NetBSD-5.0.2/sys/dev/dec/mcclock.c
/* $NetBSD: mcclock.c,v 1.21 2008/04/08 07:39:11 cegger Exp $ */
/*
* Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
* All rights reserved.
*
* Author: Chris G. Demetriou
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: mcclock.c,v 1.21 2008/04/08 07:39:11 cegger Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <dev/clock_subr.h>
#include <dev/dec/clockvar.h>
#include <dev/dec/mcclockvar.h>
#include <dev/ic/mc146818reg.h>
/*
* XXX default rate is machine-dependent.
*/
#ifdef __alpha__
#define MC_DFEAULTHZ 1024
#endif
#ifdef pmax
#define MC_DEFAULTHZ 256
#endif
void mcclock_init(struct device *);
int mcclock_get(todr_chip_handle_t, volatile struct timeval *);
int mcclock_set(todr_chip_handle_t, volatile struct timeval *);
const struct clockfns mcclock_clockfns = {
mcclock_init,
};
#define mc146818_write(dev, reg, datum) \
(*(dev)->sc_busfns->mc_bf_write)(dev, reg, datum)
#define mc146818_read(dev, reg) \
(*(dev)->sc_busfns->mc_bf_read)(dev, reg)
void
mcclock_attach(sc, busfns)
struct mcclock_softc *sc;
const struct mcclock_busfns *busfns;
{
printf(": mc146818 or compatible");
sc->sc_busfns = busfns;
/* Turn interrupts off, just in case. */
mc146818_write(sc, MC_REGB, MC_REGB_BINARY | MC_REGB_24HR);
clockattach(&sc->sc_dev, &mcclock_clockfns);
sc->sc_todr.todr_gettime = mcclock_get;
sc->sc_todr.todr_settime = mcclock_set;
sc->sc_todr.cookie = sc;
todr_attach(&sc->sc_todr);
}
void
mcclock_init(dev)
struct device *dev;
{
struct mcclock_softc *sc = (struct mcclock_softc *)dev;
int rate;
again:
switch (hz) {
case 32:
rate = MC_BASE_32_KHz | MC_RATE_32_Hz;
break;
case 64:
rate = MC_BASE_32_KHz | MC_RATE_64_Hz;
break;
case 128:
rate = MC_BASE_32_KHz | MC_RATE_128_Hz;
break;
case 256:
rate = MC_BASE_32_KHz | MC_RATE_256_Hz;
break;
case 512:
rate = MC_BASE_32_KHz | MC_RATE_512_Hz;
break;
case 1024:
rate = MC_BASE_32_KHz | MC_RATE_1024_Hz;
break;
case 2048:
rate = MC_BASE_32_KHz | MC_RATE_2048_Hz;
break;
case 4096:
rate = MC_BASE_32_KHz | MC_RATE_4096_Hz;
break;
case 8192:
rate = MC_BASE_32_KHz | MC_RATE_8192_Hz;
break;
case 16384:
rate = MC_BASE_4_MHz | MC_RATE_1;
break;
case 32768:
rate = MC_BASE_4_MHz | MC_RATE_2;
break;
default:
printf("%s: Cannot get %d Hz clock; using %d Hz\n",
device_xname(&sc->sc_dev), hz, MC_DEFAULTHZ);
hz = MC_DEFAULTHZ;
goto again;
}
mc146818_write(sc, MC_REGA, rate);
mc146818_write(sc, MC_REGB,
MC_REGB_PIE | MC_REGB_SQWE | MC_REGB_BINARY | MC_REGB_24HR);
}
/*
* Experiments (and passing years) show that Decstation PROMS
* assume the kernel uses the clock chip as a time-of-year clock.
* The PROM assumes the clock is always set to 1972 or 1973, and contains
* time-of-year in seconds. The PROM checks the clock at boot time,
* and if it's outside that range, sets it to 1972-01-01.
*
* XXX should be at the mc146818 layer?
*/
/*
* Get the time of day, based on the clock's value and/or the base value.
*/
int
mcclock_get(todr_chip_handle_t tch, volatile struct timeval *tvp)
{
struct mcclock_softc *sc = (struct mcclock_softc *)tch->cookie;
uint32_t yearsecs;
mc_todregs regs;
int s;
struct clock_ymdhms dt;
s = splclock();
MC146818_GETTOD(sc, ®s)
splx(s);
dt.dt_sec = regs[MC_SEC];
dt.dt_min = regs[MC_MIN];
dt.dt_hour = regs[MC_HOUR];
dt.dt_day = regs[MC_DOM];
dt.dt_mon = regs[MC_MONTH];
dt.dt_year = 1972;
yearsecs = clock_ymdhms_to_secs(&dt) - (72 - 70) * SECYR;
/*
* Take the actual year from the filesystem if possible;
* allow for 2 days of clock loss and 363 days of clock gain.
*/
dt.dt_year = 1972; /* or MINYEAR or base/SECYR+1970 ... */
dt.dt_mon = 1;
dt.dt_day = 1;
dt.dt_hour = 0;
dt.dt_min = 0;
dt.dt_sec = 0;
for(;;) {
tvp->tv_sec = yearsecs + clock_ymdhms_to_secs(&dt);
if (tvp->tv_sec > tch->base_time - 2 * SECDAY)
break;
dt.dt_year++;
}
tvp->tv_usec = 0;
return 0;
}
/*
* Reset the TODR based on the time value.
*/
int
mcclock_set(todr_chip_handle_t tch, volatile struct timeval *tvp)
{
struct mcclock_softc *sc = (struct mcclock_softc *)tch->cookie;
struct clock_ymdhms dt;
uint32_t yearsecs;
mc_todregs regs;
int s;
/*
* calculate seconds relative to this year
*/
clock_secs_to_ymdhms(tvp->tv_sec, &dt); /* get the year */
dt.dt_mon = 1;
dt.dt_day = 1;
dt.dt_hour = 0;
dt.dt_min = 0;
dt.dt_sec = 0;
yearsecs = tvp->tv_sec - clock_ymdhms_to_secs(&dt);
#define first72 ((72 - 70) * SECYR)
clock_secs_to_ymdhms(first72 + yearsecs, &dt);
#ifdef DEBUG
if (dt.dt_year != 1972)
printf("resettodr: botch (%d, %ld)\n", yearsecs, time_second);
#endif
s = splclock();
MC146818_GETTOD(sc, ®s);
splx(s);
regs[MC_SEC] = dt.dt_sec;
regs[MC_MIN] = dt.dt_min;
regs[MC_HOUR] = dt.dt_hour;
regs[MC_DOW] = dt.dt_wday;
regs[MC_DOM] = dt.dt_day;
regs[MC_MONTH] = dt.dt_mon;
regs[MC_YEAR] = dt.dt_year;
s = splclock();
MC146818_PUTTOD(sc, ®s);
splx(s);
return 0;
}