if (test_and_set_bit(0, &advwdt_is_open))

                return -EBUSY;

        /*

         *      Activate

         */

        advwdt_ping();

        return nonseekable_open(inode, file);

}

static int

advwdt_close(struct inode *inode, struct file *file)

{

        if (adv_expect_close == 42) {

                advwdt_disable();

        } else {

                printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");

                advwdt_ping();

        }

        clear_bit(0, &advwdt_is_open);

        adv_expect_close = 0;

        return 0;

}

/*

 *      Kernel Interfaces

 */

static const struct file_operations advwdt_fops = {

        .owner          = THIS_MODULE,

        .llseek         = no_llseek,

        .write          = advwdt_write,

        .ioctl          = advwdt_ioctl,

        .open           = advwdt_open,

        .release        = advwdt_close,

};

static struct miscdevice advwdt_miscdev = {

        .minor  = WATCHDOG_MINOR,

        .name   = "watchdog",

        .fops   = &advwdt_fops,

};

/*

 *      Init & exit routines

 */

static int __devinit

advwdt_probe(struct platform_device *dev)

{

        int ret;

        if (wdt_stop != wdt_start) {

                if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {

                        printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",

                                wdt_stop);

                        ret = -EIO;

                        goto out;

                }

        }

        if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {

                printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",

                        wdt_start);

                ret = -EIO;

                goto unreg_stop;

        }

        /* Check that the heartbeat value is within it's range ; if not reset to the default */

        if (advwdt_set_heartbeat(timeout)) {

                advwdt_set_heartbeat(WATCHDOG_TIMEOUT);

                printk (KERN_INFO PFX "timeout value must be 1<=x<=63, using %d\n",

                        timeout);

        }

        ret = misc_register(&advwdt_miscdev);

        if (ret != 0) {

                printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",

                        WATCHDOG_MINOR, ret);

                goto unreg_regions;

        }

        printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",

                timeout, nowayout);

out:

        return ret;

unreg_regions:

        release_region(wdt_start, 1);

unreg_stop:

        if (wdt_stop != wdt_start)

                release_region(wdt_stop, 1);

        goto out;

}

static int __devexit

advwdt_remove(struct platform_device *dev)

{

        misc_deregister(&advwdt_miscdev);

        release_region(wdt_start,1);

        if(wdt_stop != wdt_start)

                release_region(wdt_stop,1);

        return 0;

}

static void

advwdt_shutdown(struct platform_device *dev)

{

        /* Turn the WDT off if we have a soft shutdown */

        advwdt_disable();

}

static struct platform_driver advwdt_driver = {

        .probe          = advwdt_probe,

        .remove         = __devexit_p(advwdt_remove),

        .shutdown       = advwdt_shutdown,

        .driver         = {

                .owner  = THIS_MODULE,

                .name   = DRV_NAME,

        },

};

static int __init

advwdt_init(void)

{

        int err;

        printk(KERN_INFO "WDT driver for Advantech single board computer initialising.\n");

        err = platform_driver_register(&advwdt_driver);

        if (err)

                return err;

        advwdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);

        if (IS_ERR(advwdt_platform_device)) {

                err = PTR_ERR(advwdt_platform_device);

                goto unreg_platform_driver;

        }

        return 0;

unreg_platform_driver:

        platform_driver_unregister(&advwdt_driver);

        return err;

}

static void __exit

advwdt_exit(void)

{

        platform_device_unregister(advwdt_platform_device);

        platform_driver_unregister(&advwdt_driver);

        printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");

}

module_init(advwdt_init);

module_exit(advwdt_exit);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");

MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);