/*
 *      intel TCO Watchdog Driver
 *
 *      (c) Copyright 2006-2011 Wim Van Sebroeck <wim@iguana.be>.
 *
 *      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 Wim Van Sebroeck nor Iguana vzw. admit liability nor
 *      provide warranty for any of this software. This material is
 *      provided "AS-IS" and at no charge.
 *
 *      The TCO watchdog is implemented in the following I/O controller hubs:
 *      (See the intel documentation on http://developer.intel.com.)
 *      document number 290655-003, 290677-014: 82801AA (ICH), 82801AB (ICHO)
 *      document number 290687-002, 298242-027: 82801BA (ICH2)
 *      document number 290733-003, 290739-013: 82801CA (ICH3-S)
 *      document number 290716-001, 290718-007: 82801CAM (ICH3-M)
 *      document number 290744-001, 290745-025: 82801DB (ICH4)
 *      document number 252337-001, 252663-008: 82801DBM (ICH4-M)
 *      document number 273599-001, 273645-002: 82801E (C-ICH)
 *      document number 252516-001, 252517-028: 82801EB (ICH5), 82801ER (ICH5R)
 *      document number 300641-004, 300884-013: 6300ESB
 *      document number 301473-002, 301474-026: 82801F (ICH6)
 *      document number 313082-001, 313075-006: 631xESB, 632xESB
 *      document number 307013-003, 307014-024: 82801G (ICH7)
 *      document number 322896-001, 322897-001: NM10
 *      document number 313056-003, 313057-017: 82801H (ICH8)
 *      document number 316972-004, 316973-012: 82801I (ICH9)
 *      document number 319973-002, 319974-002: 82801J (ICH10)
 *      document number 322169-001, 322170-003: 5 Series, 3400 Series (PCH)
 *      document number 320066-003, 320257-008: EP80597 (IICH)
 *      document number 324645-001, 324646-001: Cougar Point (CPT)
 *      document number TBD                   : Patsburg (PBG)
 *      document number TBD                   : DH89xxCC
 *      document number TBD                   : Panther Point
 *      document number TBD                   : Lynx Point
 *      document number TBD                   : Lynx Point-LP
 */

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

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

/* Module and version information */
#define DRV_NAME        "iTCO_wdt"
#define DRV_VERSION     "1.11"

/* Includes */
#include <linux/module.h>               /* For module specific items */
#include <linux/moduleparam.h>          /* For new moduleparam's */
#include <linux/types.h>                /* For standard types (like size_t) */
#include <linux/errno.h>                /* For the -ENODEV/... values */
#include <linux/kernel.h>               /* For printk/panic/... */
#include <linux/miscdevice.h>           /* For MODULE_ALIAS_MISCDEV
                                                        (WATCHDOG_MINOR) */
#include <linux/watchdog.h>             /* For the watchdog specific items */
#include <linux/init.h>                 /* For __init/__exit/... */
#include <linux/fs.h>                   /* For file operations */
#include <linux/platform_device.h>      /* For platform_driver framework */
#include <linux/pci.h>                  /* For pci functions */
#include <linux/ioport.h>               /* For io-port access */
#include <linux/spinlock.h>             /* For spin_lock/spin_unlock/... */
#include <linux/uaccess.h>              /* For copy_to_user/put_user/... */
#include <linux/io.h>                   /* For inb/outb/... */
#include <linux/platform_data/itco_wdt.h>

#include "iTCO_vendor.h"

/* Address definitions for the TCO */
/* TCO base address */
#define TCOBASE         (iTCO_wdt_private.tco_res->start)
/* SMI Control and Enable Register */
#define SMI_EN          (iTCO_wdt_private.smi_res->start)

#define TCO_RLD         (TCOBASE + 0x00) /* TCO Timer Reload and Curr. Value */
#define TCOv1_TMR       (TCOBASE + 0x01) /* TCOv1 Timer Initial Value   */
#define TCO_DAT_IN      (TCOBASE + 0x02) /* TCO Data In Register        */
#define TCO_DAT_OUT     (TCOBASE + 0x03) /* TCO Data Out Register       */
#define TCO1_STS        (TCOBASE + 0x04) /* TCO1 Status Register        */
#define TCO2_STS        (TCOBASE + 0x06) /* TCO2 Status Register        */
#define TCO1_CNT        (TCOBASE + 0x08) /* TCO1 Control Register       */
#define TCO2_CNT        (TCOBASE + 0x0a) /* TCO2 Control Register       */
#define TCOv2_TMR       (TCOBASE + 0x12) /* TCOv2 Timer Initial Value   */

/* internal variables */
static struct {         /* this is private data for the iTCO_wdt device */
        /* TCO version/generation */
        unsigned int iTCO_version;
        struct resource *tco_res;
        struct resource *smi_res;
        /*
         * NO_REBOOT flag is Memory-Mapped GCS register bit 5 (TCO version 2),
         * or memory-mapped PMC register bit 4 (TCO version 3).
         */
        struct resource *gcs_pmc_res;
        unsigned long __iomem *gcs_pmc;
        /* the lock for io operations */
        spinlock_t io_lock;
        struct platform_device *dev;
        /* the PCI-device */
        struct pci_dev *pdev;
} iTCO_wdt_private;

/* module parameters */
#define WATCHDOG_TIMEOUT 30     /* 30 sec default heartbeat */
static int heartbeat = WATCHDOG_TIMEOUT;  /* in seconds */
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog timeout in seconds. "
        "5..76 (TCO v1) or 3..614 (TCO v2), 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) ")");

static int turn_SMI_watchdog_clear_off = 1;
module_param(turn_SMI_watchdog_clear_off, int, 0);
MODULE_PARM_DESC(turn_SMI_watchdog_clear_off,
        "Turn off SMI clearing watchdog (depends on TCO-version)(default=1)");

/*
 * Some TCO specific functions
 */

/*
 * The iTCO v1 and v2's internal timer is stored as ticks which decrement
 * every 0.6 seconds.  v3's internal timer is stored as seconds (some
 * datasheets incorrectly state 0.6 seconds).
 */
static inline unsigned int seconds_to_ticks(int secs)
{
        return iTCO_wdt_private.iTCO_version == 3 ? secs : (secs * 10) / 6;
}

static inline unsigned int ticks_to_seconds(int ticks)
{
        return iTCO_wdt_private.iTCO_version == 3 ? ticks : (ticks * 6) / 10;
}

static inline u32 no_reboot_bit(void)
{
        u32 enable_bit;

        switch (iTCO_wdt_private.iTCO_version) {
        case 3:
                enable_bit = 0x00000010;
                break;
        case 2:
                enable_bit = 0x00000020;
                break;
        case 4:
        case 1:
        default:
                enable_bit = 0x00000002;
                break;
        }

        return enable_bit;
}

static void iTCO_wdt_set_NO_REBOOT_bit(void)
{
        u32 val32;

        /* Set the NO_REBOOT bit: this disables reboots */
        if (iTCO_wdt_private.iTCO_version >= 2) {
                val32 = readl(iTCO_wdt_private.gcs_pmc);
                val32 |= no_reboot_bit();
                writel(val32, iTCO_wdt_private.gcs_pmc);
        } else if (iTCO_wdt_private.iTCO_version == 1) {
                pci_read_config_dword(iTCO_wdt_private.pdev, 0xd4, &val32);
                val32 |= no_reboot_bit();
                pci_write_config_dword(iTCO_wdt_private.pdev, 0xd4, val32);
        }
}

static int iTCO_wdt_unset_NO_REBOOT_bit(void)
{
        u32 enable_bit = no_reboot_bit();
        u32 val32 = 0;

        /* Unset the NO_REBOOT bit: this enables reboots */
        if (iTCO_wdt_private.iTCO_version >= 2) {
                val32 = readl(iTCO_wdt_private.gcs_pmc);
                val32 &= ~enable_bit;
                writel(val32, iTCO_wdt_private.gcs_pmc);

                val32 = readl(iTCO_wdt_private.gcs_pmc);
        } else if (iTCO_wdt_private.iTCO_version == 1) {
                pci_read_config_dword(iTCO_wdt_private.pdev, 0xd4, &val32);
                val32 &= ~enable_bit;
                pci_write_config_dword(iTCO_wdt_private.pdev, 0xd4, val32);

                pci_read_config_dword(iTCO_wdt_private.pdev, 0xd4, &val32);
        }

        if (val32 & enable_bit)
                return -EIO;

        return 0;
}

static int iTCO_wdt_start(struct watchdog_device *wd_dev)
{
        unsigned int val;

        spin_lock(&iTCO_wdt_private.io_lock);

        iTCO_vendor_pre_start(iTCO_wdt_private.smi_res, wd_dev->timeout);

        /* disable chipset's NO_REBOOT bit */
        if (iTCO_wdt_unset_NO_REBOOT_bit()) {
                spin_unlock(&iTCO_wdt_private.io_lock);
                pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware/BIOS\n");
                return -EIO;
        }

        /* Force the timer to its reload value by writing to the TCO_RLD
           register */
        if (iTCO_wdt_private.iTCO_version >= 2)
                outw(0x01, TCO_RLD);
        else if (iTCO_wdt_private.iTCO_version == 1)
                outb(0x01, TCO_RLD);

        /* Bit 11: TCO Timer Halt -> 0 = The TCO timer is enabled to count */
        val = inw(TCO1_CNT);
        val &= 0xf7ff;
        outw(val, TCO1_CNT);
        val = inw(TCO1_CNT);
        spin_unlock(&iTCO_wdt_private.io_lock);

        if (val & 0x0800)
                return -1;
        return 0;
}

static int iTCO_wdt_stop(struct watchdog_device *wd_dev)
{
        unsigned int val;

        spin_lock(&iTCO_wdt_private.io_lock);

        iTCO_vendor_pre_stop(iTCO_wdt_private.smi_res);

        /* Bit 11: TCO Timer Halt -> 1 = The TCO timer is disabled */
        val = inw(TCO1_CNT);
        val |= 0x0800;
        outw(val, TCO1_CNT);
        val = inw(TCO1_CNT);

        /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
        iTCO_wdt_set_NO_REBOOT_bit();

        spin_unlock(&iTCO_wdt_private.io_lock);

        if ((val & 0x0800) == 0)
                return -1;
        return 0;
}

static int iTCO_wdt_ping(struct watchdog_device *wd_dev)
{
        spin_lock(&iTCO_wdt_private.io_lock);

        iTCO_vendor_pre_keepalive(iTCO_wdt_private.smi_res, wd_dev->timeout);

        /* Reload the timer by writing to the TCO Timer Counter register */
        if (iTCO_wdt_private.iTCO_version >= 2) {
                outw(0x01, TCO_RLD);
        } else if (iTCO_wdt_private.iTCO_version == 1) {
                /* Reset the timeout status bit so that the timer
                 * needs to count down twice again before rebooting */
                outw(0x0008, TCO1_STS); /* write 1 to clear bit */

                outb(0x01, TCO_RLD);
        }

        spin_unlock(&iTCO_wdt_private.io_lock);
        return 0;
}

static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
{
        unsigned int val16;
        unsigned char val8;
        unsigned int tmrval;

        tmrval = seconds_to_ticks(t);

        /* For TCO v1 the timer counts down twice before rebooting */
        if (iTCO_wdt_private.iTCO_version == 1)
                tmrval /= 2;

        /* from the specs: */
        /* "Values of 0h-3h are ignored and should not be attempted" */
        if (tmrval < 0x04)
                return -EINVAL;
        if (((iTCO_wdt_private.iTCO_version >= 2) && (tmrval > 0x3ff)) ||
            ((iTCO_wdt_private.iTCO_version == 1) && (tmrval > 0x03f)))
                return -EINVAL;

        iTCO_vendor_pre_set_heartbeat(tmrval);

        /* Write new heartbeat to watchdog */
        if (iTCO_wdt_private.iTCO_version >= 2) {
                spin_lock(&iTCO_wdt_private.io_lock);
                val16 = inw(TCOv2_TMR);
                val16 &= 0xfc00;
                val16 |= tmrval;
                outw(val16, TCOv2_TMR);
                val16 = inw(TCOv2_TMR);
                spin_unlock(&iTCO_wdt_private.io_lock);

                if ((val16 & 0x3ff) != tmrval)
                        return -EINVAL;
        } else if (iTCO_wdt_private.iTCO_version == 1) {
                spin_lock(&iTCO_wdt_private.io_lock);
                val8 = inb(TCOv1_TMR);
                val8 &= 0xc0;
                val8 |= (tmrval & 0xff);
                outb(val8, TCOv1_TMR);
                val8 = inb(TCOv1_TMR);
                spin_unlock(&iTCO_wdt_private.io_lock);

                if ((val8 & 0x3f) != tmrval)
                        return -EINVAL;
        }

        wd_dev->timeout = t;
        return 0;
}

static unsigned int iTCO_wdt_get_timeleft(struct watchdog_device *wd_dev)
{
        unsigned int val16;
        unsigned char val8;
        unsigned int time_left = 0;

        /* read the TCO Timer */
        if (iTCO_wdt_private.iTCO_version >= 2) {
                spin_lock(&iTCO_wdt_private.io_lock);
                val16 = inw(TCO_RLD);
                val16 &= 0x3ff;
                spin_unlock(&iTCO_wdt_private.io_lock);

                time_left = ticks_to_seconds(val16);
        } else if (iTCO_wdt_private.iTCO_version == 1) {
                spin_lock(&iTCO_wdt_private.io_lock);
                val8 = inb(TCO_RLD);
                val8 &= 0x3f;
                if (!(inw(TCO1_STS) & 0x0008))
                        val8 += (inb(TCOv1_TMR) & 0x3f);
                spin_unlock(&iTCO_wdt_private.io_lock);

                time_left = ticks_to_seconds(val8);
        }
        return time_left;
}

/*
 *      Kernel Interfaces
 */

static const struct watchdog_info ident = {
        .options =              WDIOF_SETTIMEOUT |
                                WDIOF_KEEPALIVEPING |
                                WDIOF_MAGICCLOSE,
        .firmware_version =     0,
        .identity =             DRV_NAME,
};

static const struct watchdog_ops iTCO_wdt_ops = {
        .owner =                THIS_MODULE,
        .start =                iTCO_wdt_start,
        .stop =                 iTCO_wdt_stop,
        .ping =                 iTCO_wdt_ping,
        .set_timeout =          iTCO_wdt_set_timeout,
        .get_timeleft =         iTCO_wdt_get_timeleft,
};

static struct watchdog_device iTCO_wdt_watchdog_dev = {
        .info =         &ident,
        .ops =          &iTCO_wdt_ops,
};

/*
 *      Init & exit routines
 */

static void iTCO_wdt_cleanup(void)
{
        /* Stop the timer before we leave */
        if (!nowayout)
                iTCO_wdt_stop(&iTCO_wdt_watchdog_dev);

        /* Deregister */
        watchdog_unregister_device(&iTCO_wdt_watchdog_dev);

        /* release resources */
        release_region(iTCO_wdt_private.tco_res->start,
                        resource_size(iTCO_wdt_private.tco_res));
        release_region(iTCO_wdt_private.smi_res->start,
                        resource_size(iTCO_wdt_private.smi_res));
        if (iTCO_wdt_private.iTCO_version >= 2) {
                iounmap(iTCO_wdt_private.gcs_pmc);
                release_mem_region(iTCO_wdt_private.gcs_pmc_res->start,
                                resource_size(iTCO_wdt_private.gcs_pmc_res));
        }

        iTCO_wdt_private.tco_res = NULL;
        iTCO_wdt_private.smi_res = NULL;
        iTCO_wdt_private.gcs_pmc_res = NULL;
        iTCO_wdt_private.gcs_pmc = NULL;
}

static int iTCO_wdt_probe(struct platform_device *dev)
{
        int ret = -ENODEV;
        unsigned long val32;
        struct itco_wdt_platform_data *pdata = dev->dev.platform_data;

        if (!pdata)
                goto out;

        spin_lock_init(&iTCO_wdt_private.io_lock);

        iTCO_wdt_private.tco_res =
                platform_get_resource(dev, IORESOURCE_IO, ICH_RES_IO_TCO);
        if (!iTCO_wdt_private.tco_res)
                goto out;

        iTCO_wdt_private.smi_res =
                platform_get_resource(dev, IORESOURCE_IO, ICH_RES_IO_SMI);
        if (!iTCO_wdt_private.smi_res)
                goto out;

        iTCO_wdt_private.iTCO_version = pdata->version;
        iTCO_wdt_private.dev = dev;
        iTCO_wdt_private.pdev = to_pci_dev(dev->dev.parent);

        /*
         * Get the Memory-Mapped GCS or PMC register, we need it for the
         * NO_REBOOT flag (TCO v2 and v3).
         */
        if (iTCO_wdt_private.iTCO_version >= 2) {
                iTCO_wdt_private.gcs_pmc_res = platform_get_resource(dev,
                                                        IORESOURCE_MEM,
                                                        ICH_RES_MEM_GCS_PMC);

                if (!iTCO_wdt_private.gcs_pmc_res)
                        goto out;

                if (!request_mem_region(iTCO_wdt_private.gcs_pmc_res->start,
                        resource_size(iTCO_wdt_private.gcs_pmc_res), dev->name)) {
                        ret = -EBUSY;
                        goto out;
                }
                iTCO_wdt_private.gcs_pmc = ioremap(iTCO_wdt_private.gcs_pmc_res->start,
                        resource_size(iTCO_wdt_private.gcs_pmc_res));
                if (!iTCO_wdt_private.gcs_pmc) {
                        ret = -EIO;
                        goto unreg_gcs_pmc;
                }
        }

        /* Check chipset's NO_REBOOT bit */
        if (iTCO_wdt_unset_NO_REBOOT_bit() && iTCO_vendor_check_noreboot_on()) {
                pr_info("unable to reset NO_REBOOT flag, device disabled by hardware/BIOS\n");
                ret = -ENODEV;  /* Cannot reset NO_REBOOT bit */
                goto unmap_gcs_pmc;
        }

        /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
        iTCO_wdt_set_NO_REBOOT_bit();

        /* The TCO logic uses the TCO_EN bit in the SMI_EN register */
        if (!request_region(iTCO_wdt_private.smi_res->start,
                        resource_size(iTCO_wdt_private.smi_res), dev->name)) {
                pr_err("I/O address 0x%04llx already in use, device disabled\n",
                       (u64)SMI_EN);
                ret = -EBUSY;
                goto unmap_gcs_pmc;
        }
        if (turn_SMI_watchdog_clear_off >= iTCO_wdt_private.iTCO_version) {
                /*
                 * Bit 13: TCO_EN -> 0
                 * Disables TCO logic generating an SMI#
                 */
                val32 = inl(SMI_EN);
                val32 &= 0xffffdfff;    /* Turn off SMI clearing watchdog */
                outl(val32, SMI_EN);
        }

        if (!request_region(iTCO_wdt_private.tco_res->start,
                        resource_size(iTCO_wdt_private.tco_res), dev->name)) {
                pr_err("I/O address 0x%04llx already in use, device disabled\n",
                       (u64)TCOBASE);
                ret = -EBUSY;
                goto unreg_smi;
        }

        pr_info("Found a %s TCO device (Version=%d, TCOBASE=0x%04llx)\n",
                pdata->name, pdata->version, (u64)TCOBASE);

        /* Clear out the (probably old) status */
        switch (iTCO_wdt_private.iTCO_version) {
        case 4:
                outw(0x0008, TCO1_STS); /* Clear the Time Out Status bit */
                outw(0x0002, TCO2_STS); /* Clear SECOND_TO_STS bit */
                break;
        case 3:
                outl(0x20008, TCO1_STS);
                break;
        case 2:
        case 1:
        default:
                outw(0x0008, TCO1_STS); /* Clear the Time Out Status bit */
                outw(0x0002, TCO2_STS); /* Clear SECOND_TO_STS bit */
                outw(0x0004, TCO2_STS); /* Clear BOOT_STS bit */
                break;
        }

        iTCO_wdt_watchdog_dev.bootstatus = 0;
        iTCO_wdt_watchdog_dev.timeout = WATCHDOG_TIMEOUT;
        watchdog_set_nowayout(&iTCO_wdt_watchdog_dev, nowayout);
        iTCO_wdt_watchdog_dev.parent = &dev->dev;

        /* Make sure the watchdog is not running */
        iTCO_wdt_stop(&iTCO_wdt_watchdog_dev);

        /* Check that the heartbeat value is within it's range;
           if not reset to the default */
        if (iTCO_wdt_set_timeout(&iTCO_wdt_watchdog_dev, heartbeat)) {
                iTCO_wdt_set_timeout(&iTCO_wdt_watchdog_dev, WATCHDOG_TIMEOUT);
                pr_info("timeout value out of range, using %d\n",
                        WATCHDOG_TIMEOUT);
        }

        ret = watchdog_register_device(&iTCO_wdt_watchdog_dev);
        if (ret != 0) {
                pr_err("cannot register watchdog device (err=%d)\n", ret);
                goto unreg_tco;
        }

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

        return 0;

unreg_tco:
        release_region(iTCO_wdt_private.tco_res->start,
                        resource_size(iTCO_wdt_private.tco_res));
unreg_smi:
        release_region(iTCO_wdt_private.smi_res->start,
                        resource_size(iTCO_wdt_private.smi_res));
unmap_gcs_pmc:
        if (iTCO_wdt_private.iTCO_version >= 2)
                iounmap(iTCO_wdt_private.gcs_pmc);
unreg_gcs_pmc:
        if (iTCO_wdt_private.iTCO_version >= 2)
                release_mem_region(iTCO_wdt_private.gcs_pmc_res->start,
                                resource_size(iTCO_wdt_private.gcs_pmc_res));
out:
        iTCO_wdt_private.tco_res = NULL;
        iTCO_wdt_private.smi_res = NULL;
        iTCO_wdt_private.gcs_pmc_res = NULL;
        iTCO_wdt_private.gcs_pmc = NULL;

        return ret;
}

static int iTCO_wdt_remove(struct platform_device *dev)
{
        if (iTCO_wdt_private.tco_res || iTCO_wdt_private.smi_res)
                iTCO_wdt_cleanup();

        return 0;
}

static void iTCO_wdt_shutdown(struct platform_device *dev)
{
        iTCO_wdt_stop(NULL);
}

static struct platform_driver iTCO_wdt_driver = {
        .probe          = iTCO_wdt_probe,
        .remove         = iTCO_wdt_remove,
        .shutdown       = iTCO_wdt_shutdown,
        .driver         = {
                .owner  = THIS_MODULE,
                .name   = DRV_NAME,
        },
};

static int __init iTCO_wdt_init_module(void)
{
        int err;

        pr_info("Intel TCO WatchDog Timer Driver v%s\n", DRV_VERSION);

        err = platform_driver_register(&iTCO_wdt_driver);
        if (err)
                return err;

        return 0;
}

static void __exit iTCO_wdt_cleanup_module(void)
{
        platform_driver_unregister(&iTCO_wdt_driver);
        pr_info("Watchdog Module Unloaded\n");
}

module_init(iTCO_wdt_init_module);
module_exit(iTCO_wdt_cleanup_module);

MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
MODULE_DESCRIPTION("Intel TCO WatchDog Timer Driver");
MODULE_VERSION(DRV_VERSION);
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:" DRV_NAME);