RK系列方案中 watchdog 方案

mark83136

/*
*    Industrial Computer Source WDT501 driver
*
*    (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
*                        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 <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 <linux/io.h>
#include <linux/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;

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);
}

/**
*    wdt_start:
*
*    Start the watchdog driver.
*/

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;
}

/**
*    wdt_stop:
*
*    Stop the watchdog driver.
*/

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;
}

/**
*    wdt_ping:
*
*    Reload counter one with the watchdog heartbeat. We don't bother
*    reloading the cascade counter.
*/

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);
}

/**
*    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
*    successful 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:
*
*    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(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;
}

/**
*    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(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))
        printk(KERN_CRIT "Overheat alarm.(%d)\n", inb_p(WDT_RT));
    if (!(status & WDC_SR_PSUOVER))
        printk(KERN_CRIT &quotSU over voltage.\n");
    if (!(status & WDC_SR_PSUUNDR))
        printk(KERN_CRIT &quotSU under voltage.\n");
}

/**
*    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;

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

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

    if (type == 501) {
        wdt_decode_501(status);
        if (tachometer) {
            if (!(status & WDC_SR_FANGOOD))
                printk(KERN_CRIT &quotossible 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");
        emergency_restart();
#endif
#else
        printk(KERN_CRIT "Reset in 5ms.\n");
#endif
    }
    spin_unlock(&wdt_lock);
    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:
*    @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 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;
    }
}

/**
*    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;
}

/**
*    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 = wdt_get_temperature();

    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;
}

/**
*    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)
        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,
};

/**
*    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);
    if (type == 501)
        misc_deregister(&temp_miscdev);
    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;

    if (type != 500 && type != 501) {
        printk(KERN_ERR "wdt: 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);
        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;
    }

    if (type == 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;
        }
    }

    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;
    }

    printk(KERN_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)
        printk(KERN_INFO "wdt: 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");

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