Index: head/sys/arm64/conf/GENERIC
===================================================================
--- head/sys/arm64/conf/GENERIC
+++ head/sys/arm64/conf/GENERIC
@@ -226,6 +226,7 @@
 device		gif		# IPv6 and IPv4 tunneling
 device		firmware	# firmware assist module
 device		psci		# Support for ARM PSCI
+options 	EFIRT		# EFI Runtime Services
 
 # EXT_RESOURCES pseudo devices
 options 	EXT_RESOURCES
Index: head/sys/conf/files
===================================================================
--- head/sys/conf/files
+++ head/sys/conf/files
@@ -1615,6 +1615,7 @@
 dev/ed/if_ed_pci.c		optional ed pci
 dev/efidev/efidev.c		optional efirt
 dev/efidev/efirt.c		optional efirt
+dev/efidev/efirtc.c		optional efirt
 dev/e1000/if_em.c		optional em \
 	compile-with "${NORMAL_C} -I$S/dev/e1000"
 dev/e1000/em_txrx.c		optional em \
Index: head/sys/dev/efidev/efirtc.c
===================================================================
--- head/sys/dev/efidev/efirtc.c
+++ head/sys/dev/efidev/efirtc.c
@@ -0,0 +1,151 @@
+/*-
+ * Copyright (c) 2017 Andrew Turner
+ * All rights reserved.
+ *
+ * This software was developed by SRI International and the University of
+ * Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
+ * ("CTSRD"), as part of the DARPA CRASH research programme.
+ *
+ * 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 AUTHOR 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 AUTHOR 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/clock.h>
+#include <sys/efi.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+
+#include "clock_if.h"
+
+static void
+efirtc_identify(driver_t *driver, device_t parent)
+{
+	struct efi_tm tm;
+	int error;
+
+	/*
+	 * Check if we can read the time. This will stop us attaching when
+	 * there is no EFI Runtime support, or the gettime function is
+	 * unimplemented, e.g. on some builds of U-Boot.
+	 */
+	error = efi_get_time(&tm);
+	if (error != 0)
+		return;
+
+	if (device_find_child(parent, "efirtc", -1) != NULL)
+		return;
+	if (BUS_ADD_CHILD(parent, 0, "efirtc", -1) == NULL)
+		device_printf(parent, "add child failed\n");
+}
+
+static int
+efirtc_probe(device_t dev)
+{
+
+	device_quiet(dev);
+	return (0);
+}
+
+static int
+efirtc_attach(device_t dev)
+{
+
+	clock_register(dev, 1000000);
+	return (0);
+}
+
+static int
+efirtc_detach(device_t dev)
+{
+
+	clock_unregister(dev);
+	return (0);
+}
+
+static int
+efirtc_gettime(device_t dev, struct timespec *ts)
+{
+	struct clocktime ct;
+	struct efi_tm tm;
+	int error;
+
+	error = efi_get_time(&tm);
+	if (error != 0)
+		return (error);
+
+	ct.sec = tm.tm_sec;
+	ct.min = tm.tm_min;
+	ct.hour = tm.tm_hour;
+	ct.day = tm.tm_mday;
+	ct.mon = tm.tm_mon;
+	ct.year = tm.tm_year;
+	ct.nsec = tm.tm_nsec;
+
+	return (clock_ct_to_ts(&ct, ts));
+}
+
+static int
+efirtc_settime(device_t dev, struct timespec *ts)
+{
+	struct clocktime ct;
+	struct efi_tm tm;
+
+	clock_ts_to_ct(ts, &ct);
+
+	tm.tm_sec = ct.sec;
+	tm.tm_min = ct.min;
+	tm.tm_hour = ct.hour;
+	tm.tm_mday = ct.day;
+	tm.tm_mon = ct.mon;
+	tm.tm_year = ct.year;
+	tm.tm_nsec = ct.nsec;
+
+	return (efi_set_time(&tm));
+}
+
+static device_method_t efirtc_methods[] = {
+	/* Device interface */
+	DEVMETHOD(device_identify,	efirtc_identify),
+	DEVMETHOD(device_probe,		efirtc_probe),
+	DEVMETHOD(device_attach,	efirtc_attach),
+	DEVMETHOD(device_detach,	efirtc_detach),
+
+	/* Clock interface */
+	DEVMETHOD(clock_gettime,	efirtc_gettime),
+	DEVMETHOD(clock_settime,	efirtc_settime),
+
+	DEVMETHOD_END
+};
+
+static devclass_t efirtc_devclass;
+static driver_t efirtc_driver = {
+	"efirtc",
+	efirtc_methods,
+	0
+};
+
+DRIVER_MODULE(efirtc, nexus, efirtc_driver, efirtc_devclass, 0, 0);
Index: head/sys/modules/efirt/Makefile
===================================================================
--- head/sys/modules/efirt/Makefile
+++ head/sys/modules/efirt/Makefile
@@ -5,6 +5,7 @@
 
 KMOD=	efirt
 SRCS=	efirt.c efirt_machdep.c efidev.c
-SRCS+=  device_if.h bus_if.h
+SRCS+=	efirtc.c
+SRCS+=  device_if.h bus_if.h clock_if.h
 
 .include <bsd.kmod.mk>