build: Add BUILD.bazel file

Currently, the dtc project builds with Make.

As some consumers of this project use Bazel, and eventually all of
AOSP will need to move to Bazel anyway, add a a Bazel build
definition.

Bug: 251879933
Change-Id: I62ea59ee306eda58b764df2a9e5f2f33778e4b5c
Signed-off-by: John Moon <quic_johmoo@quicinc.com>
3 files changed
tree: 95478043033d47d0447e141e8174777cf0446efc
  1. Documentation/
  2. fuzzing/
  3. libfdt/
  4. pylibfdt/
  5. scripts/
  6. tests/
  7. .cirrus.yml
  8. .editorconfig
  9. .gitignore
  10. .travis.yml
  11. Android.bp
  12. BSD-2-Clause
  13. BUILD.bazel
  14. checks.c
  15. CONTRIBUTING.md
  16. convert-dtsv0-lexer.l
  17. data.c
  18. dtc-lexer.l
  19. dtc-parser.y
  20. dtc.c
  21. dtc.h
  22. dtdiff
  23. fdtdump.c
  24. fdtget.c
  25. fdtoverlay.c
  26. fdtput.c
  27. flattree.c
  28. fstree.c
  29. GPL
  30. LGPL
  31. LICENSE
  32. livetree.c
  33. Makefile
  34. Makefile.convert-dtsv0
  35. Makefile.dtc
  36. Makefile.utils
  37. MANIFEST.in
  38. meson.build
  39. meson_options.txt
  40. METADATA
  41. MODULE_LICENSE_BSD
  42. MODULE_LICENSE_GPL
  43. MODULE_LICENSE_LGPL
  44. OWNERS
  45. README.license
  46. README.md
  47. README.version
  48. setup.py
  49. srcpos.c
  50. srcpos.h
  51. TODO
  52. treesource.c
  53. util.c
  54. util.h
  55. version_gen.h.in
  56. version_non_gen.h
  57. WORKSPACE
  58. yamltree.c
README.md

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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