/* $NetBSD: mm58167.c,v 1.19 2025/09/07 21:45:16 thorpej Exp $ */ /* * Copyright (c) 2001 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Matthew Fredette. * * 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``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 FOUNDATION OR CONTRIBUTORS * 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. */ /* * National Semiconductor MM58167 time-of-day chip subroutines. */ #include <sys/cdefs.h> __KERNEL_RCSID(0, "$NetBSD: mm58167.c,v 1.19 2025/09/07 21:45:16 thorpej Exp $"); #include <sys/param.h> #include <sys/systm.h> #include <sys/errno.h> #include <sys/device.h> #include <sys/bus.h> #include <dev/clock_subr.h> #include <dev/ic/mm58167var.h> static int mm58167_gettime_ymdhms(todr_chip_handle_t, struct clock_ymdhms *); static int mm58167_settime_ymdhms(todr_chip_handle_t, struct clock_ymdhms *); /* * To quote SunOS's todreg.h: * "This brain damaged chip insists on keeping the time in * MM/DD HH:MM:SS format, even though it doesn't know about * leap years and Feb. 29, thus making it nearly worthless." */ #define mm58167_read(sc, r) \ bus_space_read_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r) #define mm58167_write(sc, r, v) \ bus_space_write_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r, v) todr_chip_handle_t mm58167_attach(struct mm58167_softc *sc) { struct todr_chip_handle *handle; aprint_normal(": mm58167"); handle = &sc->_mm58167_todr_handle; memset(handle, 0, sizeof(*handle)); handle->todr_dev = sc->mm58167_dev; handle->todr_gettime_ymdhms = mm58167_gettime_ymdhms; handle->todr_settime_ymdhms = mm58167_settime_ymdhms; return handle; } /* * Set up the system's time, given a `reasonable' time value. */ int mm58167_gettime_ymdhms(todr_chip_handle_t handle, struct clock_ymdhms *dt) { struct mm58167_softc *sc = device_private(handle->todr_dev); struct clock_ymdhms dt_reasonable; struct timeval now; int s; uint8_t byte_value; int leap_year, had_leap_day; /* First, read the date out of the chip. */ /* No interrupts while we're in the chip. */ s = splhigh(); /* Reset the status bit: */ byte_value = mm58167_read(sc, mm58167_status); /* * Read the date values until we get a coherent read (one * where the status stays zero, indicating no increment was * rippling through while we were reading). */ do { #define _MM58167_GET(dt_f, mm_f) \ byte_value = mm58167_read(sc, mm_f); \ dt->dt_f = bcdtobin(byte_value) _MM58167_GET(dt_mon, mm58167_mon); _MM58167_GET(dt_day, mm58167_day); _MM58167_GET(dt_hour, mm58167_hour); _MM58167_GET(dt_min, mm58167_min); _MM58167_GET(dt_sec, mm58167_sec); #undef _MM58167_GET } while ((mm58167_read(sc, mm58167_status) & 1) == 0); splx(s); /* Convert the reasonable time into a date: */ getmicrotime(&now); clock_secs_to_ymdhms(now.tv_sec, &dt_reasonable); if (dt_reasonable.dt_year == POSIX_BASE_YEAR) { /* * Not a reasonable year. * Assume called from inittodr(9) on boot and * use file system time set in inittodr(9). */ clock_secs_to_ymdhms(handle->todr_base_time, &dt_reasonable); } /* * We need to fake a hardware year. if the hardware MM/DD * HH:MM:SS date is less than the reasonable MM/DD * HH:MM:SS, call it the reasonable year plus one, else call * it the reasonable year. */ if (dt->dt_mon < dt_reasonable.dt_mon || (dt->dt_mon == dt_reasonable.dt_mon && (dt->dt_day < dt_reasonable.dt_day || (dt->dt_day == dt_reasonable.dt_day && (dt->dt_hour < dt_reasonable.dt_hour || (dt->dt_hour == dt_reasonable.dt_hour && (dt->dt_min < dt_reasonable.dt_min || (dt->dt_min == dt_reasonable.dt_min && (dt->dt_sec < dt_reasonable.dt_sec))))))))) { dt->dt_year = dt_reasonable.dt_year + 1; } else { dt->dt_year = dt_reasonable.dt_year; } /* * Make a reasonable effort to see if a leap day has passed * that we need to account for. This does the right thing * only when the system was shut down before a leap day, and * it is now after that leap day. It doesn't do the right * thing when a leap day happened while the machine was last * up. When that happens, the hardware clock becomes * instantly wrong forever, until it gets fixed for some * reason. Use NTP to deal. */ /* * This may have happened if the hardware says we're into * March in the following year. Check that following year for * a leap day. */ if (dt->dt_year > dt_reasonable.dt_year && dt->dt_mon >= 3) { leap_year = dt->dt_year; } /* * This may have happened if the hardware says we're in the * following year, and the system was shut down before March * the previous year. check that previous year for a leap * day. */ else if (dt->dt_year > dt_reasonable.dt_year && dt_reasonable.dt_mon < 3) { leap_year = dt_reasonable.dt_year; } /* * This may have happened if the hardware says we're in the * same year, but we weren't to March before, and we're in or * past March now. Check this year for a leap day. */ else if (dt->dt_year == dt_reasonable.dt_year && dt_reasonable.dt_mon < 3 && dt->dt_mon >= 3) { leap_year = dt_reasonable.dt_year; } /* * Otherwise, no leap year to check. */ else { leap_year = 0; } /* Do the real leap day check. */ had_leap_day = 0; if (leap_year > 0) { if ((leap_year & 3) == 0) { had_leap_day = 1; if ((leap_year % 100) == 0) { had_leap_day = 0; if ((leap_year % 400) == 0) had_leap_day = 1; } } } /* * If we had a leap day, adjust the value we will return, and * also update the hardware clock. */ /* * XXX - Since this update just writes back a corrected * version of what we read out above, we lose whatever * amount of time the clock has advanced since that read. * Use NTP to deal. */ if (had_leap_day) { mm58167_settime_ymdhms(handle, dt); } return 0; } int mm58167_settime_ymdhms(todr_chip_handle_t handle, struct clock_ymdhms *dt) { struct mm58167_softc *sc = device_private(handle->todr_dev); int s; uint8_t byte_value; /* No interrupts while we're in the chip. */ s = splhigh(); /* * Issue a GO command to reset everything less significant * than the minutes to zero. */ mm58167_write(sc, mm58167_go, 0xFF); /* Load everything. */ #define _MM58167_PUT(dt_f, mm_f) \ byte_value = bintobcd(dt->dt_f); \ mm58167_write(sc, mm_f, byte_value) _MM58167_PUT(dt_mon, mm58167_mon); _MM58167_PUT(dt_day, mm58167_day); _MM58167_PUT(dt_hour, mm58167_hour); _MM58167_PUT(dt_min, mm58167_min); _MM58167_PUT(dt_sec, mm58167_sec); #undef _MM58167_PUT splx(s); return 0; }
