/*      $NetBSD: bcm2835_mbox.c,v 1.17 2021/08/07 16:18:43 thorpej Exp $        */

/*-
 * Copyright (c) 2012 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Nick Hudson
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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>
__KERNEL_RCSID(0, "$NetBSD: bcm2835_mbox.c,v 1.17 2021/08/07 16:18:43 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/kernel.h>
#include <sys/timetc.h>
#include <sys/bus.h>
#include <sys/mutex.h>

#include <arm/broadcom/bcm2835_mbox.h>
#include <arm/broadcom/bcm2835_mboxreg.h>
#include <arm/broadcom/bcm2835reg.h>
#include <arm/broadcom/bcm2835var.h>

static struct bcm2835mbox_softc *bcm2835mbox_sc;

static int
bcmmbox_intr1(struct bcm2835mbox_softc *sc, int cv)
{
        uint32_t mbox, chan, data;
        int ret = 0;

        KASSERT(mutex_owned(&sc->sc_intr_lock));

        bus_space_barrier(sc->sc_iot, sc->sc_ioh, 0, BCM2835_MBOX_SIZE,
            BUS_SPACE_BARRIER_READ);

        while ((bus_space_read_4(sc->sc_iot, sc->sc_ioh,
            BCM2835_MBOX0_STATUS) & BCM2835_MBOX_STATUS_EMPTY) == 0) {

                mbox = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
                    BCM2835_MBOX0_READ);

                chan = BCM2835_MBOX_CHAN(mbox);
                data = BCM2835_MBOX_DATA(mbox);
                ret = 1;

                if (BCM2835_MBOX_CHAN(sc->sc_mbox[chan]) != 0) {
                        aprint_error("bcmmbox_intr: chan %d overflow\n",chan);
                        continue;
                }

                sc->sc_mbox[chan] = data | BCM2835_MBOX_CHANMASK;

                if (cv)
                        cv_broadcast(&sc->sc_chan[chan]);
        }

        return ret;
}

void
bcmmbox_attach(struct bcm2835mbox_softc *sc)
{
        struct bcmmbox_attach_args baa;
        int i;

        if (bcm2835mbox_sc == NULL)
                bcm2835mbox_sc = sc;

        mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
        mutex_init(&sc->sc_intr_lock, MUTEX_DEFAULT, IPL_VM);
        for (i = 0; i < BCM2835_MBOX_NUMCHANNELS; ++i)
                cv_init(&sc->sc_chan[i], "bcmmbox");

        /* enable mbox interrupt */
        if (sc->sc_intrh != NULL)
                bus_space_write_4(sc->sc_iot, sc->sc_ioh, BCM2835_MBOX_CFG,
                    BCM2835_MBOX_CFG_DATAIRQEN);

        baa.baa_dmat = sc->sc_dmat;
        sc->sc_platdev = config_found(sc->sc_dev, &baa, NULL, CFARGS_NONE);
}

int
bcmmbox_intr(void *cookie)
{
        struct bcm2835mbox_softc *sc = cookie;
        int ret;

        mutex_enter(&sc->sc_intr_lock);

        ret = bcmmbox_intr1(sc, 1);

        mutex_exit(&sc->sc_intr_lock);

        return ret;
}

void
bcmmbox_read(uint8_t chan, uint32_t *data)
{
        struct bcm2835mbox_softc *sc = bcm2835mbox_sc;

        KASSERT(sc != NULL);

        mutex_enter(&sc->sc_lock);

        mutex_enter(&sc->sc_intr_lock);
        while (BCM2835_MBOX_CHAN(sc->sc_mbox[chan]) == 0) {
                if (cold || sc->sc_intrh == NULL)
                        bcmmbox_intr1(sc, 0);
                else
                        cv_wait(&sc->sc_chan[chan], &sc->sc_intr_lock);
        }
        *data = BCM2835_MBOX_DATA(sc->sc_mbox[chan]);
        sc->sc_mbox[chan] = 0;
        mutex_exit(&sc->sc_intr_lock);

        mutex_exit(&sc->sc_lock);
}

void
bcmmbox_write(uint8_t chan, uint32_t data)
{
        struct bcm2835mbox_softc *sc = bcm2835mbox_sc;

        KASSERT(sc != NULL);
        KASSERT(BCM2835_MBOX_CHAN(chan) == chan);
        KASSERT(BCM2835_MBOX_CHAN(data) == 0);

        mutex_enter(&sc->sc_lock);

        bcm2835_mbox_write(sc->sc_iot, sc->sc_ioh, chan, data);

        mutex_exit(&sc->sc_lock);
}

int
bcmmbox_request(uint8_t chan, void *buf, size_t buflen, uint32_t *pres)
{
        struct bcm2835mbox_softc *sc = bcm2835mbox_sc;
        void *dma_buf;
        bus_dmamap_t map;
        bus_dma_segment_t segs[1];
        int nsegs;
        int error;

        KASSERT(sc != NULL);

        error = bus_dmamem_alloc(sc->sc_dmat, buflen, 16, 0, segs, 1,
            &nsegs, BUS_DMA_WAITOK);
        if (error)
                return error;
        error = bus_dmamem_map(sc->sc_dmat, segs, nsegs, buflen, &dma_buf,
            BUS_DMA_WAITOK);
        if (error)
                goto map_failed;
        error = bus_dmamap_create(sc->sc_dmat, buflen, 1, buflen, 0,
            BUS_DMA_WAITOK, &map);
        if (error)
                goto create_failed;
        error = bus_dmamap_load(sc->sc_dmat, map, dma_buf, buflen, NULL,
            BUS_DMA_WAITOK);
        if (error)
                goto load_failed;

        memcpy(dma_buf, buf, buflen);

        bus_dmamap_sync(sc->sc_dmat, map, 0, buflen,
             BUS_DMASYNC_PREWRITE|BUS_DMASYNC_PREREAD);
        bcmmbox_write(chan, map->dm_segs[0].ds_addr);
        bcmmbox_read(chan, pres);
        bus_dmamap_sync(sc->sc_dmat, map, 0, buflen,
            BUS_DMASYNC_POSTWRITE|BUS_DMASYNC_POSTREAD);

        memcpy(buf, dma_buf, buflen);

        bus_dmamap_unload(sc->sc_dmat, map);
load_failed:
        bus_dmamap_destroy(sc->sc_dmat, map);
create_failed:
        bus_dmamem_unmap(sc->sc_dmat, dma_buf, buflen);
map_failed:
        bus_dmamem_free(sc->sc_dmat, segs, nsegs);

        return error;
}