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/*

 * mpc8xx_wdt.c - MPC8xx watchdog userspace interface

 *

 * Copyright (C) 2002 Florian Schirmer <jolt@tuxbox.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.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 *

 */

#include <linux/config.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/miscdevice.h>

#include <linux/module.h>

#include <linux/watchdog.h>

#include <asm/8xx_immap.h>

#include <asm/uaccess.h>

extern int m8xx_wdt_get_timeout(void);

extern void m8xx_wdt_reset(void);

static struct semaphore wdt_sem;

static int wdt_status;

static struct watchdog_info ident = {

        .identity = "MPC8xx watchdog",

        .options = WDIOF_KEEPALIVEPING,

};

static void

mpc8xx_wdt_handler_disable(void)

{

        volatile immap_t *imap = (volatile immap_t *) IMAP_ADDR;

        imap->im_sit.sit_piscr &= ~(PISCR_PIE | PISCR_PTE);

        printk(KERN_NOTICE "mpc8xx_wdt: keep-alive handler deactivated\n");

}

static void

mpc8xx_wdt_handler_enable(void)

{

        volatile immap_t *imap = (volatile immap_t *) IMAP_ADDR;

        imap->im_sit.sit_piscr |= PISCR_PIE | PISCR_PTE;

        printk(KERN_NOTICE "mpc8xx_wdt: keep-alive handler activated\n");

}

static int

mpc8xx_wdt_open(struct inode *inode, struct file *file)

{

        switch (MINOR(inode->i_rdev)) {

        case WATCHDOG_MINOR:

                if (down_trylock(&wdt_sem))

                        return -EBUSY;

                m8xx_wdt_reset();

                mpc8xx_wdt_handler_disable();

                break;

        default:

                return -ENODEV;

        }

        return 0;

}

static int

mpc8xx_wdt_release(struct inode *inode, struct file *file)

{

        m8xx_wdt_reset();

#if !defined(CONFIG_WATCHDOG_NOWAYOUT)

        mpc8xx_wdt_handler_enable();

#endif

        up(&wdt_sem);

        return 0;

}

static ssize_t

mpc8xx_wdt_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;

        if (!len)

                return 0;

        m8xx_wdt_reset();

        return 1;

}

static int

mpc8xx_wdt_ioctl(struct inode *inode, struct file *file,

                 unsigned int cmd, unsigned long arg)

{

        switch (cmd) {

        case WDIOC_GETSUPPORT:

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

                        return -EFAULT;

                break;

        case WDIOC_GETSTATUS:

        case WDIOC_GETBOOTSTATUS:

                if (put_user(wdt_status, (int *) arg))

                        return -EFAULT;

                wdt_status &= ~WDIOF_KEEPALIVEPING;

                break;

        case WDIOC_KEEPALIVE:

                m8xx_wdt_reset();

                wdt_status |= WDIOF_KEEPALIVEPING;

                break;

        case WDIOC_GETTIMEOUT:

                {

                        int timeout = m8xx_wdt_get_timeout();

                        if (put_user(timeout, (int *) arg))

                                return -EFAULT;

                        break;

                }

        default:

                return -ENOTTY;

        }

        return 0;

}

static struct file_operations mpc8xx_wdt_fops = {

        .owner = THIS_MODULE,

        .write = mpc8xx_wdt_write,

        .ioctl = mpc8xx_wdt_ioctl,

        .open = mpc8xx_wdt_open,

        .release = mpc8xx_wdt_release,

};

static struct miscdevice mpc8xx_wdt_miscdev = {

        .minor = WATCHDOG_MINOR,

        .name = "watchdog",

        .fops = &mpc8xx_wdt_fops,

};

static int __init

mpc8xx_wdt_init(void)

{

        int ret;

        sema_init(&wdt_sem, 1);

        if ((ret = misc_register(&mpc8xx_wdt_miscdev))) {

                printk(KERN_WARNING

                       "mpc8xx_wdt: could not register userspace interface\n");

                return ret;

        }

        return 0;

}

static void __exit

mpc8xx_wdt_exit(void)

{

        misc_deregister(&mpc8xx_wdt_miscdev);

        m8xx_wdt_reset();

        mpc8xx_wdt_handler_enable();

}

module_init(mpc8xx_wdt_init);

module_exit(mpc8xx_wdt_exit);

MODULE_AUTHOR("Florian Schirmer <jolt@tuxbox.org>");

MODULE_DESCRIPTION("MPC8xx watchdog driver");

MODULE_LICENSE("GPL");