w83627hf_wdt.c

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/*
 *  w83627hf/thf WDT driver
 *
 *  (c) Copyright 2007 Vlad Drukker <[email protected]>
 *      added support for W83627THF.
 *
 *  (c) Copyright 2003,2007 Pádraig Brady <[email protected]>
 *
 *  Based on advantechwdt.c which is based on wdt.c.
 *  Original copyright messages:
 *
 *  (c) Copyright 2000-2001 Marek Michalkiewicz <[email protected]>
 *
 *  (c) Copyright 1996 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]>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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/spinlock.h>
#include <linux/io.h>
#include <linux/uaccess.h>


#define WATCHDOG_NAME "w83627hf/thf/hg/dhg WDT"
#define WATCHDOG_TIMEOUT 60     /* 60 sec default timeout */

static unsigned long wdt_is_open;
static char expect_close;
static DEFINE_SPINLOCK(io_lock);

/* You must set this - there is no sane way to probe for this board. */
static int wdt_io = 0x2E;
module_param(wdt_io, int, 0);
MODULE_PARM_DESC(wdt_io, "w83627hf/thf WDT io port (default 0x2E)");

static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
        "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
                __MODULE_STRING(WATCHDOG_TIMEOUT) ".");

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) ")");

/*
 *  Kernel methods.
 */

#define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
#define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register
                            (same as EFER) */
#define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */

static void w83627hf_select_wd_register(void)
{
    unsigned char c;
    outb_p(0x87, WDT_EFER); /* Enter extended function mode */
    outb_p(0x87, WDT_EFER); /* Again according to manual */

    outb(0x20, WDT_EFER);   /* check chip version   */
    c = inb(WDT_EFDR);
    if (c == 0x82) {    /* W83627THF        */
        outb_p(0x2b, WDT_EFER); /* select GPIO3 */
        c = ((inb_p(WDT_EFDR) & 0xf7) | 0x04); /* select WDT0 */
        outb_p(0x2b, WDT_EFER);
        outb_p(c, WDT_EFDR);    /* set GPIO3 to WDT0 */
    } else if (c == 0x88 || c == 0xa0) {    /* W83627EHF / W83627DHG */
        outb_p(0x2d, WDT_EFER); /* select GPIO5 */
        c = inb_p(WDT_EFDR) & ~0x01; /* PIN77 -> WDT0# */
        outb_p(0x2d, WDT_EFER);
        outb_p(c, WDT_EFDR); /* set GPIO5 to WDT0 */
    }

    outb_p(0x07, WDT_EFER); /* point to logical device number reg */
    outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
    outb_p(0x30, WDT_EFER); /* select CR30 */
    outb_p(0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
}

static void w83627hf_unselect_wd_register(void)
{
    outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
}

/* tyan motherboards seem to set F5 to 0x4C ?
 * So explicitly init to appropriate value. */

static void w83627hf_init(void)
{
    unsigned char t;

    w83627hf_select_wd_register();

    outb_p(0xF6, WDT_EFER); /* Select CRF6 */
    t = inb_p(WDT_EFDR);      /* read CRF6 */
    if (t != 0) {
        pr_info("Watchdog already running. Resetting timeout to %d sec\n",
            timeout);
        outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
    }

    outb_p(0xF5, WDT_EFER); /* Select CRF5 */
    t = inb_p(WDT_EFDR);      /* read CRF5 */
    t &= ~0x0C;               /* set second mode & disable keyboard
                    turning off watchdog */
    t |= 0x02;        /* enable the WDTO# output low pulse
                    to the KBRST# pin (PIN60) */
    outb_p(t, WDT_EFDR);    /* Write back to CRF5 */

    outb_p(0xF7, WDT_EFER); /* Select CRF7 */
    t = inb_p(WDT_EFDR);      /* read CRF7 */
    t &= ~0xC0;               /* disable keyboard & mouse turning off
                    watchdog */
    outb_p(t, WDT_EFDR);    /* Write back to CRF7 */

    w83627hf_unselect_wd_register();
}

static void wdt_set_time(int timeout)
{
    spin_lock(&io_lock);

    w83627hf_select_wd_register();

    outb_p(0xF6, WDT_EFER);    /* Select CRF6 */
    outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF6 */

    w83627hf_unselect_wd_register();

    spin_unlock(&io_lock);
}

static int wdt_ping(void)
{
    wdt_set_time(timeout);
    return 0;
}

static int wdt_disable(void)
{
    wdt_set_time(0);
    return 0;
}

static int wdt_set_heartbeat(int t)
{
    if (t < 1 || t > 255)
        return -EINVAL;
    timeout = t;
    return 0;
}

static int wdt_get_time(void)
{
    int timeleft;

    spin_lock(&io_lock);

    w83627hf_select_wd_register();

    outb_p(0xF6, WDT_EFER);    /* Select CRF6 */
    timeleft = inb_p(WDT_EFDR); /* Read Timeout counter to CRF6 */

    w83627hf_unselect_wd_register();

    spin_unlock(&io_lock);

    return timeleft;
}

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;

            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 timeval;
    static const struct watchdog_info ident = {
        .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
                            WDIOF_MAGICCLOSE,
        .firmware_version = 1,
        .identity = "W83627HF WDT",
    };

    switch (cmd) {
    case WDIOC_GETSUPPORT:
        if (copy_to_user(argp, &ident, sizeof(ident)))
            return -EFAULT;
        break;
    case WDIOC_GETSTATUS:
    case WDIOC_GETBOOTSTATUS:
        return put_user(0, p);
    case WDIOC_SETOPTIONS:
    {
        int options, retval = -EINVAL;

        if (get_user(options, p))
            return -EFAULT;
        if (options & WDIOS_DISABLECARD) {
            wdt_disable();
            retval = 0;
        }
        if (options & WDIOS_ENABLECARD) {
            wdt_ping();
            retval = 0;
        }
        return retval;
    }
    case WDIOC_KEEPALIVE:
        wdt_ping();
        break;
    case WDIOC_SETTIMEOUT:
        if (get_user(timeval, p))
            return -EFAULT;
        if (wdt_set_heartbeat(timeval))
            return -EINVAL;
        wdt_ping();
        /* Fall */
    case WDIOC_GETTIMEOUT:
        return put_user(timeout, p);
    case WDIOC_GETTIMELEFT:
        timeval = wdt_get_time();
        return put_user(timeval, p);
    default:
        return -ENOTTY;
    }
    return 0;
}

static int wdt_open(struct inode *inode, struct file *file)
{
    if (test_and_set_bit(0, &wdt_is_open))
        return -EBUSY;
    /*
     *  Activate
     */

    wdt_ping();
    return nonseekable_open(inode, file);
}

static int wdt_close(struct inode *inode, struct file *file)
{
    if (expect_close == 42)
        wdt_disable();
    else {
        pr_crit("Unexpected close, not stopping watchdog!\n");
        wdt_ping();
    }
    expect_close = 0;
    clear_bit(0, &wdt_is_open);
    return 0;
}

/*
 *  Notifier for system down
 */

static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
    void *unused)
{
    if (code == SYS_DOWN || code == SYS_HALT)
        wdt_disable();  /* Turn the WDT off */

    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_close,
};

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

/*
 *  The WDT 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 int __init wdt_init(void)
{
    int ret;

    pr_info("WDT driver for the Winbond(TM) W83627HF/THF/HG/DHG Super I/O chip initialising\n");

    if (wdt_set_heartbeat(timeout)) {
        wdt_set_heartbeat(WATCHDOG_TIMEOUT);
        pr_info("timeout value must be 1 <= timeout <= 255, using %d\n",
            WATCHDOG_TIMEOUT);
    }

    if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
        pr_err("I/O address 0x%04x already in use\n", wdt_io);
        ret = -EIO;
        goto out;
    }

    w83627hf_init();

    ret = register_reboot_notifier(&wdt_notifier);
    if (ret != 0) {
        pr_err("cannot register reboot notifier (err=%d)\n", ret);
        goto unreg_regions;
    }

    ret = misc_register(&wdt_miscdev);
    if (ret != 0) {
        pr_err("cannot register miscdev on minor=%d (err=%d)\n",
               WATCHDOG_MINOR, ret);
        goto unreg_reboot;
    }

    pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
        timeout, nowayout);

out:
    return ret;
unreg_reboot:
    unregister_reboot_notifier(&wdt_notifier);
unreg_regions:
    release_region(wdt_io, 1);
    goto out;
}

static void __exit wdt_exit(void)
{
    misc_deregister(&wdt_miscdev);
    unregister_reboot_notifier(&wdt_notifier);
    release_region(wdt_io, 1);
}

module_init(wdt_init);
module_exit(wdt_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pádraig  Brady <[email protected]>");
MODULE_DESCRIPTION("w83627hf/thf WDT driver");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);