编译U-boot和Linux内核的步骤和详解

1、准备材料

linux内核和uboot的源码包—- 6818GEC.tar.gz 环境：VMware12.0 Ubuntu16.04（64位）

（1）先将 6818GEC.tar.gz 放在Ubuntu的共享目录下，然后将 6818GEC.tar.gz 拷贝到家目录下进行解压。

解压命令： gec@ubuntu:~$ tar -zxvf 6818GEC.tar.gz

2、如何编译u-boot

（2）gec@ubuntu:~/6818GEC$ ./mk -u

编译输出

LD u-boot —–>链接成u-boot可执行映像文件

OBJCOPY u-boot.srec

OBJCOPY u-boot.bin —>将u-boot可执行映像文件进行格式转换，转换成bin格式的文件

./tools/mk6818 GECuboot.bin nsih.txt 2ndboot u-boot.bin —->将nsih.txt 2ndboot u-boot.bin打包生成GECuboot.bin–>eMMC

NSIH : 189 line processed.

NSIH : 512 bytes generated.

Generate destination file: GECuboot.bin

‘/home/gec/6818GEC/GEC6818uboot/GECuboot.bin’ -> ‘/home/gec/6818GEC/out/release/GECuboot.bin’

‘/home/gec/6818GEC/GEC6818uboot/readme.txt’ -> ‘/home/gec/6818GEC/out/release/readme.txt’

‘/home/gec/6818GEC/GEC6818uboot/env.txt’ -> ‘/home/gec/6818GEC/out/release/env.txt’

‘/home/gec/6818GEC/GEC6818uboot/GEC6818-sdmmc.sh’ -> ‘/home/gec/6818GEC/out/release/GEC6818-sdmmc.sh’

^_^ uboot path: /home/gec/6818GEC/out/release/GECuboot.bin —->将GECuboot.bin拷贝到out/release/下

3、如何编译linux内核

（3） gec@ubuntu:~/6818GEC$ ./mk -k

编译输出：

Kernel: arch/arm/boot/Image is ready

Kernel: arch/arm/boot/zImage is ready

UIMAGE arch/arm/boot/uImage

Image Name: Linux-3.4.39-gec

Created: Mon Feb 26 22:06:56 2018

Image Type: ARM Linux Kernel Image (uncompressed)

Data Size: 5532568 Bytes = 5402.90 kB = 5.28 MB

Load Address: 40008000

Entry Point: 40008000

Image arch/arm/boot/uImage is ready

boot.img -> /home/gec/6818GEC/out/release

‘/home/gec/6818GEC/kernel/arch/arm/boot/uImage’ -> ‘/home/gec/6818GEC/out/target/product/GEC6818//boot/uImage’

make_ext4fs -s -T -1 -l 67108864 -a boot /home/gec/6818GEC/out/target/product/GEC6818//boot.img /home/gec/6818GEC/out/target/product/GEC6818//boot

Creating filesystem with parameters:

Size: 67108864

Block size: 4096

Blocks per group: 32768

Inodes per group: 4096

Inode size: 256

Journal blocks: 1024

Label:

Blocks: 16384

Block groups: 1

Reserved block group size: 7

Created filesystem with 18/4096 inodes and 4212/16384 blocks

‘/home/gec/6818GEC/out/target/product/GEC6818//boot.img’ -> ‘/home/gec/6818GEC/out/release/boot.img’

内核映像文件的生成过程：

内核源码—>Image–>压缩–>zImage—>使用mkimage工具，在zImage的前面加一个头–>uImage—>经过文件系统打包，生成boot.img

/home/gec/6818GEC/out/release/boot.img

4、源码包的分析

1、GEC6818uboot

—–>u-boot的源码包

gec@ubuntu:~/6818GEC$ ls GEC6818uboot/

2ndboot board config.mk doc env.txt GEC6818-sdmmc.sh Kbuild MAKEALL net nsih-2G16b-533M.txt nsih.txt readme.txt System.map u-boot u-boot.map

api boards.cfg CREDITS drivers examples GECuboot.bin lib Makefile nsih-1G16b-533M.txt nsih-2G16b-800M.txt post scripts test u-boot.bin u-boot.srec

arch common disk dts fs include Licenses mkconfig nsih-1G16b-800M.txt nsih-2G8b.txt README snapshot.commit tools u-boot.lds

2、kernel

——>linux内核的源码

gec@ubuntu:~/6818GEC$ ls kernel

android COPYING Documentation fs init Kconfig MAINTAINERS modules.builtin net samples sound usr vmlinux.o

arch CREDITS drivers gec6818_linux_config ipc kernel Makefile modules.order README scripts System.map virt

block crypto firmware include Kbuild lib mm Module.symvers REPORTING-BUGS security tools vmlinux

3、prebuilts

——>编译u-boot和kernel的编译器

gec@ubuntu:~/6818GEC/prebuilts/gcc/linux-x86/arm/arm-eabi-4.8/bin$ ./arm-eabi-gcc -v

Using built-in specs.

COLLECT_GCC=./arm-eabi-gcc

COLLECT_LTO_WRAPPER=/home/gec/6818GEC/prebuilts/gcc/linux-x86/arm/arm-eabi-4.8/bin/../libexec/gcc/arm-eabi/4.8/lto-wrapper

Target: arm-eabi

Configured with: /tmp/AOSP-toolchain/build/../gcc/gcc-4.8/configure –prefix=/tmp/toolchain-build-eabi/prefix –target=arm-eabi –host=x86_64-linux-gnu –build=x86_64-linux-gnu –with-gnu-as –with-gnu-ld –enable-languages=c,c++ –with-gmp=/tmp/toolchain-build-eabi/temp-install –with-mpfr=/tmp/toolchain-build-eabi/temp-install –with-mpc=/tmp/toolchain-build-eabi/temp-install –with-cloog=/tmp/toolchain-build-eabi/temp-install –with-isl=/tmp/toolchain-build-eabi/temp-install –with-ppl=/tmp/toolchain-build-eabi/temp-install –disable-ppl-version-check –disable-cloog-version-check –disable-isl-version-check –enable-cloog-backend=isl –with-host-libstdcxx=’-static-libgcc -Wl,-Bstatic,-lstdc++,-Bdynamic -lm’ –disable-libssp –enable-threads –disable-nls –disable-libmudflap –disable-libgomp –disable-libstdc__-v3 –disable-sjlj-exceptions –disable-shared –disable-tls –disable-libitm –with-float=soft –with-fpu=vfp –with-arch=armv5te –enable-target-optspace –with-abi=aapcs –enable-initfini-array –disable-nls –prefix=/tmp/toolchain-build-eabi/prefix –with-sysroot=/tmp/toolchain-build-eabi/prefix/sysroot –with-binutils-version=2.23 –with-mpfr-version=3.1.1 –with-mpc-version=1.0.1 –with-gmp-version=5.0.5 –with-gcc-version=4.8 –with-gdb-version=7.6 –with-gxx-include-dir=/tmp/toolchain-build-eabi/prefix/include/c++/4.8 –with-bugurl=http://source.android.com/source/report-bugs.html –disable-bootstrap –disable-libquadmath –enable-plugins –enable-libgomp –disable-libsanitizer –enable-gold –enable-graphite=yes –with-cloog-version=0.18.0 –with-isl-version=0.11.1 –enable-eh-frame-hdr-for-static –with-arch=armv5te –disable-gold –disable-libgomp –program-transform-name=’s&^&arm-eabi-&’

Thread model: single

gcc version 4.8 (GCC)

4、out

——>编译生成的u-boot和kernel的映像文件

/out/release/GECuboot.bin

/out/release/boot.img

5、prototype

——->linux内核使用的一些固件程序，这些固件程序是针对S5P6818底层外设，如：串口、看门狗、定时器、USB.、、、、

6、tools

——->编译u-boot或kernel使用的一些工具

7、linux

——->linux内核使用的一些固件程序，这些固件程序是针对S5P6818中视频处理模块的。

8、buildroot

——->生成跟文件系统的内容

5、GEC6818更新系统的方法

1、使用fastboot

2、使用恢复卡（micro SD==TF卡）