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/*

 *      Industrial Computer Source WDT500/501 driver for Linux 2.1.x

 *

 *      (c) Copyright 1996-1997 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@lxorguk.ukuu.org.uk>

 *

 *      Release 0.08.

 *

 *      Fixes

 *              Dave Gregorich  :       Modularisation and minor bugs

 *              Alan Cox        :       Added the watchdog ioctl() stuff

 *              Alan Cox        :       Fixed the reboot problem (as noted by

 *                                      Matt Crocker).

 *              Alan Cox        :       Added wdt= boot option

 *              Alan Cox        :       Cleaned up copy/user stuff

 *              Tim Hockin      :       Added insmod parameters, comment cleanup

 *                                      Parameterized timeout

 *              Tigran Aivazian :       Restructured wdt_init() to handle failures

 *              Joel Becker     :       Added WDIOC_GET/SETTIMEOUT

 *              Matt Domsch     :       Added nowayout module option

 */

#include <linux/config.h>

#include <linux/module.h>

#include <linux/version.h>

#include <linux/types.h>

#include <linux/errno.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/smp_lock.h>

#include <linux/miscdevice.h>

#include <linux/watchdog.h>

#include "wd501p.h"

#include <linux/slab.h>

#include <linux/ioport.h>

#include <linux/fcntl.h>

#include <asm/io.h>

#include <asm/uaccess.h>

#include <asm/system.h>

#include <linux/notifier.h>

#include <linux/reboot.h>

#include <linux/init.h>

static unsigned long wdt_is_open;

static int expect_close;

/*

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

 *      You can use wdt=x,y to set these now.

 */

static int io=0x240;

static int irq=11;

/* Default margin */

#define WD_TIMO (100*60)                /* 1 minute */

static int wd_margin = WD_TIMO;

#ifdef CONFIG_WATCHDOG_NOWAYOUT

static int nowayout = 1;

#else

static int nowayout = 0;

#endif

MODULE_PARM(nowayout,"i");

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

#ifndef MODULE

/**

 *      wdt_setup:

 *      @str: command line string

 *

 *      Setup options. The board isn't really probe-able so we have to

 *      get the user to tell us the configuration. Sane people build it

 *      modular but the others come here.

 */

static int __init wdt_setup(char *str)

{

        int ints[4];

        str = get_options (str, ARRAY_SIZE(ints), ints);

        if (ints[0] > 0)

        {

                io = ints[1];

                if(ints[0] > 1)

                        irq = ints[2];

        }

        return 1;

}

__setup("wdt=", wdt_setup);

#endif /* !MODULE */

MODULE_PARM(io, "i");

MODULE_PARM_DESC(io, "WDT io port (default=0x240)");

MODULE_PARM(irq, "i");

MODULE_PARM_DESC(irq, "WDT irq (default=11)");

/*

 *      Programming support

 */

static void wdt_ctr_mode(int ctr, int mode)

{

        ctr<<=6;

        ctr|=0x30;

        ctr|=(mode<<1);

        outb_p(ctr, WDT_CR);

}

static void wdt_ctr_load(int ctr, int val)

{

        outb_p(val&0xFF, WDT_COUNT0+ctr);

        outb_p(val>>8, WDT_COUNT0+ctr);

}

/*

 *      Kernel methods.

 */

/**

 *      wdt_status:

 *

 *      Extract the status information from a WDT watchdog device. There are

 *      several board variants so we have to know which bits are valid. Some

 *      bits default to one and some to zero in order to be maximally painful.

 *

 *      we then map the bits onto the status ioctl flags.

 */

static int wdt_status(void)

{

        /*

         *      Status register to bit flags

         */

        int flag=0;

        unsigned char status=inb_p(WDT_SR);

        status|=FEATUREMAP1;

        status&=~FEATUREMAP2;

        if(!(status&WDC_SR_TGOOD))

                flag|=WDIOF_OVERHEAT;

        if(!(status&WDC_SR_PSUOVER))

                flag|=WDIOF_POWEROVER;

        if(!(status&WDC_SR_PSUUNDR))

                flag|=WDIOF_POWERUNDER;

        if(!(status&WDC_SR_FANGOOD))

                flag|=WDIOF_FANFAULT;

        if(status&WDC_SR_ISOI0)

                flag|=WDIOF_EXTERN1;

        if(status&WDC_SR_ISII1)

                flag|=WDIOF_EXTERN2;

        return flag;

}

/**

 *      wdt_interrupt:

 *      @irq:           Interrupt number

 *      @dev_id:        Unused as we don't allow multiple devices.

 *      @regs:          Unused.

 *

 *      Handle an interrupt from the board. These are raised when the status

 *      map changes in what the board considers an interesting way. That means

 *      a failure condition occuring.

 */

void wdt_interrupt(int irq, void *dev_id, struct pt_regs *regs)

{

        /*

         *      Read the status register see what is up and

         *      then printk it.

         */

        unsigned char status=inb_p(WDT_SR);

        status|=FEATUREMAP1;

        status&=~FEATUREMAP2;

        printk(KERN_CRIT "WDT status %d\n", status);

        if(!(status&WDC_SR_TGOOD))

                printk(KERN_CRIT "Overheat alarm.(%d)\n",inb_p(WDT_RT));

        if(!(status&WDC_SR_PSUOVER))

                printk(KERN_CRIT "PSU over voltage.\n");

        if(!(status&WDC_SR_PSUUNDR))

                printk(KERN_CRIT "PSU under voltage.\n");

        if(!(status&WDC_SR_FANGOOD))

                printk(KERN_CRIT "Possible fan fault.\n");

        if(!(status&WDC_SR_WCCR))

#ifdef SOFTWARE_REBOOT

#ifdef ONLY_TESTING

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

#else           

                printk(KERN_CRIT "Initiating system reboot.\n");

                machine_restart(NULL);

#endif          

#else

                printk(KERN_CRIT "Reset in 5ms.\n");

#endif          

}

/**

 *      wdt_ping:

 *

 *      Reload counter one with the watchdog timeout. We don't bother reloading

 *      the cascade counter.

 */

static void wdt_ping(void)

{

        /* Write a watchdog value */

        inb_p(WDT_DC);

        wdt_ctr_mode(1,2);

        wdt_ctr_load(1,wd_margin);              /* Timeout */

        outb_p(0, WDT_DC);

}

/**

 *      wdt_write:

 *      @file: file handle to the watchdog

 *      @buf: buffer to write (unused as data does not matter here

 *      @count: count of bytes

 *      @ppos: pointer to the position to write. No seeks allowed

 *

 *      A write to a watchdog device is defined as a keepalive signal. Any

 *      write of data will do, as we we don't define content meaning.

 */

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

{

        /*  Can't seek (pwrite) on this device  */

        if (ppos != &file->f_pos)

                return -ESPIPE;

        if(count)

        {

                if (!nowayout) {

                        size_t i;

                        /* In case it was set long ago */

                        expect_close = 0;

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

                                char c;

                                if (get_user(c, buf + i))

                                        return -EFAULT;

                                if (c == 'V')

                                        expect_close = 1;

                        }

                }

                wdt_ping();

                return 1;

        }

        return 0;

}

/**

 *      wdt_read:

 *      @file: file handle to the watchdog board

 *      @buf: buffer to write 1 byte into

 *      @count: length of buffer

 *      @ptr: offset (no seek allowed)

 *

 *      Read reports the temperature in degrees Fahrenheit. The API is in

 *      farenheit. It was designed by an imperial measurement luddite.

 */

static ssize_t wdt_read(struct file *file, char *buf, size_t count, loff_t *ptr)

{

        unsigned short c=inb_p(WDT_RT);

        unsigned char cp;

        /*  Can't seek (pread) on this device  */

        if (ptr != &file->f_pos)

                return -ESPIPE;

        switch(MINOR(file->f_dentry->d_inode->i_rdev))

        {

                case TEMP_MINOR:

                        c*=11;

                        c/=15;

                        cp=c+7;

                        if(copy_to_user(buf,&cp,1))

                                return -EFAULT;

                        return 1;

                default:

                        return -EINVAL;

        }

}

/**

 *      wdt_ioctl:

 *      @inode: inode of the device

 *      @file: file handle to the device

 *      @cmd: watchdog command

 *      @arg: argument pointer

 *

 *      The watchdog API defines a common set of functions for all watchdogs

 *      according to their available features. We only actually usefully support

 *      querying capabilities and current status.

 */

static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,

        unsigned long arg)

{

        int new_margin;

        static struct watchdog_info ident=

        {

                WDIOF_OVERHEAT|WDIOF_POWERUNDER|WDIOF_POWEROVER

                        |WDIOF_EXTERN1|WDIOF_EXTERN2|WDIOF_FANFAULT

                        |WDIOF_SETTIMEOUT|WDIOF_MAGICCLOSE,

                1,

                "WDT500/501"

        };

        ident.options&=WDT_OPTION_MASK; /* Mask down to the card we have */

        switch(cmd)

        {

                default:

                        return -ENOTTY;

                case WDIOC_GETSUPPORT:

                        return copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident))?-EFAULT:0;

                case WDIOC_GETSTATUS:

                        return put_user(wdt_status(),(int *)arg);

                case WDIOC_GETBOOTSTATUS:

                        return put_user(0, (int *)arg);

                case WDIOC_KEEPALIVE:

                        wdt_ping();

                        return 0;

                case WDIOC_SETTIMEOUT:

                        if (get_user(new_margin, (int *)arg))

                                return -EFAULT;

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

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

                                return -EINVAL;

                        wd_margin = new_margin * 100;

                        wdt_ping();

                        /* Fall */

                case WDIOC_GETTIMEOUT:

                        return put_user(wd_margin / 100, (int *)arg);

        }

}

/**

 *      wdt_open:

 *      @inode: inode of device

 *      @file: file handle to device

 *

 *      One of our two misc devices has been opened. The watchdog device is

 *      single open and on opening we load the counters. Counter zero is a

 *      100Hz cascade, into counter 1 which downcounts to reboot. When the

 *      counter triggers counter 2 downcounts the length of the reset pulse

 *      which set set to be as long as possible.

 */

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

{

        switch(MINOR(inode->i_rdev))

        {

                case WATCHDOG_MINOR:

                        if(test_and_set_bit(0, &wdt_is_open))

                                return -EBUSY;

                        /*

                         *      Activate

                         */

                        wdt_is_open=1;

                        inb_p(WDT_DC);          /* Disable */

                        wdt_ctr_mode(0,3);

                        wdt_ctr_mode(1,2);

                        wdt_ctr_mode(2,0);

                        wdt_ctr_load(0, 8948);           /* count at 100Hz */

                        wdt_ctr_load(1,wd_margin);      /* Timeout 120 seconds */

                        wdt_ctr_load(2,65535);

                        outb_p(0, WDT_DC);       /* Enable */

                        return 0;

                case TEMP_MINOR:

                        return 0;

                default:

                        return -ENODEV;

        }

}

/**

 *      wdt_close:

 *      @inode: inode to board

 *      @file: file handle to board

 *

 *      The watchdog has a configurable API. There is a religious dispute

 *      between people who want their watchdog to be able to shut down and

 *      those who want to be sure if the watchdog manager dies the machine

 *      reboots. In the former case we disable the counters, in the latter

 *      case you have to open it again very soon.

 */

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

{

        if(MINOR(inode->i_rdev)==WATCHDOG_MINOR)

        {

                if (expect_close) {

                        inb_p(WDT_DC);          /* Disable counters */

                        wdt_ctr_load(2,0);       /* 0 length reset pulses now */

                } else {

                        printk(KERN_CRIT "wdt: WDT device closed unexpectedly.  WDT will not stop!\n");

                }

                clear_bit(0, &wdt_is_open);

        }

        return 0;

}

/**

 *      notify_sys:

 *      @this: our notifier block

 *      @code: the event being reported

 *      @unused: unused

 *

 *      Our notifier is called on system shutdowns. We want to turn the card

 *      off at reboot otherwise the machine will reboot again during memory

 *      test or worse yet during the following fsck. This would suck, in fact

 *      trust me - if it happens it does suck.

 */

static int wdt_notify_sys(struct notifier_block *this, unsigned long code,

        void *unused)

{

        if(code==SYS_DOWN || code==SYS_HALT)

        {

                /* Turn the card off */

                inb_p(WDT_DC);

                wdt_ctr_load(2,0);

        }

        return NOTIFY_DONE;

}

/*

 *      Kernel Interfaces

 */

static struct file_operations wdt_fops = {

        owner:          THIS_MODULE,

        llseek:         no_llseek,

        read:           wdt_read,

        write:          wdt_write,

        ioctl:          wdt_ioctl,

        open:           wdt_open,

        release:        wdt_release,

};

static struct miscdevice wdt_miscdev=

{

        WATCHDOG_MINOR,

        "watchdog",

        &wdt_fops

};

#ifdef CONFIG_WDT_501

static struct miscdevice temp_miscdev=

{

        TEMP_MINOR,

        "temperature",

        &wdt_fops

};

#endif

/*

 *      The WDT card needs to learn about soft shutdowns in order to

 *      turn the timebomb registers off.

 */

static struct notifier_block wdt_notifier=

{

        wdt_notify_sys,

        NULL,

};

/**

 *      cleanup_module:

 *

 *      Unload the watchdog. You cannot do this with any file handles open.

 *      If your watchdog is set to continue ticking on close and you unload

 *      it, well it keeps ticking. We won't get the interrupt but the board

 *      will not touch PC memory so all is fine. You just have to load a new

 *      module in 60 seconds or reboot.

 */

static void __exit wdt_exit(void)

{

        misc_deregister(&wdt_miscdev);

#ifdef CONFIG_WDT_501   

        misc_deregister(&temp_miscdev);

#endif  

        unregister_reboot_notifier(&wdt_notifier);

        release_region(io,8);

        free_irq(irq, NULL);

}

/**

 *      wdt_init:

 *

 *      Set up the WDT watchdog board. All we have to do is grab the

 *      resources we require and bitch if anyone beat us to them.

 *      The open() function will actually kick the board off.

 */

static int __init wdt_init(void)

{

        int ret;

        ret = misc_register(&wdt_miscdev);

        if (ret) {

                printk(KERN_ERR "wdt: can't misc_register on minor=%d\n", WATCHDOG_MINOR);

                goto out;

        }

        ret = request_irq(irq, wdt_interrupt, SA_INTERRUPT, "wdt501p", NULL);

        if(ret) {

                printk(KERN_ERR "wdt: IRQ %d is not free.\n", irq);

                goto outmisc;

        }

        if (!request_region(io, 8, "wdt501p")) {

                printk(KERN_ERR "wdt: IO %X is not free.\n", io);

                ret = -EBUSY;

                goto outirq;

        }

        ret = register_reboot_notifier(&wdt_notifier);

        if(ret) {

                printk(KERN_ERR "wdt: can't register reboot notifier (err=%d)\n", ret);

                goto outreg;

        }

#ifdef CONFIG_WDT_501

        ret = misc_register(&temp_miscdev);

        if (ret) {

                printk(KERN_ERR "wdt: can't misc_register (temp) on minor=%d\n", TEMP_MINOR);

                goto outrbt;

        }

#endif

        ret = 0;

        printk(KERN_INFO "WDT500/501-P driver 0.07 at %X (Interrupt %d)\n", io, irq);

out:

        return ret;

#ifdef CONFIG_WDT_501

outrbt:

        unregister_reboot_notifier(&wdt_notifier);

#endif

outreg:

        release_region(io,8);

outirq:

        free_irq(irq, NULL);

outmisc:

        misc_deregister(&wdt_miscdev);

        goto out;

}

module_init(wdt_init);

module_exit(wdt_exit);

MODULE_AUTHOR("Alan Cox");

MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");

MODULE_LICENSE("GPL");

EXPORT_NO_SYMBOLS;