移植 linux-5.8.5 到 iTOP-4412（一）build & config

文章目录

一、下载
二、配置
三、build kernel
- 1. 编译报错
- 2. 编译成功
四、build dts
- 1. 修改 dtsi
- 2. build
五、后续
参考

一、下载

https://www.kernel.org/

这里就下载目前最新的版本，今天是 2020.08.30，所以就下载前两天刚发布的稳定版本。
在这里插入图片描述

二、配置

源码下载解压后，设置编译器等路径，然后 make menuconfig 打开配置选项界面，选择类似的开发板的配置。

拷贝一份类似的配置，难度就会小一些。

cd arch/arm/configs/
cp exynos_defconfig xhr4412_defconfig
make xhr4412_defconfig
make menuconfig

1. 裁剪掉一些配置

> System Type > Samsung Exynos
我们可以只保留 Exynos 4 相关的，其他的可以去掉，减少内核大小。

2. 设置调试串口

将 UART2 设置为 low-level debug 串口输出。

> Kernel hacking > arm Debugging
[*] Kernel low-level debugging functions (read help!)
      Kernel low-level debugging port (Use Samsung S3C UART 2 for low-level debug)  --->
[*] Early printk

3. 网卡驱动

> Device Drivers > Network device support > USB Network Adapters

<*>     Davicom DM96xx based USB 10/100 ethernet devices

4. 压缩模式

设置内核压缩模式为 LZMA，可以减小文件大小。

> General setup
	    Kernel compression mode (LZMA)  --->

三、build kernel

make uImage LOADADDR=0x40007000 -j$(nproc)

这里需要指定 LOADADDR 的值，才能生成正确的 uImage 文件。因为在 uboot 启动内核时，会先解析 uImage 中的前 64B 文件头信息。具体定义可以在网上找找。

1. 编译报错

scripts/extract-cert.c:21:10: fatal error: openssl/bio.h: No such file or directory

sudo apt-get install libssl-dev
“mkimage” command not found - U-Boot images will not be built

sudo apt-get install uboot-mkimage (似乎已经遗弃)
sudo apt-get install u-boot-tools

2. 编译成功

xhr@ubuntu:~/iTop4412/xhr4412/linux/linux-5.8.5$ make uImage LOADADDR=0x40008000 -j$(nproc)
make[1]: Entering directory '/home/xhr/iTop4412/xhr4412/linux/linux-5.8.5/out'
  GEN     Makefile
  CALL    ../scripts/atomic/check-atomics.sh
  CALL    ../scripts/checksyscalls.sh
  CHK     include/generated/compile.h
  Kernel: arch/arm/boot/Image is ready
  Kernel: arch/arm/boot/zImage is ready
  UIMAGE  arch/arm/boot/uImage
Image Name:   Linux-5.8.5
Created:      Sun Aug 30 13:16:01 2020
Image Type:   ARM Linux Kernel Image (uncompressed)
Data Size:    5222448 Bytes = 5100.05 KiB = 4.98 MiB
Load Address: 40007000
Entry Point:  40007000
  Kernel: arch/arm/boot/uImage is ready
make[1]: Leaving directory '/home/xhr/iTop4412/xhr4412/linux/linux-5.8.5/out'

四、build dts

查看一下会编译的 dts 文件：

vim arch/arm/boot/dts/Makefile

看起来官方的 kernel 有支持 itop 的板子，应该简单移植一下就可以支持了。

dtb-$(CONFIG_ARCH_EXYNOS4) += \
        exynos4210-i9100.dtb \
        exynos4210-origen.dtb \
        exynos4210-smdkv310.dtb \
        exynos4210-trats.dtb \
        exynos4210-universal_c210.dtb \
        exynos4412-i9300.dtb \
        exynos4412-i9305.dtb \
        exynos4412-itop-elite.dtb \
        exynos4412-n710x.dtb \
        exynos4412-odroidu3.dtb \
        exynos4412-odroidx.dtb \
        exynos4412-odroidx2.dtb \
        exynos4412-origen.dtb \
        exynos4412-smdk4412.dtb \
        exynos4412-tiny4412.dtb \
        exynos4412-trats2.dtb

1. 修改 dtsi

修改文件 arch/arm/boot/dts/exynos4412-itop-scp-core.dtsi

屏蔽掉firmware节点(安全相关，不启用，也不知道怎么用…)
修改bus_dmc 节点devfreq-events为devfreq-event
修改regulators 节点参数(参考原理图中的参数)

修改如下：

--- a/arch/arm/boot/dts/exynos4412-itop-scp-core.dtsi
+++ b/arch/arm/boot/dts/exynos4412-itop-scp-core.dtsi
@@ -23,10 +23,12 @@
 		reg = <0x40000000 0x40000000>;
 	};
 
+#if 0
 	firmware@203f000 {
 		compatible = "samsung,secure-firmware";
 		reg = <0x0203F000 0x1000>;
 	};
+#endif
 
 	fixed-rate-clocks {
 		xxti {
@@ -70,7 +72,7 @@
 };
 
 &bus_dmc {
-	devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
+	devfreq-event = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
 	vdd-supply = <&buck1_reg>;
 	status = "okay";
 };
@@ -167,8 +169,8 @@
 		regulators {
 			ldo1_reg: LDO1 {
 				regulator-name = "VDD_ALIVE";
-				regulator-min-microvolt = <1100000>;
-				regulator-max-microvolt = <1100000>;
+				regulator-min-microvolt = <1000000>;
+				regulator-max-microvolt = <1000000>;
 				regulator-always-on;
 				regulator-boot-on;
 				op_mode = <1>; /* Normal Mode */
@@ -230,8 +232,8 @@
 
 			ldo9_reg: LDO9 {
 				regulator-name = "VDD33_LCD";
-				regulator-min-microvolt = <3300000>;
-				regulator-max-microvolt = <3300000>;
+				regulator-min-microvolt = <3000000>;
+				regulator-max-microvolt = <3000000>;
 				op_mode = <1>; /* Normal Mode */
 			};
 
@@ -252,8 +254,8 @@
 
 			ldo12_reg: LDO12 {
 				regulator-name = "VDD33_UOTG";
-				regulator-min-microvolt = <3300000>;
-				regulator-max-microvolt = <3300000>;
+				regulator-min-microvolt = <3000000>;
+				regulator-max-microvolt = <3000000>;
 				regulator-always-on;
 				op_mode = <1>; /* Normal Mode */
 			};
@@ -300,8 +302,8 @@
 			/* Used by HSIC */
 			ldo18_reg: LDO18 {
 				regulator-name = "VDDIOPERI_28";
-				regulator-min-microvolt = <3300000>;
-				regulator-max-microvolt = <3300000>;
+				regulator-min-microvolt = <2800000>;
+				regulator-max-microvolt = <2800000>;
 				regulator-always-on;
 				op_mode = <1>; /* Normal Mode */
 			};
@@ -313,15 +315,15 @@
 
 			ldo20_reg: LDO20 {
 				regulator-name = "VDD28_CAM";
-				regulator-min-microvolt = <1800000>;
-				regulator-max-microvolt = <2800000>;
+				regulator-min-microvolt = <3000000>;
+				regulator-max-microvolt = <3000000>;
 				op_mode = <1>; /* Normal Mode */
 			};
 
 			ldo21_reg: LDO21 {
 				regulator-name = "VDD28_AF";
-				regulator-min-microvolt = <1800000>;
-				regulator-max-microvolt = <2800000>;
+				regulator-min-microvolt = <3000000>;
+				regulator-max-microvolt = <3000000>;
 				op_mode = <1>; /* Normal Mode */
 			};
 
@@ -341,8 +343,8 @@
 
 			ldo24_reg: LDO24 {
 				regulator-name = "VDD33_A31";
-				regulator-min-microvolt = <3300000>;
-				regulator-max-microvolt = <3300000>;
+				regulator-min-microvolt = <3000000>;
+				regulator-max-microvolt = <3000000>;
 				op_mode = <1>; /* Normal Mode */
 			};
 
@@ -430,8 +432,8 @@
 
 			buck7_reg: BUCK7 {
 				regulator-name = "pvdd_buck7";
-				regulator-min-microvolt = <750000>;
-				regulator-max-microvolt = <2000000>;
+				regulator-min-microvolt = <2050000>;
+				regulator-max-microvolt = <2050000>;
 				regulator-boot-on;
 				regulator-always-on;
 				op_mode = <1>; /* Normal Mode */

2. build

make dtbs

编译成功，文件在：

arch/arm/boot/dts/exynos4412-itop-elite.dtb

五、后续

到目前为止还比较顺利，毕竟只是下载后简单修改，能够编译通过，但是是否能够烧写到开发板上 boot 起来还是个问题。