/*-
 * Copyright (C) 2018 Justin Hibbits
 *
 * 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 ``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 TOOLS GMBH 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/kernel.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/bus.h>
#include <sys/kthread.h>
#include <sys/proc.h>
#include <sys/selinfo.h>
#include <sys/sysctl.h>

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

#include <machine/bus.h>

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

#include <sys/ipmi.h>
#include <dev/ipmi/ipmivars.h>

#include <powerpc/powernv/opal.h>

/*
 * OPAL_IPMI_DEBUG
 *
 * 0 - disabled
 * 1 - enable error messages (EPRINTF)
 * 2 - enable error and debug messages (DPRINTF)
 */
#define OPAL_IPMI_DEBUG         0
#if OPAL_IPMI_DEBUG >= 2
/* debug printf */
#define DPRINTF(fmt, ...)       printf("ipmi: " fmt "\n", ## __VA_ARGS__)
#else
#define DPRINTF(fmt, ...)       ((void)0)
#endif
#if OPAL_IPMI_DEBUG >= 1
/* error printf: to print messages only when something fails */
#define EPRINTF(fmt, ...)       printf("ipmi: " fmt "\n", ## __VA_ARGS__)
#else
#define EPRINTF(fmt, ...)       ((void)0)
#endif

struct opal_ipmi_softc {
        struct ipmi_softc ipmi;
        uint64_t sc_interface;
        int sc_timedout;
        struct opal_ipmi_msg *sc_msg; /* Protected by IPMI lock */
};

static MALLOC_DEFINE(M_IPMI, "ipmi", "OPAL IPMI");

static int
opal_ipmi_recv(struct opal_ipmi_softc *sc, uint64_t *msg_len, int timo)
{
        int err;

        if (timo == 0)
                timo = MAX_TIMEOUT;
        timo *= 10; /* Timeout is in milliseconds, we delay in 100us */

        for (;;) {
                *msg_len = sizeof(struct opal_ipmi_msg) + IPMI_MAX_RX;
                /* Crank the OPAL state machine while we poll for a reply. */
                opal_call(OPAL_POLL_EVENTS, NULL);
                err = opal_call(OPAL_IPMI_RECV, sc->sc_interface,
                    vtophys(sc->sc_msg), vtophys(msg_len));
                *msg_len = be64toh(*msg_len);
                if (err != OPAL_EMPTY)
                        break;

                DELAY(100);
                if (timo-- <= 0) {
                        sc->sc_timedout = 1;
                        break;
                }
        }

        if (err != OPAL_SUCCESS)
                EPRINTF("RECV: error: %d", err);

        switch (err) {
        case OPAL_SUCCESS:
                DPRINTF("RECV: rv=%02x len=%ld",
                    sc->sc_msg->data[0], *msg_len);
                return (0);
        case OPAL_RESOURCE:
                return (ENOMEM);
        case OPAL_EMPTY:
                return (EAGAIN);
        default:
                return (EIO);
        }
}

static void
opal_ipmi_discard_msgs(struct opal_ipmi_softc *sc)
{
        uint64_t msg_len;
        int err, i = 0;

        /* OPAL_IPMI_RECV fails when msg version is not set. */
        sc->sc_msg->version = OPAL_IPMI_MSG_FORMAT_VERSION_1;

        /* Wait up to 100ms for the 1st timedout message. */
        err = opal_ipmi_recv(sc, &msg_len, 100);
        while (err == 0) {
                i++;
                /* Wait only 10ms for the remaining messages. */
                err = opal_ipmi_recv(sc, &msg_len, 10);
        }
        if (i > 0)
                EPRINTF("Discarded %d message(s)", i);
        sc->sc_timedout = 0;
}

static int
opal_ipmi_polled_request(struct opal_ipmi_softc *sc, struct ipmi_request *req,
    int timo)
{
        uint64_t msg_len;
        int err;

        /*
         * Discard timed out messages before sending a new one, to avoid
         * them being confused with the reply of the new message.
         */
        if (sc->sc_timedout)
                opal_ipmi_discard_msgs(sc);

        /* Construct and send the message. */
        sc->sc_msg->version = OPAL_IPMI_MSG_FORMAT_VERSION_1;
        sc->sc_msg->netfn = req->ir_addr;
        sc->sc_msg->cmd = req->ir_command;

        if (req->ir_requestlen > IPMI_MAX_RX) {
                err = ENOMEM;
                goto out;
        }
        memcpy(sc->sc_msg->data, req->ir_request, req->ir_requestlen);

        msg_len = sizeof(*sc->sc_msg) + req->ir_requestlen;
        err = opal_call(OPAL_IPMI_SEND, sc->sc_interface, vtophys(sc->sc_msg),
            msg_len);

        DPRINTF("SEND: cmd=%02x netfn=%02x len=%ld -> %d",
            sc->sc_msg->cmd, sc->sc_msg->netfn, msg_len, err);

        if (err != OPAL_SUCCESS)
                EPRINTF("SEND: error: %d", err);

        switch (err) {
        case OPAL_SUCCESS:
                break;
        case OPAL_PARAMETER:
        case OPAL_UNSUPPORTED:
                err = EINVAL;
                goto out;
        case OPAL_RESOURCE:
                err = ENOMEM;
                goto out;
        case OPAL_HARDWARE:
        default:
                err = EIO;
                goto out;
        }

        if ((err = opal_ipmi_recv(sc, &msg_len, timo)) == 0) {
                /* Subtract one extra for the completion code. */
                req->ir_replylen = msg_len - sizeof(struct opal_ipmi_msg) - 1;
                req->ir_replylen = min(req->ir_replylen, req->ir_replybuflen);
                memcpy(req->ir_reply, &sc->sc_msg->data[1], req->ir_replylen);
                req->ir_compcode = sc->sc_msg->data[0];
        }

out:
        return (err);
}

static int
opal_ipmi_probe(device_t dev)
{
        if (!ofw_bus_is_compatible(dev, "ibm,opal-ipmi"))
                return (ENXIO);

        device_set_desc(dev, "OPAL IPMI System Interface");

        return (BUS_PROBE_DEFAULT);
}

static void
opal_ipmi_loop(void *arg)
{
        struct opal_ipmi_softc *sc = arg;
        struct ipmi_request *req;
        int i, err;

        IPMI_LOCK(&sc->ipmi);
        while ((req = ipmi_dequeue_request(&sc->ipmi)) != NULL) {
                IPMI_UNLOCK(&sc->ipmi);
                err = EIO;
                for (i = 0; i < 3 && err != 0; i++) {
                        IPMI_IO_LOCK(&sc->ipmi);
                        err = opal_ipmi_polled_request(sc, req, MAX_TIMEOUT);
                        IPMI_IO_UNLOCK(&sc->ipmi);
                }
                req->ir_error = err == 0 ? 0 : EIO;
                IPMI_LOCK(&sc->ipmi);
                ipmi_complete_request(&sc->ipmi, req);
        }
        IPMI_UNLOCK(&sc->ipmi);
        kproc_exit(0);
}

static int
opal_ipmi_startup(struct ipmi_softc *sc)
{

        return (kproc_create(opal_ipmi_loop, sc, &sc->ipmi_kthread, 0, 0,
            "%s: opal", device_get_nameunit(sc->ipmi_dev)));
}

static int
opal_ipmi_driver_request(struct ipmi_softc *isc, struct ipmi_request *req)
{
        struct opal_ipmi_softc *sc = (struct opal_ipmi_softc *)isc;
        int i, err;

        for (i = 0; i < 3; i++) {
                IPMI_LOCK(&sc->ipmi);
                err = opal_ipmi_polled_request(sc, req, 0);
                IPMI_UNLOCK(&sc->ipmi);
                if (err == 0)
                        break;
        }

        req->ir_error = err;

        return (err);
}

static int
opal_ipmi_attach(device_t dev)
{
        struct opal_ipmi_softc *sc;
        pcell_t ifid;

        sc = device_get_softc(dev);

        if (OF_getencprop(ofw_bus_get_node(dev), "ibm,ipmi-interface-id",
            &ifid, sizeof(ifid)) < 0) {
                device_printf(dev, "Missing interface id\n");
                return (ENXIO);
        }
        sc->sc_interface = ifid;
        sc->ipmi.ipmi_startup = opal_ipmi_startup;
        sc->ipmi.ipmi_driver_request = opal_ipmi_driver_request;
        sc->ipmi.ipmi_enqueue_request = ipmi_polled_enqueue_request;
        sc->ipmi.ipmi_driver_requests_polled = 1;
        sc->ipmi.ipmi_dev = dev;

        sc->sc_msg = malloc(sizeof(struct opal_ipmi_msg) + IPMI_MAX_RX, M_IPMI,
            M_WAITOK | M_ZERO);

        /* Discard old messages that may have remained in receive queue. */
        opal_ipmi_discard_msgs(sc);

        return (ipmi_attach(dev));
}

static int
opal_ipmi_detach(device_t dev)
{
        struct opal_ipmi_softc *sc;
        int err;

        sc = device_get_softc(dev);
        err = ipmi_detach(dev);
        if (err == 0)
                free(sc->sc_msg, M_IPMI);

        return (err);
}

static device_method_t  opal_ipmi_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         opal_ipmi_probe),
        DEVMETHOD(device_attach,        opal_ipmi_attach),
        DEVMETHOD(device_detach,        opal_ipmi_detach),
        DEVMETHOD_END
};

static driver_t opal_ipmi_driver = {
        "ipmi",
        opal_ipmi_methods,
        sizeof(struct opal_ipmi_softc)
};

DRIVER_MODULE(opal_ipmi, opal, opal_ipmi_driver, NULL, NULL);