/*-
 * Copyright (c) 2015 Nathan Whitehorn
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/module.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/clock.h>
#include <sys/cpu.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/reboot.h>
#include <sys/sysctl.h>
#include <sys/endian.h>

#include <vm/vm.h>
#include <vm/pmap.h>

#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/ofw/openfirm.h>

#include "clock_if.h"
#include "opal.h"

static int      opaldev_probe(device_t);
static int      opaldev_attach(device_t);
/* clock interface */
static int      opal_gettime(device_t dev, struct timespec *ts);
static int      opal_settime(device_t dev, struct timespec *ts);
/* ofw bus interface */
static const struct ofw_bus_devinfo *opaldev_get_devinfo(device_t dev,
    device_t child);

static void     opal_shutdown(void *arg, int howto);
static void     opal_handle_shutdown_message(void *unused,
    struct opal_msg *msg);
static void     opal_intr(void *);

static device_method_t  opaldev_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         opaldev_probe),
        DEVMETHOD(device_attach,        opaldev_attach),

        /* clock interface */
        DEVMETHOD(clock_gettime,        opal_gettime),
        DEVMETHOD(clock_settime,        opal_settime),

        /* Bus interface */
        DEVMETHOD(bus_child_pnpinfo,    ofw_bus_gen_child_pnpinfo),

        /* ofw_bus interface */
        DEVMETHOD(ofw_bus_get_devinfo,  opaldev_get_devinfo),
        DEVMETHOD(ofw_bus_get_compat,   ofw_bus_gen_get_compat),
        DEVMETHOD(ofw_bus_get_model,    ofw_bus_gen_get_model),
        DEVMETHOD(ofw_bus_get_name,     ofw_bus_gen_get_name),
        DEVMETHOD(ofw_bus_get_node,     ofw_bus_gen_get_node),
        DEVMETHOD(ofw_bus_get_type,     ofw_bus_gen_get_type),

        DEVMETHOD_END
};

static driver_t opaldev_driver = {
        "opal",
        opaldev_methods,
        0
};

EARLY_DRIVER_MODULE(opaldev, ofwbus, opaldev_driver, 0, 0, BUS_PASS_BUS);

static void opal_heartbeat(void);
static void opal_handle_messages(void);

static struct proc *opal_hb_proc;
static struct kproc_desc opal_heartbeat_kp = {
        "opal_heartbeat",
        opal_heartbeat,
        &opal_hb_proc
};

SYSINIT(opal_heartbeat_setup, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, kproc_start,
    &opal_heartbeat_kp);

static int opal_heartbeat_ms;
EVENTHANDLER_LIST_DEFINE(OPAL_ASYNC_COMP);
EVENTHANDLER_LIST_DEFINE(OPAL_EPOW);
EVENTHANDLER_LIST_DEFINE(OPAL_SHUTDOWN);
EVENTHANDLER_LIST_DEFINE(OPAL_HMI_EVT);
EVENTHANDLER_LIST_DEFINE(OPAL_DPO);
EVENTHANDLER_LIST_DEFINE(OPAL_OCC);

#define OPAL_SOFT_OFF           0
#define OPAL_SOFT_REBOOT        1

static void
opal_heartbeat(void)
{
        uint64_t events;

        if (opal_heartbeat_ms == 0)
                kproc_exit(0);

        while (1) {
                events = 0;
                /* Turn the OPAL state crank */
                opal_call(OPAL_POLL_EVENTS, vtophys(&events));
                if (be64toh(events) & OPAL_EVENT_MSG_PENDING)
                        opal_handle_messages();
                tsleep(opal_hb_proc, 0, "opal",
                    MSEC_2_TICKS(opal_heartbeat_ms));
        }
}

static int
opaldev_probe(device_t dev)
{
        phandle_t iparent;
        pcell_t *irqs;
        int i, n_irqs;

        if (!ofw_bus_is_compatible(dev, "ibm,opal-v3"))
                return (ENXIO);
        if (opal_check() != 0)
                return (ENXIO);

        device_set_desc(dev, "OPAL Abstraction Firmware");

        /* Manually add IRQs before attaching */
        if (OF_hasprop(ofw_bus_get_node(dev), "opal-interrupts")) {
                iparent = OF_finddevice("/interrupt-controller@0");
                iparent = OF_xref_from_node(iparent);

                n_irqs = OF_getproplen(ofw_bus_get_node(dev),
                    "opal-interrupts") / sizeof(*irqs);
                irqs = malloc(n_irqs * sizeof(*irqs), M_DEVBUF, M_WAITOK);
                OF_getencprop(ofw_bus_get_node(dev), "opal-interrupts", irqs,
                    n_irqs * sizeof(*irqs));
                for (i = 0; i < n_irqs; i++)
                        bus_set_resource(dev, SYS_RES_IRQ, i,
                            ofw_bus_map_intr(dev, iparent, 1, &irqs[i]), 1);
                free(irqs, M_DEVBUF);
        }

        return (BUS_PROBE_SPECIFIC);
}

static int
opaldev_attach(device_t dev)
{
        phandle_t child;
        device_t cdev;
        uint64_t junk;
        int i, rv;
        uint32_t async_count;
        struct ofw_bus_devinfo *dinfo;
        struct resource *irq;

        /* Test for RTC support and register clock if it works */
        rv = opal_call(OPAL_RTC_READ, vtophys(&junk), vtophys(&junk));
        do {
                rv = opal_call(OPAL_RTC_READ, vtophys(&junk), vtophys(&junk));
                if (rv == OPAL_BUSY_EVENT)
                        rv = opal_call(OPAL_POLL_EVENTS, 0);
        } while (rv == OPAL_BUSY_EVENT);

        if (rv == OPAL_SUCCESS)
                clock_register(dev, 2000);

        EVENTHANDLER_REGISTER(OPAL_SHUTDOWN, opal_handle_shutdown_message,
            NULL, EVENTHANDLER_PRI_ANY);
        EVENTHANDLER_REGISTER(shutdown_final, opal_shutdown, NULL,
            SHUTDOWN_PRI_LAST);

        OF_getencprop(ofw_bus_get_node(dev), "ibm,heartbeat-ms",
            &opal_heartbeat_ms, sizeof(opal_heartbeat_ms));
        /* Bind to interrupts */
        for (i = 0; (irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &i,
            RF_ACTIVE)) != NULL; i++)
                bus_setup_intr(dev, irq, INTR_TYPE_TTY | INTR_MPSAFE |
                    INTR_ENTROPY, NULL, opal_intr, (void *)rman_get_start(irq),
                    NULL);

        OF_getencprop(ofw_bus_get_node(dev), "opal-msg-async-num",
            &async_count, sizeof(async_count));
        opal_init_async_tokens(async_count);

        for (child = OF_child(ofw_bus_get_node(dev)); child != 0;
            child = OF_peer(child)) {
                dinfo = malloc(sizeof(*dinfo), M_DEVBUF, M_WAITOK | M_ZERO);
                if (ofw_bus_gen_setup_devinfo(dinfo, child) != 0) {
                        free(dinfo, M_DEVBUF);
                        continue;
                }
                cdev = device_add_child(dev, NULL, DEVICE_UNIT_ANY);
                if (cdev == NULL) {
                        device_printf(dev, "<%s>: device_add_child failed\n",
                            dinfo->obd_name);
                        ofw_bus_gen_destroy_devinfo(dinfo);
                        free(dinfo, M_DEVBUF);
                        continue;
                }
                device_set_ivars(cdev, dinfo);
        }

        bus_attach_children(dev);
        return (0);
}

static int
bcd2bin32(int bcd)
{
        int out = 0;

        out += bcd2bin(bcd & 0xff);
        out += 100*bcd2bin((bcd & 0x0000ff00) >> 8);
        out += 10000*bcd2bin((bcd & 0x00ff0000) >> 16);
        out += 1000000*bcd2bin((bcd & 0xffff0000) >> 24);

        return (out);
}

static int
bin2bcd32(int bin)
{
        int out = 0;
        int tmp;

        tmp = bin % 100;
        out += bin2bcd(tmp) * 0x1;
        bin = bin / 100;

        tmp = bin % 100;
        out += bin2bcd(tmp) * 0x100;
        bin = bin / 100;

        tmp = bin % 100;
        out += bin2bcd(tmp) * 0x10000;

        return (out);
}

static int
opal_gettime(device_t dev, struct timespec *ts)
{
        int rv;
        struct clocktime ct;
        uint32_t ymd;
        uint64_t hmsm;

        rv = opal_call(OPAL_RTC_READ, vtophys(&ymd), vtophys(&hmsm));
        while (rv == OPAL_BUSY_EVENT)  {
                opal_call(OPAL_POLL_EVENTS, 0);
                pause("opalrtc", 1);
                rv = opal_call(OPAL_RTC_READ, vtophys(&ymd), vtophys(&hmsm));
        }

        if (rv != OPAL_SUCCESS)
                return (ENXIO);

        hmsm = be64toh(hmsm);
        ymd = be32toh(ymd);

        ct.nsec = bcd2bin32((hmsm & 0x000000ffffff0000) >> 16) * 1000;
        ct.sec  = bcd2bin((hmsm & 0x0000ff0000000000) >> 40);
        ct.min  = bcd2bin((hmsm & 0x00ff000000000000) >> 48);
        ct.hour = bcd2bin((hmsm & 0xff00000000000000) >> 56);

        ct.day  = bcd2bin((ymd & 0x000000ff) >> 0);
        ct.mon  = bcd2bin((ymd & 0x0000ff00) >> 8);
        ct.year = bcd2bin32((ymd & 0xffff0000) >> 16);

        return (clock_ct_to_ts(&ct, ts));
}

static int
opal_settime(device_t dev, struct timespec *ts)
{
        int rv;
        struct clocktime ct;
        uint32_t ymd = 0;
        uint64_t hmsm = 0;

        clock_ts_to_ct(ts, &ct);

        ymd |= (uint32_t)bin2bcd(ct.day);
        ymd |= ((uint32_t)bin2bcd(ct.mon) << 8);
        ymd |= ((uint32_t)bin2bcd32(ct.year) << 16);

        hmsm |= ((uint64_t)bin2bcd32(ct.nsec/1000) << 16);
        hmsm |= ((uint64_t)bin2bcd(ct.sec) << 40);
        hmsm |= ((uint64_t)bin2bcd(ct.min) << 48);
        hmsm |= ((uint64_t)bin2bcd(ct.hour) << 56);

        /*
         * We do NOT swap endian here, because the values are being sent
         * via registers instead of indirect via memory.
         */
        do {
                rv = opal_call(OPAL_RTC_WRITE, ymd, hmsm);
                if (rv == OPAL_BUSY_EVENT) {
                        rv = opal_call(OPAL_POLL_EVENTS, 0);
                        pause("opalrtc", 1);
                }
        } while (rv == OPAL_BUSY_EVENT);

        if (rv != OPAL_SUCCESS)
                return (ENXIO);

        return (0);
}

static const struct ofw_bus_devinfo *
opaldev_get_devinfo(device_t dev, device_t child)
{
        return (device_get_ivars(child));
}

static void
opal_shutdown(void *arg, int howto)
{

        if ((howto & RB_POWEROFF) != 0)
                opal_call(OPAL_CEC_POWER_DOWN, 0 /* Normal power off */);
        else if ((howto & RB_HALT) == 0)
                opal_call(OPAL_CEC_REBOOT);
        else
                return;

        opal_call(OPAL_RETURN_CPU);
}

static void
opal_handle_shutdown_message(void *unused, struct opal_msg *msg)
{
        int howto;

        switch (be64toh(msg->params[0])) {
        case OPAL_SOFT_OFF:
                howto = RB_POWEROFF;
                break;
        case OPAL_SOFT_REBOOT:
                howto = RB_REROOT;
                break;
        }
        shutdown_nice(howto);
}

static void
opal_handle_messages(void)
{
        static struct opal_msg msg;
        uint64_t rv;
        uint32_t type;

        rv = opal_call(OPAL_GET_MSG, vtophys(&msg), sizeof(msg));

        switch (rv) {
        case OPAL_SUCCESS:
                break;
        case OPAL_RESOURCE:
                /* no available messages - return */
                return;
        case OPAL_PARAMETER:
                printf("%s error: invalid buffer. Please file a bug report.\n", __func__);
                return;
        case OPAL_PARTIAL:
                printf("%s error: buffer is too small and messages was discarded. Please file a bug report.\n", __func__);
                return;
        default:
                printf("%s opal_call returned unknown result <%lu>\n", __func__, rv);
                return;
        }

        type = be32toh(msg.msg_type);
        switch (type) {
        case OPAL_MSG_ASYNC_COMP:
                EVENTHANDLER_DIRECT_INVOKE(OPAL_ASYNC_COMP, &msg);
                break;
        case OPAL_MSG_EPOW:
                EVENTHANDLER_DIRECT_INVOKE(OPAL_EPOW, &msg);
                break;
        case OPAL_MSG_SHUTDOWN:
                EVENTHANDLER_DIRECT_INVOKE(OPAL_SHUTDOWN, &msg);
                break;
        case OPAL_MSG_HMI_EVT:
                EVENTHANDLER_DIRECT_INVOKE(OPAL_HMI_EVT, &msg);
                break;
        case OPAL_MSG_DPO:
                EVENTHANDLER_DIRECT_INVOKE(OPAL_DPO, &msg);
                break;
        case OPAL_MSG_OCC:
                EVENTHANDLER_DIRECT_INVOKE(OPAL_OCC, &msg);
                break;
        default:
                printf("%s Unknown OPAL message type %d\n", __func__, type);
        }
}

static void
opal_intr(void *xintr)
{
        uint64_t events = 0;

        opal_call(OPAL_HANDLE_INTERRUPT, (uint32_t)(uint64_t)xintr,
            vtophys(&events));
        /* Wake up the heartbeat, if it's been setup. */
        if (be64toh(events) != 0 && opal_hb_proc != NULL)
                wakeup(opal_hb_proc);

}