Index: head/sys/arm64/conf/GENERIC
===================================================================
--- head/sys/arm64/conf/GENERIC
+++ head/sys/arm64/conf/GENERIC
@@ -106,6 +106,9 @@
 device		al_serdes		# Serializer/Deserializer
 device		al_udma			# Universal DMA
 
+# Qualcomm Snapdragon drivers
+device		qcom_gcc		# Global Clock Controller
+
 # VirtIO support
 device		virtio
 device		virtio_pci
Index: head/sys/arm64/qualcomm/qcom_gcc.c
===================================================================
--- head/sys/arm64/qualcomm/qcom_gcc.c
+++ head/sys/arm64/qualcomm/qcom_gcc.c
@@ -0,0 +1,148 @@
+/*-
+ * Copyright (c) 2018 Ruslan Bukin <br@bsdpad.com>
+ * All rights reserved.
+ *
+ * This software was developed by BAE Systems, the University of Cambridge
+ * Computer Laboratory, and Memorial University under DARPA/AFRL contract
+ * FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent Computing
+ * (TC) research program.
+ *
+ * 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/kthread.h>
+#include <sys/rman.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+#include <machine/bus.h>
+
+#include <dev/ofw/ofw_bus.h>
+#include <dev/ofw/ofw_bus_subr.h>
+
+#define	GCC_QDSS_BCR			0x29000
+#define	 GCC_QDSS_BCR_BLK_ARES		(1 << 0) /* Async software reset. */
+#define	GCC_QDSS_CFG_AHB_CBCR		0x29008
+#define	 AHB_CBCR_CLK_ENABLE		(1 << 0) /* AHB clk branch ctrl */
+#define	GCC_QDSS_ETR_USB_CBCR		0x29028
+#define	 ETR_USB_CBCR_CLK_ENABLE	(1 << 0) /* ETR USB clk branch ctrl */
+#define	GCC_QDSS_DAP_CBCR		0x29084
+#define	 DAP_CBCR_CLK_ENABLE		(1 << 0) /* DAP clk branch ctrl */
+
+static struct ofw_compat_data compat_data[] = {
+	{ "qcom,gcc-msm8916",			1 },
+	{ NULL,					0 }
+};
+
+struct qcom_gcc_softc {
+	struct resource		*res;
+};
+
+static struct resource_spec qcom_gcc_spec[] = {
+	{ SYS_RES_MEMORY,	0,	RF_ACTIVE },
+	{ -1, 0 }
+};
+
+/*
+ * Qualcomm Debug Subsystem (QDSS)
+ * block enabling routine.
+ */
+static void
+qcom_qdss_enable(struct qcom_gcc_softc *sc)
+{
+
+	/* Put QDSS block to reset */
+	bus_write_4(sc->res, GCC_QDSS_BCR, GCC_QDSS_BCR_BLK_ARES);
+
+	/* Enable AHB clock branch */
+	bus_write_4(sc->res, GCC_QDSS_CFG_AHB_CBCR, AHB_CBCR_CLK_ENABLE);
+
+	/* Enable DAP clock branch */
+	bus_write_4(sc->res, GCC_QDSS_DAP_CBCR, DAP_CBCR_CLK_ENABLE);
+
+	/* Enable ETR USB clock branch */
+	bus_write_4(sc->res, GCC_QDSS_ETR_USB_CBCR, ETR_USB_CBCR_CLK_ENABLE);
+
+	/* Out of reset */
+	bus_write_4(sc->res, GCC_QDSS_BCR, 0);
+}
+
+static int
+qcom_gcc_probe(device_t dev)
+{
+	if (!ofw_bus_status_okay(dev))
+		return (ENXIO);
+
+	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
+		return (ENXIO);
+
+	device_set_desc(dev, "Qualcomm Global Clock Controller");
+
+	return (BUS_PROBE_DEFAULT);
+}
+
+static int
+qcom_gcc_attach(device_t dev)
+{
+	struct qcom_gcc_softc *sc;
+
+	sc = device_get_softc(dev);
+
+	if (bus_alloc_resources(dev, qcom_gcc_spec, &sc->res) != 0) {
+		device_printf(dev, "cannot allocate resources for device\n");
+		return (ENXIO);
+	}
+
+	/*
+	 * Enable debug unit.
+	 * This is required for Coresight operation.
+	 * This also enables USB clock branch.
+	 */
+	qcom_qdss_enable(sc);
+
+	return (0);
+}
+
+static device_method_t qcom_gcc_methods[] = {
+	/* Device interface */
+	DEVMETHOD(device_probe,		qcom_gcc_probe),
+	DEVMETHOD(device_attach,	qcom_gcc_attach),
+
+	DEVMETHOD_END
+};
+
+static driver_t qcom_gcc_driver = {
+	"qcom_gcc",
+	qcom_gcc_methods,
+	sizeof(struct qcom_gcc_softc),
+};
+
+static devclass_t qcom_gcc_devclass;
+
+EARLY_DRIVER_MODULE(qcom_gcc, simplebus, qcom_gcc_driver, qcom_gcc_devclass,
+    0, 0, BUS_PASS_BUS + BUS_PASS_ORDER_MIDDLE);
+MODULE_VERSION(qcom_gcc, 1);
Index: head/sys/conf/files.arm64
===================================================================
--- head/sys/conf/files.arm64
+++ head/sys/conf/files.arm64
@@ -151,6 +151,7 @@
 arm64/coresight/coresight-etm4x.c		standard
 arm64/coresight/coresight-funnel.c		standard
 arm64/coresight/coresight-tmc.c			standard
+arm64/qualcomm/qcom_gcc.c			optional qcom_gcc fdt
 contrib/vchiq/interface/compat/vchi_bsd.c	optional vchiq soc_brcm_bcm2837 \
 	compile-with "${NORMAL_C} -DUSE_VCHIQ_ARM -D__VCCOREVER__=0x04000000 -I$S/contrib/vchiq"
 contrib/vchiq/interface/vchiq_arm/vchiq_2835_arm.c	optional vchiq soc_brcm_bcm2837 \