/*      $OpenBSD: syscon.c,v 1.8 2023/09/22 01:10:44 jsg Exp $  */
/*
 * Copyright (c) 2017 Mark Kettenis
 *
 * 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>

#include <machine/simplebusvar.h>

extern void (*cpuresetfn)(void);
extern void (*powerdownfn)(void);

struct syscon_softc {
        struct simplebus_softc  sc_sbus;
        bus_space_tag_t         sc_iot;
        bus_space_handle_t      sc_ioh;
        uint32_t                sc_regmap;
        bus_size_t              sc_offset;
        uint32_t                sc_mask;
        uint32_t                sc_value;
};

struct syscon_softc *syscon_reboot_sc;
struct syscon_softc *syscon_poweroff_sc;

int     syscon_match(struct device *, void *, void *);
void    syscon_attach(struct device *, struct device *, void *);

const struct cfattach syscon_ca = {
        sizeof(struct syscon_softc), syscon_match, syscon_attach
};

struct cfdriver syscon_cd = {
        NULL, "syscon", DV_DULL
};

void    syscon_reset(void);
void    syscon_powerdown(void);

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

        return OF_is_compatible(faa->fa_node, "syscon") ||
            OF_is_compatible(faa->fa_node, "syscon-reboot") ||
            OF_is_compatible(faa->fa_node, "syscon-poweroff");
}

void
syscon_attach(struct device *parent, struct device *self, void *aux)
{
        struct syscon_softc *sc = (struct syscon_softc *)self;
        struct fdt_attach_args *faa = aux;
        char name[32];

        OF_getprop(faa->fa_node, "name", name, sizeof(name));
        name[sizeof(name) - 1] = 0;

        if (OF_is_compatible(faa->fa_node, "syscon")) {
                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;
                }

                regmap_register(faa->fa_node, sc->sc_iot, sc->sc_ioh,
                    faa->fa_reg[0].size);
        }

        if (OF_is_compatible(faa->fa_node, "simple-mfd"))
                simplebus_attach(parent, &sc->sc_sbus.sc_dev, faa);
        else
                printf(": \"%s\"\n", name);

        if (OF_is_compatible(faa->fa_node, "syscon-reboot") ||
            OF_is_compatible(faa->fa_node, "syscon-poweroff")) {
                sc->sc_regmap = OF_getpropint(faa->fa_node, "regmap", 0);
                if (sc->sc_regmap == 0)
                        return;

                if (OF_getproplen(faa->fa_node, "offset") != sizeof(uint32_t))
                        return;

                /* At least one of "mask" and "value" should be provided. */
                if (OF_getproplen(faa->fa_node, "mask") != sizeof(uint32_t) &&
                    OF_getproplen(faa->fa_node, "value") != sizeof(uint32_t))
                        return;

                sc->sc_offset = OF_getpropint(faa->fa_node, "offset", 0);
                sc->sc_mask = OF_getpropint(faa->fa_node, "mask", 0xffffffff);
                sc->sc_value = OF_getpropint(faa->fa_node, "value", 0);

                /*
                 * Old binding used "mask" as the value to write with
                 * an all-ones mask.  This is still supported.
                 */
                if (OF_getproplen(faa->fa_node, "value") != sizeof(uint32_t)) {
                        sc->sc_value = sc->sc_mask;
                        sc->sc_mask = 0xffffffff;
                }

                if (OF_is_compatible(faa->fa_node, "syscon-reboot")) {
                        syscon_reboot_sc = sc;
                        cpuresetfn = syscon_reset;
                } else if (OF_is_compatible(faa->fa_node, "syscon-poweroff")) {
                        syscon_poweroff_sc = sc;
                        powerdownfn = syscon_powerdown;
                }
        }
}

void
syscon_reset(void)
{
        struct syscon_softc *sc = syscon_reboot_sc;
        struct regmap *rm;
        uint32_t value;

        rm = regmap_byphandle(sc->sc_regmap);
        if (rm == NULL)
                return;

        value = regmap_read_4(rm, sc->sc_offset);
        value &= ~sc->sc_mask;
        value |= sc->sc_value;
        regmap_write_4(rm, sc->sc_offset, value);
        delay(1000000);
}

void
syscon_powerdown(void)
{
        struct syscon_softc *sc = syscon_poweroff_sc;
        struct regmap *rm;
        uint32_t value;

        rm = regmap_byphandle(sc->sc_regmap);
        if (rm == NULL)
                return;

        value = regmap_read_4(rm, sc->sc_offset);
        value &= ~sc->sc_mask;
        value |= sc->sc_value;
        regmap_write_4(rm, sc->sc_offset, value);
        delay(1000000);
}