NetBSD-5.0.2/sys/dev/ic/mm58167.c
/* $NetBSD: mm58167.c,v 1.11 2008/07/06 13:29:50 tsutsui 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 1.11 2008/07/06 13:29:50 tsutsui Exp $");
#include <sys/param.h>
#include <sys/malloc.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>
int mm58167_gettime(todr_chip_handle_t, volatile struct timeval *);
int mm58167_settime(todr_chip_handle_t, volatile struct timeval *);
/*
* 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->cookie = sc;
handle->todr_gettime = mm58167_gettime;
handle->todr_settime = mm58167_settime;
return handle;
}
/*
* Set up the system's time, given a `reasonable' time value.
*/
int
mm58167_gettime(todr_chip_handle_t handle, volatile struct timeval *tv)
{
struct mm58167_softc *sc = handle->cookie;
struct clock_ymdhms dt_hardware;
struct clock_ymdhms dt_reasonable;
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_hardware.dt_f = FROMBCD(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: */
clock_secs_to_ymdhms(tv->tv_sec, &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_hardware.dt_mon < dt_reasonable.dt_mon ||
(dt_hardware.dt_mon == dt_reasonable.dt_mon &&
(dt_hardware.dt_day < dt_reasonable.dt_day ||
(dt_hardware.dt_day == dt_reasonable.dt_day &&
(dt_hardware.dt_hour < dt_reasonable.dt_hour ||
(dt_hardware.dt_hour == dt_reasonable.dt_hour &&
(dt_hardware.dt_min < dt_reasonable.dt_min ||
(dt_hardware.dt_min == dt_reasonable.dt_min &&
(dt_hardware.dt_sec < dt_reasonable.dt_sec))))))))) {
dt_hardware.dt_year = dt_reasonable.dt_year + 1;
} else {
dt_hardware.dt_year = dt_reasonable.dt_year;
}
/* convert the hardware date into a time: */
tv->tv_sec = clock_ymdhms_to_secs(&dt_hardware);
tv->tv_usec = 0;
/*
* 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_hardware.dt_year > dt_reasonable.dt_year &&
dt_hardware.dt_mon >= 3) {
leap_year = dt_hardware.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_hardware.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_hardware.dt_year == dt_reasonable.dt_year
&& dt_reasonable.dt_mon < 3
&& dt_hardware.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) {
tv->tv_sec += SECDAY;
todr_settime(handle, tv);
}
return 0;
}
int
mm58167_settime(todr_chip_handle_t handle, volatile struct timeval *tv)
{
struct mm58167_softc *sc = handle->cookie;
struct clock_ymdhms dt_hardware;
int s;
uint8_t byte_value;
/* Convert the seconds into ymdhms. */
clock_secs_to_ymdhms(tv->tv_sec, &dt_hardware);
/* 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 = TOBCD(dt_hardware.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;
}