rk3568修改波特率

一、概述

        以下以rk3568为例，讲述如何修改串口波特率115200->1500000

二、修改

 2.1 uboot中修改

        修改配置文件：u-boot/configs/firefly-rk3568_defconfig
        CONFIG_BAUDRATE=115200
        该修改影响=》uboot阶段串口波特率

2.2  kernel中修改

        修改设备树文件：kernel/arch/arm64/boot/dts/rockchip/rk3568-linux.dtsi

@@ -15,7 +15,7 @@
                rockchip,wake-irq = <0>;
                /* If enable uart uses irq instead of fiq */
                rockchip,irq-mode-enable = <1>;
-               rockchip,baudrate = <1500000>;  /* Only 115200 and 1500000 */
+               rockchip,baudrate = <115200>;  /* Only 115200 and 1500000 */
                interrupts = <GIC_SPI 252 IRQ_TYPE_LEVEL_LOW>;
                pinctrl-names = "default";
                pinctrl-0 = <&uart2m0_xfer>;

        该修改影响=》kernel阶段串口波特率

2.3 如果固件使用的是闭源方案，还需要改ddr bin(uboot的前置阶段)

1）修改rkbin/tools/ddrbin_param.txt

@@ -10,7 +10,7 @@ lp4x_freq=
 
 uart id=
 uart iomux=
-uart baudrate=
+uart baudrate=115200
 
 sr_idle=
 pd_idle=

2）更新ddr bin文件
具体可查看rkbin/tools/ddrbin_tool_user_guide.txt文件

cd rkbin/tools
./ddrbin_tool ddrbin_param.txt ../bin/rk35/rk3568_ddr_1560MHz_v1.10.bin

三、ddr bin流程

rk3568默认使用闭源方案：

BOOTROM => ddr bin => Miniloader => TRUST => U-BOOT => KERNEL  => rootfs

其中ddr bin是rk提供的闭源img，相当于uboot的tpl/spl阶段

u-boot/make.sh
    select_ini_file
        INI_LOADER=${RKBIN}/RKBOOT/${RKCHIP_LOADER}MINIALL.ini 
            => rkbin/RKBOOT/RK3568MINIALL.ini
RK3568MINIALL.ini
    13 [LOADER_OPTION]
    14 NUM=2
    15 LOADER1=FlashData
    16 LOADER2=FlashBoot
    17 FlashData=bin/rk35/rk3568_ddr_1560MHz_v1.10.bin
    18 FlashBoot=bin/rk35/rk356x_spl_v1.11.bin
    19 [OUTPUT]
    20 PATH=rk356x_spl_loader_v1.10.111.bin


编译时将通过FlashData和FlashBoot生成rk356x_spl_loader_v1.10.111.bin作为闭源spl（ddr bin）

通过ddrbin_param.txt可以对ddr bin进行配置，具体请看ddrbin_tool_user_guide.txt