/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2019 Mitchell Horne <mhorne@FreeBSD.org>
 * Copyright (c) 2021 Jessica Clarke <jrtc27@FreeBSD.org>
 *
 * 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/bus.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/reboot.h>

#include <machine/md_var.h>
#include <machine/sbi.h>

/* SBI Implementation-Specific Definitions */
#define OPENSBI_VERSION_MAJOR_OFFSET    16
#define OPENSBI_VERSION_MINOR_MASK      0xFFFF

struct sbi_softc {
        device_t                dev;
};

struct sbi_devinfo {
        struct resource_list    rl;
};

static struct sbi_softc *sbi_softc = NULL;

static u_long sbi_spec_version;
static u_long sbi_impl_id;
static u_long sbi_impl_version;

static bool has_time_extension = false;
static bool has_ipi_extension = false;
static bool has_rfnc_extension = false;
static bool has_srst_extension = false;

static struct sbi_ret
sbi_get_spec_version(void)
{
        return (SBI_CALL0(SBI_EXT_ID_BASE, SBI_BASE_GET_SPEC_VERSION));
}

static struct sbi_ret
sbi_get_impl_id(void)
{
        return (SBI_CALL0(SBI_EXT_ID_BASE, SBI_BASE_GET_IMPL_ID));
}

static struct sbi_ret
sbi_get_impl_version(void)
{
        return (SBI_CALL0(SBI_EXT_ID_BASE, SBI_BASE_GET_IMPL_VERSION));
}

static struct sbi_ret
sbi_get_mvendorid(void)
{
        return (SBI_CALL0(SBI_EXT_ID_BASE, SBI_BASE_GET_MVENDORID));
}

static struct sbi_ret
sbi_get_marchid(void)
{
        return (SBI_CALL0(SBI_EXT_ID_BASE, SBI_BASE_GET_MARCHID));
}

static struct sbi_ret
sbi_get_mimpid(void)
{
        return (SBI_CALL0(SBI_EXT_ID_BASE, SBI_BASE_GET_MIMPID));
}

static void
sbi_shutdown_final(void *dummy __unused, int howto)
{
        if ((howto & RB_POWEROFF) != 0)
                sbi_system_reset(SBI_SRST_TYPE_SHUTDOWN, SBI_SRST_REASON_NONE);
}

void
sbi_system_reset(u_long reset_type, u_long reset_reason)
{
        /* Use the SRST extension, if available. */
        if (has_srst_extension) {
                (void)SBI_CALL2(SBI_EXT_ID_SRST, SBI_SRST_SYSTEM_RESET,
                    reset_type, reset_reason);
        }
        (void)SBI_CALL0(SBI_SHUTDOWN, 0);
}

void
sbi_print_version(void)
{
        u_int major;
        u_int minor;

        /* For legacy SBI implementations. */
        if (sbi_spec_version == 0) {
                printf("SBI: Unknown (Legacy) Implementation\n");
                printf("SBI Specification Version: 0.1\n");
                return;
        }

        switch (sbi_impl_id) {
        case (SBI_IMPL_ID_BBL):
                printf("SBI: Berkely Boot Loader %lu\n", sbi_impl_version);
                break;
        case (SBI_IMPL_ID_OPENSBI):
                major = sbi_impl_version >> OPENSBI_VERSION_MAJOR_OFFSET;
                minor = sbi_impl_version & OPENSBI_VERSION_MINOR_MASK;
                printf("SBI: OpenSBI v%u.%u\n", major, minor);
                break;
        case (SBI_IMPL_ID_XVISOR):
                printf("SBI: eXtensible Versatile hypervISOR %lu\n",
                    sbi_impl_version);
                break;
        case (SBI_IMPL_ID_KVM):
                printf("SBI: Kernel-based Virtual Machine %lu\n",
                    sbi_impl_version);
                break;
        case (SBI_IMPL_ID_RUSTSBI):
                printf("SBI: RustSBI %lu\n", sbi_impl_version);
                break;
        case (SBI_IMPL_ID_DIOSIX):
                printf("SBI: Diosix %lu\n", sbi_impl_version);
                break;
        case (SBI_IMPL_ID_COFFER):
                printf("SBI: Coffer %lu\n", sbi_impl_version);
                break;
        case (SBI_IMPL_ID_XEN_PROJECT):
                printf("SBI: Xen Project %lu\n", sbi_impl_version);
                break;
        case (SBI_IMPL_ID_POLARFIRE_HSS):
                printf("SBI: PolarFire Hart Software Services %lu\n",
                    sbi_impl_version);
                break;
        case (SBI_IMPL_ID_COREBOOT):
                printf("SBI: coreboot %lu\n", sbi_impl_version);
                break;
        case (SBI_IMPL_ID_OREBOOT):
                printf("SBI: oreboot %lu\n", sbi_impl_version);
                break;
        case (SBI_IMPL_ID_BHYVE):
                printf("SBI: bhyve %lu\n", sbi_impl_version);
                break;
        default:
                printf("SBI: Unrecognized Implementation: %lu\n", sbi_impl_id);
                break;
        }

        major = (sbi_spec_version & SBI_SPEC_VERS_MAJOR_MASK) >>
            SBI_SPEC_VERS_MAJOR_OFFSET;
        minor = (sbi_spec_version & SBI_SPEC_VERS_MINOR_MASK);
        printf("SBI Specification Version: %u.%u\n", major, minor);
}

void
sbi_set_timer(uint64_t val)
{
        struct sbi_ret ret __diagused;

        /* Use the TIME legacy replacement extension, if available. */
        if (has_time_extension) {
                ret = SBI_CALL1(SBI_EXT_ID_TIME, SBI_TIME_SET_TIMER, val);
                MPASS(ret.error == SBI_SUCCESS);
        } else {
                (void)SBI_CALL1(SBI_SET_TIMER, 0, val);
        }
}

void
sbi_send_ipi(const u_long *hart_mask)
{
        struct sbi_ret ret __diagused;

        /* Use the IPI legacy replacement extension, if available. */
        if (has_ipi_extension) {
                ret = SBI_CALL2(SBI_EXT_ID_IPI, SBI_IPI_SEND_IPI,
                    *hart_mask, 0);
                MPASS(ret.error == SBI_SUCCESS);
        } else {
                (void)SBI_CALL1(SBI_SEND_IPI, 0, (uint64_t)hart_mask);
        }
}

void
sbi_remote_fence_i(const u_long *hart_mask)
{
        struct sbi_ret ret __diagused;

        /* Use the RFENCE legacy replacement extension, if available. */
        if (has_rfnc_extension) {
                ret = SBI_CALL2(SBI_EXT_ID_RFNC, SBI_RFNC_REMOTE_FENCE_I,
                    *hart_mask, 0);
                MPASS(ret.error == SBI_SUCCESS);
        } else {
                (void)SBI_CALL1(SBI_REMOTE_FENCE_I, 0, (uint64_t)hart_mask);
        }
}

void
sbi_remote_sfence_vma(const u_long *hart_mask, u_long start, u_long size)
{
        struct sbi_ret ret __diagused;

        /* Use the RFENCE legacy replacement extension, if available. */
        if (has_rfnc_extension) {
                ret = SBI_CALL4(SBI_EXT_ID_RFNC, SBI_RFNC_REMOTE_SFENCE_VMA,
                    *hart_mask, 0, start, size);
                MPASS(ret.error == SBI_SUCCESS);
        } else {
                (void)SBI_CALL3(SBI_REMOTE_SFENCE_VMA, 0, (uint64_t)hart_mask,
                    start, size);
        }
}

void
sbi_remote_sfence_vma_asid(const u_long *hart_mask, u_long start, u_long size,
    u_long asid)
{
        struct sbi_ret ret __diagused;

        /* Use the RFENCE legacy replacement extension, if available. */
        if (has_rfnc_extension) {
                ret = SBI_CALL5(SBI_EXT_ID_RFNC,
                    SBI_RFNC_REMOTE_SFENCE_VMA_ASID, *hart_mask, 0, start,
                    size, asid);
                MPASS(ret.error == SBI_SUCCESS);
        } else {
                (void)SBI_CALL4(SBI_REMOTE_SFENCE_VMA_ASID, 0,
                    (uint64_t)hart_mask, start, size, asid);
        }
}

int
sbi_hsm_hart_start(u_long hart, u_long start_addr, u_long priv)
{
        struct sbi_ret ret;

        ret = SBI_CALL3(SBI_EXT_ID_HSM, SBI_HSM_HART_START, hart, start_addr,
            priv);
        return (ret.error != 0 ? (int)ret.error : 0);
}

void
sbi_hsm_hart_stop(void)
{
        (void)SBI_CALL0(SBI_EXT_ID_HSM, SBI_HSM_HART_STOP);
}

int
sbi_hsm_hart_status(u_long hart)
{
        struct sbi_ret ret;

        ret = SBI_CALL1(SBI_EXT_ID_HSM, SBI_HSM_HART_STATUS, hart);

        return (ret.error != 0 ? (int)ret.error : (int)ret.value);
}

void
sbi_init(void)
{
        struct sbi_ret sret;

        /*
         * Get the spec version. For legacy SBI implementations this will
         * return an error, otherwise it is guaranteed to succeed.
         */
        sret = sbi_get_spec_version();
        if (sret.error != 0) {
                /* We are running a legacy SBI implementation. */
                sbi_spec_version = 0;
                return;
        }

        /* Set the SBI implementation info. */
        sbi_spec_version = sret.value;
        sbi_impl_id = sbi_get_impl_id().value;
        sbi_impl_version = sbi_get_impl_version().value;

        /* Set the hardware implementation info. */
        mvendorid = sbi_get_mvendorid().value;
        marchid = sbi_get_marchid().value;
        mimpid = sbi_get_mimpid().value;

        /* Probe for legacy replacement extensions. */
        if (sbi_probe_extension(SBI_EXT_ID_TIME) != 0)
                has_time_extension = true;
        if (sbi_probe_extension(SBI_EXT_ID_IPI) != 0)
                has_ipi_extension = true;
        if (sbi_probe_extension(SBI_EXT_ID_RFNC) != 0)
                has_rfnc_extension = true;
        if (sbi_probe_extension(SBI_EXT_ID_SRST) != 0)
                has_srst_extension = true;

        /*
         * Probe for legacy extensions. We still rely on many of them to be
         * implemented, but this is not guaranteed by the spec.
         */
        KASSERT(has_time_extension || sbi_probe_extension(SBI_SET_TIMER) != 0,
            ("SBI doesn't implement sbi_set_timer()"));
        KASSERT(sbi_probe_extension(SBI_CONSOLE_PUTCHAR) != 0,
            ("SBI doesn't implement sbi_console_putchar()"));
        KASSERT(sbi_probe_extension(SBI_CONSOLE_GETCHAR) != 0,
            ("SBI doesn't implement sbi_console_getchar()"));
        KASSERT(has_ipi_extension || sbi_probe_extension(SBI_SEND_IPI) != 0,
            ("SBI doesn't implement sbi_send_ipi()"));
        KASSERT(has_rfnc_extension ||
            sbi_probe_extension(SBI_REMOTE_FENCE_I) != 0,
            ("SBI doesn't implement sbi_remote_fence_i()"));
        KASSERT(has_rfnc_extension ||
            sbi_probe_extension(SBI_REMOTE_SFENCE_VMA) != 0,
            ("SBI doesn't implement sbi_remote_sfence_vma()"));
        KASSERT(has_rfnc_extension ||
            sbi_probe_extension(SBI_REMOTE_SFENCE_VMA_ASID) != 0,
            ("SBI doesn't implement sbi_remote_sfence_vma_asid()"));
        KASSERT(has_srst_extension || sbi_probe_extension(SBI_SHUTDOWN) != 0,
            ("SBI doesn't implement a shutdown or reset extension"));
}

static void
sbi_identify(driver_t *driver, device_t parent)
{
        device_t dev;

        if (device_find_child(parent, "sbi", DEVICE_UNIT_ANY) != NULL)
                return;

        dev = BUS_ADD_CHILD(parent, 0, "sbi", DEVICE_UNIT_ANY);
        if (dev == NULL)
                device_printf(parent, "Can't add sbi child\n");
}

static int
sbi_probe(device_t dev)
{
        device_set_desc(dev, "RISC-V Supervisor Binary Interface");

        return (BUS_PROBE_NOWILDCARD);
}

static int
sbi_attach(device_t dev)
{
        struct sbi_softc *sc;
#ifdef SMP
        device_t child;
        struct sbi_devinfo *di;
#endif

        if (sbi_softc != NULL)
                return (ENXIO);

        sc = device_get_softc(dev);
        sc->dev = dev;
        sbi_softc = sc;

        EVENTHANDLER_REGISTER(shutdown_final, sbi_shutdown_final, NULL,
            SHUTDOWN_PRI_LAST);

#ifdef SMP
        di = malloc(sizeof(*di), M_DEVBUF, M_WAITOK | M_ZERO);
        resource_list_init(&di->rl);
        child = device_add_child(dev, "sbi_ipi", DEVICE_UNIT_ANY);
        if (child == NULL) {
                device_printf(dev, "Could not add sbi_ipi child\n");
                return (ENXIO);
        }

        device_set_ivars(child, di);
#endif

        return (0);
}

static struct resource_list *
sbi_get_resource_list(device_t bus, device_t child)
{
        struct sbi_devinfo *di;

        di = device_get_ivars(child);
        KASSERT(di != NULL, ("%s: No devinfo", __func__));

        return (&di->rl);
}

static device_method_t sbi_methods[] = {
        /* Device interface */
        DEVMETHOD(device_identify,      sbi_identify),
        DEVMETHOD(device_probe,         sbi_probe),
        DEVMETHOD(device_attach,        sbi_attach),

        /* Bus interface */
        DEVMETHOD(bus_alloc_resource,   bus_generic_rl_alloc_resource),
        DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
        DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
        DEVMETHOD(bus_release_resource, bus_generic_rl_release_resource),
        DEVMETHOD(bus_setup_intr,       bus_generic_setup_intr),
        DEVMETHOD(bus_teardown_intr,    bus_generic_teardown_intr),
        DEVMETHOD(bus_get_resource_list, sbi_get_resource_list),
        DEVMETHOD(bus_set_resource,     bus_generic_rl_set_resource),
        DEVMETHOD(bus_get_resource,     bus_generic_rl_get_resource),

        DEVMETHOD_END
};

DEFINE_CLASS_0(sbi, sbi_driver, sbi_methods, sizeof(struct sbi_softc));
EARLY_DRIVER_MODULE(sbi, nexus, sbi_driver, 0, 0,
    BUS_PASS_CPU + BUS_PASS_ORDER_FIRST);