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/*

 *      Industrial Computer Source WDT500/501 driver

 *

 *      (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 0.10.

 *

 *      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/interrupt.h>

#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/notifier.h>

#include <linux/reboot.h>

#include <linux/init.h>

#include <asm/io.h>

#include <asm/uaccess.h>

#include <asm/system.h>

#include "wd501p.h"

static unsigned long wdt_is_open;

static char expect_close;

/*

 *      Module parameters

 */

#define WD_TIMO 60                      /* Default heartbeat = 60 seconds */

static int heartbeat = WD_TIMO;

static int wd_heartbeat;

module_param(heartbeat, int, 0);

MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (0<heartbeat<65536, default=" __MODULE_STRING(WD_TIMO) ")");

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) ")");

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

static int io=0x240;

static int irq=11;

module_param(io, int, 0);

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

module_param(irq, int, 0);

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

#ifdef CONFIG_WDT_501

/* Support for the Fan Tachometer on the WDT501-P */

static int tachometer;

module_param(tachometer, int, 0);

MODULE_PARM_DESC(tachometer, "WDT501-P Fan Tachometer support (0=disable, default=0)");

#endif /* CONFIG_WDT_501 */

/*

 *      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);

}

/**

 *      wdt_start:

 *

 *      Start the watchdog driver.

 */

static int wdt_start(void)

{

        inb_p(WDT_DC);                  /* Disable watchdog */

        wdt_ctr_mode(0,3);               /* Program CTR0 for Mode 3: Square Wave Generator */

        wdt_ctr_mode(1,2);              /* Program CTR1 for Mode 2: Rate Generator */

        wdt_ctr_mode(2,0);               /* Program CTR2 for Mode 0: Pulse on Terminal Count */

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

        wdt_ctr_load(1,wd_heartbeat);   /* Heartbeat */

        wdt_ctr_load(2,65535);          /* Length of reset pulse */

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

        return 0;

}

/**

 *      wdt_stop:

 *

 *      Stop the watchdog driver.

 */

static int wdt_stop (void)

{

        /* Turn the card off */

        inb_p(WDT_DC);                  /* Disable watchdog */

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

        return 0;

}

/**

 *      wdt_ping:

 *

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

 *      the cascade counter.

 */

static int wdt_ping(void)

{

        /* Write a watchdog value */

        inb_p(WDT_DC);                  /* Disable watchdog */

        wdt_ctr_mode(1,2);              /* Re-Program CTR1 for Mode 2: Rate Generator */

        wdt_ctr_load(1,wd_heartbeat);   /* Heartbeat */

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

        return 0;

}

/**

 *      wdt_set_heartbeat:

 *      @t:             the new heartbeat value that needs to be set.

 *

 *      Set a new heartbeat value for the watchdog device. If the heartbeat value is

 *      incorrect we keep the old value and return -EINVAL. If successfull we

 *      return 0.

 */

static int wdt_set_heartbeat(int t)

{

        if ((t < 1) || (t > 65535))

                return -EINVAL;

        heartbeat = t;

        wd_heartbeat = t * 100;

        return 0;

}

/**

 *      wdt_get_status:

 *      @status:                the new 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_get_status(int *status)

{

        unsigned char new_status=inb_p(WDT_SR);

        *status=0;

        if (new_status & WDC_SR_ISOI0)

                *status |= WDIOF_EXTERN1;

        if (new_status & WDC_SR_ISII1)

                *status |= WDIOF_EXTERN2;

#ifdef CONFIG_WDT_501

        if (!(new_status & WDC_SR_TGOOD))

                *status |= WDIOF_OVERHEAT;

        if (!(new_status & WDC_SR_PSUOVER))

                *status |= WDIOF_POWEROVER;

        if (!(new_status & WDC_SR_PSUUNDR))

                *status |= WDIOF_POWERUNDER;

        if (tachometer) {

                if (!(new_status & WDC_SR_FANGOOD))

                        *status |= WDIOF_FANFAULT;

        }

#endif /* CONFIG_WDT_501 */

        return 0;

}

#ifdef CONFIG_WDT_501

/**

 *      wdt_get_temperature:

 *

 *      Reports the temperature in degrees Fahrenheit. The API is in

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

 */

static int wdt_get_temperature(int *temperature)

{

        unsigned short c=inb_p(WDT_RT);

        *temperature = (c * 11 / 15) + 7;

        return 0;

}

#endif /* CONFIG_WDT_501 */

/**

 *      wdt_interrupt:

 *      @irq:           Interrupt number

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

 *

 *      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 occurring.

 */

static irqreturn_t wdt_interrupt(int irq, void *dev_id)

{

        /*

         *      Read the status register see what is up and

         *      then printk it.

         */

        unsigned char status=inb_p(WDT_SR);

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

#ifdef CONFIG_WDT_501

        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 (tachometer) {

                if (!(status & WDC_SR_FANGOOD))

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

        }

#endif /* CONFIG_WDT_501 */

        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");

                emergency_restart();

#endif

#else

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

#endif

        }

        return IRQ_HANDLED;

}

/**

 *      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 __user *buf, size_t count, loff_t *ppos)

{

        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 = 42;

                        }

                }

                wdt_ping();

        }

        return count;

}

/**

 *      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)

{

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

        int __user *p = argp;

        int new_heartbeat;

        int status;

        static struct watchdog_info ident = {

                .options =              WDIOF_SETTIMEOUT|

                                        WDIOF_MAGICCLOSE|

                                        WDIOF_KEEPALIVEPING,

                .firmware_version =     1,

                .identity =             "WDT500/501",

        };

        /* Add options according to the card we have */

        ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);

#ifdef CONFIG_WDT_501

        ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|WDIOF_POWEROVER);

        if (tachometer)

                ident.options |= WDIOF_FANFAULT;

#endif /* CONFIG_WDT_501 */

        switch(cmd)

        {

                default:

                        return -ENOTTY;

                case WDIOC_GETSUPPORT:

                        return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;

                case WDIOC_GETSTATUS:

                        wdt_get_status(&status);

                        return put_user(status, p);

                case WDIOC_GETBOOTSTATUS:

                        return put_user(0, p);

                case WDIOC_KEEPALIVE:

                        wdt_ping();

                        return 0;

                case WDIOC_SETTIMEOUT:

                        if (get_user(new_heartbeat, p))

                                return -EFAULT;

                        if (wdt_set_heartbeat(new_heartbeat))

                                return -EINVAL;

                        wdt_ping();

                        /* Fall */

                case WDIOC_GETTIMEOUT:

                        return put_user(heartbeat, p);

        }

}

/**

 *      wdt_open:

 *      @inode: inode of device

 *      @file: file handle to device

 *

 *      The watchdog device 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)

{

        if(test_and_set_bit(0, &wdt_is_open))

                return -EBUSY;

        /*

         *      Activate

         */

        wdt_start();

        return nonseekable_open(inode, file);

}

/**

 *      wdt_release:

 *      @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 (expect_close == 42) {

                wdt_stop();

                clear_bit(0, &wdt_is_open);

        } else {

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

                wdt_ping();

        }

        expect_close = 0;

        return 0;

}

#ifdef CONFIG_WDT_501

/**

 *      wdt_temp_read:

 *      @file: file handle to the watchdog board

 *      @buf: buffer to write 1 byte into

 *      @count: length of buffer

 *      @ptr: offset (no seek allowed)

 *

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

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

 */

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

{

        int temperature;

        if (wdt_get_temperature(&temperature))

                return -EFAULT;

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

                return -EFAULT;

        return 1;

}

/**

 *      wdt_temp_open:

 *      @inode: inode of device

 *      @file: file handle to device

 *

 *      The temperature device has been opened.

 */

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

{

        return nonseekable_open(inode, file);

}

/**

 *      wdt_temp_release:

 *      @inode: inode to board

 *      @file: file handle to board

 *

 *      The temperature device has been closed.

 */

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

{

        return 0;

}

#endif /* CONFIG_WDT_501 */

/**

 *      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 */

                wdt_stop();

        }

        return NOTIFY_DONE;

}

/*

 *      Kernel Interfaces

 */

static const struct file_operations wdt_fops = {

        .owner          = THIS_MODULE,

        .llseek         = no_llseek,

        .write          = wdt_write,

        .ioctl          = wdt_ioctl,

        .open           = wdt_open,

        .release        = wdt_release,

};

static struct miscdevice wdt_miscdev = {

        .minor  = WATCHDOG_MINOR,

        .name   = "watchdog",

        .fops   = &wdt_fops,

};

#ifdef CONFIG_WDT_501

static const struct file_operations wdt_temp_fops = {

        .owner          = THIS_MODULE,

        .llseek         = no_llseek,

        .read           = wdt_temp_read,

        .open           = wdt_temp_open,

        .release        = wdt_temp_release,

};

static struct miscdevice temp_miscdev = {

        .minor  = TEMP_MINOR,

        .name   = "temperature",

        .fops   = &wdt_temp_fops,

};

#endif /* CONFIG_WDT_501 */

/*

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

 *      turn the timebomb registers off.

 */

static struct notifier_block wdt_notifier = {

        .notifier_call = wdt_notify_sys,

};

/**

 *      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 /* CONFIG_WDT_501 */

        unregister_reboot_notifier(&wdt_notifier);

        free_irq(irq, NULL);

        release_region(io,8);

}

/**

 *      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;

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

        if (wdt_set_heartbeat(heartbeat)) {

                wdt_set_heartbeat(WD_TIMO);

                printk(KERN_INFO "wdt: heartbeat value must be 0<heartbeat<65536, using %d\n",

                        WD_TIMO);

        }

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

                printk(KERN_ERR "wdt: I/O address 0x%04x already in use\n", io);

                ret = -EBUSY;

                goto out;

        }

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

        if(ret) {

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

                goto outreg;

        }

        ret = register_reboot_notifier(&wdt_notifier);

        if(ret) {

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

                goto outirq;

        }

#ifdef CONFIG_WDT_501

        ret = misc_register(&temp_miscdev);

        if (ret) {

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

                        TEMP_MINOR, ret);

                goto outrbt;

        }

#endif /* CONFIG_WDT_501 */

        ret = misc_register(&wdt_miscdev);

        if (ret) {

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

                        WATCHDOG_MINOR, ret);

                goto outmisc;

        }

        ret = 0;

        printk(KERN_INFO "WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",

                io, irq, heartbeat, nowayout);

#ifdef CONFIG_WDT_501

        printk(KERN_INFO "wdt: Fan Tachometer is %s\n", (tachometer ? "Enabled" : "Disabled"));

#endif /* CONFIG_WDT_501 */

out:

        return ret;

outmisc:

#ifdef CONFIG_WDT_501

        misc_deregister(&temp_miscdev);

outrbt:

#endif /* CONFIG_WDT_501 */

        unregister_reboot_notifier(&wdt_notifier);

outirq:

        free_irq(irq, NULL);

outreg:

        release_region(io,8);

        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_ALIAS_MISCDEV(WATCHDOG_MINOR);

MODULE_ALIAS_MISCDEV(TEMP_MINOR);

MODULE_LICENSE("GPL");