查看Raspberry的源代码

== Kernel 编译 ==

获取 kernel code: https://github.com/raspberrypi/linux

根据您当前系统的内核版本选 branch，比如此 Raspberry 3 model B 的内核版本为 linux 4.4.13，则选 rpi-4.4.y，然后点 code -> Local -> HTTPS -> Download ZIP:
<source lang=bash>
$ cat /proc/version
Linux version 4.4.13-v7+ (dc4@dc4-XPS13-9333) (gcc version 4.9.3 (crosstool-NG crosstool-ng-1.22.0-88-g8460611) ) #894 SMP Mon Jun 13 13:13:27 BST 2016
$ cat /proc/cpuinfo
processor       : 0
model name      : ARMv7 Processor rev 4 (v7l)
BogoMIPS        : 38.40
Features        : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm crc32
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 4

processor       : 1
model name      : ARMv7 Processor rev 4 (v7l)
BogoMIPS        : 38.40
Features        : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm crc32
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 4

processor       : 2
model name      : ARMv7 Processor rev 4 (v7l)
BogoMIPS        : 38.40
Features        : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm crc32
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 4

processor       : 3
model name      : ARMv7 Processor rev 4 (v7l)
BogoMIPS        : 38.40
Features        : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm crc32
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 4

Hardware        : BCM2709
Revision        : a22082
Serial          : 0000000036ac63be

#  Raspberry 3 model B 主 SoC 为 BCM2837 芯片，支持硬浮点 (vfp)
</source>

解压后，为目录 linux-rpi-4.4.y

;;Toolchain:
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads  选 AArch32 GNU/Linux target with hard float (arm-none-linux-gnueabihf)


;; Build:

<source lang=bash>
$ cd linux-rpi-4.4.y/
$ export PATH=$PATH:/path/to/toolchain/bin
$ make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabihf- bcm2709_defconfig # 生成 .config
$ make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabihf- zImage -j8

$ make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabihf- dtbs
$ make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabihf- M=drivers/your/drv/ modules
</source>

gcc 版本过高可能出错：
<source lang=bash>
  HOSTLD  scripts/dtc/dtc
/usr/bin/ld: scripts/dtc/dtc-parser.tab.o:(.bss+0x10): multiple definition of `yylloc'; scripts/dtc/dtc-lexer.lex.o:(.bss+0x0): first defined here
collect2: error: ld returned 1 exit status
</source>

编辑 vim scripts/dtc/dtc-lexer.lex.c，找到 ”YYLTYPE yylloc;“ 加上 extern："extern YYLTYPE yylloc;"  即可


;; 部署

bootloader 加载内核优先顺序：
* config.txt 中的 kernel = xxxx
* kernel8.img kernel8-32.img (armv8-aarch64, armv8-aarch32)
* kernel7.img (armv7)
* kernel.img (old version)

<br>