[WATCHDOG] show default value for nowayout in module parameter

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / char / watchdog / i8xx_tco.c

/*
 *      i8xx_tco:       TCO timer driver for i8xx chipsets
 *
 *      (c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights Reserved.
 *                              http://www.kernelconcepts.de
 *
 *      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 kernel concepts nor Nils Faerber admit liability nor provide
 *      warranty for any of this software. This material is provided
 *      "AS-IS" and at no charge.
 *
 *      (c) Copyright 2000      kernel concepts <nils@kernelconcepts.de>
 *                              developed for
 *                              Jentro AG, Haar/Munich (Germany)
 *
 *      TCO timer driver for i8xx chipsets
 *      based on softdog.c by Alan Cox <alan@redhat.com>
 *
 *      The TCO timer is implemented in the following I/O controller hubs:
 *      (See the intel documentation on http://developer.intel.com.)
 *      82801AA  (ICH)    : document number 290655-003, 290677-014,
 *      82801AB  (ICHO)   : document number 290655-003, 290677-014,
 *      82801BA  (ICH2)   : document number 290687-002, 298242-027,
 *      82801BAM (ICH2-M) : document number 290687-002, 298242-027,
 *      82801CA  (ICH3-S) : document number 290733-003, 290739-013,
 *      82801CAM (ICH3-M) : document number 290716-001, 290718-007,
 *      82801DB  (ICH4)   : document number 290744-001, 290745-020,
 *      82801DBM (ICH4-M) : document number 252337-001, 252663-005,
 *      82801E   (C-ICH)  : document number 273599-001, 273645-002,
 *      82801EB  (ICH5)   : document number 252516-001, 252517-003,
 *      82801ER  (ICH5R)  : document number 252516-001, 252517-003,
 *
 *  20000710 Nils Faerber
 *      Initial Version 0.01
 *  20000728 Nils Faerber
 *      0.02 Fix for SMI_EN->TCO_EN bit, some cleanups
 *  20011214 Matt Domsch <Matt_Domsch@dell.com>
 *      0.03 Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
 *           Didn't add timeout option as i810_margin already exists.
 *  20020224 Joel Becker, Wim Van Sebroeck
 *      0.04 Support for 82801CA(M) chipset, timer margin needs to be > 3,
 *           add support for WDIOC_SETTIMEOUT and WDIOC_GETTIMEOUT.
 *  20020412 Rob Radez <rob@osinvestor.com>, Wim Van Sebroeck
 *      0.05 Fix possible timer_alive race, add expect close support,
 *           clean up ioctls (WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS and
 *           WDIOC_SETOPTIONS), made i810tco_getdevice __init,
 *           removed boot_status, removed tco_timer_read,
 *           added support for 82801DB and 82801E chipset,
 *           added support for 82801EB and 8280ER chipset,
 *           general cleanup.
 *  20030921 Wim Van Sebroeck <wim@iguana.be>
 *      0.06 change i810_margin to heartbeat, use module_param,
 *           added notify system support, renamed module to i8xx_tco.
 *  20050128 Wim Van Sebroeck <wim@iguana.be>
 *      0.07 Added support for the ICH4-M, ICH6, ICH6R, ICH6-M, ICH6W and ICH6RW
 *           chipsets. Also added support for the "undocumented" ICH7 chipset.
 *  20050807 Wim Van Sebroeck <wim@iguana.be>
 *      0.08 Make sure that the watchdog is only "armed" when started.
 *           (Kernel Bug 4251)
 *  20060416 Wim Van Sebroeck <wim@iguana.be>
 *      0.09 Remove support for the ICH6, ICH6R, ICH6-M, ICH6W and ICH6RW and
 *           ICH7 chipsets. (See Kernel Bug 6031 - other code will support these
 *           chipsets)
 */

/*
 *      Includes, defines, variables, module parameters, ...
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/pci.h>
#include <linux/ioport.h>

#include <asm/uaccess.h>
#include <asm/io.h>

#include "i8xx_tco.h"

/* Module and version information */
#define TCO_VERSION "0.09"
#define TCO_MODULE_NAME "i8xx TCO timer"
#define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION
#define PFX TCO_MODULE_NAME ": "

/* internal variables */
static unsigned int ACPIBASE;
static spinlock_t tco_lock;     /* Guards the hardware */
static unsigned long timer_alive;
static char tco_expect_close;
static struct pci_dev *i8xx_tco_pci;

/* module parameters */
#define WATCHDOG_HEARTBEAT 30   /* 30 sec default heartbeat (2<heartbeat<39) */
static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");

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) ")");

/*
 * Some TCO specific functions
 */

static inline unsigned char seconds_to_ticks(int seconds)
{
        /* the internal timer is stored as ticks which decrement
         * every 0.6 seconds */
        return (seconds * 10) / 6;
}

static int tco_timer_start (void)
{
        unsigned char val;

        spin_lock(&tco_lock);

        /* disable chipset's NO_REBOOT bit */
        pci_read_config_byte (i8xx_tco_pci, 0xd4, &val);
        val &= 0xfd;
        pci_write_config_byte (i8xx_tco_pci, 0xd4, val);

        /* Bit 11: TCO Timer Halt -> 0 = The TCO timer is enabled to count */
        val = inb (TCO1_CNT + 1);
        val &= 0xf7;
        outb (val, TCO1_CNT + 1);
        val = inb (TCO1_CNT + 1);

        spin_unlock(&tco_lock);

        if (val & 0x08)
                return -1;
        return 0;
}

static int tco_timer_stop (void)
{
        unsigned char val, val1;

        spin_lock(&tco_lock);
        /* Bit 11: TCO Timer Halt -> 1 = The TCO timer is disabled */
        val = inb (TCO1_CNT + 1);
        val |= 0x08;
        outb (val, TCO1_CNT + 1);
        val = inb (TCO1_CNT + 1);

        /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
        pci_read_config_byte (i8xx_tco_pci, 0xd4, &val1);
        val1 |= 0x02;
        pci_write_config_byte (i8xx_tco_pci, 0xd4, val1);

        spin_unlock(&tco_lock);

        if ((val & 0x08) == 0)
                return -1;
        return 0;
}

static int tco_timer_keepalive (void)
{
        spin_lock(&tco_lock);
        /* Reload the timer by writing to the TCO Timer Reload register */
        outb (0x01, TCO1_RLD);
        spin_unlock(&tco_lock);
        return 0;
}

static int tco_timer_set_heartbeat (int t)
{
        unsigned char val;
        unsigned char tmrval;

        tmrval = seconds_to_ticks(t);
        /* from the specs: */
        /* "Values of 0h-3h are ignored and should not be attempted" */
        if (tmrval > 0x3f || tmrval < 0x04)
                return -EINVAL;

        /* Write new heartbeat to watchdog */
        spin_lock(&tco_lock);
        val = inb (TCO1_TMR);
        val &= 0xc0;
        val |= tmrval;
        outb (val, TCO1_TMR);
        val = inb (TCO1_TMR);
        spin_unlock(&tco_lock);

        if ((val & 0x3f) != tmrval)
                return -EINVAL;

        heartbeat = t;
        return 0;
}

static int tco_timer_get_timeleft (int *time_left)
{
        unsigned char val;

        spin_lock(&tco_lock);

        /* read the TCO Timer */
        val = inb (TCO1_RLD);
        val &= 0x3f;

        spin_unlock(&tco_lock);

        *time_left = (int)((val * 6) / 10);

        return 0;
}

/*
 *      /dev/watchdog handling
 */

static int i8xx_tco_open (struct inode *inode, struct file *file)
{
        /* /dev/watchdog can only be opened once */
        if (test_and_set_bit(0, &timer_alive))
                return -EBUSY;

        /*
         *      Reload and activate timer
         */
        tco_timer_keepalive ();
        tco_timer_start ();
        return nonseekable_open(inode, file);
}

static int i8xx_tco_release (struct inode *inode, struct file *file)
{
        /*
         *      Shut off the timer.
         */
        if (tco_expect_close == 42) {
                tco_timer_stop ();
        } else {
                printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
                tco_timer_keepalive ();
        }
        clear_bit(0, &timer_alive);
        tco_expect_close = 0;
        return 0;
}

static ssize_t i8xx_tco_write (struct file *file, const char __user *data,
                              size_t len, loff_t * ppos)
{
        /* See if we got the magic character 'V' and reload the timer */
        if (len) {
                if (!nowayout) {
                        size_t i;

                        /* note: just in case someone wrote the magic character
                         * five months ago... */
                        tco_expect_close = 0;

                        /* scan to see whether or not we got the magic character */
                        for (i = 0; i != len; i++) {
                                char c;
                                if(get_user(c, data+i))
                                        return -EFAULT;
                                if (c == 'V')
                                        tco_expect_close = 42;
                        }
                }

                /* someone wrote to us, we should reload the timer */
                tco_timer_keepalive ();
        }
        return len;
}

static int i8xx_tco_ioctl (struct inode *inode, struct file *file,
                          unsigned int cmd, unsigned long arg)
{
        int new_options, retval = -EINVAL;
        int new_heartbeat;
        int time_left;
        void __user *argp = (void __user *)arg;
        int __user *p = argp;
        static struct watchdog_info ident = {
                .options =              WDIOF_SETTIMEOUT |
                                        WDIOF_KEEPALIVEPING |
                                        WDIOF_MAGICCLOSE,
                .firmware_version =     0,
                .identity =             TCO_MODULE_NAME,
        };

        switch (cmd) {
                case WDIOC_GETSUPPORT:
                        return copy_to_user(argp, &ident,
                                sizeof (ident)) ? -EFAULT : 0;

                case WDIOC_GETSTATUS:
                case WDIOC_GETBOOTSTATUS:
                        return put_user (0, p);

                case WDIOC_KEEPALIVE:
                        tco_timer_keepalive ();
                        return 0;

                case WDIOC_SETOPTIONS:
                {
                        if (get_user (new_options, p))
                                return -EFAULT;

                        if (new_options & WDIOS_DISABLECARD) {
                                tco_timer_stop ();
                                retval = 0;
                        }

                        if (new_options & WDIOS_ENABLECARD) {
                                tco_timer_keepalive ();
                                tco_timer_start ();
                                retval = 0;
                        }

                        return retval;
                }

                case WDIOC_SETTIMEOUT:
                {
                        if (get_user(new_heartbeat, p))
                                return -EFAULT;

                        if (tco_timer_set_heartbeat(new_heartbeat))
                                return -EINVAL;

                        tco_timer_keepalive ();
                        /* Fall */
                }

                case WDIOC_GETTIMEOUT:
                        return put_user(heartbeat, p);

                case WDIOC_GETTIMELEFT:
                {
                        if (tco_timer_get_timeleft(&time_left))
                                return -EINVAL;

                        return put_user(time_left, p);
                }

                default:
                        return -ENOTTY;
        }
}

/*
 *      Notify system
 */

static int i8xx_tco_notify_sys (struct notifier_block *this, unsigned long code, void *unused)
{
        if (code==SYS_DOWN || code==SYS_HALT) {
                /* Turn the WDT off */
                tco_timer_stop ();
        }

        return NOTIFY_DONE;
}

/*
 *      Kernel Interfaces
 */

static const struct file_operations i8xx_tco_fops = {
        .owner =        THIS_MODULE,
        .llseek =       no_llseek,
        .write =        i8xx_tco_write,
        .ioctl =        i8xx_tco_ioctl,
        .open =         i8xx_tco_open,
        .release =      i8xx_tco_release,
};

static struct miscdevice i8xx_tco_miscdev = {
        .minor =        WATCHDOG_MINOR,
        .name =         "watchdog",
        .fops =         &i8xx_tco_fops,
};

static struct notifier_block i8xx_tco_notifier = {
        .notifier_call =        i8xx_tco_notify_sys,
};

/*
 * Data for PCI driver interface
 *
 * This data only exists for exporting the supported
 * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
 * register a pci_driver, because someone else might one day
 * want to register another driver on the same PCI id.
 */
static struct pci_device_id i8xx_tco_pci_tbl[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801AA_0) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801AB_0) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801BA_0) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801BA_10) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801CA_0) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801CA_12) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801DB_0) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801DB_12) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801E_0) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801EB_0) },
        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_1) },
        { },                    /* End of list */
};
MODULE_DEVICE_TABLE (pci, i8xx_tco_pci_tbl);

/*
 *      Init & exit routines
 */

static unsigned char __init i8xx_tco_getdevice (void)
{
        struct pci_dev *dev = NULL;
        u8 val1, val2;
        u16 badr;
        /*
         *      Find the PCI device
         */

        for_each_pci_dev(dev)
                if (pci_match_id(i8xx_tco_pci_tbl, dev)) {
                        i8xx_tco_pci = dev;
                        break;
                }

        if (i8xx_tco_pci) {
                /*
                 *      Find the ACPI base I/O address which is the base
                 *      for the TCO registers (TCOBASE=ACPIBASE + 0x60)
                 *      ACPIBASE is bits [15:7] from 0x40-0x43
                 */
                pci_read_config_byte (i8xx_tco_pci, 0x40, &val1);
                pci_read_config_byte (i8xx_tco_pci, 0x41, &val2);
                badr = ((val2 << 1) | (val1 >> 7)) << 7;
                ACPIBASE = badr;
                /* Something's wrong here, ACPIBASE has to be set */
                if (badr == 0x0001 || badr == 0x0000) {
                        printk (KERN_ERR PFX "failed to get TCOBASE address\n");
                        pci_dev_put(i8xx_tco_pci);
                        return 0;
                }

                /* Check chipset's NO_REBOOT bit */
                pci_read_config_byte (i8xx_tco_pci, 0xd4, &val1);
                if (val1 & 0x02) {
                        val1 &= 0xfd;
                        pci_write_config_byte (i8xx_tco_pci, 0xd4, val1);
                        pci_read_config_byte (i8xx_tco_pci, 0xd4, &val1);
                        if (val1 & 0x02) {
                                printk (KERN_ERR PFX "failed to reset NO_REBOOT flag, reboot disabled by hardware\n");
                                pci_dev_put(i8xx_tco_pci);
                                return 0;       /* Cannot reset NO_REBOOT bit */
                        }
                }
                /* Disable reboots untill the watchdog starts */
                val1 |= 0x02;
                pci_write_config_byte (i8xx_tco_pci, 0xd4, val1);

                /* Set the TCO_EN bit in SMI_EN register */
                if (!request_region (SMI_EN + 1, 1, "i8xx TCO")) {
                        printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
                                SMI_EN + 1);
                        pci_dev_put(i8xx_tco_pci);
                        return 0;
                }
                val1 = inb (SMI_EN + 1);
                val1 &= 0xdf;
                outb (val1, SMI_EN + 1);
                release_region (SMI_EN + 1, 1);
                return 1;
        }
        return 0;
}

static int __init watchdog_init (void)
{
        int ret;

        spin_lock_init(&tco_lock);

        /* Check whether or not the hardware watchdog is there */
        if (!i8xx_tco_getdevice () || i8xx_tco_pci == NULL)
                return -ENODEV;

        if (!request_region (TCOBASE, 0x10, "i8xx TCO")) {
                printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
                        TCOBASE);
                ret = -EIO;
                goto out;
        }

        /* Clear out the (probably old) status */
        outb (0, TCO1_STS);
        outb (3, TCO2_STS);

        /* Check that the heartbeat value is within it's range ; if not reset to the default */
        if (tco_timer_set_heartbeat (heartbeat)) {
                heartbeat = WATCHDOG_HEARTBEAT;
                tco_timer_set_heartbeat (heartbeat);
                printk(KERN_INFO PFX "heartbeat value must be 2<heartbeat<39, using %d\n",
                        heartbeat);
        }

        ret = register_reboot_notifier(&i8xx_tco_notifier);
        if (ret != 0) {
                printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
                        ret);
                goto unreg_region;
        }

        ret = misc_register(&i8xx_tco_miscdev);
        if (ret != 0) {
                printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
                        WATCHDOG_MINOR, ret);
                goto unreg_notifier;
        }

        tco_timer_stop ();

        printk (KERN_INFO PFX "initialized (0x%04x). heartbeat=%d sec (nowayout=%d)\n",
                TCOBASE, heartbeat, nowayout);

        return 0;

unreg_notifier:
        unregister_reboot_notifier(&i8xx_tco_notifier);
unreg_region:
        release_region (TCOBASE, 0x10);
out:
        pci_dev_put(i8xx_tco_pci);
        return ret;
}

static void __exit watchdog_cleanup (void)
{
        /* Stop the timer before we leave */
        if (!nowayout)
                tco_timer_stop ();

        /* Deregister */
        misc_deregister (&i8xx_tco_miscdev);
        unregister_reboot_notifier(&i8xx_tco_notifier);
        release_region (TCOBASE, 0x10);

        pci_dev_put(i8xx_tco_pci);
}

module_init(watchdog_init);
module_exit(watchdog_cleanup);

MODULE_AUTHOR("Nils Faerber");
MODULE_DESCRIPTION("TCO timer driver for i8xx chipsets");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);