// SPDX-License-Identifier: GPL-2.0-only
/*
 *      HPE WatchDog Driver
 *      based on
 *
 *      SoftDog 0.05:   A Software Watchdog Device
 *
 *      (c) Copyright 2018 Hewlett Packard Enterprise Development LP
 *      Thomas Mingarelli <thomas.mingarelli@hpe.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/device.h>
#include <linux/hex.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/pci.h>
#include <linux/pci_ids.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#ifdef CONFIG_HPWDT_NMI_DECODING
#include <asm/nmi.h>
#endif
#include <linux/crash_dump.h>

#define HPWDT_VERSION                   "2.0.4"
#define SECS_TO_TICKS(secs)             ((secs) * 1000 / 128)
#define TICKS_TO_SECS(ticks)            ((ticks) * 128 / 1000)
#define HPWDT_MAX_TICKS                 65535
#define HPWDT_MAX_TIMER                 TICKS_TO_SECS(HPWDT_MAX_TICKS)
#define DEFAULT_MARGIN                  30
#define PRETIMEOUT_SEC                  9

static unsigned int soft_margin = DEFAULT_MARGIN;       /* in seconds */
static bool nowayout = WATCHDOG_NOWAYOUT;
static bool pretimeout = IS_ENABLED(CONFIG_HPWDT_NMI_DECODING);
static int kdumptimeout = -1;

static void __iomem *pci_mem_addr;              /* the PCI-memory address */
static unsigned long __iomem *hpwdt_nmistat;
static unsigned long __iomem *hpwdt_timer_reg;
static unsigned long __iomem *hpwdt_timer_con;

static const struct pci_device_id hpwdt_devices[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_COMPAQ, 0xB203) },   /* iLO2 */
        { PCI_DEVICE(PCI_VENDOR_ID_HP, 0x3306) },       /* iLO3 */
        { PCI_DEVICE(PCI_VENDOR_ID_HP_3PAR, 0x0389) },  /* PCtrl */
        {0},                    /* terminate list */
};
MODULE_DEVICE_TABLE(pci, hpwdt_devices);

static const struct pci_device_id hpwdt_blacklist[] = {
        { PCI_DEVICE_SUB(PCI_VENDOR_ID_HP, 0x3306, PCI_VENDOR_ID_HP, 0x1979) }, /* auxilary iLO */
        { PCI_DEVICE_SUB(PCI_VENDOR_ID_HP, 0x3306, PCI_VENDOR_ID_HP_3PAR, 0x0289) },  /* CL */
        {0},                    /* terminate list */
};

static struct watchdog_device hpwdt_dev;
/*
 *      Watchdog operations
 */
static int hpwdt_hw_is_running(void)
{
        return ioread8(hpwdt_timer_con) & 0x01;
}

static int hpwdt_start(struct watchdog_device *wdd)
{
        int control = 0x81 | (pretimeout ? 0x4 : 0);
        int reload = SECS_TO_TICKS(min(wdd->timeout, wdd->max_hw_heartbeat_ms/1000));

        dev_dbg(wdd->parent, "start watchdog 0x%08x:0x%08x:0x%02x\n", wdd->timeout, reload, control);
        iowrite16(reload, hpwdt_timer_reg);
        iowrite8(control, hpwdt_timer_con);

        return 0;
}

static void hpwdt_stop(void)
{
        unsigned long data;

        pr_debug("stop  watchdog\n");

        data = ioread8(hpwdt_timer_con);
        data &= 0xFE;
        iowrite8(data, hpwdt_timer_con);
}

static int hpwdt_stop_core(struct watchdog_device *wdd)
{
        hpwdt_stop();

        return 0;
}

static void hpwdt_ping_ticks(int val)
{
        val = min(val, HPWDT_MAX_TICKS);
        iowrite16(val, hpwdt_timer_reg);
}

static int hpwdt_ping(struct watchdog_device *wdd)
{
        int reload = SECS_TO_TICKS(min(wdd->timeout, wdd->max_hw_heartbeat_ms/1000));

        dev_dbg(wdd->parent, "ping  watchdog 0x%08x:0x%08x\n", wdd->timeout, reload);
        hpwdt_ping_ticks(reload);

        return 0;
}

static unsigned int hpwdt_gettimeleft(struct watchdog_device *wdd)
{
        return TICKS_TO_SECS(ioread16(hpwdt_timer_reg));
}

static int hpwdt_settimeout(struct watchdog_device *wdd, unsigned int val)
{
        dev_dbg(wdd->parent, "set_timeout = %d\n", val);

        wdd->timeout = val;
        if (val <= wdd->pretimeout) {
                dev_dbg(wdd->parent, "pretimeout < timeout. Setting to zero\n");
                wdd->pretimeout = 0;
                pretimeout = false;
                if (watchdog_active(wdd))
                        hpwdt_start(wdd);
        }
        hpwdt_ping(wdd);

        return 0;
}

#ifdef CONFIG_HPWDT_NMI_DECODING
static int hpwdt_set_pretimeout(struct watchdog_device *wdd, unsigned int req)
{
        unsigned int val = 0;

        dev_dbg(wdd->parent, "set_pretimeout = %d\n", req);
        if (req) {
                val = PRETIMEOUT_SEC;
                if (val >= wdd->timeout)
                        return -EINVAL;
        }

        if (val != req)
                dev_dbg(wdd->parent, "Rounding pretimeout to: %d\n", val);

        wdd->pretimeout = val;
        pretimeout = !!val;

        if (watchdog_active(wdd))
                hpwdt_start(wdd);

        return 0;
}

static int hpwdt_my_nmi(void)
{
        return ioread8(hpwdt_nmistat) & 0x6;
}

/*
 *      NMI Handler
 */
static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
{
        unsigned int mynmi = hpwdt_my_nmi();
        static char panic_msg[] =
                "00: An NMI occurred. Depending on your system the reason "
                "for the NMI is logged in any one of the following resources:\n"
                "1. Integrated Management Log (IML)\n"
                "2. OA Syslog\n"
                "3. OA Forward Progress Log\n"
                "4. iLO Event Log";

        if (ulReason == NMI_UNKNOWN && !mynmi)
                return NMI_DONE;

        if (kdumptimeout < 0)
                hpwdt_stop();
        else if (kdumptimeout == 0)
                ;
        else {
                unsigned int val = max((unsigned int)kdumptimeout, hpwdt_dev.timeout);
                hpwdt_ping_ticks(SECS_TO_TICKS(val));
        }

        hex_byte_pack(panic_msg, mynmi);
        nmi_panic(regs, panic_msg);

        return NMI_HANDLED;
}
#endif /* CONFIG_HPWDT_NMI_DECODING */


static const struct watchdog_info ident = {
        .options = WDIOF_PRETIMEOUT    |
                   WDIOF_SETTIMEOUT    |
                   WDIOF_KEEPALIVEPING |
                   WDIOF_MAGICCLOSE,
        .identity = "HPE iLO2+ HW Watchdog Timer",
};

/*
 *      Kernel interfaces
 */

static const struct watchdog_ops hpwdt_ops = {
        .owner          = THIS_MODULE,
        .start          = hpwdt_start,
        .stop           = hpwdt_stop_core,
        .ping           = hpwdt_ping,
        .set_timeout    = hpwdt_settimeout,
        .get_timeleft   = hpwdt_gettimeleft,
#ifdef CONFIG_HPWDT_NMI_DECODING
        .set_pretimeout = hpwdt_set_pretimeout,
#endif
};

static struct watchdog_device hpwdt_dev = {
        .info           = &ident,
        .ops            = &hpwdt_ops,
        .min_timeout    = 1,
        .timeout        = DEFAULT_MARGIN,
        .pretimeout     = PRETIMEOUT_SEC,
        .max_hw_heartbeat_ms    = HPWDT_MAX_TIMER * 1000,
};


/*
 *      Init & Exit
 */

static int hpwdt_init_nmi_decoding(struct pci_dev *dev)
{
#ifdef CONFIG_HPWDT_NMI_DECODING
        int retval;
        /*
         * Only one function can register for NMI_UNKNOWN
         */
        retval = register_nmi_handler(NMI_UNKNOWN, hpwdt_pretimeout, 0, "hpwdt");
        if (retval)
                goto error;
        retval = register_nmi_handler(NMI_SERR, hpwdt_pretimeout, 0, "hpwdt");
        if (retval)
                goto error1;
        retval = register_nmi_handler(NMI_IO_CHECK, hpwdt_pretimeout, 0, "hpwdt");
        if (retval)
                goto error2;

        dev_info(&dev->dev,
                "HPE Watchdog Timer Driver: NMI decoding initialized\n");

        return 0;

error2:
        unregister_nmi_handler(NMI_SERR, "hpwdt");
error1:
        unregister_nmi_handler(NMI_UNKNOWN, "hpwdt");
error:
        dev_warn(&dev->dev,
                "Unable to register a die notifier (err=%d).\n",
                retval);
        return retval;
#endif  /* CONFIG_HPWDT_NMI_DECODING */
        return 0;
}

static void hpwdt_exit_nmi_decoding(void)
{
#ifdef CONFIG_HPWDT_NMI_DECODING
        unregister_nmi_handler(NMI_UNKNOWN, "hpwdt");
        unregister_nmi_handler(NMI_SERR, "hpwdt");
        unregister_nmi_handler(NMI_IO_CHECK, "hpwdt");
#endif
}

static int hpwdt_init_one(struct pci_dev *dev,
                                        const struct pci_device_id *ent)
{
        int retval;

        /*
         * First let's find out if we are on an iLO2+ server. We will
         * not run on a legacy ASM box.
         * So we only support the G5 ProLiant servers and higher.
         */
        if (dev->subsystem_vendor != PCI_VENDOR_ID_HP &&
            dev->subsystem_vendor != PCI_VENDOR_ID_HP_3PAR) {
                dev_warn(&dev->dev,
                        "This server does not have an iLO2+ ASIC.\n");
                return -ENODEV;
        }

        if (pci_match_id(hpwdt_blacklist, dev)) {
                dev_dbg(&dev->dev, "Not supported on this device\n");
                return -ENODEV;
        }

        if (pci_enable_device(dev)) {
                dev_warn(&dev->dev,
                        "Not possible to enable PCI Device: 0x%x:0x%x.\n",
                        ent->vendor, ent->device);
                return -ENODEV;
        }

        pci_mem_addr = pci_iomap(dev, 1, 0x80);
        if (!pci_mem_addr) {
                dev_warn(&dev->dev,
                        "Unable to detect the iLO2+ server memory.\n");
                retval = -ENOMEM;
                goto error_pci_iomap;
        }
        hpwdt_nmistat   = pci_mem_addr + 0x6e;
        hpwdt_timer_reg = pci_mem_addr + 0x70;
        hpwdt_timer_con = pci_mem_addr + 0x72;

        /* Have the core update running timer until user space is ready */
        if (hpwdt_hw_is_running()) {
                dev_info(&dev->dev, "timer is running\n");
                set_bit(WDOG_HW_RUNNING, &hpwdt_dev.status);
        }

        /* Initialize NMI Decoding functionality */
        retval = hpwdt_init_nmi_decoding(dev);
        if (retval != 0)
                goto error_init_nmi_decoding;

        watchdog_stop_on_unregister(&hpwdt_dev);
        watchdog_set_nowayout(&hpwdt_dev, nowayout);
        watchdog_init_timeout(&hpwdt_dev, soft_margin, NULL);

        if (is_kdump_kernel()) {
                pretimeout = false;
                kdumptimeout = 0;
        }

        if (pretimeout && hpwdt_dev.timeout <= PRETIMEOUT_SEC) {
                dev_warn(&dev->dev, "timeout <= pretimeout. Setting pretimeout to zero\n");
                pretimeout = false;
        }
        hpwdt_dev.pretimeout = pretimeout ? PRETIMEOUT_SEC : 0;
        kdumptimeout = min(kdumptimeout, HPWDT_MAX_TIMER);

        hpwdt_dev.parent = &dev->dev;
        retval = watchdog_register_device(&hpwdt_dev);
        if (retval < 0)
                goto error_wd_register;

        dev_info(&dev->dev, "HPE Watchdog Timer Driver: Version: %s\n",
                                HPWDT_VERSION);
        dev_info(&dev->dev, "timeout: %d seconds (nowayout=%d)\n",
                                hpwdt_dev.timeout, nowayout);
        dev_info(&dev->dev, "pretimeout: %s.\n",
                                pretimeout ? "on" : "off");
        dev_info(&dev->dev, "kdumptimeout: %d.\n", kdumptimeout);

        return 0;

error_wd_register:
        hpwdt_exit_nmi_decoding();
error_init_nmi_decoding:
        pci_iounmap(dev, pci_mem_addr);
error_pci_iomap:
        pci_disable_device(dev);
        return retval;
}

static void hpwdt_exit(struct pci_dev *dev)
{
        watchdog_unregister_device(&hpwdt_dev);
        hpwdt_exit_nmi_decoding();
        pci_iounmap(dev, pci_mem_addr);
        pci_disable_device(dev);
}

static int hpwdt_suspend(struct device *dev)
{
        if (watchdog_active(&hpwdt_dev))
                hpwdt_stop();

        return 0;
}

static int hpwdt_resume(struct device *dev)
{
        if (watchdog_active(&hpwdt_dev))
                hpwdt_start(&hpwdt_dev);

        return 0;
}

static const struct dev_pm_ops hpwdt_pm_ops = {
        LATE_SYSTEM_SLEEP_PM_OPS(hpwdt_suspend, hpwdt_resume)
};

static struct pci_driver hpwdt_driver = {
        .name = "hpwdt",
        .id_table = hpwdt_devices,
        .probe = hpwdt_init_one,
        .remove = hpwdt_exit,

        .driver = {
                .name = "hpwdt",
                .pm = &hpwdt_pm_ops,
        }
};

MODULE_AUTHOR("Tom Mingarelli");
MODULE_DESCRIPTION("hpe watchdog driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(HPWDT_VERSION);

module_param(soft_margin, int, 0);
MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");

module_param_named(timeout, soft_margin, int, 0);
MODULE_PARM_DESC(timeout, "Alias of soft_margin");

module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

module_param(kdumptimeout, int, 0444);
MODULE_PARM_DESC(kdumptimeout, "Timeout applied for crash kernel transition in seconds");

#ifdef CONFIG_HPWDT_NMI_DECODING
module_param(pretimeout, bool, 0);
MODULE_PARM_DESC(pretimeout, "Watchdog pretimeout enabled");
#endif

module_pci_driver(hpwdt_driver);