diff --git a/arch/arm/mach-rockchip/rk3188-board-spl.c b/arch/arm/mach-rockchip/rk3188-board-spl.c
index 5adbca1..1877855 100644
--- a/arch/arm/mach-rockchip/rk3188-board-spl.c
+++ b/arch/arm/mach-rockchip/rk3188-board-spl.c
@@ -103,6 +103,16 @@
 
 	/* Example code showing how to enable the debug UART on RK3188 */
 #ifdef EARLY_UART
+	enum {
+		GPIO1B1_SHIFT		= 2,
+		GPIO1B1_MASK		= 3,
+		GPIO1B1_UART2_SOUT	= 1,
+
+		GPIO1B0_SHIFT		= 0,
+		GPIO1B0_MASK		= 3,
+		GPIO1B0_UART2_SIN	= 1,
+	};
+
 	/* Enable early UART on the RK3188 */
 	rk_clrsetreg(&grf->gpio1b_iomux,
 		     GPIO1B1_MASK << GPIO1B1_SHIFT |