rockchip rk3368(px5)车载开发之路1，原生代码系统正常启动

本系列记载作者来到一个新的车载后装市场小公司，负责从新开始维护一套代码的心路过程。系统使用瑞芯微的rk3368芯片，版本是PX5_Android_8.0_release_20180726,从无到有的每个patch修改以及思考。其中着重点是驱动和系统相关，由于涉及到公司保密，所以APP部分暂时不贴过多的代码，只是针对系统bug进行记录。

2020_02_10 ---- 2020_02_13
将对应版本解压后编译并且下载到了我们自己的主机上，但是出现奇怪的无法启动的log，系统一直重启，经过对比分析觉得是调试口修改问题（不是很清楚原因，估计是硬件上调试口更换，软件没换导致的），最后解决办法也是，通过修改了uboot和内核的调试口，从而系统可以正常启动进入系统，并且屏幕正常显示（此处窃喜）。

其中编译脚本如下：

cd u-boot
make clean
make px5_kernel4.4_defconfig
make ARCHV=aarch64 -j12
cd ..


cd kernel
make ARCH=arm64 rockchip_defconfig
make ARCH=arm64 rk3368-px5-evb-android.img -j12
cd ..

source build/envsetup.sh
lunch px5-userdebug
make -j12

./mkimage.sh

PACK_TOOL_DIR=RKTools/linux/Linux_Pack_Firmware
mkdir -p $PACK_TOOL_DIR/rockdev/Image/
cp -f rockdev/Image-px5/* $PACK_TOOL_DIR/rockdev/Image/

echo "Make update.img"
cd $PACK_TOOL_DIR/rockdev && ./mkupdate.sh
if [ $? -eq 0 ]; then
    echo "Make update image ok!"
else
    echo "Make update image failed!"
    exit 1
fi
cd -

mv $PACK_TOOL_DIR/rockdev/update.img rockdev/Image-px5/
rm $PACK_TOOL_DIR/rockdev/Image -rf

修改的patch有两个部分：
1.内核：

diff --git a/arch/arm64/boot/dts/rockchip/rk3368-px5-evb-android.dts b/arch/arm64/boot/dts/rockchip/rk3368-px5-evb-android.dts
index 3eb50bb..3496368 100644
--- a/arch/arm64/boot/dts/rockchip/rk3368-px5-evb-android.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3368-px5-evb-android.dts
@@ -52,19 +52,19 @@
        compatible = "rockchip,px5-evb", "rockchip,px5", "rockchip,rk3368";

        chosen {
-               bootargs = "earlycon=uart8250,mmio32,0xff1c0000 swiotlb=1 firmware_class.path=/system/vendor/firmware";
+               bootargs = "earlycon=uart8250,mmio32,0xff690000 swiotlb=1 firmware_class.path=/system/vendor/firmware";
        };

        fiq_debugger: fiq-debugger {
                compatible = "rockchip,fiq-debugger";
-                       rockchip,serial-id = <4>;
+                       rockchip,serial-id = <2>;
                        rockchip,wake-irq = <0>;
                        /* If enable uart uses irq instead of fiq */
                        rockchip,irq-mode-enable = <0>;
                        /* Only 115200 and 1500000 */
                        rockchip,baudrate = <115200>;
                        pinctrl-names = "default";
-                       pinctrl-0 = <&uart4_xfer>;
+                       pinctrl-0 = <&uart2_xfer>;
                        interrupts = ;
        };

@@ -1218,7 +1218,7 @@
 };

 &uart2 {
-       status = "disabled";
+       status = "okay";
 };

2.uboot:

diff --git a/configs/px5_kernel4.4_defconfig b/configs/px5_kernel4.4_defconfig
index 10e7482..5b119de 100644
--- a/configs/px5_kernel4.4_defconfig
+++ b/configs/px5_kernel4.4_defconfig
@@ -1,4 +1,4 @@
-CONFIG_SYS_EXTRA_OPTIONS="RKCHIP_PX5_KERNEL4_4,RKCHIP_RK3368,PRODUCT_MID,NORMAL_WORLD,SECOND_LEVEL_BOOTLOADER,UART_NUM=UART_CH4"
+CONFIG_SYS_EXTRA_OPTIONS="RKCHIP_PX5_KERNEL4_4,RKCHIP_RK3368,PRODUCT_MID,NORMAL_WORLD,SECOND_LEVEL_BOOTLOADER,UART_NUM=UART_CH2"
 CONFIG_ARM=y
 CONFIG_ROCKCHIP_ARCH64=y
 CONFIG_PLAT_RK33XX=y

u-boot/include/autoconf.mk

CONFIG_UART_NUM="UART_CH2"