c74fc16e2d
mutex instead of a MTX_DEF one in order to defer preemption while reading the date and time registers. If we don't manage to read them within the time slot where we are guaranteed that no updates occur we might actually read them during an update in which case the output is undefined.
288 lines
7.6 KiB
C
288 lines
7.6 KiB
C
/*-
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* Copyright (c) 2003 Izumi Tsutsui. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* from: NetBSD: mc146818.c,v 1.4 2003/11/24 06:20:40 tsutsui Exp
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* mc146818 and compatible time of day chip subroutines
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bus.h>
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#include <sys/clock.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <machine/bus.h>
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#include <dev/mc146818/mc146818reg.h>
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#include <dev/mc146818/mc146818var.h>
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#include "clock_if.h"
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static u_int mc146818_def_getcent(device_t);
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static void mc146818_def_setcent(device_t, u_int);
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static u_int mc146818_def_read(device_t, u_int);
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static void mc146818_def_write(device_t, u_int, u_int);
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int
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mc146818_attach(device_t dev)
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{
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struct mc146818_softc *sc;
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sc = device_get_softc(dev);
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if (mtx_initialized(&sc->sc_mtx) == 0) {
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device_printf(dev, "%s: mutex not initialized\n", __func__);
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return (ENXIO);
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}
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if (sc->sc_mcread == NULL)
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sc->sc_mcread = mc146818_def_read;
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if (sc->sc_mcwrite == NULL)
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sc->sc_mcwrite = mc146818_def_write;
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if (sc->sc_flag & MC146818_NO_CENT_ADJUST) {
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/*
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* Note that setting MC146818_NO_CENT_ADJUST means that
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* the century has to be stored in NVRAM somewhere.
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*/
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if (sc->sc_getcent == NULL)
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sc->sc_getcent = mc146818_def_getcent;
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if (sc->sc_setcent == NULL)
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sc->sc_setcent = mc146818_def_setcent;
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}
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mtx_lock_spin(&sc->sc_mtx);
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if (!(*sc->sc_mcread)(dev, MC_REGD) & MC_REGD_VRT) {
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mtx_unlock_spin(&sc->sc_mtx);
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device_printf(dev, "%s: battery low\n", __func__);
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return (ENXIO);
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}
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sc->sc_rega = MC_BASE_32_KHz;
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(*sc->sc_mcwrite)(dev, MC_REGA, sc->sc_rega);
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sc->sc_regb = 0;
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sc->sc_regb |= (sc->sc_flag & MC146818_BCD) ? 0 : MC_REGB_BINARY;
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sc->sc_regb |= (sc->sc_flag & MC146818_12HR) ? 0 : MC_REGB_24HR;
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(*sc->sc_mcwrite)(dev, MC_REGB, sc->sc_regb);
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mtx_unlock_spin(&sc->sc_mtx);
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clock_register(dev, 1000000); /* 1 second resolution. */
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return (0);
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}
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/*
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* Get time of day and convert it to a struct timespec.
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* Return 0 on success, an error number otherwise.
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*/
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int
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mc146818_gettime(device_t dev, struct timespec *ts)
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{
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struct mc146818_softc *sc;
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struct clocktime ct;
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int timeout, cent, year;
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sc = device_get_softc(dev);
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timeout = 1000000; /* XXX how long should we wait? */
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/*
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* If MC_REGA_UIP is 0 we have at least 244us before the next
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* update. If it's 1 an update is imminent.
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*/
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for (;;) {
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mtx_lock_spin(&sc->sc_mtx);
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if (!((*sc->sc_mcread)(dev, MC_REGA) & MC_REGA_UIP))
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break;
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mtx_unlock_spin(&sc->sc_mtx);
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if (--timeout < 0) {
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device_printf(dev, "%s: timeout\n", __func__);
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return (EBUSY);
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}
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}
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#define FROMREG(x) ((sc->sc_flag & MC146818_BCD) ? FROMBCD(x) : (x))
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ct.nsec = 0;
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ct.sec = FROMREG((*sc->sc_mcread)(dev, MC_SEC));
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ct.min = FROMREG((*sc->sc_mcread)(dev, MC_MIN));
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ct.hour = FROMREG((*sc->sc_mcread)(dev, MC_HOUR));
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/* Map dow from 1 - 7 to 0 - 6. */
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ct.dow = FROMREG((*sc->sc_mcread)(dev, MC_DOW)) - 1;
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ct.day = FROMREG((*sc->sc_mcread)(dev, MC_DOM));
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ct.mon = FROMREG((*sc->sc_mcread)(dev, MC_MONTH));
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year = FROMREG((*sc->sc_mcread)(dev, MC_YEAR));
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year += sc->sc_year0;
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if (sc->sc_flag & MC146818_NO_CENT_ADJUST) {
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cent = (*sc->sc_getcent)(dev);
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year += cent * 100;
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} else if (year < POSIX_BASE_YEAR)
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year += 100;
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mtx_unlock_spin(&sc->sc_mtx);
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ct.year = year;
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return (clock_ct_to_ts(&ct, ts));
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}
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#ifdef notyet
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int
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mc146818_getsecs(device_t dev, int *secp)
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{
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struct mc146818_softc *sc;
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int sec, timeout;
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sc = device_get_softc(dev);
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timeout = 1000000; /* XXX how long should we wait? */
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for (;;) {
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mtx_lock_spin(&sc->sc_mtx);
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if (!((*sc->sc_mcread)(dev, MC_REGA) & MC_REGA_UIP)) {
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sec = FROMREG((*sc->sc_mcread)(dev, MC_SEC));
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mtx_unlock_spin(&sc->sc_mtx);
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break;
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}
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mtx_unlock_spin(&sc->sc_mtx);
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if (--timeout == 0) {
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device_printf(dev, "%s: timeout\n", __func__);
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return (EBUSY);
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}
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}
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#undef FROMREG
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*secp = sec;
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return (0);
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}
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#endif
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/*
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* Set the time of day clock based on the value of the struct timespec arg.
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* Return 0 on success, an error number otherwise.
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*/
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int
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mc146818_settime(device_t dev, struct timespec *ts)
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{
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struct mc146818_softc *sc;
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struct clocktime ct;
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int cent, year;
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sc = device_get_softc(dev);
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/* Accuracy is only one second. */
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if (ts->tv_nsec >= 500000000)
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ts->tv_sec++;
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ts->tv_nsec = 0;
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clock_ts_to_ct(ts, &ct);
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mtx_lock_spin(&sc->sc_mtx);
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/* Disable RTC updates and interrupts (if enabled). */
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(*sc->sc_mcwrite)(dev, MC_REGB,
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((sc->sc_regb & (MC_REGB_BINARY | MC_REGB_24HR)) | MC_REGB_SET));
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#define TOREG(x) ((sc->sc_flag & MC146818_BCD) ? TOBCD(x) : (x))
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(*sc->sc_mcwrite)(dev, MC_SEC, TOREG(ct.sec));
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(*sc->sc_mcwrite)(dev, MC_MIN, TOREG(ct.min));
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(*sc->sc_mcwrite)(dev, MC_HOUR, TOREG(ct.hour));
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/* Map dow from 0 - 6 to 1 - 7. */
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(*sc->sc_mcwrite)(dev, MC_DOW, TOREG(ct.dow + 1));
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(*sc->sc_mcwrite)(dev, MC_DOM, TOREG(ct.day));
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(*sc->sc_mcwrite)(dev, MC_MONTH, TOREG(ct.mon));
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year = ct.year - sc->sc_year0;
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if (sc->sc_flag & MC146818_NO_CENT_ADJUST) {
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cent = year / 100;
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(*sc->sc_setcent)(dev, cent);
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year -= cent * 100;
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} else if (year > 99)
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year -= 100;
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(*sc->sc_mcwrite)(dev, MC_YEAR, TOREG(year));
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/* Reenable RTC updates and interrupts. */
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(*sc->sc_mcwrite)(dev, MC_REGB, sc->sc_regb);
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mtx_unlock_spin(&sc->sc_mtx);
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#undef TOREG
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return (0);
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}
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#define MC_ADDR 0
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#define MC_DATA 1
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static u_int
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mc146818_def_read(device_t dev, u_int reg)
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{
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struct mc146818_softc *sc;
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sc = device_get_softc(dev);
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bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_ADDR, reg);
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return (bus_space_read_1(sc->sc_bst, sc->sc_bsh, MC_DATA));
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}
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static void
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mc146818_def_write(device_t dev, u_int reg, u_int val)
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{
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struct mc146818_softc *sc;
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sc = device_get_softc(dev);
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bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_ADDR, reg);
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bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_DATA, val);
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}
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/*
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* Looks like it's common even across platforms to store the century at
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* 0x32 in the NVRAM of the mc146818.
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*/
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#define MC_CENT 0x32
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static u_int
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mc146818_def_getcent(device_t dev)
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{
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struct mc146818_softc *sc;
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sc = device_get_softc(dev);
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return ((*sc->sc_mcread)(dev, MC_CENT));
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}
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static void
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mc146818_def_setcent(device_t dev, u_int cent)
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{
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struct mc146818_softc *sc;
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sc = device_get_softc(dev);
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(*sc->sc_mcwrite)(dev, MC_CENT, cent);
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}
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