diff --git a/plat/rockchip/rk3399/drivers/dram/suspend.c b/plat/rockchip/rk3399/drivers/dram/suspend.c
index 8bc66e1..7f9fad1 100644
--- a/plat/rockchip/rk3399/drivers/dram/suspend.c
+++ b/plat/rockchip/rk3399/drivers/dram/suspend.c
@@ -172,7 +172,7 @@
 		mmio_clrsetbits_32(PHY_REG(ch, 8 + (128 * byte)), 0x1 << 16,
 				   1 << 16);
 		mmio_clrsetbits_32(PHY_REG(ch, 63 + (128 * byte)),
-				   0xffff << 16,
+				   0xffffu << 16,
 				   0x200 << 16);
 	}
 
@@ -656,7 +656,7 @@
 	mmio_write_32(CRU_BASE + CRU_PLL_CON(pll_id, 3), src[3] | REG_SOC_WMSK);
 
 	while ((mmio_read_32(CRU_BASE + CRU_PLL_CON(pll_id, 2)) &
-		(1 << 31)) == 0x0)
+		(1U << 31)) == 0x0)
 		;
 }