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  1. e3cf23a Add new build rule for running dtc on Android by Jaewan Kim · 2 weeks ago main master
  2. 5379c87 Set dtc as dependency of dtdiff by Jaewan Kim · 4 weeks ago
  3. d202bf0 ANDROID: Format Android.bp by Jaewan Kim · 4 weeks ago
  4. 7ebab26 ANDROID: Add dtdiff target for testing by Jaewan Kim · 4 weeks ago
  5. 5ec1ec0 Merge changes I1e5a8903,I43c6ad22,If9a102a6,I702e619c into main am: e5b8c171c5 am: 132ab4d211 am: 59703fa923 am: cc558f2f2a by Pierre-Clément Tosi · 4 months ago android-u-qpr2-beta-2-gpl android-u-qpr3-beta-1-gpl

Device Tree Compiler and libfdt

The source tree contains the Device Tree Compiler (dtc) toolchain for working with device tree source and binary files and also libfdt, a utility library for reading and manipulating the binary format.

dtc and libfdt are maintained by:

Python library

A Python library wrapping libfdt is also available. To build this you will need to install swig and Python development files. On Debian distributions:

$ sudo apt-get install swig python3-dev

The library provides an Fdt class which you can use like this:

$ PYTHONPATH=../pylibfdt python3
>>> import libfdt
>>> fdt = libfdt.Fdt(open('test_tree1.dtb', mode='rb').read())
>>> node = fdt.path_offset('/subnode@1')
>>> print(node)
124
>>> prop_offset = fdt.first_property_offset(node)
>>> prop = fdt.get_property_by_offset(prop_offset)
>>> print('%s=%s' % (prop.name, prop.as_str()))
compatible=subnode1
>>> node2 = fdt.path_offset('/')
>>> print(fdt.getprop(node2, 'compatible').as_str())
test_tree1

You will find tests in tests/pylibfdt_tests.py showing how to use each method. Help is available using the Python help command, e.g.:

$ cd pylibfdt
$ python3 -c "import libfdt; help(libfdt)"

If you add new features, please check code coverage:

$ sudo apt-get install python3-coverage
$ cd tests
# It's just 'coverage' on most other distributions
$ python3-coverage run pylibfdt_tests.py
$ python3-coverage html
# Open 'htmlcov/index.html' in your browser

The library can be installed with pip from a local source tree:

$ pip install . [--user|--prefix=/path/to/install_dir]

Or directly from a remote git repo:

$ pip install git+git://git.kernel.org/pub/scm/utils/dtc/dtc.git@main

The install depends on libfdt shared library being installed on the host system first. Generally, using --user or --prefix is not necessary and pip will use the default location for the Python installation which varies if the user is root or not.

You can also install everything via make if you like, but pip is recommended.

To install both libfdt and pylibfdt you can use:

$ make install [PREFIX=/path/to/install_dir]

To disable building the python library, even if swig and Python are available, use:

$ make NO_PYTHON=1

More work remains to support all of libfdt, including access to numeric values.

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