/*      $NetBSD: mc146818.c,v 1.22 2025/09/07 21:45:16 thorpej Exp $    */

/*-
 * Copyright (c) 2003 Izumi Tsutsui.  All rights reserved.
 *
 * 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 AUTHOR ``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 AUTHOR 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.
 */

/*
 * mc146818 and compatible time of day chip subroutines
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: mc146818.c,v 1.22 2025/09/07 21:45:16 thorpej Exp $");

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

#include <sys/bus.h>

#include <dev/clock_subr.h>

#include <dev/ic/mc146818reg.h>
#include <dev/ic/mc146818var.h>

void
mc146818_attach(struct mc146818_softc *sc)
{
        todr_chip_handle_t handle;

#ifdef DIAGNOSTIC
        if (sc->sc_mcread == NULL ||
            sc->sc_mcwrite == NULL)
                panic("%s: invalid read/write functions", __func__);
#endif

        aprint_normal(": mc146818 compatible time-of-day clock");

        handle = &sc->sc_handle;
        handle->todr_dev = sc->sc_dev;
        KASSERT(handle->todr_gettime == NULL);
        KASSERT(handle->todr_settime == NULL);
        if (handle->todr_gettime_ymdhms == NULL) {
                handle->todr_gettime_ymdhms = mc146818_gettime_ymdhms;
        }
        if (handle->todr_settime_ymdhms == NULL) {
                handle->todr_settime_ymdhms = mc146818_settime_ymdhms;
        }

        todr_attach(handle);
}

/*
 * todr_gettime function:
 *  Get time of day and convert it to a struct timeval.
 *  Return 0 on success, an error number othersize.
 */
int
mc146818_gettime_ymdhms(todr_chip_handle_t handle, struct clock_ymdhms *dt)
{
        struct mc146818_softc *sc = device_private(handle->todr_dev);
        int s, timeout, cent, year;

        s = splclock();         /* XXX really needed? */

        timeout = 1000000;      /* XXX how long should we wait? */
        for (;;) {
                if (((*sc->sc_mcread)(sc, MC_REGA) & MC_REGA_UIP) == 0)
                        break;
                if (--timeout < 0) {
                        printf("%s: timeout\n", __func__);
                        return EBUSY;
                }
        }

#define FROMREG(x)      ((sc->sc_flag & MC146818_BCD) ? bcdtobin(x) : (x))

        dt->dt_sec  = FROMREG((*sc->sc_mcread)(sc, MC_SEC));
        dt->dt_min  = FROMREG((*sc->sc_mcread)(sc, MC_MIN));
        dt->dt_hour = FROMREG((*sc->sc_mcread)(sc, MC_HOUR));
        dt->dt_wday = FROMREG((*sc->sc_mcread)(sc, MC_DOW));
        dt->dt_day  = FROMREG((*sc->sc_mcread)(sc, MC_DOM));
        dt->dt_mon  = FROMREG((*sc->sc_mcread)(sc, MC_MONTH));
        year        = FROMREG((*sc->sc_mcread)(sc, MC_YEAR));
        if (sc->sc_getcent) {
                cent = (*sc->sc_getcent)(sc);
                year += cent * 100;
        }

#undef FROMREG

        year += sc->sc_year0;
        if (year < POSIX_BASE_YEAR &&
            (sc->sc_flag & MC146818_NO_CENT_ADJUST) == 0)
                year += 100;
        dt->dt_year = year;

        splx(s);

        return 0;
}

/*
 * todr_settime function:
 *  Set the time of day clock based on the value of the struct timeval arg.
 *  Return 0 on success, an error number othersize.
 */
int
mc146818_settime_ymdhms(todr_chip_handle_t handle, struct clock_ymdhms *dt)
{
        struct mc146818_softc *sc = device_private(handle->todr_dev);
        int s, cent, year;

        s = splclock();         /* XXX really needed? */

        /*
         * Disable RTC updates during clock updates
         */

        (*sc->sc_mcwrite)(sc, MC_REGB,
            (*sc->sc_mcread)(sc, MC_REGB) | MC_REGB_SET);

#define TOREG(x)        ((sc->sc_flag & MC146818_BCD) ? bintobcd(x) : (x))

        (*sc->sc_mcwrite)(sc, MC_SEC, TOREG(dt->dt_sec));
        (*sc->sc_mcwrite)(sc, MC_MIN, TOREG(dt->dt_min));
        (*sc->sc_mcwrite)(sc, MC_HOUR, TOREG(dt->dt_hour));
        (*sc->sc_mcwrite)(sc, MC_DOW, TOREG(dt->dt_wday));
        (*sc->sc_mcwrite)(sc, MC_DOM, TOREG(dt->dt_day));
        (*sc->sc_mcwrite)(sc, MC_MONTH, TOREG(dt->dt_mon));

        year = dt->dt_year - sc->sc_year0;
        if (sc->sc_setcent) {
                cent = year / 100;
                (*sc->sc_setcent)(sc, cent);
                year -= cent * 100;
        }
        if (year > 99 &&
            (sc->sc_flag & MC146818_NO_CENT_ADJUST) == 0)
                year -= 100;
        (*sc->sc_mcwrite)(sc, MC_YEAR, TOREG(year));

#undef TOREG

        /*
         * Re-enable RTC updates
         */

        (*sc->sc_mcwrite)(sc, MC_REGB,
            (*sc->sc_mcread)(sc, MC_REGB) & ~MC_REGB_SET);

        splx(s);

        return 0;
}