/*      $OpenBSD: qcmtx.c,v 1.1 2023/05/17 23:30:58 patrick Exp $       */
/*
 * Copyright (c) 2023 Patrick Wildt <patrick@blueri.se>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/malloc.h>

#include <machine/bus.h>
#include <machine/fdt.h>

#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_misc.h>
#include <dev/ofw/fdt.h>

#define QCMTX_OFF(idx)          ((idx) * 0x1000)
#define QCMTX_NUM_LOCKS         32
#define QCMTX_APPS_PROC_ID      1

#define HREAD4(sc, reg)                                                 \
        (bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg)))
#define HWRITE4(sc, reg, val)                                           \
        bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))

struct qcmtx_softc {
        struct device           sc_dev;
        bus_space_tag_t         sc_iot;
        bus_space_handle_t      sc_ioh;
        int                     sc_node;

        struct hwlock_device    sc_hd;
};

int     qcmtx_match(struct device *, void *, void *);
void    qcmtx_attach(struct device *, struct device *, void *);

int     qcmtx_lock(void *, uint32_t *, int);

const struct cfattach qcmtx_ca = {
        sizeof (struct qcmtx_softc), qcmtx_match, qcmtx_attach
};

struct cfdriver qcmtx_cd = {
        NULL, "qcmtx", DV_DULL
};

int
qcmtx_match(struct device *parent, void *match, void *aux)
{
        struct fdt_attach_args *faa = aux;

        return OF_is_compatible(faa->fa_node, "qcom,tcsr-mutex");
}

void
qcmtx_attach(struct device *parent, struct device *self, void *aux)
{
        struct qcmtx_softc *sc = (struct qcmtx_softc *)self;
        struct fdt_attach_args *faa = aux;

        if (faa->fa_nreg < 1) {
                printf(": no registers\n");
                return;
        }

        sc->sc_node = faa->fa_node;
        sc->sc_iot = faa->fa_iot;
        if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
            faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
                printf(": can't map registers\n");
                return;
        }

        printf("\n");

        sc->sc_hd.hd_node = faa->fa_node;
        sc->sc_hd.hd_cookie = sc;
        sc->sc_hd.hd_lock = qcmtx_lock;
        hwlock_register(&sc->sc_hd);
}

int
qcmtx_lock(void *cookie, uint32_t *cells, int lock)
{
        struct qcmtx_softc *sc = cookie;
        int idx = cells[0];

        if (idx >= QCMTX_NUM_LOCKS)
                return ENXIO;

        if (lock) {
                HWRITE4(sc, QCMTX_OFF(idx), QCMTX_APPS_PROC_ID);
                if (HREAD4(sc, QCMTX_OFF(idx)) !=
                    QCMTX_APPS_PROC_ID)
                        return EAGAIN;
                KASSERT(HREAD4(sc, QCMTX_OFF(idx)) == QCMTX_APPS_PROC_ID);
        } else {
                KASSERT(HREAD4(sc, QCMTX_OFF(idx)) == QCMTX_APPS_PROC_ID);
                HWRITE4(sc, QCMTX_OFF(idx), 0);
        }

        return 0;
}