Add initial support for the FreeBSD/alpha kernel. This is very much a

work in progress and has never booted a real machine.  Initial
development and testing was done using SimOS (see
http://simos.stanford.edu for details).  On the SimOS simulator, this
port successfully reaches single-user mode and has been tested with
loads as high as one copy of /bin/ls :-).

Obtained from: partly from NetBSD/alpha

5 files changed, 632 insertions, 0 deletions

diff --git a/sys/dev/dec/clockvar.h b/sys/dev/dec/clockvar.h
new file mode 100644
index 0000000..920d162
--- /dev/null
+++ b/sys/dev/dec/clockvar.h
@@ -0,0 +1,62 @@
+/* $NetBSD: clockvar.h,v 1.4 1997/06/22 08:02:18 jonathan Exp $ */
+
+/*
+ * Copyright (c) 1994, 1995 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.
+ */
+
+/*
+ * Definitions for cpu-independent clock handling for the alpha and pmax.
+ */
+
+/*
+ * clocktime structure:
+ *
+ * structure passed to TOY clocks when setting them.  broken out this
+ * way, so that the time_t -> field conversion can be shared.
+ */
+struct clocktime {
+	int	year;			/* year - 1900 */
+	int	mon;			/* month (1 - 12) */
+	int	day;			/* day (1 - 31) */
+	int	hour;			/* hour (0 - 23) */
+	int	min;			/* minute (0 - 59) */
+	int	sec;			/* second (0 - 59) */
+	int	dow;			/* day of week (0 - 6; 0 = Sunday) */
+};
+
+/*
+ * clockfns structure:
+ *
+ * function switch used by chip-independent clock code, to access
+ * chip-dependent routines.
+ */
+struct clockfns {
+	void	(*cf_init) __P((struct device *));
+	void	(*cf_get) __P((struct device *, time_t, struct clocktime *));
+	void	(*cf_set) __P((struct device *, struct clocktime *));
+};
+
+void clockattach __P((device_t, const struct clockfns *));
diff --git a/sys/dev/dec/mc146818reg.h b/sys/dev/dec/mc146818reg.h
new file mode 100644
index 0000000..95c3ccf
--- /dev/null
+++ b/sys/dev/dec/mc146818reg.h
@@ -0,0 +1,194 @@
+/*	$NetBSD: mc146818reg.h,v 1.2 1997/03/12 06:53:42 cgd Exp $	*/
+
+/*
+ * Copyright (c) 1995 Carnegie-Mellon University.
+ * All rights reserved.
+ * 
+ * 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.
+ */
+
+/*
+ * Definitions for the Motorola MC146818A Real Time Clock.
+ * They also apply for the (compatible) Dallas Semicontuctor DS1287A RTC.
+ *
+ * Though there are undoubtedly other (better) sources, this material was
+ * culled from the DEC "KN121 System Module Programmer's Reference
+ * Information."
+ *
+ * The MC146818A has 16 registers.  The first 10 contain time-of-year
+ * and alarm data.  The rest contain various control and status bits.
+ *
+ * To read or write the registers, one writes the register number to
+ * the RTC's control port, then either reads from or writes the new
+ * data to the RTC's data port.  Since the locations of these ports
+ * and the method used to access them can be machine-dependent, the
+ * low-level details of reading and writing the RTC's registers are
+ * handled by machine-specific functions.
+ *
+ * The time-of-year and alarm data can be expressed in either binary
+ * or BCD, and they are selected by a bit in register B.
+ *
+ * The "hour" time-of-year and alarm fields can either be expressed in
+ * AM/PM format, or in 24-hour format.  If AM/PM format is chosen, the
+ * hour fields can have the values: 1-12 and 81-92 (the latter being
+ * PM).  If the 24-hour format is chosen, they can have the values
+ * 0-24.  The hour format is selectable by a bit in register B.
+ * (XXX IS AM/PM MODE DESCRIPTION CORRECT?)
+ *
+ * It is assumed the if systems are going to use BCD (rather than
+ * binary) mode, or AM/PM hour format, they'll do the appropriate
+ * conversions in machine-dependent code.  Also, if the clock is
+ * switched between BCD and binary mode, or between AM/PM mode and
+ * 24-hour mode, the time-of-day and alarm registers are NOT
+ * automatically reset; they must be reprogrammed with correct values.
+ */
+
+/*
+ * The registers, and the bits within each register.
+ */
+
+#define	MC_SEC		0x0	/* Time of year: seconds (0-59) */
+#define	MC_ASEC		0x1	/* Alarm: seconds */
+#define	MC_MIN		0x2	/* Time of year: minutes (0-59) */
+#define	MC_AMIN		0x3	/* Alarm: minutes */
+#define	MC_HOUR		0x4	/* Time of year: hour (see above) */
+#define	MC_AHOUR	0x5	/* Alarm: hour */
+#define	MC_DOW		0x6	/* Time of year: day of week (1-7) */
+#define	MC_DOM		0x7	/* Time of year: day of month (1-31) */
+#define	MC_MONTH	0x8	/* Time of year: month (1-12) */
+#define	MC_YEAR		0x9	/* Time of year: year in century (0-99) */
+
+#define	MC_REGA		0xa	/* Control register A */
+
+#define	 MC_REGA_RSMASK	0x0f	/* Interrupt rate select mask (see below) */
+#define	 MC_REGA_DVMASK	0x70	/* Divisor select mask (see below) */
+#define	 MC_REGA_UIP	0x80	/* Update in progress; read only. */
+
+#define	MC_REGB		0xb	/* Control register B */
+
+#define	 MC_REGB_DSE	0x01	/* Daylight Savings Enable */
+#define	 MC_REGB_24HR	0x02	/* 24-hour mode (AM/PM mode when clear) */
+#define	 MC_REGB_BINARY	0x04	/* Binary mode (BCD mode when clear) */
+#define	 MC_REGB_SQWE	0x08	/* Square Wave Enable */
+#define	 MC_REGB_UIE	0x10	/* Update End interrupt enable */
+#define	 MC_REGB_AIE	0x20	/* Alarm interrupt enable */
+#define	 MC_REGB_PIE	0x40	/* Periodic interrupt enable */
+#define	 MC_REGB_SET	0x80	/* Allow time to be set; stops updates */
+
+#define	MC_REGC		0xc	/* Control register C */
+
+/*	 MC_REGC_UNUSED	0x0f	UNUSED */
+#define	 MC_REGC_UF	0x10	/* Update End interrupt flag */
+#define	 MC_REGC_AF	0x20	/* Alarm interrupt flag */
+#define	 MC_REGC_PF	0x40	/* Periodic interrupt flag */
+#define	 MC_REGC_IRQF	0x80	/* Interrupt request pending flag */
+
+#define	MC_REGD		0xd	/* Control register D */
+
+/*	 MC_REGD_UNUSED	0x7f	UNUSED */
+#define	 MC_REGD_VRT	0x80	/* Valid RAM and Time bit */
+
+
+#define	MC_NREGS	0xe	/* 14 registers; CMOS follows */
+#define	MC_NTODREGS	0xa	/* 10 of those regs are for TOD and alarm */
+
+#define	MC_NVRAM_START	0xe	/* start of NVRAM: offset 14 */
+#define	MC_NVRAM_SIZE	50	/* 50 bytes of NVRAM */
+
+/*
+ * Periodic Interrupt Rate Select constants (Control register A)
+ */
+#define	MC_RATE_NONE	0x0	/* No periodic interrupt */
+#define	MC_RATE_1	0x1     /* 256 Hz if MC_BASE_32_KHz, else 32768 Hz */
+#define	MC_RATE_2	0x2     /* 128 Hz if MC_BASE_32_KHz, else 16384 Hz */
+#define	MC_RATE_8192_Hz	0x3	/* 122.070 us period */
+#define	MC_RATE_4096_Hz	0x4	/* 244.141 us period */
+#define	MC_RATE_2048_Hz	0x5	/* 488.281 us period */
+#define	MC_RATE_1024_Hz	0x6	/* 976.562 us period */
+#define	MC_RATE_512_Hz	0x7	/* 1.953125 ms period */
+#define	MC_RATE_256_Hz	0x8	/* 3.90625 ms period */
+#define	MC_RATE_128_Hz	0x9	/* 7.8125 ms period */
+#define	MC_RATE_64_Hz	0xa	/* 15.625 ms period */
+#define	MC_RATE_32_Hz	0xb	/* 31.25 ms period */
+#define	MC_RATE_16_Hz	0xc	/* 62.5 ms period */
+#define	MC_RATE_8_Hz	0xd	/* 125 ms period */
+#define	MC_RATE_4_Hz	0xe	/* 250 ms period */
+#define	MC_RATE_2_Hz	0xf	/* 500 ms period */
+
+/*
+ * Time base (divisor select) constants (Control register A)
+ */
+#define	MC_BASE_4_MHz	0x00		/* 4MHz crystal */
+#define	MC_BASE_1_MHz	0x10		/* 1MHz crystal */
+#define	MC_BASE_32_KHz	0x20		/* 32KHz crystal */
+#define	MC_BASE_NONE	0x60		/* actually, both of these reset */
+#define	MC_BASE_RESET	0x70
+
+
+/*
+ * RTC register/NVRAM read and write functions -- machine-dependent.
+ * Appropriately manipulate RTC registers to get/put data values.
+ */
+u_int mc146818_read __P((void *sc, u_int reg));
+void mc146818_write __P((void *sc, u_int reg, u_int datum));
+
+/*
+ * A collection of TOD/Alarm registers.
+ */
+typedef u_int mc_todregs[MC_NTODREGS];
+
+/*
+ * Get all of the TOD/Alarm registers
+ * Must be called at splhigh(), and with the RTC properly set up.
+ */
+#define MC146818_GETTOD(sc, regs)					\
+	do {								\
+		int i;							\
+									\
+		/* update in progress; spin loop */			\
+		while (mc146818_read(sc, MC_REGA) & MC_REGA_UIP)	\
+			;						\
+									\
+		/* read all of the tod/alarm regs */			\
+		for (i = 0; i < MC_NTODREGS; i++)			\
+			(*regs)[i] = mc146818_read(sc, i);		\
+	} while (0);
+
+/*
+ * Set all of the TOD/Alarm registers
+ * Must be called at splhigh(), and with the RTC properly set up.
+ */
+#define MC146818_PUTTOD(sc, regs)					\
+	do {								\
+		int i;							\
+									\
+		/* stop updates while setting */			\
+		mc146818_write(sc, MC_REGB,				\
+		    mc146818_read(sc, MC_REGB) | MC_REGB_SET);		\
+									\
+		/* write all of the tod/alarm regs */			\
+		for (i = 0; i < MC_NTODREGS; i++)			\
+			mc146818_write(sc, i, (*regs)[i]);		\
+									\
+		/* reenable updates */					\
+		mc146818_write(sc, MC_REGB,				\
+		    mc146818_read(sc, MC_REGB) & ~MC_REGB_SET);		\
+	} while (0);
diff --git a/sys/dev/dec/mcclock.c b/sys/dev/dec/mcclock.c
new file mode 100644
index 0000000..76e3805
--- /dev/null
+++ b/sys/dev/dec/mcclock.c
@@ -0,0 +1,141 @@
+/* $Id$ */
+/* $NetBSD: mcclock.c,v 1.11 1998/04/19 07:50:25 jonathan 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/param.h>
+#include <sys/kernel.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+
+#include <dev/dec/clockvar.h>
+#include <dev/dec/mcclockvar.h>
+#include <dev/dec/mc146818reg.h>
+
+/*
+ * XXX rate is machine-dependent.
+ */
+#ifdef __alpha__
+#define MC_DEFAULTRATE MC_RATE_1024_Hz
+#endif
+#ifdef __pmax__
+#define MC_DEFAULTRATE MC_RATE_256_Hz
+#endif
+
+
+void	mcclock_init __P((struct device *));
+void	mcclock_get __P((struct device *, time_t, struct clocktime *));
+void	mcclock_set __P((struct device *, struct clocktime *));
+
+const struct clockfns mcclock_clockfns = {
+	mcclock_init, mcclock_get, mcclock_set,
+};
+
+#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;
+{
+	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);
+}
+
+void
+mcclock_init(dev)
+	device_t dev;
+{
+	struct mcclock_softc *sc = device_get_softc(dev);
+
+	mc146818_write(sc, MC_REGA, MC_BASE_32_KHz | MC_DEFAULTRATE);
+	mc146818_write(sc, MC_REGB,
+	    MC_REGB_PIE | MC_REGB_SQWE | MC_REGB_BINARY | MC_REGB_24HR);
+}
+
+/*
+ * Get the time of day, based on the clock's value and/or the base value.
+ */
+void
+mcclock_get(dev, base, ct)
+	struct device *dev;
+	time_t base;
+	struct clocktime *ct;
+{
+	struct mcclock_softc *sc = device_get_softc(dev);
+	mc_todregs regs;
+	int s;
+
+	s = splclock();
+	MC146818_GETTOD(sc, &regs)
+	splx(s);
+
+	ct->sec = regs[MC_SEC];
+	ct->min = regs[MC_MIN];
+	ct->hour = regs[MC_HOUR];
+	ct->dow = regs[MC_DOW];
+	ct->day = regs[MC_DOM];
+	ct->mon = regs[MC_MONTH];
+	ct->year = regs[MC_YEAR];
+}
+
+/*
+ * Reset the TODR based on the time value.
+ */
+void
+mcclock_set(dev, ct)
+	struct device *dev;
+	struct clocktime *ct;
+{
+	struct mcclock_softc *sc = device_get_softc(dev);
+	mc_todregs regs;
+	int s;
+
+	s = splclock();
+	MC146818_GETTOD(sc, &regs);
+	splx(s);
+
+	regs[MC_SEC] = ct->sec;
+	regs[MC_MIN] = ct->min;
+	regs[MC_HOUR] = ct->hour;
+	regs[MC_DOW] = ct->dow;
+	regs[MC_DOM] = ct->day;
+	regs[MC_MONTH] = ct->mon;
+	regs[MC_YEAR] = ct->year;
+
+	s = splclock();
+	MC146818_PUTTOD(sc, &regs);
+	splx(s);
+}
diff --git a/sys/dev/dec/mcclockvar.h b/sys/dev/dec/mcclockvar.h
new file mode 100644
index 0000000..d2c0ac8
--- /dev/null
+++ b/sys/dev/dec/mcclockvar.h
@@ -0,0 +1,41 @@
+/* $NetBSD: mcclockvar.h,v 1.4 1997/06/22 08:02:19 jonathan Exp $ */
+
+/*
+ * Copyright (c) 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.
+ */
+
+struct mcclock_softc {
+	device_t	sc_dev;
+	const struct mcclock_busfns *sc_busfns;
+};
+
+struct mcclock_busfns {
+	void    (*mc_bf_write) __P((struct mcclock_softc *, u_int, u_int));
+	u_int   (*mc_bf_read) __P((struct mcclock_softc *, u_int));
+};
+
+void	mcclock_attach __P((struct mcclock_softc *,
+	    const struct mcclock_busfns *));
diff --git a/sys/dev/mc146818/mc146818reg.h b/sys/dev/mc146818/mc146818reg.h
new file mode 100644
index 0000000..95c3ccf
--- /dev/null
+++ b/sys/dev/mc146818/mc146818reg.h
@@ -0,0 +1,194 @@
+/*	$NetBSD: mc146818reg.h,v 1.2 1997/03/12 06:53:42 cgd Exp $	*/
+
+/*
+ * Copyright (c) 1995 Carnegie-Mellon University.
+ * All rights reserved.
+ * 
+ * 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.
+ */
+
+/*
+ * Definitions for the Motorola MC146818A Real Time Clock.
+ * They also apply for the (compatible) Dallas Semicontuctor DS1287A RTC.
+ *
+ * Though there are undoubtedly other (better) sources, this material was
+ * culled from the DEC "KN121 System Module Programmer's Reference
+ * Information."
+ *
+ * The MC146818A has 16 registers.  The first 10 contain time-of-year
+ * and alarm data.  The rest contain various control and status bits.
+ *
+ * To read or write the registers, one writes the register number to
+ * the RTC's control port, then either reads from or writes the new
+ * data to the RTC's data port.  Since the locations of these ports
+ * and the method used to access them can be machine-dependent, the
+ * low-level details of reading and writing the RTC's registers are
+ * handled by machine-specific functions.
+ *
+ * The time-of-year and alarm data can be expressed in either binary
+ * or BCD, and they are selected by a bit in register B.
+ *
+ * The "hour" time-of-year and alarm fields can either be expressed in
+ * AM/PM format, or in 24-hour format.  If AM/PM format is chosen, the
+ * hour fields can have the values: 1-12 and 81-92 (the latter being
+ * PM).  If the 24-hour format is chosen, they can have the values
+ * 0-24.  The hour format is selectable by a bit in register B.
+ * (XXX IS AM/PM MODE DESCRIPTION CORRECT?)
+ *
+ * It is assumed the if systems are going to use BCD (rather than
+ * binary) mode, or AM/PM hour format, they'll do the appropriate
+ * conversions in machine-dependent code.  Also, if the clock is
+ * switched between BCD and binary mode, or between AM/PM mode and
+ * 24-hour mode, the time-of-day and alarm registers are NOT
+ * automatically reset; they must be reprogrammed with correct values.
+ */
+
+/*
+ * The registers, and the bits within each register.
+ */
+
+#define	MC_SEC		0x0	/* Time of year: seconds (0-59) */
+#define	MC_ASEC		0x1	/* Alarm: seconds */
+#define	MC_MIN		0x2	/* Time of year: minutes (0-59) */
+#define	MC_AMIN		0x3	/* Alarm: minutes */
+#define	MC_HOUR		0x4	/* Time of year: hour (see above) */
+#define	MC_AHOUR	0x5	/* Alarm: hour */
+#define	MC_DOW		0x6	/* Time of year: day of week (1-7) */
+#define	MC_DOM		0x7	/* Time of year: day of month (1-31) */
+#define	MC_MONTH	0x8	/* Time of year: month (1-12) */
+#define	MC_YEAR		0x9	/* Time of year: year in century (0-99) */
+
+#define	MC_REGA		0xa	/* Control register A */
+
+#define	 MC_REGA_RSMASK	0x0f	/* Interrupt rate select mask (see below) */
+#define	 MC_REGA_DVMASK	0x70	/* Divisor select mask (see below) */
+#define	 MC_REGA_UIP	0x80	/* Update in progress; read only. */
+
+#define	MC_REGB		0xb	/* Control register B */
+
+#define	 MC_REGB_DSE	0x01	/* Daylight Savings Enable */
+#define	 MC_REGB_24HR	0x02	/* 24-hour mode (AM/PM mode when clear) */
+#define	 MC_REGB_BINARY	0x04	/* Binary mode (BCD mode when clear) */
+#define	 MC_REGB_SQWE	0x08	/* Square Wave Enable */
+#define	 MC_REGB_UIE	0x10	/* Update End interrupt enable */
+#define	 MC_REGB_AIE	0x20	/* Alarm interrupt enable */
+#define	 MC_REGB_PIE	0x40	/* Periodic interrupt enable */
+#define	 MC_REGB_SET	0x80	/* Allow time to be set; stops updates */
+
+#define	MC_REGC		0xc	/* Control register C */
+
+/*	 MC_REGC_UNUSED	0x0f	UNUSED */
+#define	 MC_REGC_UF	0x10	/* Update End interrupt flag */
+#define	 MC_REGC_AF	0x20	/* Alarm interrupt flag */
+#define	 MC_REGC_PF	0x40	/* Periodic interrupt flag */
+#define	 MC_REGC_IRQF	0x80	/* Interrupt request pending flag */
+
+#define	MC_REGD		0xd	/* Control register D */
+
+/*	 MC_REGD_UNUSED	0x7f	UNUSED */
+#define	 MC_REGD_VRT	0x80	/* Valid RAM and Time bit */
+
+
+#define	MC_NREGS	0xe	/* 14 registers; CMOS follows */
+#define	MC_NTODREGS	0xa	/* 10 of those regs are for TOD and alarm */
+
+#define	MC_NVRAM_START	0xe	/* start of NVRAM: offset 14 */
+#define	MC_NVRAM_SIZE	50	/* 50 bytes of NVRAM */
+
+/*
+ * Periodic Interrupt Rate Select constants (Control register A)
+ */
+#define	MC_RATE_NONE	0x0	/* No periodic interrupt */
+#define	MC_RATE_1	0x1     /* 256 Hz if MC_BASE_32_KHz, else 32768 Hz */
+#define	MC_RATE_2	0x2     /* 128 Hz if MC_BASE_32_KHz, else 16384 Hz */
+#define	MC_RATE_8192_Hz	0x3	/* 122.070 us period */
+#define	MC_RATE_4096_Hz	0x4	/* 244.141 us period */
+#define	MC_RATE_2048_Hz	0x5	/* 488.281 us period */
+#define	MC_RATE_1024_Hz	0x6	/* 976.562 us period */
+#define	MC_RATE_512_Hz	0x7	/* 1.953125 ms period */
+#define	MC_RATE_256_Hz	0x8	/* 3.90625 ms period */
+#define	MC_RATE_128_Hz	0x9	/* 7.8125 ms period */
+#define	MC_RATE_64_Hz	0xa	/* 15.625 ms period */
+#define	MC_RATE_32_Hz	0xb	/* 31.25 ms period */
+#define	MC_RATE_16_Hz	0xc	/* 62.5 ms period */
+#define	MC_RATE_8_Hz	0xd	/* 125 ms period */
+#define	MC_RATE_4_Hz	0xe	/* 250 ms period */
+#define	MC_RATE_2_Hz	0xf	/* 500 ms period */
+
+/*
+ * Time base (divisor select) constants (Control register A)
+ */
+#define	MC_BASE_4_MHz	0x00		/* 4MHz crystal */
+#define	MC_BASE_1_MHz	0x10		/* 1MHz crystal */
+#define	MC_BASE_32_KHz	0x20		/* 32KHz crystal */
+#define	MC_BASE_NONE	0x60		/* actually, both of these reset */
+#define	MC_BASE_RESET	0x70
+
+
+/*
+ * RTC register/NVRAM read and write functions -- machine-dependent.
+ * Appropriately manipulate RTC registers to get/put data values.
+ */
+u_int mc146818_read __P((void *sc, u_int reg));
+void mc146818_write __P((void *sc, u_int reg, u_int datum));
+
+/*
+ * A collection of TOD/Alarm registers.
+ */
+typedef u_int mc_todregs[MC_NTODREGS];
+
+/*
+ * Get all of the TOD/Alarm registers
+ * Must be called at splhigh(), and with the RTC properly set up.
+ */
+#define MC146818_GETTOD(sc, regs)					\
+	do {								\
+		int i;							\
+									\
+		/* update in progress; spin loop */			\
+		while (mc146818_read(sc, MC_REGA) & MC_REGA_UIP)	\
+			;						\
+									\
+		/* read all of the tod/alarm regs */			\
+		for (i = 0; i < MC_NTODREGS; i++)			\
+			(*regs)[i] = mc146818_read(sc, i);		\
+	} while (0);
+
+/*
+ * Set all of the TOD/Alarm registers
+ * Must be called at splhigh(), and with the RTC properly set up.
+ */
+#define MC146818_PUTTOD(sc, regs)					\
+	do {								\
+		int i;							\
+									\
+		/* stop updates while setting */			\
+		mc146818_write(sc, MC_REGB,				\
+		    mc146818_read(sc, MC_REGB) | MC_REGB_SET);		\
+									\
+		/* write all of the tod/alarm regs */			\
+		for (i = 0; i < MC_NTODREGS; i++)			\
+			mc146818_write(sc, i, (*regs)[i]);		\
+									\
+		/* reenable updates */					\
+		mc146818_write(sc, MC_REGB,				\
+		    mc146818_read(sc, MC_REGB) & ~MC_REGB_SET);		\
+	} while (0);