wdt.c

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/*
 *  Industrial Computer Source WDT501 driver
 *
 *  (c) Copyright 1996-1997 Alan Cox <[email protected]>,
 *                      All Rights Reserved.
 *
 *  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 <[email protected]>
 *
 *  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
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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 <linux/io.h>
#include <linux/uaccess.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 bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 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;

static DEFINE_SPINLOCK(wdt_lock);

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)");

/* 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)");

static int type = 500;
module_param(type, int, 0);
MODULE_PARM_DESC(type,
        "WDT501-P Card type (500 or 501, default=500)");

/*
 *  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);
}

static int wdt_start(void)
{
    unsigned long flags;
    spin_lock_irqsave(&wdt_lock, flags);
    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 */
    spin_unlock_irqrestore(&wdt_lock, flags);
    return 0;
}

static int wdt_stop(void)
{
    unsigned long flags;
    spin_lock_irqsave(&wdt_lock, flags);
    /* Turn the card off */
    inb_p(WDT_DC);          /* Disable watchdog */
    wdt_ctr_load(2, 0);     /* 0 length reset pulses now */
    spin_unlock_irqrestore(&wdt_lock, flags);
    return 0;
}

static void wdt_ping(void)
{
    unsigned long flags;
    spin_lock_irqsave(&wdt_lock, flags);
    /* 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 */
    spin_unlock_irqrestore(&wdt_lock, flags);
}

static int wdt_set_heartbeat(int t)
{
    if (t < 1 || t > 65535)
        return -EINVAL;

    heartbeat = t;
    wd_heartbeat = t * 100;
    return 0;
}

static int wdt_get_status(void)
{
    unsigned char new_status;
    int status = 0;
    unsigned long flags;

    spin_lock_irqsave(&wdt_lock, flags);
    new_status = inb_p(WDT_SR);
    spin_unlock_irqrestore(&wdt_lock, flags);

    if (new_status & WDC_SR_ISOI0)
        status |= WDIOF_EXTERN1;
    if (new_status & WDC_SR_ISII1)
        status |= WDIOF_EXTERN2;
    if (type == 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;
        }
    }
    return status;
}

static int wdt_get_temperature(void)
{
    unsigned short c;
    unsigned long flags;

    spin_lock_irqsave(&wdt_lock, flags);
    c = inb_p(WDT_RT);
    spin_unlock_irqrestore(&wdt_lock, flags);
    return (c * 11 / 15) + 7;
}

static void wdt_decode_501(int status)
{
    if (!(status & WDC_SR_TGOOD))
        pr_crit("Overheat alarm (%d)\n", inb_p(WDT_RT));
    if (!(status & WDC_SR_PSUOVER))
        pr_crit("PSU over voltage\n");
    if (!(status & WDC_SR_PSUUNDR))
        pr_crit("PSU under voltage\n");
}

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;

    spin_lock(&wdt_lock);
    status = inb_p(WDT_SR);

    pr_crit("WDT status %d\n", status);

    if (type == 501) {
        wdt_decode_501(status);
        if (tachometer) {
            if (!(status & WDC_SR_FANGOOD))
                pr_crit("Possible fan fault\n");
        }
    }
    if (!(status & WDC_SR_WCCR)) {
#ifdef SOFTWARE_REBOOT
#ifdef ONLY_TESTING
        pr_crit("Would Reboot\n");
#else
        pr_crit("Initiating system reboot\n");
        emergency_restart();
#endif
#else
        pr_crit("Reset in 5ms\n");
#endif
    }
    spin_unlock(&wdt_lock);
    return IRQ_HANDLED;
}


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;
}

static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    void __user *argp = (void __user *)arg;
    int __user *p = argp;
    int new_heartbeat;
    int status;

    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);
    if (type == 501) {
        ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|
                            WDIOF_POWEROVER);
        if (tachometer)
            ident.options |= WDIOF_FANFAULT;
    }

    switch (cmd) {
    case WDIOC_GETSUPPORT:
        return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
    case WDIOC_GETSTATUS:
        status = wdt_get_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);
    default:
        return -ENOTTY;
    }
}

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);
}

static int wdt_release(struct inode *inode, struct file *file)
{
    if (expect_close == 42) {
        wdt_stop();
        clear_bit(0, &wdt_is_open);
    } else {
        pr_crit("WDT device closed unexpectedly.  WDT will not stop!\n");
        wdt_ping();
    }
    expect_close = 0;
    return 0;
}

static ssize_t wdt_temp_read(struct file *file, char __user *buf,
                        size_t count, loff_t *ptr)
{
    int temperature = wdt_get_temperature();

    if (copy_to_user(buf, &temperature, 1))
        return -EFAULT;

    return 1;
}

static int wdt_temp_open(struct inode *inode, struct file *file)
{
    return nonseekable_open(inode, file);
}

static int wdt_temp_release(struct inode *inode, struct file *file)
{
    return 0;
}

static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
    void *unused)
{
    if (code == SYS_DOWN || code == SYS_HALT)
        wdt_stop();
    return NOTIFY_DONE;
}

/*
 *  Kernel Interfaces
 */


static const struct file_operations wdt_fops = {
    .owner      = THIS_MODULE,
    .llseek     = no_llseek,
    .write      = wdt_write,
    .unlocked_ioctl = wdt_ioctl,
    .open       = wdt_open,
    .release    = wdt_release,
};

static struct miscdevice wdt_miscdev = {
    .minor  = WATCHDOG_MINOR,
    .name   = "watchdog",
    .fops   = &wdt_fops,
};

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,
};

/*
 *  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,
};

static void __exit wdt_exit(void)
{
    misc_deregister(&wdt_miscdev);
    if (type == 501)
        misc_deregister(&temp_miscdev);
    unregister_reboot_notifier(&wdt_notifier);
    free_irq(irq, NULL);
    release_region(io, 8);
}

static int __init wdt_init(void)
{
    int ret;

    if (type != 500 && type != 501) {
        pr_err("unknown card type '%d'\n", type);
        return -ENODEV;
    }

    /* 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);
        pr_info("heartbeat value must be 0 < heartbeat < 65536, using %d\n",
            WD_TIMO);
    }

    if (!request_region(io, 8, "wdt501p")) {
        pr_err("I/O address 0x%04x already in use\n", io);
        ret = -EBUSY;
        goto out;
    }

    ret = request_irq(irq, wdt_interrupt, 0, "wdt501p", NULL);
    if (ret) {
        pr_err("IRQ %d is not free\n", irq);
        goto outreg;
    }

    ret = register_reboot_notifier(&wdt_notifier);
    if (ret) {
        pr_err("cannot register reboot notifier (err=%d)\n", ret);
        goto outirq;
    }

    if (type == 501) {
        ret = misc_register(&temp_miscdev);
        if (ret) {
            pr_err("cannot register miscdev on minor=%d (err=%d)\n",
                   TEMP_MINOR, ret);
            goto outrbt;
        }
    }

    ret = misc_register(&wdt_miscdev);
    if (ret) {
        pr_err("cannot register miscdev on minor=%d (err=%d)\n",
               WATCHDOG_MINOR, ret);
        goto outmisc;
    }

    pr_info("WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
        io, irq, heartbeat, nowayout);
    if (type == 501)
        pr_info("Fan Tachometer is %s\n",
            tachometer ? "Enabled" : "Disabled");
    return 0;

outmisc:
    if (type == 501)
        misc_deregister(&temp_miscdev);
outrbt:
    unregister_reboot_notifier(&wdt_notifier);
outirq:
    free_irq(irq, NULL);
outreg:
    release_region(io, 8);
out:
    return ret;
}

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");