diff --git a/arch/arm/mach-rockchip/rk3188-board.c b/arch/arm/mach-rockchip/rk3188-board.c
index 16f38559afff430d6135419890d1c09b20d0e176..c370156e4c04b9315ff745b4c193b3e82f197659 100644
--- a/arch/arm/mach-rockchip/rk3188-board.c
+++ b/arch/arm/mach-rockchip/rk3188-board.c
@@ -56,8 +56,22 @@ err:
 
 int dram_init(void)
 {
-	/* FIXME: read back ram size from sys_reg2 */
-	gd->ram_size = 0x40000000;
+	struct ram_info ram;
+	struct udevice *dev;
+	int ret;
+
+	ret = uclass_get_device(UCLASS_RAM, 0, &dev);
+	if (ret) {
+		debug("DRAM init failed: %d\n", ret);
+		return ret;
+	}
+	ret = ram_get_info(dev, &ram);
+	if (ret) {
+		debug("Cannot get DRAM size: %d\n", ret);
+		return ret;
+	}
+	debug("SDRAM base=%lx, size=%x\n", ram.base, ram.size);
+	gd->ram_size = ram.size;
 
 	return 0;
 }