/*      $NetBSD: mc146818.c,v 1.21 2024/03/06 02:31:44 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 1.21 2024/03/06 02:31:44 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->cookie = sc;
       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;
       int s, timeout, cent, year;

       sc = handle->cookie;

       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;
       int s, cent, year;

       sc = handle->cookie;

       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;
}