设备树（device tree）学习笔记一

 

如何查看编译生成的设备树的内容？

在设备树学习的时候，如果可以看到最终生成的设备树的内容，对于我们学习设备树以及分析问题有很大帮助。这里我们需要使用设备树生成工具dtc的反编译功能

root@pengdl-VirtualBox:~/tq2440/Linux/linux-4.0.1# ./scripts/dtc/dtc -h Usage: dtc [options] <input file> Options: -[qI:O:o:V:d:R:S:p:fb:i:H:sW:E:hv] -q, --quiet Quiet: -q suppress warnings, -qq errors, -qqq all -I, --in-format <arg> Input formats are: dts - device tree source text dtb - device tree blob fs - /proc/device-tree style directory -o, --out <arg> Output file -O, --out-format <arg> Output formats are: dts - device tree source text dtb - device tree blob asm - assembler source -V, --out-version <arg> Blob version to produce, defaults to %d (for dtb and asm output) -d, --out-dependency <arg> Output dependency file
  -R, --reserve <arg> tMake space for <number> reserve map entries (for dtb and asm output) -S, --space <arg> Make the blob at least <bytes> long (extra space) -p, --pad <arg> Add padding to the blob of <bytes> long (extra space) -b, --boot-cpu <arg> Set the physical boot cpu -f, --force Try to produce output even if the input tree has errors -i, --include <arg> Add a path to search for include files -s, --sort Sort nodes and properties before outputting (useful for comparing trees) -H, --phandle <arg> Valid phandle formats are: legacy - "linux,phandle" properties only epapr - "phandle" properties only both - Both "linux,phandle" and "phandle" properties -W, --warning <arg> Enable/disable warnings (prefix with "no-") -E, --error <arg> Enable/disable errors (prefix with "no-") -h, --help Print this help and exit -v, --version Print version and exit

假设我们最终的设备树文件是：arch/arm/boot/dts/s3c2416-smdk2416.dtb

./scripts/dtc/dtc -I dtb -O dts -o output.dts arch/arm/boot/dts/s3c2416-smdk2416.dtb

输出文件output.dts就是反汇编的结果，他就是实际生成的设备树。

Linux配置，支持设备树

make menuconfig ---> Boot options ---> Flattened Device Tree support

Linux 编译设备树

可以看看arch/arm/boot/dts/Makefile中你要的那个设备树的dtb文件是否配置上了。

make dtbs

 

 

 

 

 

 

 

 

 

 

 

 

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