/*      $OpenBSD: aplefuse.c,v 1.2 2024/05/13 01:15:50 jsg Exp $        */
/*
 * Copyright (c) 2022 Mark Kettenis <kettenis@openbsd.org>
 *
 * 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 <machine/bus.h>
#include <machine/fdt.h>

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

struct aplefuse_softc {
        struct device           sc_dev;
        bus_space_tag_t         sc_iot;
        bus_space_handle_t      sc_ioh;
        bus_size_t              sc_ios;

        struct nvmem_device     sc_nd;
};

int     aplefuse_match(struct device *, void *, void *);
void    aplefuse_attach(struct device *, struct device *, void *);

const struct cfattach aplefuse_ca = {
        sizeof (struct aplefuse_softc), aplefuse_match, aplefuse_attach
};

struct cfdriver aplefuse_cd = {
        NULL, "aplefuse", DV_DULL
};

int     aplefuse_nvmem_read(void *, bus_addr_t, void *, bus_size_t);

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

        return OF_is_compatible(faa->fa_node, "apple,efuses");
}

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

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

        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;
        }
        sc->sc_ios = faa->fa_reg[0].size;

        printf("\n");

        sc->sc_nd.nd_node = faa->fa_node;
        sc->sc_nd.nd_cookie = sc;
        sc->sc_nd.nd_read = aplefuse_nvmem_read;
        nvmem_register(&sc->sc_nd);
}

int
aplefuse_nvmem_read(void *cookie, bus_addr_t addr, void *data, bus_size_t size)
{
        struct aplefuse_softc *sc = cookie;
        uint8_t *p = data;
        uint32_t value;
        uint8_t buf[4];
        int offset;

        if (addr > sc->sc_ios || size > sc->sc_ios - addr)
                return EINVAL;

        offset = addr & 0x3;
        addr &= ~0x3;
        while (size > 0) {
                value = bus_space_read_4(sc->sc_iot, sc->sc_ioh, addr);
                htolem32(buf, value);
                memcpy(p, &buf[offset], MIN(size, 4 - offset));
                size -= MIN(size, 4 - offset);
                p += MIN(size, 4 - offset);
                addr += 4;
                offset = 0;
        }

        return 0;
}