diff --git a/arch/arm/include/asm/arch-rockchip/cru_rk3368.h b/arch/arm/include/asm/arch-rockchip/cru_rk3368.h
index 21f11e0..2b1197f 100644
--- a/arch/arm/include/asm/arch-rockchip/cru_rk3368.h
+++ b/arch/arm/include/asm/arch-rockchip/cru_rk3368.h
@@ -89,6 +89,9 @@
 	MCU_CLK_DIV_SHIFT		= 0,
 	MCU_CLK_DIV_MASK		= GENMASK(4, 0),
 
+	/* CLKSEL43_CON */
+	GMAC_MUX_SEL_EXTCLK             = BIT(8),
+
 	/* CLKSEL51_CON */
 	MMC_PLL_SEL_SHIFT		= 8,
 	MMC_PLL_SEL_MASK		= GENMASK(9, 8),