MFi386: RTC related cleanups.

- Use generic RTC handling code.
- Make clock_if.m and subr_rtc.c standard.
- Nuke MD inittodr(), resettodr() functions.
- Add new "pcrtc" device driver.
- Add hints for "pcrtc" driver.

2 files changed, 428 insertions, 282 deletions

diff --git a/sys/pc98/cbus/clock.c b/sys/pc98/cbus/clock.c
index 05d34c5..81f61b9 100644
--- a/sys/pc98/cbus/clock.c
+++ b/sys/pc98/cbus/clock.c
@@ -119,10 +119,6 @@ static	int	using_lapic_timer;
 #define	ACQUIRE_PENDING	3
 
 static	u_char	timer1_state;
-static void rtc_serialcombit(int);
-static void rtc_serialcom(int);
-static int rtc_inb(void);
-static void rtc_outb(int);
 
 static	unsigned i8254_get_timecount(struct timecounter *tc);
 static	unsigned i8254_simple_get_timecount(struct timecounter *tc);
@@ -400,137 +396,6 @@ startrtclock()
 	init_TSC();
 }
 
-static void
-rtc_serialcombit(int i)
-{
-	outb(IO_RTC, ((i&0x01)<<5)|0x07);
-	DELAY(1);
-	outb(IO_RTC, ((i&0x01)<<5)|0x17);
-	DELAY(1);
-	outb(IO_RTC, ((i&0x01)<<5)|0x07);
-	DELAY(1);
-}
-
-static void
-rtc_serialcom(int i)
-{
-	rtc_serialcombit(i&0x01);
-	rtc_serialcombit((i&0x02)>>1);
-	rtc_serialcombit((i&0x04)>>2);
-	rtc_serialcombit((i&0x08)>>3);
-	outb(IO_RTC, 0x07);
-	DELAY(1);
-	outb(IO_RTC, 0x0f);
-	DELAY(1);
-	outb(IO_RTC, 0x07);
- 	DELAY(1);
-}
-
-static void
-rtc_outb(int val)
-{
-	int s;
-	int sa = 0;
-
-	for (s=0;s<8;s++) {
-	    sa = ((val >> s) & 0x01) ? 0x27 : 0x07;
-	    outb(IO_RTC, sa);		/* set DI & CLK 0 */
-	    DELAY(1);
-	    outb(IO_RTC, sa | 0x10);	/* CLK 1 */
-	    DELAY(1);
-	}
-	outb(IO_RTC, sa & 0xef);	/* CLK 0 */
-}
-
-static int
-rtc_inb(void)
-{
-	int s;
-	int sa = 0;
-
-	for (s=0;s<8;s++) {
-	    sa |= ((inb(0x33) & 0x01) << s);
-	    outb(IO_RTC, 0x17);	/* CLK 1 */
-	    DELAY(1);
-	    outb(IO_RTC, 0x07);	/* CLK 0 */
-	    DELAY(2);
-	}
-	return sa;
-}
-
-/*
- * Initialize the time of day register, based on the time base which is, e.g.
- * from a filesystem.
- */
-void
-inittodr(time_t base)
-{
-	struct timespec ts;
-	struct clocktime ct;
-	int i;
-
-	if (base) {
-		ts.tv_sec = base;
-		ts.tv_nsec = 0;
-		tc_setclock(&ts);
-	}
-
-	rtc_serialcom(0x03);	/* Time Read */
-	rtc_serialcom(0x01);	/* Register shift command. */
-	DELAY(20);
-
-	ct.nsec = 0;
-	ct.sec = bcd2bin(rtc_inb() & 0xff);		/* sec */
-	ct.min = bcd2bin(rtc_inb() & 0xff);		/* min */
-	ct.hour = bcd2bin(rtc_inb() & 0xff);		/* hour */
-	ct.day = bcd2bin(rtc_inb() & 0xff);		/* date */
-	i = rtc_inb();
-	ct.dow = i & 0x0f;				/* dow */
-	ct.mon = (i >> 4) & 0x0f;			/* month */
-	ct.year = bcd2bin(rtc_inb() & 0xff) + 1900;	/* year */
-	if (ct.year < 1995)
-		ct.year += 100;
-	/* Set dow = -1 because some clocks don't set it correctly. */
-	ct.dow = -1;
-	if (clock_ct_to_ts(&ct, &ts)) {
-		printf("Invalid time in clock: check and reset the date!\n");
-		return;
-	}
-	ts.tv_sec += utc_offset();
-	tc_setclock(&ts);
-}
-
-/*
- * Write system time back to RTC
- */
-void
-resettodr()
-{
-	struct timespec	ts;
-	struct clocktime ct;
-
-	if (disable_rtc_set)
-		return;
-
-	getnanotime(&ts);
-	ts.tv_sec -= utc_offset();
-	clock_ts_to_ct(&ts, &ct);
-
-	rtc_serialcom(0x01);	/* Register shift command. */
-
-	rtc_outb(bin2bcd(ct.sec)); 		/* Write back Seconds */
-	rtc_outb(bin2bcd(ct.min)); 		/* Write back Minutes */
-	rtc_outb(bin2bcd(ct.hour)); 		/* Write back Hours   */
-
-	rtc_outb(bin2bcd(ct.day));		/* Write back Day     */
-	rtc_outb((ct.mon << 4) | ct.dow);	/* Write back Month and DOW */
-	rtc_outb(bin2bcd(ct.year % 100));	/* Write back Year    */
-
-	rtc_serialcom(0x02);	/* Time set & Counter hold command. */
-	rtc_serialcom(0x00);	/* Register hold command. */
-}
-
-
 /*
  * Start both clocks running.
  */
@@ -619,7 +484,8 @@ i8254_get_timecount(struct timecounter *tc)
 	count = i8254_max_count - ((high << 8) | low);
 	if (count < i8254_lastcount ||
 	    (!i8254_ticked && (clkintr_pending ||
-	    ((count < 20 || (!(eflags & PSL_I) && count < i8254_max_count / 2u)) &&
+	    ((count < 20 || (!(eflags & PSL_I) &&
+	    count < i8254_max_count / 2u)) &&
 	    i8254_pending != NULL && i8254_pending(i8254_intsrc))))) {
 		i8254_ticked = 1;
 		i8254_offset += i8254_max_count;
@@ -632,11 +498,10 @@ i8254_get_timecount(struct timecounter *tc)
 
 #ifdef DEV_ISA
 /*
- * Attach to the ISA PnP descriptors for the timer and realtime clock.
+ * Attach to the ISA PnP descriptors for the timer
  */
 static struct isa_pnp_id attimer_ids[] = {
 	{ 0x0001d041 /* PNP0100 */, "AT timer" },
-	{ 0x000bd041 /* PNP0B00 */, "AT realtime clock" },
 	{ 0 }
 };
 
@@ -645,7 +510,8 @@ attimer_probe(device_t dev)
 {
 	int result;
 	
-	if ((result = ISA_PNP_PROBE(device_get_parent(dev), dev, attimer_ids)) <= 0)
+	result = ISA_PNP_PROBE(device_get_parent(dev), dev, attimer_ids);
+	if (result <= 0)
 		device_quiet(dev);
 	return(result);
 }
@@ -662,8 +528,8 @@ static device_method_t attimer_methods[] = {
 	DEVMETHOD(device_attach,	attimer_attach),
 	DEVMETHOD(device_detach,	bus_generic_detach),
 	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
-	DEVMETHOD(device_suspend,	bus_generic_suspend),	/* XXX stop statclock? */
-	DEVMETHOD(device_resume,	bus_generic_resume),	/* XXX restart statclock? */
+	DEVMETHOD(device_suspend,	bus_generic_suspend),
+	DEVMETHOD(device_resume,	bus_generic_resume),
 	{ 0, 0 }
 };
 
@@ -676,4 +542,211 @@ static driver_t attimer_driver = {
 static devclass_t attimer_devclass;
 
 DRIVER_MODULE(attimer, isa, attimer_driver, attimer_devclass, 0, 0);
+
+#endif /* DEV_ISA */
+
+#ifdef DEV_ISA
+
+/**********************************************************************
+ * RTC driver for subr_rtc
+ */
+
+#include "clock_if.h"
+
+#include <sys/rman.h>
+
+static void rtc_serialcombit(int);
+static void rtc_serialcom(int);
+static int rtc_inb(void);
+static void rtc_outb(int);
+
+static void
+rtc_serialcombit(int i)
+{
+	outb(IO_RTC, ((i&0x01)<<5)|0x07);
+	DELAY(1);
+	outb(IO_RTC, ((i&0x01)<<5)|0x17);
+	DELAY(1);
+	outb(IO_RTC, ((i&0x01)<<5)|0x07);
+	DELAY(1);
+}
+
+static void
+rtc_serialcom(int i)
+{
+	rtc_serialcombit(i&0x01);
+	rtc_serialcombit((i&0x02)>>1);
+	rtc_serialcombit((i&0x04)>>2);
+	rtc_serialcombit((i&0x08)>>3);
+	outb(IO_RTC, 0x07);
+	DELAY(1);
+	outb(IO_RTC, 0x0f);
+	DELAY(1);
+	outb(IO_RTC, 0x07);
+ 	DELAY(1);
+}
+
+static void
+rtc_outb(int val)
+{
+	int s;
+	int sa = 0;
+
+	for (s=0;s<8;s++) {
+	    sa = ((val >> s) & 0x01) ? 0x27 : 0x07;
+	    outb(IO_RTC, sa);		/* set DI & CLK 0 */
+	    DELAY(1);
+	    outb(IO_RTC, sa | 0x10);	/* CLK 1 */
+	    DELAY(1);
+	}
+	outb(IO_RTC, sa & 0xef);	/* CLK 0 */
+}
+
+static int
+rtc_inb(void)
+{
+	int s;
+	int sa = 0;
+
+	for (s=0;s<8;s++) {
+	    sa |= ((inb(0x33) & 0x01) << s);
+	    outb(IO_RTC, 0x17);	/* CLK 1 */
+	    DELAY(1);
+	    outb(IO_RTC, 0x07);	/* CLK 0 */
+	    DELAY(2);
+	}
+	return sa;
+}
+
+struct pcrtc_softc {
+	int port_rid1, port_rid2;
+	struct resource *port_res1, *port_res2;
+};
+
+/*
+ * Attach to the ISA PnP descriptors for the timer and realtime clock.
+ */
+static struct isa_pnp_id pcrtc_ids[] = {
+	{ 0x000bd041 /* PNP0B00 */, "AT realtime clock" },
+	{ 0 }
+};
+
+static int
+pcrtc_probe(device_t dev)
+{
+	int result;
+
+	device_set_desc(dev, "PC Real Time Clock");
+	result = ISA_PNP_PROBE(device_get_parent(dev), dev, pcrtc_ids);
+	/* ENXIO if wrong PnP-ID, ENOENT ifno PnP-ID, zero if good PnP-iD */
+	if (result != ENOENT)
+		return(result);
+	/* All PC's have an RTC, and we're hosed without it, so... */
+	return (BUS_PROBE_LOW_PRIORITY);
+}
+
+static int
+pcrtc_attach(device_t dev)
+{
+	struct pcrtc_softc *sc;
+
+	/*
+	 * Not that we need them or anything, but grab our resources
+	 * so they show up, correctly attributed, in the big picture.
+	 */
+	sc = device_get_softc(dev);
+	sc->port_rid1 = 0;
+	bus_set_resource(dev, SYS_RES_IOPORT, sc->port_rid1, IO_RTC, 1);
+	if (!(sc->port_res1 = bus_alloc_resource(dev, SYS_RES_IOPORT,
+	    &sc->port_rid1, IO_RTC, IO_RTC, 1, RF_ACTIVE)))
+		device_printf(dev, "Warning: Couldn't map I/O.\n");
+	sc->port_rid2 = 1;
+	bus_set_resource(dev, SYS_RES_IOPORT, sc->port_rid2, 0x33, 1);
+	if (!(sc->port_res2 = bus_alloc_resource(dev, SYS_RES_IOPORT,
+	    &sc->port_rid2, 0x33, 0x33, 1, RF_ACTIVE)))
+		device_printf(dev, "Warning: Couldn't map I/O.\n");
+
+	clock_register(dev, 1000000);
+	return(0);
+}
+
+static int
+pcrtc_settime(device_t dev __unused, struct timespec *ts)
+{
+	struct clocktime ct;
+
+	clock_ts_to_ct(ts, &ct);
+
+	rtc_serialcom(0x01);	/* Register shift command. */
+
+	rtc_outb(bin2bcd(ct.sec)); 		/* Write back Seconds */
+	rtc_outb(bin2bcd(ct.min)); 		/* Write back Minutes */
+	rtc_outb(bin2bcd(ct.hour)); 		/* Write back Hours   */
+
+	rtc_outb(bin2bcd(ct.day));		/* Write back Day     */
+	rtc_outb((ct.mon << 4) | ct.dow);	/* Write back Month and DOW */
+	rtc_outb(bin2bcd(ct.year % 100));	/* Write back Year    */
+
+	rtc_serialcom(0x02);	/* Time set & Counter hold command. */
+	rtc_serialcom(0x00);	/* Register hold command. */
+
+	return (0);
+}
+
+static int
+pcrtc_gettime(device_t dev, struct timespec *ts)
+{
+	struct clocktime ct;
+	int i;
+
+	rtc_serialcom(0x03);	/* Time Read */
+	rtc_serialcom(0x01);	/* Register shift command. */
+	DELAY(20);
+
+	ct.nsec = 0;
+	ct.sec = bcd2bin(rtc_inb() & 0xff);		/* sec */
+	ct.min = bcd2bin(rtc_inb() & 0xff);		/* min */
+	ct.hour = bcd2bin(rtc_inb() & 0xff);		/* hour */
+	ct.day = bcd2bin(rtc_inb() & 0xff);		/* date */
+	i = rtc_inb();
+	ct.dow = i & 0x0f;				/* dow */
+	ct.mon = (i >> 4) & 0x0f;			/* month */
+	ct.year = bcd2bin(rtc_inb() & 0xff) + 1900;	/* year */
+	if (ct.year < 1995)
+		ct.year += 100;
+
+	/* Set dow = -1 because some clocks don't set it correctly. */
+	ct.dow = -1;
+
+	return (clock_ct_to_ts(&ct, ts));
+}
+
+static device_method_t pcrtc_methods[] = {
+	/* Device interface */
+	DEVMETHOD(device_probe,		pcrtc_probe),
+	DEVMETHOD(device_attach,	pcrtc_attach),
+	DEVMETHOD(device_detach,	bus_generic_detach),
+	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
+	DEVMETHOD(device_suspend,	bus_generic_suspend),
+		/* XXX stop statclock? */
+	DEVMETHOD(device_resume,	bus_generic_resume),
+		/* XXX restart statclock? */
+
+	/* clock interface */
+	DEVMETHOD(clock_gettime,	pcrtc_gettime),
+	DEVMETHOD(clock_settime,	pcrtc_settime),
+
+	{ 0, 0 }
+};
+
+static driver_t pcrtc_driver = {
+	"pcrtc",
+	pcrtc_methods,
+	sizeof(struct pcrtc_softc),
+};
+
+static devclass_t pcrtc_devclass;
+
+DRIVER_MODULE(pcrtc, isa, pcrtc_driver, pcrtc_devclass, 0, 0);
+
 #endif /* DEV_ISA */
diff --git a/sys/pc98/cbus/pcrtc.c b/sys/pc98/cbus/pcrtc.c
index 05d34c5..81f61b9 100644
--- a/sys/pc98/cbus/pcrtc.c
+++ b/sys/pc98/cbus/pcrtc.c
@@ -119,10 +119,6 @@ static	int	using_lapic_timer;
 #define	ACQUIRE_PENDING	3
 
 static	u_char	timer1_state;
-static void rtc_serialcombit(int);
-static void rtc_serialcom(int);
-static int rtc_inb(void);
-static void rtc_outb(int);
 
 static	unsigned i8254_get_timecount(struct timecounter *tc);
 static	unsigned i8254_simple_get_timecount(struct timecounter *tc);
@@ -400,137 +396,6 @@ startrtclock()
 	init_TSC();
 }
 
-static void
-rtc_serialcombit(int i)
-{
-	outb(IO_RTC, ((i&0x01)<<5)|0x07);
-	DELAY(1);
-	outb(IO_RTC, ((i&0x01)<<5)|0x17);
-	DELAY(1);
-	outb(IO_RTC, ((i&0x01)<<5)|0x07);
-	DELAY(1);
-}
-
-static void
-rtc_serialcom(int i)
-{
-	rtc_serialcombit(i&0x01);
-	rtc_serialcombit((i&0x02)>>1);
-	rtc_serialcombit((i&0x04)>>2);
-	rtc_serialcombit((i&0x08)>>3);
-	outb(IO_RTC, 0x07);
-	DELAY(1);
-	outb(IO_RTC, 0x0f);
-	DELAY(1);
-	outb(IO_RTC, 0x07);
- 	DELAY(1);
-}
-
-static void
-rtc_outb(int val)
-{
-	int s;
-	int sa = 0;
-
-	for (s=0;s<8;s++) {
-	    sa = ((val >> s) & 0x01) ? 0x27 : 0x07;
-	    outb(IO_RTC, sa);		/* set DI & CLK 0 */
-	    DELAY(1);
-	    outb(IO_RTC, sa | 0x10);	/* CLK 1 */
-	    DELAY(1);
-	}
-	outb(IO_RTC, sa & 0xef);	/* CLK 0 */
-}
-
-static int
-rtc_inb(void)
-{
-	int s;
-	int sa = 0;
-
-	for (s=0;s<8;s++) {
-	    sa |= ((inb(0x33) & 0x01) << s);
-	    outb(IO_RTC, 0x17);	/* CLK 1 */
-	    DELAY(1);
-	    outb(IO_RTC, 0x07);	/* CLK 0 */
-	    DELAY(2);
-	}
-	return sa;
-}
-
-/*
- * Initialize the time of day register, based on the time base which is, e.g.
- * from a filesystem.
- */
-void
-inittodr(time_t base)
-{
-	struct timespec ts;
-	struct clocktime ct;
-	int i;
-
-	if (base) {
-		ts.tv_sec = base;
-		ts.tv_nsec = 0;
-		tc_setclock(&ts);
-	}
-
-	rtc_serialcom(0x03);	/* Time Read */
-	rtc_serialcom(0x01);	/* Register shift command. */
-	DELAY(20);
-
-	ct.nsec = 0;
-	ct.sec = bcd2bin(rtc_inb() & 0xff);		/* sec */
-	ct.min = bcd2bin(rtc_inb() & 0xff);		/* min */
-	ct.hour = bcd2bin(rtc_inb() & 0xff);		/* hour */
-	ct.day = bcd2bin(rtc_inb() & 0xff);		/* date */
-	i = rtc_inb();
-	ct.dow = i & 0x0f;				/* dow */
-	ct.mon = (i >> 4) & 0x0f;			/* month */
-	ct.year = bcd2bin(rtc_inb() & 0xff) + 1900;	/* year */
-	if (ct.year < 1995)
-		ct.year += 100;
-	/* Set dow = -1 because some clocks don't set it correctly. */
-	ct.dow = -1;
-	if (clock_ct_to_ts(&ct, &ts)) {
-		printf("Invalid time in clock: check and reset the date!\n");
-		return;
-	}
-	ts.tv_sec += utc_offset();
-	tc_setclock(&ts);
-}
-
-/*
- * Write system time back to RTC
- */
-void
-resettodr()
-{
-	struct timespec	ts;
-	struct clocktime ct;
-
-	if (disable_rtc_set)
-		return;
-
-	getnanotime(&ts);
-	ts.tv_sec -= utc_offset();
-	clock_ts_to_ct(&ts, &ct);
-
-	rtc_serialcom(0x01);	/* Register shift command. */
-
-	rtc_outb(bin2bcd(ct.sec)); 		/* Write back Seconds */
-	rtc_outb(bin2bcd(ct.min)); 		/* Write back Minutes */
-	rtc_outb(bin2bcd(ct.hour)); 		/* Write back Hours   */
-
-	rtc_outb(bin2bcd(ct.day));		/* Write back Day     */
-	rtc_outb((ct.mon << 4) | ct.dow);	/* Write back Month and DOW */
-	rtc_outb(bin2bcd(ct.year % 100));	/* Write back Year    */
-
-	rtc_serialcom(0x02);	/* Time set & Counter hold command. */
-	rtc_serialcom(0x00);	/* Register hold command. */
-}
-
-
 /*
  * Start both clocks running.
  */
@@ -619,7 +484,8 @@ i8254_get_timecount(struct timecounter *tc)
 	count = i8254_max_count - ((high << 8) | low);
 	if (count < i8254_lastcount ||
 	    (!i8254_ticked && (clkintr_pending ||
-	    ((count < 20 || (!(eflags & PSL_I) && count < i8254_max_count / 2u)) &&
+	    ((count < 20 || (!(eflags & PSL_I) &&
+	    count < i8254_max_count / 2u)) &&
 	    i8254_pending != NULL && i8254_pending(i8254_intsrc))))) {
 		i8254_ticked = 1;
 		i8254_offset += i8254_max_count;
@@ -632,11 +498,10 @@ i8254_get_timecount(struct timecounter *tc)
 
 #ifdef DEV_ISA
 /*
- * Attach to the ISA PnP descriptors for the timer and realtime clock.
+ * Attach to the ISA PnP descriptors for the timer
  */
 static struct isa_pnp_id attimer_ids[] = {
 	{ 0x0001d041 /* PNP0100 */, "AT timer" },
-	{ 0x000bd041 /* PNP0B00 */, "AT realtime clock" },
 	{ 0 }
 };
 
@@ -645,7 +510,8 @@ attimer_probe(device_t dev)
 {
 	int result;
 	
-	if ((result = ISA_PNP_PROBE(device_get_parent(dev), dev, attimer_ids)) <= 0)
+	result = ISA_PNP_PROBE(device_get_parent(dev), dev, attimer_ids);
+	if (result <= 0)
 		device_quiet(dev);
 	return(result);
 }
@@ -662,8 +528,8 @@ static device_method_t attimer_methods[] = {
 	DEVMETHOD(device_attach,	attimer_attach),
 	DEVMETHOD(device_detach,	bus_generic_detach),
 	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
-	DEVMETHOD(device_suspend,	bus_generic_suspend),	/* XXX stop statclock? */
-	DEVMETHOD(device_resume,	bus_generic_resume),	/* XXX restart statclock? */
+	DEVMETHOD(device_suspend,	bus_generic_suspend),
+	DEVMETHOD(device_resume,	bus_generic_resume),
 	{ 0, 0 }
 };
 
@@ -676,4 +542,211 @@ static driver_t attimer_driver = {
 static devclass_t attimer_devclass;
 
 DRIVER_MODULE(attimer, isa, attimer_driver, attimer_devclass, 0, 0);
+
+#endif /* DEV_ISA */
+
+#ifdef DEV_ISA
+
+/**********************************************************************
+ * RTC driver for subr_rtc
+ */
+
+#include "clock_if.h"
+
+#include <sys/rman.h>
+
+static void rtc_serialcombit(int);
+static void rtc_serialcom(int);
+static int rtc_inb(void);
+static void rtc_outb(int);
+
+static void
+rtc_serialcombit(int i)
+{
+	outb(IO_RTC, ((i&0x01)<<5)|0x07);
+	DELAY(1);
+	outb(IO_RTC, ((i&0x01)<<5)|0x17);
+	DELAY(1);
+	outb(IO_RTC, ((i&0x01)<<5)|0x07);
+	DELAY(1);
+}
+
+static void
+rtc_serialcom(int i)
+{
+	rtc_serialcombit(i&0x01);
+	rtc_serialcombit((i&0x02)>>1);
+	rtc_serialcombit((i&0x04)>>2);
+	rtc_serialcombit((i&0x08)>>3);
+	outb(IO_RTC, 0x07);
+	DELAY(1);
+	outb(IO_RTC, 0x0f);
+	DELAY(1);
+	outb(IO_RTC, 0x07);
+ 	DELAY(1);
+}
+
+static void
+rtc_outb(int val)
+{
+	int s;
+	int sa = 0;
+
+	for (s=0;s<8;s++) {
+	    sa = ((val >> s) & 0x01) ? 0x27 : 0x07;
+	    outb(IO_RTC, sa);		/* set DI & CLK 0 */
+	    DELAY(1);
+	    outb(IO_RTC, sa | 0x10);	/* CLK 1 */
+	    DELAY(1);
+	}
+	outb(IO_RTC, sa & 0xef);	/* CLK 0 */
+}
+
+static int
+rtc_inb(void)
+{
+	int s;
+	int sa = 0;
+
+	for (s=0;s<8;s++) {
+	    sa |= ((inb(0x33) & 0x01) << s);
+	    outb(IO_RTC, 0x17);	/* CLK 1 */
+	    DELAY(1);
+	    outb(IO_RTC, 0x07);	/* CLK 0 */
+	    DELAY(2);
+	}
+	return sa;
+}
+
+struct pcrtc_softc {
+	int port_rid1, port_rid2;
+	struct resource *port_res1, *port_res2;
+};
+
+/*
+ * Attach to the ISA PnP descriptors for the timer and realtime clock.
+ */
+static struct isa_pnp_id pcrtc_ids[] = {
+	{ 0x000bd041 /* PNP0B00 */, "AT realtime clock" },
+	{ 0 }
+};
+
+static int
+pcrtc_probe(device_t dev)
+{
+	int result;
+
+	device_set_desc(dev, "PC Real Time Clock");
+	result = ISA_PNP_PROBE(device_get_parent(dev), dev, pcrtc_ids);
+	/* ENXIO if wrong PnP-ID, ENOENT ifno PnP-ID, zero if good PnP-iD */
+	if (result != ENOENT)
+		return(result);
+	/* All PC's have an RTC, and we're hosed without it, so... */
+	return (BUS_PROBE_LOW_PRIORITY);
+}
+
+static int
+pcrtc_attach(device_t dev)
+{
+	struct pcrtc_softc *sc;
+
+	/*
+	 * Not that we need them or anything, but grab our resources
+	 * so they show up, correctly attributed, in the big picture.
+	 */
+	sc = device_get_softc(dev);
+	sc->port_rid1 = 0;
+	bus_set_resource(dev, SYS_RES_IOPORT, sc->port_rid1, IO_RTC, 1);
+	if (!(sc->port_res1 = bus_alloc_resource(dev, SYS_RES_IOPORT,
+	    &sc->port_rid1, IO_RTC, IO_RTC, 1, RF_ACTIVE)))
+		device_printf(dev, "Warning: Couldn't map I/O.\n");
+	sc->port_rid2 = 1;
+	bus_set_resource(dev, SYS_RES_IOPORT, sc->port_rid2, 0x33, 1);
+	if (!(sc->port_res2 = bus_alloc_resource(dev, SYS_RES_IOPORT,
+	    &sc->port_rid2, 0x33, 0x33, 1, RF_ACTIVE)))
+		device_printf(dev, "Warning: Couldn't map I/O.\n");
+
+	clock_register(dev, 1000000);
+	return(0);
+}
+
+static int
+pcrtc_settime(device_t dev __unused, struct timespec *ts)
+{
+	struct clocktime ct;
+
+	clock_ts_to_ct(ts, &ct);
+
+	rtc_serialcom(0x01);	/* Register shift command. */
+
+	rtc_outb(bin2bcd(ct.sec)); 		/* Write back Seconds */
+	rtc_outb(bin2bcd(ct.min)); 		/* Write back Minutes */
+	rtc_outb(bin2bcd(ct.hour)); 		/* Write back Hours   */
+
+	rtc_outb(bin2bcd(ct.day));		/* Write back Day     */
+	rtc_outb((ct.mon << 4) | ct.dow);	/* Write back Month and DOW */
+	rtc_outb(bin2bcd(ct.year % 100));	/* Write back Year    */
+
+	rtc_serialcom(0x02);	/* Time set & Counter hold command. */
+	rtc_serialcom(0x00);	/* Register hold command. */
+
+	return (0);
+}
+
+static int
+pcrtc_gettime(device_t dev, struct timespec *ts)
+{
+	struct clocktime ct;
+	int i;
+
+	rtc_serialcom(0x03);	/* Time Read */
+	rtc_serialcom(0x01);	/* Register shift command. */
+	DELAY(20);
+
+	ct.nsec = 0;
+	ct.sec = bcd2bin(rtc_inb() & 0xff);		/* sec */
+	ct.min = bcd2bin(rtc_inb() & 0xff);		/* min */
+	ct.hour = bcd2bin(rtc_inb() & 0xff);		/* hour */
+	ct.day = bcd2bin(rtc_inb() & 0xff);		/* date */
+	i = rtc_inb();
+	ct.dow = i & 0x0f;				/* dow */
+	ct.mon = (i >> 4) & 0x0f;			/* month */
+	ct.year = bcd2bin(rtc_inb() & 0xff) + 1900;	/* year */
+	if (ct.year < 1995)
+		ct.year += 100;
+
+	/* Set dow = -1 because some clocks don't set it correctly. */
+	ct.dow = -1;
+
+	return (clock_ct_to_ts(&ct, ts));
+}
+
+static device_method_t pcrtc_methods[] = {
+	/* Device interface */
+	DEVMETHOD(device_probe,		pcrtc_probe),
+	DEVMETHOD(device_attach,	pcrtc_attach),
+	DEVMETHOD(device_detach,	bus_generic_detach),
+	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
+	DEVMETHOD(device_suspend,	bus_generic_suspend),
+		/* XXX stop statclock? */
+	DEVMETHOD(device_resume,	bus_generic_resume),
+		/* XXX restart statclock? */
+
+	/* clock interface */
+	DEVMETHOD(clock_gettime,	pcrtc_gettime),
+	DEVMETHOD(clock_settime,	pcrtc_settime),
+
+	{ 0, 0 }
+};
+
+static driver_t pcrtc_driver = {
+	"pcrtc",
+	pcrtc_methods,
+	sizeof(struct pcrtc_softc),
+};
+
+static devclass_t pcrtc_devclass;
+
+DRIVER_MODULE(pcrtc, isa, pcrtc_driver, pcrtc_devclass, 0, 0);
+
 #endif /* DEV_ISA */