/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2022 Ruslan Bukin <br@bsdpad.com>
 * Copyright (c) 2023 Arm Ltd
 *
 * This work was supported by Innovate UK project 105694, "Digital Security
 * by Design (DSbD) Technology Platform Prototype".
 *
 * 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/cdefs.h>

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/cpu.h>
#include <sys/kernel.h>
#include <sys/module.h>

#include <dev/fdt/simplebus.h>
#include <dev/fdt/fdt_common.h>
#include <dev/ofw/ofw_bus_subr.h>

#include <dev/psci/smccc.h>

#include "scmi.h"
#include "scmi_protocols.h"
#include "scmi_shmem.h"

struct scmi_smc_softc {
        struct scmi_softc       base;
        uint32_t                smc_id;
        device_t                a2p_dev;
};

static int      scmi_smc_transport_init(device_t);
static int      scmi_smc_xfer_msg(device_t, struct scmi_msg *);
static int      scmi_smc_poll_msg(device_t, struct scmi_msg *, unsigned int);
static int      scmi_smc_collect_reply(device_t, struct scmi_msg *);
static void     scmi_smc_tx_complete(device_t, void *);

static int      scmi_smc_probe(device_t);

static int
scmi_smc_transport_init(device_t dev)
{
        struct scmi_smc_softc *sc;
        phandle_t node;
        ssize_t len;

        sc = device_get_softc(dev);

        node = ofw_bus_get_node(dev);
        len = OF_getencprop(node, "arm,smc-id", &sc->smc_id,
            sizeof(sc->smc_id));
        if (len <= 0) {
                device_printf(dev, "No SMC ID found\n");
                return (EINVAL);
        }

        device_printf(dev, "smc id %x\n", sc->smc_id);

        sc->a2p_dev = scmi_shmem_get(dev, node, SCMI_CHAN_A2P);
        if (sc->a2p_dev == NULL) {
                device_printf(dev, "A2P shmem dev not found.\n");
                return (ENXIO);
        }

        sc->base.trs_desc.no_completion_irq = true;
        sc->base.trs_desc.reply_timo_ms = 30;

        return (0);
}

static int
scmi_smc_xfer_msg(device_t dev, struct scmi_msg *msg)
{
        struct scmi_smc_softc *sc;
        int ret;

        sc = device_get_softc(dev);

        ret = scmi_shmem_prepare_msg(sc->a2p_dev, (uint8_t *)&msg->hdr,
            msg->tx_len, msg->polling);
        if (ret != 0)
                return (ret);

        arm_smccc_invoke_smc(sc->smc_id, NULL);

        return (0);
}

static int
scmi_smc_poll_msg(device_t dev, struct scmi_msg *msg, unsigned int tmo)
{
        struct scmi_smc_softc *sc;

        sc = device_get_softc(dev);

        /*
         * Nothing to poll since commands are completed as soon as smc
         * returns ... but did we get back what we were poling for ?
         */
        scmi_shmem_read_msg_header(sc->a2p_dev, &msg->hdr, &msg->rx_len);

        return (0);
}

static int
scmi_smc_collect_reply(device_t dev, struct scmi_msg *msg)
{
        struct scmi_smc_softc *sc;
        int ret;

        sc = device_get_softc(dev);

        ret = scmi_shmem_read_msg_payload(sc->a2p_dev,
            msg->payld, msg->rx_len - SCMI_MSG_HDR_SIZE, msg->rx_len);

        return (ret);
}

static void
scmi_smc_tx_complete(device_t dev, void *chan)
{
        struct scmi_smc_softc *sc;

        sc = device_get_softc(dev);
        scmi_shmem_tx_complete(sc->a2p_dev);
}

static int
scmi_smc_probe(device_t dev)
{

        if (!ofw_bus_is_compatible(dev, "arm,scmi-smc"))
                return (ENXIO);

        if (!ofw_bus_status_okay(dev))
                return (ENXIO);

        device_set_desc(dev, "ARM SCMI SMC Transport driver");

        return (BUS_PROBE_DEFAULT);
}

static device_method_t scmi_smc_methods[] = {
        DEVMETHOD(device_probe,         scmi_smc_probe),

        /* SCMI interface */
        DEVMETHOD(scmi_transport_init,          scmi_smc_transport_init),
        DEVMETHOD(scmi_xfer_msg,                scmi_smc_xfer_msg),
        DEVMETHOD(scmi_poll_msg,                scmi_smc_poll_msg),
        DEVMETHOD(scmi_collect_reply,           scmi_smc_collect_reply),
        DEVMETHOD(scmi_tx_complete,             scmi_smc_tx_complete),

        DEVMETHOD_END
};

DEFINE_CLASS_1(scmi_smc, scmi_smc_driver, scmi_smc_methods,
    sizeof(struct scmi_smc_softc), scmi_driver);

/* Needs to be after the mmio_sram driver */
EARLY_DRIVER_MODULE(scmi_smc, simplebus, scmi_smc_driver, 0, 0,
    BUS_PASS_SUPPORTDEV + BUS_PASS_ORDER_LATE);
MODULE_VERSION(scmi_smc, 1);