diff --git a/drivers/ram/rockchip/sdram_rk3188.c b/drivers/ram/rockchip/sdram_rk3188.c
index cc9bd02..7aedb4f 100644
--- a/drivers/ram/rockchip/sdram_rk3188.c
+++ b/drivers/ram/rockchip/sdram_rk3188.c
@@ -25,6 +25,7 @@
 #include <asm/arch-rockchip/pmu_rk3188.h>
 #include <asm/arch-rockchip/sdram.h>
 #include <asm/arch-rockchip/sdram_rk3288.h>
+#include <linux/delay.h>
 #include <linux/err.h>
 
 struct chan_info {