Add a driver back end for MC146818 and compatible clocks based on the

respective NetBSD driver for use with the genclock interface.
It's first use will be on sparc64 but it was also tested on alpha with
a preliminary patch to switch alpha to use the genclock code together
with this driver instead of the respective code in alpha/alpha/clock.c
and the rather MD mcclock(4). Using it on i386 and amd64 won't be that
hard but some changes/extensions to improve the genclock code in general
should be done first, e.g. add locking and make it easier to access the
NVRAM usually coupled with RTCs.

3 files changed, 340 insertions, 47 deletions

diff --git a/sys/dev/mc146818/mc146818.c b/sys/dev/mc146818/mc146818.c
new file mode 100644
index 0000000..48d36a7
--- /dev/null
+++ b/sys/dev/mc146818/mc146818.c
@@ -0,0 +1,275 @@
+/*
+ * Copyright (c) 2003 Izumi Tsutsui.  All rights reserved.
+ *
+ * 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ *
+ *	from: NetBSD: mc146818.c,v 1.4 2003/11/24 06:20:40 tsutsui Exp
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+/*
+ * mc146818 and compatible time of day chip subroutines
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/clock.h>
+
+#include <machine/bus.h>
+
+#include <dev/mc146818/mc146818reg.h>
+#include <dev/mc146818/mc146818var.h>
+
+#include "clock_if.h"
+
+static u_int	mc146818_def_getcent(device_t);
+static void	mc146818_def_setcent(device_t, u_int);
+static u_int	mc146818_def_read(device_t, u_int);
+static void	mc146818_def_write(device_t, u_int, u_int);
+
+int
+mc146818_attach(device_t dev)
+{
+	struct mc146818_softc *sc;
+
+	sc = device_get_softc(dev);
+
+	if (sc->sc_mcread == NULL)
+		sc->sc_mcread = mc146818_def_read;
+	if (sc->sc_mcwrite == NULL)
+		sc->sc_mcwrite = mc146818_def_write;
+
+	if (sc->sc_flag & MC146818_NO_CENT_ADJUST) {
+		/*
+		 * Note that setting MC146818_NO_CENT_ADJUST means that
+		 * the century has to be stored in NVRAM somewhere.
+		 */
+		if (sc->sc_getcent == NULL)
+			sc->sc_getcent = mc146818_def_getcent;
+		if (sc->sc_setcent == NULL)
+			sc->sc_setcent = mc146818_def_setcent;
+	}
+
+	if (!(*sc->sc_mcread)(dev, MC_REGD) & MC_REGD_VRT) {
+		device_printf(dev, "mc146818_attach: battery low\n");
+		return (ENXIO);
+	}
+
+	sc->sc_rega = MC_BASE_32_KHz;
+	(*sc->sc_mcwrite)(dev, MC_REGA, sc->sc_rega);
+
+	sc->sc_regb = 0;
+	sc->sc_regb |= (sc->sc_flag & MC146818_BCD) ? 0 : MC_REGB_BINARY;
+	sc->sc_regb |= (sc->sc_flag & MC146818_12HR) ? 0 : MC_REGB_24HR;
+	(*sc->sc_mcwrite)(dev, MC_REGB, sc->sc_regb);
+
+	clock_register(dev, 1000000);	/* 1 second resolution. */
+
+	return (0);
+}
+
+/*
+ * Get time of day and convert it to a struct timespec.
+ * Return 0 on success, an error number otherwise.
+ */
+int
+mc146818_gettime(device_t dev, struct timespec *ts)
+{
+	struct mc146818_softc *sc;
+	struct clocktime ct;
+	int timeout, cent, year;
+
+	sc = device_get_softc(dev);
+
+	timeout = 1000000;	/* XXX how long should we wait? */
+
+	/*
+	 * XXX:	Use a spinlock to mutex register access and increase the
+	 *	likelihood that all registers are read before an update
+	 *	occurs.
+	 */
+
+	/*
+	 * If MC_REGA_UIP is 0 we have at least 244us before the next
+	 * update. If it's 1 an update is imminent.
+	 */
+	for (;;) {
+		if (!((*sc->sc_mcread)(dev, MC_REGA) & MC_REGA_UIP))
+			break;
+		if (--timeout < 0) {
+			device_printf(dev, "mc146818_gettime: timeout\n");
+			return (EBUSY);
+		}
+	}
+
+#define	FROMREG(x)	((sc->sc_flag & MC146818_BCD) ? FROMBCD(x) : (x))
+
+	ct.nsec = 0;
+	ct.sec = FROMREG((*sc->sc_mcread)(dev, MC_SEC));
+	ct.min = FROMREG((*sc->sc_mcread)(dev, MC_MIN));
+	ct.hour = FROMREG((*sc->sc_mcread)(dev, MC_HOUR));
+	ct.dow = FROMREG((*sc->sc_mcread)(dev, MC_DOW)) - 1;
+	ct.day = FROMREG((*sc->sc_mcread)(dev, MC_DOM));
+	ct.mon = FROMREG((*sc->sc_mcread)(dev, MC_MONTH));
+	year = FROMREG((*sc->sc_mcread)(dev, MC_YEAR));
+	if (sc->sc_getcent) {
+		cent = (*sc->sc_getcent)(dev);
+		year += cent * 100;
+	}
+
+	year += sc->sc_year0;
+	if (year < POSIX_BASE_YEAR && !(sc->sc_flag & MC146818_NO_CENT_ADJUST))
+		year += 100;
+	ct.year = year;
+
+	return (clock_ct_to_ts(&ct, ts));
+}
+
+#ifdef notyet
+int
+mc146818_getsecs(device_t dev, int *secp)
+{
+	struct mc146818_softc *sc;
+	int sec, timeout;
+
+	sc = device_get_softc(dev);
+
+	timeout = 1000000;	/* XXX how long should we wait? */
+
+	for (;;) {
+		if (!((*sc->sc_mcread)(dev, MC_REGA) & MC_REGA_UIP)) {
+			sec = FROMREG((*sc->sc_mcread)(dev, MC_SEC));
+			break;
+		}
+		if (--timeout == 0) {
+			device_printf(dev, "mc146818_getsecs: timeout\n");
+			return (EBUSY);
+		}
+	}
+
+#undef FROMREG
+
+	*secp = sec;
+	return (0);
+}
+#endif
+
+/*
+ * Set the time of day clock based on the value of the struct timespec arg.
+ * Return 0 on success, an error number otherwise.
+ */
+int
+mc146818_settime(device_t dev, struct timespec *ts)
+{
+	struct mc146818_softc *sc;
+	struct clocktime ct;
+	int cent, year;
+
+	sc = device_get_softc(dev);
+
+	/* Accuracy is only one second. */
+	if (ts->tv_nsec >= 500000000)
+		ts->tv_sec++;
+	ts->tv_nsec = 0;
+	clock_ts_to_ct(ts, &ct);
+
+	/* Disable RTC updates and interrupts (if enabled). */
+	(*sc->sc_mcwrite)(dev, MC_REGB,
+	    ((sc->sc_regb & (MC_REGB_BINARY | MC_REGB_24HR)) | MC_REGB_SET));
+
+#define	TOREG(x)	((sc->sc_flag & MC146818_BCD) ? TOBCD(x) : (x))
+
+	(*sc->sc_mcwrite)(dev, MC_SEC, TOREG(ct.sec));
+	(*sc->sc_mcwrite)(dev, MC_MIN, TOREG(ct.min));
+	(*sc->sc_mcwrite)(dev, MC_HOUR, TOREG(ct.hour));
+	(*sc->sc_mcwrite)(dev, MC_DOW, TOREG(ct.dow + 1));
+	(*sc->sc_mcwrite)(dev, MC_DOM, TOREG(ct.day));
+	(*sc->sc_mcwrite)(dev, MC_MONTH, TOREG(ct.mon));
+
+	year = ct.year - sc->sc_year0;
+	if (sc->sc_setcent) {
+		cent = year / 100;
+		(*sc->sc_setcent)(dev, cent);
+		year -= cent * 100;
+	}
+	if (year > 99 && (sc->sc_flag & MC146818_NO_CENT_ADJUST) == 0)
+		year -= 100;
+	(*sc->sc_mcwrite)(dev, MC_YEAR, TOREG(year));
+
+	/* Reenable RTC updates and interrupts. */
+	(*sc->sc_mcwrite)(dev, MC_REGB, sc->sc_regb);
+
+#undef TOREG
+
+	return (0);
+}
+
+#define	MC_ADDR	0
+#define	MC_DATA	1
+
+static u_int
+mc146818_def_read(device_t dev, u_int reg)
+{
+	struct mc146818_softc *sc;
+
+	sc = device_get_softc(dev);
+	bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_ADDR, reg);
+	return (bus_space_read_1(sc->sc_bst, sc->sc_bsh, MC_DATA));
+}
+
+static void
+mc146818_def_write(device_t dev, u_int reg, u_int val)
+{
+	struct mc146818_softc *sc;
+
+	sc = device_get_softc(dev);
+	bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_ADDR, reg);
+	bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_DATA, val);
+}
+
+/*
+ * Looks like it's common even across platforms to store the century at
+ * 0x32 in the NVRAM of the mc146818.
+ */
+#define	MC_CENT	0x32
+
+static u_int
+mc146818_def_getcent(device_t dev)
+{
+	struct mc146818_softc *sc;
+
+	sc = device_get_softc(dev);
+	return ((*sc->sc_mcread)(dev, MC_CENT));
+}
+
+static void
+mc146818_def_setcent(device_t dev, u_int cent)
+{
+	struct mc146818_softc *sc;
+
+	sc = device_get_softc(dev);
+	(*sc->sc_mcwrite)(dev, MC_CENT, cent);
+}
diff --git a/sys/dev/mc146818/mc146818reg.h b/sys/dev/mc146818/mc146818reg.h
index e60d043..48d558c 100644
--- a/sys/dev/mc146818/mc146818reg.h
+++ b/sys/dev/mc146818/mc146818reg.h
@@ -1,6 +1,3 @@
-/* $FreeBSD$ */
-/*	$NetBSD: mc146818reg.h,v 1.2 1997/03/12 06:53:42 cgd Exp $	*/
-
 /*
  * Copyright (c) 1995 Carnegie-Mellon University.
  * All rights reserved.
@@ -24,11 +21,15 @@
  *
  * any improvements or extensions that they make and grant Carnegie the
  * rights to redistribute these changes.
+ *
+ *	from: NetBSD: mc146818reg.h,v 1.5 2003/11/02 11:07:45 wiz Exp
+ *
+ * $FreeBSD$
  */
 
 /*
  * Definitions for the Motorola MC146818A Real Time Clock.
- * They also apply for the (compatible) Dallas Semicontuctor DS1287A RTC.
+ * They also apply for the (compatible) Dallas Semiconductor DS1287A RTC.
  *
  * Though there are undoubtedly other (better) sources, this material was
  * culled from the DEC "KN121 System Module Programmer's Reference
@@ -142,46 +143,3 @@
 #define	MC_BASE_32_KHz	0x20		/* 32KHz crystal */
 #define	MC_BASE_NONE	0x60		/* actually, both of these reset */
 #define	MC_BASE_RESET	0x70
-
-/*
- * 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(dev, regs)					\
-	do {								\
-		int i;							\
-									\
-		/* update in progress; spin loop */			\
-		while (MCCLOCK_READ(dev, MC_REGA) & MC_REGA_UIP)	\
-			;						\
-									\
-		/* read all of the tod/alarm regs */			\
-		for (i = 0; i < MC_NTODREGS; i++)			\
-			(*regs)[i] = MCCLOCK_READ(dev, 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(dev, regs)					\
-	do {								\
-		int i;							\
-									\
-		/* stop updates while setting */			\
-		MCCLOCK_WRITE(dev, MC_REGB,				\
-		    MCCLOCK_READ(dev, MC_REGB) | MC_REGB_SET);		\
-									\
-		/* write all of the tod/alarm regs */			\
-		for (i = 0; i < MC_NTODREGS; i++)			\
-			MCCLOCK_WRITE(dev, i, (*regs)[i]);		\
-									\
-		/* reenable updates */					\
-		MCCLOCK_WRITE(dev, MC_REGB,				\
-		    MCCLOCK_READ(dev, MC_REGB) & ~MC_REGB_SET);		\
-	} while (0);
diff --git a/sys/dev/mc146818/mc146818var.h b/sys/dev/mc146818/mc146818var.h
new file mode 100644
index 0000000..78d9945
--- /dev/null
+++ b/sys/dev/mc146818/mc146818var.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2003 Izumi Tsutsui.  All rights reserved.
+ *
+ * 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ *
+ *	from: NetBSD: mc146818var.h,v 1.3 2003/11/24 06:20:40 tsutsui Exp
+ *
+ * $FreeBSD$
+ */
+
+struct mc146818_softc {
+	bus_space_tag_t	sc_bst;			/* bus space tag */
+	bus_space_handle_t sc_bsh;		/* bus space handle */
+
+	u_char sc_rega;				/* register A */
+	u_char sc_regb;				/* register B */
+
+	u_int sc_year0;				/* year counter offset */
+	u_int sc_flag;				/* MD flags */
+#define MC146818_NO_CENT_ADJUST	0x0001		/* don't adjust century */
+#define MC146818_BCD		0x0002		/* use BCD mode */
+#define MC146818_12HR		0x0004		/* use AM/PM mode */
+
+	/* MD chip register read/write functions */
+	u_int (*sc_mcread)(device_t, u_int);
+	void (*sc_mcwrite)(device_t, u_int, u_int);
+	/* MD century get/set functions */
+	u_int (*sc_getcent)(device_t);
+	void (*sc_setcent)(device_t, u_int);
+};
+
+/* Chip attach function */
+int mc146818_attach(device_t);
+
+/* Methods for the clock interface */
+#ifdef notyet
+int mc146818_getsecs(device_t, int *);
+#endif
+int mc146818_gettime(device_t, struct timespec *);
+int mc146818_settime(device_t, struct timespec *);