/*      $NetBSD: rtc.c,v 1.23 2025/09/07 21:45:15 thorpej Exp $ */

/*
 * Copyright (c) 2001 Valeriy E. Ushakov
 * 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * 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.
 */

/*
 * `rtc' is a DS1287A (== MC146818A) time-of-day clock at EBus.
 * In Krups it's not used to store idprom so this driver doesn't
 * support it.  Don't know about other ms-IIep systems.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: rtc.c,v 1.23 2025/09/07 21:45:15 thorpej Exp $");

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/systm.h>
#ifdef GPROF
#include <sys/gmon.h>
#endif

#include <sys/bus.h>
#include <machine/autoconf.h>

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

#include <dev/ebus/ebusreg.h>
#include <dev/ebus/ebusvar.h>

struct rtc_ebus_softc {
        device_t                sc_dev;
        bus_space_tag_t         sc_bt;  /* parent bus tag */
        bus_space_handle_t      sc_bh;  /* handle for registers */
        struct todr_chip_handle sc_todr;/* TODR handle */
};

static int      rtcmatch_ebus(device_t, cfdata_t, void *);
static void     rtcattach_ebus(device_t, device_t, void *);

CFATTACH_DECL_NEW(rtc_ebus, sizeof(struct rtc_ebus_softc),
    rtcmatch_ebus, rtcattach_ebus, NULL, NULL);

/* todr(9) methods */
static int rtc_gettime_ymdhms(todr_chip_handle_t, struct clock_ymdhms *);
static int rtc_settime_ymdhms(todr_chip_handle_t, struct clock_ymdhms *);

int rtc_auto_century_adjust = 1; /* XXX: do we ever want not to? */

/*
 * MD read/write functions declared in mc146818reg.h
 */
#define RTC_ADDR        0
#define RTC_DATA        1

u_int
mc146818_read(void *cookie, u_int reg)
{
        struct rtc_ebus_softc *sc = cookie;

        bus_space_write_1(sc->sc_bt, sc->sc_bh, RTC_ADDR, reg);
        return (bus_space_read_1(sc->sc_bt, sc->sc_bh, RTC_DATA));
}

void
mc146818_write(void *cookie, u_int reg, u_int datum)
{
        struct rtc_ebus_softc *sc = cookie;

        bus_space_write_1(sc->sc_bt, sc->sc_bh, RTC_ADDR, reg);
        bus_space_write_1(sc->sc_bt, sc->sc_bh, RTC_DATA, datum);
}


static int
rtcmatch_ebus(device_t parent, cfdata_t cf, void *aux)
{
        struct ebus_attach_args *ea = aux;

        return (strcmp(cf->cf_name, ea->ea_name) == 0);
}

static void
rtcattach_ebus(device_t parent, device_t self, void *aux)
{
        struct rtc_ebus_softc *sc = device_private(self);
        struct ebus_attach_args *ea = aux;
        todr_chip_handle_t handle;

        sc->sc_dev = self;
        sc->sc_bt = ea->ea_bustag;
        if (bus_space_map(sc->sc_bt, EBUS_ADDR_FROM_REG(&ea->ea_reg[0]),
                          ea->ea_reg[0].size, 0, &sc->sc_bh) != 0)
        {
                printf(": unable to map registers\n");
                return;
        }

        /* XXX: no "model" property in Krups */
        printf(": time-of-day clock\n");

        /*
         * Turn interrupts off (clear MC_REGB_?IE bits), just in case
         * (although they shouldn't be wired to an interrupt
         * controller on sparcs).
         */
        mc146818_write(sc, MC_REGB, MC_REGB_BINARY | MC_REGB_24HR);

        /* setup our todr_handle */
        handle = &sc->sc_todr;
        handle->todr_dev = self;
        handle->todr_gettime_ymdhms = rtc_gettime_ymdhms;
        handle->todr_settime_ymdhms = rtc_settime_ymdhms;

        todr_attach(handle);
}


static int
rtc_gettime_ymdhms(todr_chip_handle_t handle, struct clock_ymdhms *dt)
{
        struct rtc_ebus_softc *sc = device_private(handle->todr_dev);
        u_int year;

        /* update in progress; spin loop */
        while (mc146818_read(sc, MC_REGA) & MC_REGA_UIP)
                continue;

        /* stop updates (XXX: do we need that???) */
        mc146818_write(sc, MC_REGB,
                       (mc146818_read(sc, MC_REGB) | MC_REGB_SET));

        /* read time */
        dt->dt_sec  = mc146818_read(sc, MC_SEC);
        dt->dt_min  = mc146818_read(sc, MC_MIN);
        dt->dt_hour = mc146818_read(sc, MC_HOUR);
        dt->dt_day  = mc146818_read(sc, MC_DOM);
        dt->dt_mon  = mc146818_read(sc, MC_MONTH);
        year        = mc146818_read(sc, MC_YEAR);

        /* reenable updates */
        mc146818_write(sc, MC_REGB,
                       (mc146818_read(sc, MC_REGB) & ~MC_REGB_SET));

        /* year in the century 0..99: adjust to AD */
        year += 1900;
        if (year < POSIX_BASE_YEAR && rtc_auto_century_adjust != 0)
                year += 100;
        dt->dt_year = year;

        return (0);
}

static int
rtc_settime_ymdhms(todr_chip_handle_t handle, struct clock_ymdhms *dt)
{
        struct rtc_ebus_softc *sc = device_private(handle->todr_dev);
        u_int year;

        year = dt->dt_year - 1900;
        if (year >= 100 && rtc_auto_century_adjust != 0)
                year -= 100;

        /* stop updates */
        mc146818_write(sc, MC_REGB,
                       (mc146818_read(sc, MC_REGB) | MC_REGB_SET));

        mc146818_write(sc, MC_SEC,   dt->dt_sec);
        mc146818_write(sc, MC_MIN,   dt->dt_min);
        mc146818_write(sc, MC_HOUR,  dt->dt_hour);
        mc146818_write(sc, MC_DOW,   dt->dt_wday + 1);
        mc146818_write(sc, MC_DOM,   dt->dt_day);
        mc146818_write(sc, MC_MONTH, dt->dt_mon);
        mc146818_write(sc, MC_YEAR,  year);

        /* reenable updates */
        mc146818_write(sc, MC_REGB,
                       (mc146818_read(sc, MC_REGB) & ~MC_REGB_SET));
        return (0);
}