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/*

 * sma cpu5 watchdog driver

 *

 * Copyright (C) 2003 Heiko Ronsdorf <hero@ihg.uni-duisburg.de>

 *

 * 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/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 <asm/io.h>

#include <asm/uaccess.h>

#include <linux/watchdog.h>

/* adjustable parameters */

static int verbose = 0;

static int port = 0x91;

static int ticks = 10000;

#define PFX                     "cpu5wdt: "

#define CPU5WDT_EXTENT          0x0A

#define CPU5WDT_STATUS_REG      0x00

#define CPU5WDT_TIME_A_REG      0x02

#define CPU5WDT_TIME_B_REG      0x03

#define CPU5WDT_MODE_REG        0x04

#define CPU5WDT_TRIGGER_REG     0x07

#define CPU5WDT_ENABLE_REG      0x08

#define CPU5WDT_RESET_REG       0x09

#define CPU5WDT_INTERVAL        (HZ/10+1)

/* some device data */

static struct {

        struct completion stop;

        volatile int running;

        struct timer_list timer;

        volatile int queue;

        int default_ticks;

        unsigned long inuse;

} cpu5wdt_device;

/* generic helper functions */

static void cpu5wdt_trigger(unsigned long unused)

{

        if ( verbose > 2 )

                printk(KERN_DEBUG PFX "trigger at %i ticks\n", ticks);

        if( cpu5wdt_device.running )

                ticks--;

        /* keep watchdog alive */

        outb(1, port + CPU5WDT_TRIGGER_REG);

        /* requeue?? */

        if (cpu5wdt_device.queue && ticks)

                mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);

        else {

                /* ticks doesn't matter anyway */

                complete(&cpu5wdt_device.stop);

        }

}

static void cpu5wdt_reset(void)

{

        ticks = cpu5wdt_device.default_ticks;

        if ( verbose )

                printk(KERN_DEBUG PFX "reset (%i ticks)\n", (int) ticks);

}

static void cpu5wdt_start(void)

{

        if ( !cpu5wdt_device.queue ) {

                cpu5wdt_device.queue = 1;

                outb(0, port + CPU5WDT_TIME_A_REG);

                outb(0, port + CPU5WDT_TIME_B_REG);

                outb(1, port + CPU5WDT_MODE_REG);

                outb(0, port + CPU5WDT_RESET_REG);

                outb(0, port + CPU5WDT_ENABLE_REG);

                mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);

        }

        /* if process dies, counter is not decremented */

        cpu5wdt_device.running++;

}

static int cpu5wdt_stop(void)

{

        if ( cpu5wdt_device.running )

                cpu5wdt_device.running = 0;

        ticks = cpu5wdt_device.default_ticks;

        if ( verbose )

                printk(KERN_CRIT PFX "stop not possible\n");

        return -EIO;

}

/* filesystem operations */

static int cpu5wdt_open(struct inode *inode, struct file *file)

{

        if ( test_and_set_bit(0, &cpu5wdt_device.inuse) )

                return -EBUSY;

        return nonseekable_open(inode, file);

}

static int cpu5wdt_release(struct inode *inode, struct file *file)

{

        clear_bit(0, &cpu5wdt_device.inuse);

        return 0;

}

static int cpu5wdt_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 = "CPU5 WDT",

        };

        switch(cmd) {

                case WDIOC_KEEPALIVE:

                        cpu5wdt_reset();

                        break;

                case WDIOC_GETSTATUS:

                        value = inb(port + CPU5WDT_STATUS_REG);

                        value = (value >> 2) & 1;

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

                                return -EFAULT;

                        break;

                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:

                                        cpu5wdt_start();

                                        break;

                                case WDIOS_DISABLECARD:

                                        return cpu5wdt_stop();

                                default:

                                        return -EINVAL;

                        }

                        break;

                default:

                        return -ENOTTY;

        }

        return 0;

}

static ssize_t cpu5wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)

{

        if ( !count )

                return -EIO;

        cpu5wdt_reset();

        return count;

}

static const struct file_operations cpu5wdt_fops = {

        .owner          = THIS_MODULE,

        .llseek         = no_llseek,

        .ioctl          = cpu5wdt_ioctl,

        .open           = cpu5wdt_open,

        .write          = cpu5wdt_write,

        .release        = cpu5wdt_release,

};

static struct miscdevice cpu5wdt_misc = {

        .minor  = WATCHDOG_MINOR,

        .name   = "watchdog",

        .fops   = &cpu5wdt_fops,

};

/* init/exit function */

static int __devinit cpu5wdt_init(void)

{

        unsigned int val;

        int err;

        if ( verbose )

                printk(KERN_DEBUG PFX "port=0x%x, verbose=%i\n", port, verbose);

        if ( !request_region(port, CPU5WDT_EXTENT, PFX) ) {

                printk(KERN_ERR PFX "request_region failed\n");

                err = -EBUSY;

                goto no_port;

        }

        if ( (err = misc_register(&cpu5wdt_misc)) < 0 ) {

                printk(KERN_ERR PFX "misc_register failed\n");

                goto no_misc;

        }

        /* watchdog reboot? */

        val = inb(port + CPU5WDT_STATUS_REG);

        val = (val >> 2) & 1;

        if ( !val )

                printk(KERN_INFO PFX "sorry, was my fault\n");

        init_completion(&cpu5wdt_device.stop);

        cpu5wdt_device.queue = 0;

        clear_bit(0, &cpu5wdt_device.inuse);

        setup_timer(&cpu5wdt_device.timer, cpu5wdt_trigger, 0);

        cpu5wdt_device.default_ticks = ticks;

        printk(KERN_INFO PFX "init success\n");

        return 0;

no_misc:

        release_region(port, CPU5WDT_EXTENT);

no_port:

        return err;

}

static int __devinit cpu5wdt_init_module(void)

{

        return cpu5wdt_init();

}

static void __devexit cpu5wdt_exit(void)

{

        if ( cpu5wdt_device.queue ) {

                cpu5wdt_device.queue = 0;

                wait_for_completion(&cpu5wdt_device.stop);

        }

        misc_deregister(&cpu5wdt_misc);

        release_region(port, CPU5WDT_EXTENT);

}

static void __devexit cpu5wdt_exit_module(void)

{

        cpu5wdt_exit();

}

/* module entry points */

module_init(cpu5wdt_init_module);

module_exit(cpu5wdt_exit_module);

MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>");

MODULE_DESCRIPTION("sma cpu5 watchdog driver");

MODULE_SUPPORTED_DEVICE("sma cpu5 watchdog");

MODULE_LICENSE("GPL");

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

module_param(port, int, 0);

MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");

module_param(verbose, int, 0);

MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");

module_param(ticks, int, 0);

MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");