How to use the command 'dtc' (with examples)
The Device Tree Compiler (dtc) is a powerful tool used to recompile device trees between different formats. Device trees describe the hardware components available in a system and are used by the operating system to understand what hardware is present at boot time. The dtc tool primarily converts between the binary format (.dtb) and the device tree source format (.dts), which is human-readable. This capability is crucial for developers and engineers who need to modify or analyze the configuration of a hardware system.
Use case 1: Decompile a .dtb file into a readable .dts file
Code:
dtc -I dtb -O dts -o path/to/output_file.dts path/to/input_file.dtb
Motivation:
When working with custom hardware or embedded systems, developers often need to understand the system layout and configuration that the operating system uses during the boot process. Binary device tree files (.dtb) are not human-readable, making it challenging to decipher their content directly. However, to modify the device configuration or understand the existing setup, developers may require a more accessible format, which is why converting .dtb files into .dts files is highly beneficial. This conversion allows developers to read and analyze the device setup, make necessary adjustments, and potentially recompile it back into a .dtb file after modifications.
Explanation:
dtc: This is the command for invoking the Device Tree Compiler. It serves as the tool to convert between different device tree file formats.-I dtb: Specifies the input format is a device tree blob (.dtb) file. It instructs the compiler to read the input as a binary format, which is not human-readable.-O dts: Specifies the output format as a device tree source (.dts) file. This flag converts the binary .dtb file into a human-readable format, making it easier to interpret and modify.-o path/to/output_file.dts: Indicates the output file path and name where the resulting .dts file should be stored. This argument directs the compiler to save the converted file at a specified location.path/to/input_file.dtb: Provides the path to the input .dtb file that needs to be decompiled into the .dts format. The input file is the starting point of the conversion process.
Example Output:
After running the above command, you should have a new file at path/to/output_file.dts, containing the textual representation of your device tree. This file can be opened and read with any text editor, and it will display the structure and configuration of the hardware in a human-readable format.
Conclusion:
The Device Tree Compiler is an invaluable tool for developers working with hardware and embedded systems. By converting binary device tree files into a human-readable format, it empowers developers to inspect and customize the hardware configuration of their systems. The decompilation process detailed above is a foundational step for ensuring that system configurations match the developer’s requirements or for troubleshooting existing hardware setups. Using the dtc command effectively facilitates greater transparency and comprehension of the device layouts in modern computing environments.
