/*      $OpenBSD: exrtc.c,v 1.5 2022/10/17 19:09:46 kettenis Exp $      */
/*
 * Copyright (c) 2017 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 <sys/time.h>

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

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

#include <dev/clock_subr.h>

#define RTCCTRL         0x40
#define RTCCTRL_RTCEN   (1 << 0)

#define RTCSEC          0x70
#define RTCMIN          0x74
#define RTCHOUR         0x78
#define RTCDAY          0x7c
#define RTCMON          0x84
#define RTCYEAR         0x88

#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 exrtc_softc {
        struct device   sc_dev;
        bus_space_tag_t         sc_iot;
        bus_space_handle_t      sc_ioh;
        struct todr_chip_handle sc_todr;
};

int     exrtc_match(struct device *, void *, void *);
void    exrtc_attach(struct device *, struct device *, void *);

const struct cfattach exrtc_ca = {
        sizeof(struct exrtc_softc), exrtc_match, exrtc_attach
};

struct cfdriver exrtc_cd = {
        NULL, "exrtc", DV_DULL
};

int     exrtc_gettime(todr_chip_handle_t, struct timeval *);
int     exrtc_settime(todr_chip_handle_t, struct timeval *);

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

        return OF_is_compatible(faa->fa_node, "samsung,s3c6410-rtc");
}

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

        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))
                panic("%s: bus_space_map failed!", __func__);

        printf("\n");

        sc->sc_todr.cookie = sc;
        sc->sc_todr.todr_gettime = exrtc_gettime;
        sc->sc_todr.todr_settime = exrtc_settime;
        sc->sc_todr.todr_quality = 0;
        todr_attach(&sc->sc_todr);
}

int
exrtc_gettime(todr_chip_handle_t handle, struct timeval *tv)
{
        struct exrtc_softc *sc = handle->cookie;
        struct clock_ymdhms dt;
        int retried = 0;

retry:
        dt.dt_sec = FROMBCD(HREAD4(sc, RTCSEC));
        dt.dt_min = FROMBCD(HREAD4(sc, RTCMIN));
        dt.dt_hour = FROMBCD(HREAD4(sc, RTCHOUR));
        dt.dt_day = FROMBCD(HREAD4(sc, RTCDAY));
        dt.dt_mon = FROMBCD(HREAD4(sc, RTCMON));
        dt.dt_year = FROMBCD(HREAD4(sc, RTCYEAR)) + 1900;

        /* If the second counter rolled over, retry. */
        if (dt.dt_sec > FROMBCD(HREAD4(sc, RTCSEC)) && !retried) {
                retried = 1;
                goto retry;
        }

        if (dt.dt_sec > 59 || dt.dt_min > 59 || dt.dt_hour > 23 ||
            dt.dt_day > 31 || dt.dt_day == 0 ||
            dt.dt_mon > 12 || dt.dt_mon == 0 ||
            dt.dt_year < POSIX_BASE_YEAR)
                return 1;

        tv->tv_sec = clock_ymdhms_to_secs(&dt);
        tv->tv_usec = 0;
        return 0;
}

int
exrtc_settime(todr_chip_handle_t handle, struct timeval *tv)
{
        struct exrtc_softc *sc = handle->cookie;
        struct clock_ymdhms dt;
        uint32_t val;

        clock_secs_to_ymdhms(tv->tv_sec, &dt);

        HWRITE4(sc, RTCSEC, TOBCD(dt.dt_sec));
        HWRITE4(sc, RTCMIN, TOBCD(dt.dt_min));
        HWRITE4(sc, RTCHOUR, TOBCD(dt.dt_hour));
        HWRITE4(sc, RTCDAY, TOBCD(dt.dt_day));
        HWRITE4(sc, RTCMON, TOBCD(dt.dt_mon));
        HWRITE4(sc, RTCYEAR, TOBCD(dt.dt_year - 1900));

        val = HREAD4(sc, RTCCTRL);
        HWRITE4(sc, RTCCTRL, val | RTCCTRL_RTCEN);

        return 0;
}