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/*

 *      i810-tco 0.05:  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 & 82801AB  chip : document number 290655-003, 290677-004,

 *      82801BA & 82801BAM chip : document number 290687-002, 298242-005,

 *      82801CA & 82801CAM chip : document number 290716-001, 290718-001,

 *      82801DB & 82801E   chip : document number 290744-001, 273599-001,

 *      82801EB & 82801ER  chip : document number 252516-001

 *

 *  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.

 */

#include <linux/module.h>

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/fs.h>

#include <linux/mm.h>

#include <linux/miscdevice.h>

#include <linux/watchdog.h>

#include <linux/reboot.h>

#include <linux/init.h>

#include <linux/pci.h>

#include <linux/ioport.h>

#include <asm/uaccess.h>

#include <asm/io.h>

#include "i810-tco.h"

/* Module and version information */

#define TCO_VERSION "0.05"

#define TCO_MODULE_NAME "i810 TCO timer"

#define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION

/* Default expire timeout */

#define TIMER_MARGIN    50      /* steps of 0.6sec, 3<n<64. Default is 30 seconds */

static unsigned int ACPIBASE;

static spinlock_t tco_lock;     /* Guards the hardware */

static int i810_margin = TIMER_MARGIN;  /* steps of 0.6sec */

MODULE_PARM(i810_margin, "i");

MODULE_PARM_DESC(i810_margin, "i810-tco timeout in steps of 0.6sec, 3<n<64. Default = 50 (30 seconds)");

#ifdef CONFIG_WATCHDOG_NOWAYOUT

static int nowayout = 1;

#else

static int nowayout = 0;

#endif

MODULE_PARM(nowayout,"i");

MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");

/*

 *      Timer active flag

 */

static unsigned long timer_alive;

static char tco_expect_close;

/*

 * Some TCO specific functions

 */

/*

 * Start the timer countdown

 */

static int tco_timer_start (void)

{

        unsigned char val;

        spin_lock(&tco_lock);

        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;

}

/*

 * Stop the timer countdown

 */

static int tco_timer_stop (void)

{

        unsigned char val;

        spin_lock(&tco_lock);

        val = inb (TCO1_CNT + 1);

        val |= 0x08;

        outb (val, TCO1_CNT + 1);

        val = inb (TCO1_CNT + 1);

        spin_unlock(&tco_lock);

        if ((val & 0x08) == 0)

                return -1;

        return 0;

}

/*

 * Set the timer reload value

 */

static int tco_timer_settimer (unsigned char tmrval)

{

        unsigned char val;

        /* from the specs: */

        /* "Values of 0h-3h are ignored and should not be attempted" */

        if (tmrval > 0x3f || tmrval < 0x04)

                return -1;

        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 -1;

        return 0;

}

/*

 * Reload (trigger) the timer. Lock is needed so we dont reload it during

 * a reprogramming event

 */

static void tco_timer_reload (void)

{

        spin_lock(&tco_lock);

        outb (0x01, TCO1_RLD);

        spin_unlock(&tco_lock);

}

/*

 *      Allow only one person to hold it open

 */

static int i810tco_open (struct inode *inode, struct file *file)

{

        if (test_and_set_bit(0, &timer_alive))

                return -EBUSY;

        /*

         *      Reload and activate timer

         */

        tco_timer_reload ();

        tco_timer_start ();

        return 0;

}

static int i810tco_release (struct inode *inode, struct file *file)

{

        /*

         *      Shut off the timer.

         */

        if (tco_expect_close == 42 && !nowayout) {

                tco_timer_stop ();

        } else {

                tco_timer_reload ();

                printk(KERN_CRIT TCO_MODULE_NAME ": Unexpected close, not stopping watchdog!\n");

        }

        clear_bit(0, &timer_alive);

        tco_expect_close = 0;

        return 0;

}

static ssize_t i810tco_write (struct file *file, const char *data,

                              size_t len, loff_t * ppos)

{

        /*  Can't seek (pwrite) on this device  */

        if (ppos != &file->f_pos)

                return -ESPIPE;

        /* See if we got the magic character 'V' and reload the timer */

        if (len) {

                size_t i;

                tco_expect_close = 0;

                /* scan to see wether or not we got the magic character */

                for (i = 0; i != len; i++) {

                        u8 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_reload ();

                return 1;

        }

        return 0;

}

static int i810tco_ioctl (struct inode *inode, struct file *file,

                          unsigned int cmd, unsigned long arg)

{

        int new_margin, u_margin;

        int options, retval = -EINVAL;

        static struct watchdog_info ident = {

                options:                WDIOF_SETTIMEOUT |

                                        WDIOF_KEEPALIVEPING |

                                        WDIOF_MAGICCLOSE,

                firmware_version:       0,

                identity:               "i810 TCO timer",

        };

        switch (cmd) {

                default:

                        return -ENOTTY;

                case WDIOC_GETSUPPORT:

                        if (copy_to_user

                            ((struct watchdog_info *) arg, &ident, sizeof (ident)))

                                return -EFAULT;

                        return 0;

                case WDIOC_GETSTATUS:

                case WDIOC_GETBOOTSTATUS:

                        return put_user (0, (int *) arg);

                case WDIOC_SETOPTIONS:

                        if (get_user (options, (int *) arg))

                                return -EFAULT;

                        if (options & WDIOS_DISABLECARD) {

                                tco_timer_stop ();

                                retval = 0;

                        }

                        if (options & WDIOS_ENABLECARD) {

                                tco_timer_reload ();

                                tco_timer_start ();

                                retval = 0;

                        }

                        return retval;

                case WDIOC_KEEPALIVE:

                        tco_timer_reload ();

                        return 0;

                case WDIOC_SETTIMEOUT:

                        if (get_user (u_margin, (int *) arg))

                                return -EFAULT;

                        new_margin = (u_margin * 10 + 5) / 6;

                        if ((new_margin < 4) || (new_margin > 63))

                                return -EINVAL;

                        if (tco_timer_settimer ((unsigned char) new_margin))

                            return -EINVAL;

                        i810_margin = new_margin;

                        tco_timer_reload ();

                        /* Fall */

                case WDIOC_GETTIMEOUT:

                        return put_user ((int)(i810_margin * 6 / 10), (int *) arg);

        }

}

/*

 * 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 i810tco_pci_tbl[] __initdata = {

        { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801AA_0,   PCI_ANY_ID, PCI_ANY_ID, },

        { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801AB_0,   PCI_ANY_ID, PCI_ANY_ID, },

        { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801BA_0,   PCI_ANY_ID, PCI_ANY_ID, },

        { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801BA_10,  PCI_ANY_ID, PCI_ANY_ID, },

        { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801CA_0,   PCI_ANY_ID, PCI_ANY_ID, },

        { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801CA_12,  PCI_ANY_ID, PCI_ANY_ID, },

        { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801DB_0,   PCI_ANY_ID, PCI_ANY_ID, },

        { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801E_0,    PCI_ANY_ID, PCI_ANY_ID, },

        { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801EB_0,   PCI_ANY_ID, PCI_ANY_ID, },

        { 0, },

};

MODULE_DEVICE_TABLE (pci, i810tco_pci_tbl);

static struct pci_dev *i810tco_pci;

static unsigned char __init i810tco_getdevice (void)

{

        struct pci_dev *dev;

        u8 val1, val2;

        u16 badr;

        /*

         *      Find the PCI device

         */

        pci_for_each_dev(dev) {

                if (pci_match_device(i810tco_pci_tbl, dev)) {

                        i810tco_pci = dev;

                        break;

                }

        }

        if (i810tco_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 (i810tco_pci, 0x40, &val1);

                pci_read_config_byte (i810tco_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 TCO_MODULE_NAME " init: failed to get TCOBASE address\n");

                        return 0;

                }

                /*

                 * Check chipset's NO_REBOOT bit

                 */

                pci_read_config_byte (i810tco_pci, 0xd4, &val1);

                if (val1 & 0x02) {

                        val1 &= 0xfd;

                        pci_write_config_byte (i810tco_pci, 0xd4, val1);

                        pci_read_config_byte (i810tco_pci, 0xd4, &val1);

                        if (val1 & 0x02) {

                                printk (KERN_ERR TCO_MODULE_NAME " init: failed to reset NO_REBOOT flag, reboot disabled by hardware\n");

                                return 0;        /* Cannot reset NO_REBOOT bit */

                        }

                }

                /* Set the TCO_EN bit in SMI_EN register */

                val1 = inb (SMI_EN + 1);

                val1 &= 0xdf;

                outb (val1, SMI_EN + 1);

                /* Clear out the (probably old) status */

                outb (0, TCO1_STS);

                outb (3, TCO2_STS);

                return 1;

        }

        return 0;

}

static struct file_operations i810tco_fops = {

        owner:          THIS_MODULE,

        write:          i810tco_write,

        ioctl:          i810tco_ioctl,

        open:           i810tco_open,

        release:        i810tco_release,

};

static struct miscdevice i810tco_miscdev = {

        minor:          WATCHDOG_MINOR,

        name:           "watchdog",

        fops:           &i810tco_fops,

};

static int __init watchdog_init (void)

{

        spin_lock_init(&tco_lock);

        if (!i810tco_getdevice () || i810tco_pci == NULL)

                return -ENODEV;

        if (!request_region (TCOBASE, 0x10, "i810 TCO")) {

                printk (KERN_ERR TCO_MODULE_NAME

                        ": I/O address 0x%04x already in use\n",

                        TCOBASE);

                return -EIO;

        }

        if (misc_register (&i810tco_miscdev) != 0) {

                release_region (TCOBASE, 0x10);

                printk (KERN_ERR TCO_MODULE_NAME ": cannot register miscdev\n");

                return -EIO;

        }

        tco_timer_settimer ((unsigned char) i810_margin);

        tco_timer_reload ();

        printk (KERN_INFO TCO_DRIVER_NAME

                ": timer margin: %d sec (0x%04x) (nowayout=%d)\n",

                (int) (i810_margin * 6 / 10), TCOBASE, nowayout);

        return 0;

}

static void __exit watchdog_cleanup (void)

{

        u8 val;

        /* Reset the timer before we leave */

        tco_timer_reload ();

        /* Set the NO_REBOOT bit to prevent later reboots, just for sure */

        pci_read_config_byte (i810tco_pci, 0xd4, &val);

        val |= 0x02;

        pci_write_config_byte (i810tco_pci, 0xd4, val);

        release_region (TCOBASE, 0x10);

        misc_deregister (&i810tco_miscdev);

}

module_init(watchdog_init);

module_exit(watchdog_cleanup);

MODULE_AUTHOR("Nils Faerber");

MODULE_DESCRIPTION("TCO timer driver for i8xx chipsets");

MODULE_LICENSE("GPL");

EXPORT_NO_SYMBOLS;