Index: sys/dev/sdhci/sdhci_fdt.c
===================================================================
--- sys/dev/sdhci/sdhci_fdt.c
+++ sys/dev/sdhci/sdhci_fdt.c
@@ -52,6 +52,9 @@
 #include <dev/ofw/ofw_bus.h>
 #include <dev/ofw/ofw_bus_subr.h>

+#include <dev/extres/clk/clk.h>
+#include <dev/extres/syscon/syscon.h>
+
 #include <dev/mmc/bridge.h>

 #include <dev/sdhci/sdhci.h>
@@ -61,16 +64,30 @@

 #include "opt_mmccam.h"

+#include "syscon_if.h"
+
 #define	MAX_SLOTS		6
 #define	SDHCI_FDT_ARMADA38X	1
 #define	SDHCI_FDT_GENERIC	2
 #define	SDHCI_FDT_XLNX_ZY7	3
 #define	SDHCI_FDT_QUALCOMM	4
+#define	SDHCI_FDT_RK3399	5

+#define	RK3399_GRF_EMMCCORE_CON0		0xf000
+#define	 RK3399_CORECFG_BASECLKFREQ		(1 << 15) | (1 << 8)
+#define	 RK3399_CORECFG_TIMEOUTCLKUNIT		(1 << 7)
+#define	 RK3399_CORECFG_TUNINGCOUNT		(1 << 5) | (1 << 0)
+#define	RK3399_GRF_EMMCCORE_CON11		0xf02c
+#define	 RK3399_CORECFG_CLOCKMULTIPLIER		(1 << 7) | (1 << 0)
+
+#define	LOWEST_SET_BIT(mask)	((((mask) - 1) & (mask)) ^ (mask))
+#define	SHIFTIN(x, mask)	((x) * LOWEST_SET_BIT(mask))
+
 static struct ofw_compat_data compat_data[] = {
 	{ "marvell,armada-380-sdhci",	SDHCI_FDT_ARMADA38X },
 	{ "sdhci_generic",		SDHCI_FDT_GENERIC },
 	{ "qcom,sdhci-msm-v4",		SDHCI_FDT_QUALCOMM },
+	{ "rockchip,rk3399-sdhci-5.1",	SDHCI_FDT_RK3399 },
 	{ "xlnx,zy7_sdhci",		SDHCI_FDT_XLNX_ZY7 },
 	{ NULL, 0 }
 };
@@ -90,8 +107,28 @@

 	bool		wp_inverted;	/* WP pin is inverted */
 	bool		no_18v;		/* No 1.8V support */
+
+	clk_t		clk_xin;
+	clk_t		clk_ahb;
 };

+static void
+sdhc_init_rk3399(struct syscon *grf, phandle_t node, uint64_t freq)
+{
+	uint32_t mask, val;
+
+	/* Disable clock multiplier */
+	mask = RK3399_CORECFG_CLOCKMULTIPLIER;
+	val = 0;
+	SYSCON_WRITE_4(grf, RK3399_GRF_EMMCCORE_CON11, (mask << 16) | val);
+
+	/* Set base clock frequency */
+	mask = RK3399_CORECFG_BASECLKFREQ;
+	val = SHIFTIN((freq + (1000000 / 2)) / 1000000,
+	    RK3399_CORECFG_BASECLKFREQ);
+	SYSCON_WRITE_4(grf, RK3399_GRF_EMMCCORE_CON0, (mask << 16) | val);
+}
+
 static uint8_t
 sdhci_fdt_read_1(device_t dev, struct sdhci_slot *slot, bus_size_t off)
 {
@@ -188,8 +225,11 @@
 sdhci_fdt_probe(device_t dev)
 {
 	struct sdhci_fdt_softc *sc = device_get_softc(dev);
+	struct syscon *grf = NULL;
 	phandle_t node;
 	pcell_t cid;
+	uint64_t freq;
+	int error;

 	sc->quirks = 0;
 	sc->num_slots = 1;
@@ -198,6 +238,8 @@
 	if (!ofw_bus_status_okay(dev))
 		return (ENXIO);

+	node = ofw_bus_get_node(dev);
+
 	switch (ofw_bus_search_compatible(dev, compat_data)->ocd_data) {
 	case SDHCI_FDT_ARMADA38X:
 		sc->quirks = SDHCI_QUIRK_BROKEN_AUTO_STOP;
@@ -212,6 +254,42 @@
 		sc->sdma_boundary = SDHCI_BLKSZ_SDMA_BNDRY_4K;
 		device_set_desc(dev, "Qualcomm FDT SDHCI controller");
 		break;
+	case SDHCI_FDT_RK3399:
+		/* Get and activate clocks */
+		error = clk_get_by_ofw_name(dev, 0, "clk_xin", &sc->clk_xin);
+		if (error != 0) {
+			device_printf(dev, "cannot get xin clock\n");
+			return (ENXIO);
+		}
+		error = clk_enable(sc->clk_xin);
+		if (error != 0) {
+			device_printf(dev, "cannot enable xin clock\n");
+			return (ENXIO);
+		}
+		error = clk_get_freq(sc->clk_xin, &freq);
+		if (error != 0) {
+			device_printf(dev, "cannot get xin clock frequency\n");
+			return (ENXIO);
+		}
+		error = clk_get_by_ofw_name(dev, 0, "clk_ahb", &sc->clk_ahb);
+		if (error != 0) {
+			device_printf(dev, "cannot get ahb clock\n");
+			return (ENXIO);
+		}
+		error = clk_enable(sc->clk_ahb);
+		if (error != 0) {
+			device_printf(dev, "cannot enable ahb clock\n");
+			return (ENXIO);
+		}
+		if (OF_hasprop(node, "arasan,soc-ctl-syscon") &&
+		    syscon_get_by_ofw_property(dev, node,
+		    "arasan,soc-ctl-syscon", &grf) != 0) {
+			device_printf(dev, "cannot get grf driver handle\n");
+			return (ENXIO);
+		}
+		sdhc_init_rk3399(grf, node, freq);
+		device_set_desc(dev, "Rockchip RK3399 fdt SDHCI controller");
+		break;
 	case SDHCI_FDT_XLNX_ZY7:
 		sc->quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK;
 		device_set_desc(dev, "Zynq-7000 generic fdt SDHCI controller");
@@ -220,8 +298,6 @@
 		return (ENXIO);
 	}

-	node = ofw_bus_get_node(dev);
-
 	/* Allow dts to patch quirks, slots, and max-frequency. */
 	if ((OF_getencprop(node, "quirks", &cid, sizeof(cid))) > 0)
 		sc->quirks = cid;