6b08fb5cc4
The distutils package is deprecated. The upstream libfdt repo uses setuptools for building the pylibfdt module, so bring in that code, suitably modified for U-Boot. Also bring in the README. The modifications include setting the version correctly, making use of the environment variables provided by the Makefile and various tweaks to the directories. Note that the version omits the minus character at the start of EXTRAVERSION, since this creates a warning. The build is really just used within U-Boot itself, so it doesn't matter too much if the version matches upstream, or exactly matches U-Boot. Signed-off-by: Simon Glass <sjg@chromium.org>
107 lines
3.2 KiB
Plaintext
107 lines
3.2 KiB
Plaintext
The source tree contains the Device Tree Compiler (dtc) toolchain for
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working with device tree source and binary files and also libfdt, a
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utility library for reading and manipulating the binary format.
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DTC and LIBFDT are maintained by:
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David Gibson <david@gibson.dropbear.id.au>
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Jon Loeliger <loeliger@gmail.com>
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Python library
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--------------
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A Python library is also available. To build this you will need to install
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swig and Python development files. On Debian distributions:
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sudo apt-get install swig python3-dev
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The library provides an Fdt class which you can use like this:
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$ PYTHONPATH=../pylibfdt python3
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>>> import libfdt
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>>> fdt = libfdt.Fdt(open('test_tree1.dtb', mode='rb').read())
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>>> node = fdt.path_offset('/subnode@1')
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>>> print(node)
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124
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>>> prop_offset = fdt.first_property_offset(node)
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>>> prop = fdt.get_property_by_offset(prop_offset)
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>>> print('%s=%s' % (prop.name, prop.as_str()))
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compatible=subnode1
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>>> node2 = fdt.path_offset('/')
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>>> print(fdt.getprop(node2, 'compatible').as_str())
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test_tree1
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You will find tests in tests/pylibfdt_tests.py showing how to use each
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method. Help is available using the Python help command, e.g.:
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$ cd pylibfdt
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$ python3 -c "import libfdt; help(libfdt)"
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If you add new features, please check code coverage:
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$ sudo apt-get install python3-coverage
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$ cd tests
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# It's just 'coverage' on most other distributions
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$ python3-coverage run pylibfdt_tests.py
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$ python3-coverage html
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# Open 'htmlcov/index.html' in your browser
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The library can be installed with pip from a local source tree:
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pip install . [--user|--prefix=/path/to/install_dir]
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Or directly from a remote git repo:
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pip install git+git://git.kernel.org/pub/scm/utils/dtc/dtc.git@main
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The install depends on libfdt shared library being installed on the host system
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first. Generally, using --user or --prefix is not necessary and pip will use the
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default location for the Python installation which varies if the user is root or
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not.
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You can also install everything via make if you like, but pip is recommended.
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To install both libfdt and pylibfdt you can use:
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make install [PREFIX=/path/to/install_dir]
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To disable building the python library, even if swig and Python are available,
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use:
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make NO_PYTHON=1
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More work remains to support all of libfdt, including access to numeric
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values.
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Adding a new function to libfdt.h
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---------------------------------
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The shared library uses libfdt/version.lds to list the exported functions, so
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add your new function there. Check that your function works with pylibfdt. If
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it cannot be supported, put the declaration in libfdt.h behind #ifndef SWIG so
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that swig ignores it.
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Tests
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-----
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Test files are kept in the tests/ directory. Use 'make check' to build and run
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all tests.
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If you want to adjust a test file, be aware that tree_tree1.dts is compiled
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and checked against a binary tree from assembler macros in trees.S. So
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if you change that file you must change tree.S also.
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Mailing list
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------------
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The following list is for discussion about dtc and libfdt implementation
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mailto:devicetree-compiler@vger.kernel.org
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Core device tree bindings are discussed on the devicetree-spec list:
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mailto:devicetree-spec@vger.kernel.org
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