瑞芯微SDK默认将uart2_m0作为调试串口，以下方法将调试串口修改为uart5_m1。
修改bootloader
修改/OK3568-linux-source/rkbin/tools/ddrbin_param.txt文件，5表示串口5。1表示复用m1。
执行./ddrbin_tool ddrbin_param.txt ../bin/rk35/rk3568_ddr_1560MHz_v1.11.bin命令
修改uboot
diff --git a/arch/arm/dts/OK3568-C.dts b/arch/arm/dts/OK3568-C.dts
index ddbdaee..56c8e7c 100644
--- a/arch/arm/dts/OK3568-C.dts
+++ b/arch/arm/dts/OK3568-C.dts
@@ -105,6 +105,10 @@status = "okay";};+&uart5 {
+ status = "okay";
+};
+&vop {assigned-clocks = <&cru DCLK_
