/*-
 * Copyright (c) 2018-2020 Ruslan Bukin <br@bsdpad.com>
 * All rights reserved.
 *
 * This software was developed by BAE Systems, the University of Cambridge
 * Computer Laboratory, and Memorial University under DARPA/AFRL contract
 * FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent Computing
 * (TC) research program.
 *
 * 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/rman.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <machine/bus.h>

#include <arm64/coresight/coresight.h>
#include <arm64/coresight/coresight_etm4x.h>

#include "coresight_if.h"

#define ETM_DEBUG
#undef ETM_DEBUG
   
#ifdef ETM_DEBUG
#define dprintf(fmt, ...)       printf(fmt, ##__VA_ARGS__)
#else
#define dprintf(fmt, ...)
#endif

/*
 * Typical trace flow:
 *
 * CPU0 -> ETM0 -> funnel1 -> funnel0 -> ETF -> replicator -> ETR -> DRAM
 * CPU1 -> ETM1 -> funnel1 -^
 * CPU2 -> ETM2 -> funnel1 -^
 * CPU3 -> ETM3 -> funnel1 -^
 */

static struct resource_spec etm_spec[] = {
        { SYS_RES_MEMORY,       0,      RF_ACTIVE },
        { -1, 0 }
};

static int
etm_prepare(device_t dev, struct coresight_event *event)
{
        struct etm_softc *sc;
        uint32_t reg;
        int i;

        sc = device_get_softc(dev);

        /* Configure ETM */

        /*
         * Enable the return stack, global timestamping,
         * Context ID, and Virtual context identifier tracing.
         */
        reg = TRCCONFIGR_RS | TRCCONFIGR_TS;
        reg |= TRCCONFIGR_CID | TRCCONFIGR_VMID;
        reg |= TRCCONFIGR_INSTP0_LDRSTR;
        reg |= TRCCONFIGR_COND_ALL;
        bus_write_4(sc->res, TRCCONFIGR, reg);

        /* Disable all event tracing. */
        bus_write_4(sc->res, TRCEVENTCTL0R, 0);
        bus_write_4(sc->res, TRCEVENTCTL1R, 0);

        /* Disable stalling, if implemented. */
        bus_write_4(sc->res, TRCSTALLCTLR, 0);

        /* Enable trace synchronization every 4096 bytes of trace. */
        bus_write_4(sc->res, TRCSYNCPR, TRCSYNCPR_4K);

        /* Set a value for the trace ID */
        bus_write_4(sc->res, TRCTRACEIDR, event->etm.trace_id);

        /*
         * Disable the timestamp event. The trace unit still generates
         * timestamps due to other reasons such as trace synchronization.
         */
        bus_write_4(sc->res, TRCTSCTLR, 0);

        /*
         * Enable ViewInst to trace everything, with the start/stop
         * logic started.
         */
        reg = TRCVICTLR_SSSTATUS;

        /* The number of the single resource used to activate the event. */
        reg |= (1 << EVENT_SEL_S);

        if (event->excp_level > 2)
                return (-1);

        reg |= TRCVICTLR_EXLEVEL_NS_M;
        reg &= ~TRCVICTLR_EXLEVEL_NS(event->excp_level);
        reg |= TRCVICTLR_EXLEVEL_S_M;
        reg &= ~TRCVICTLR_EXLEVEL_S(event->excp_level);
        bus_write_4(sc->res, TRCVICTLR, reg);

        for (i = 0; i < event->naddr * 2; i++) {
                dprintf("configure range %d, address %lx\n",
                    i, event->addr[i]);
                bus_write_8(sc->res, TRCACVR(i), event->addr[i]);

                reg = 0;
                /* Secure state */
                reg |= TRCACATR_EXLEVEL_S_M;
                reg &= ~TRCACATR_EXLEVEL_S(event->excp_level);
                /* Non-secure state */
                reg |= TRCACATR_EXLEVEL_NS_M;
                reg &= ~TRCACATR_EXLEVEL_NS(event->excp_level);
                bus_write_4(sc->res, TRCACATR(i), reg);

                /* Address range is included */
                reg = bus_read_4(sc->res, TRCVIIECTLR);
                reg |= (1 << (TRCVIIECTLR_INCLUDE_S + i / 2));
                bus_write_4(sc->res, TRCVIIECTLR, reg);
        }

        /* No address filtering for ViewData. */
        bus_write_4(sc->res, TRCVDARCCTLR, 0);

        /* Clear the STATUS bit to zero */
        bus_write_4(sc->res, TRCSSCSR(0), 0);

        if (event->naddr == 0) {
                /* No address range filtering for ViewInst. */
                bus_write_4(sc->res, TRCVIIECTLR, 0);
        }

        /* No start or stop points for ViewInst. */
        bus_write_4(sc->res, TRCVISSCTLR, 0);

        /* Disable ViewData */
        bus_write_4(sc->res, TRCVDCTLR, 0);

        /* No address filtering for ViewData. */
        bus_write_4(sc->res, TRCVDSACCTLR, 0);

        return (0);
}

static int
etm_init(device_t dev)
{
        struct etm_softc *sc;
        uint32_t reg __unused;

        sc = device_get_softc(dev);

        /* Unlocking Coresight */
        bus_write_4(sc->res, CORESIGHT_LAR, CORESIGHT_UNLOCK);

        /* Unlocking ETM */
        bus_write_4(sc->res, TRCOSLAR, 0);

        reg = bus_read_4(sc->res, TRCIDR(1));
        dprintf("ETM Version: %d.%d\n",
            (reg & TRCIDR1_TRCARCHMAJ_M) >> TRCIDR1_TRCARCHMAJ_S,
            (reg & TRCIDR1_TRCARCHMIN_M) >> TRCIDR1_TRCARCHMIN_S);

        return (0);
}

static int
etm_enable(device_t dev, struct endpoint *endp,
    struct coresight_event *event)
{
        struct etm_softc *sc;
        uint32_t reg;

        sc = device_get_softc(dev);

        etm_prepare(dev, event);

        /* Enable the trace unit */
        bus_write_4(sc->res, TRCPRGCTLR, TRCPRGCTLR_EN);

        /* Wait for an IDLE bit to be LOW */
        do {
                reg = bus_read_4(sc->res, TRCSTATR);
        } while ((reg & TRCSTATR_IDLE) == 1);

        if ((bus_read_4(sc->res, TRCPRGCTLR) & TRCPRGCTLR_EN) == 0)
                panic("etm is not enabled\n");

        return (0);
}

static void
etm_disable(device_t dev, struct endpoint *endp,
    struct coresight_event *event)
{
        struct etm_softc *sc;
        uint32_t reg;

        sc = device_get_softc(dev);

        /* Disable the trace unit */
        bus_write_4(sc->res, TRCPRGCTLR, 0);

        /* Wait for an IDLE bit */
        do {
                reg = bus_read_4(sc->res, TRCSTATR);
        } while ((reg & TRCSTATR_IDLE) == 0);
}

int
etm_attach(device_t dev)
{
        struct coresight_desc desc;
        struct etm_softc *sc;

        sc = device_get_softc(dev);

        if (bus_alloc_resources(dev, etm_spec, &sc->res) != 0) {
                device_printf(dev, "cannot allocate resources for device\n");
                return (ENXIO);
        }

        desc.pdata = sc->pdata;
        desc.dev = dev;
        desc.dev_type = CORESIGHT_ETMV4;
        coresight_register(&desc);

        return (0);
}

static device_method_t etm_methods[] = {
        /* Coresight interface */
        DEVMETHOD(coresight_init,       etm_init),
        DEVMETHOD(coresight_enable,     etm_enable),
        DEVMETHOD(coresight_disable,    etm_disable),
        DEVMETHOD_END
};

DEFINE_CLASS_0(etm, etm_driver, etm_methods, sizeof(struct etm_softc));