8e20ccf52f
Extend the parser to record positions, in build_node, build_node_delete, and build_property. srcpos structures are added to the property and node types, and to the parameter lists of the above functions that construct these types. Nodes and properties that are created by the compiler rather than from parsing source code have NULL as the srcpos value. merge_nodes, defined in livetree.c, uses srcpos_extend to combine multiple positions, resulting in a list of positions. srcpos_extend is defined in srcpos.c. New elements are added at the end. This requires the srcpos type, define in srcpos.h, to be a list structure with a next field. This next field is initialized to NULL in srcpos.h, in the macro YYLLOC_DEFAULT invoked implicitly by the generated parser code. Another change to srcpos.c is to make srcpos_copy always do a full copy, including a copy of the file substructure. This is required because when dtc is used on the output of cpp, the successive detected file names overwrite the file name in the file structure. The next field does not need to be deep copied, because it is always NULL when srcpos_copy is called; an assert checks for this. File names are only updated in uncopied position structures. Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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:
David Gibson <david@gibson.dropbear.id.au>
Jon Loeliger <jdl@jdl.com>
Python library
--------------
A Python library is also available. To build this you will need to install
swig and Python development files. On Debian distributions:
sudo apt-get install swig python-dev
The library provides an Fdt class which you can use like this:
$ PYTHONPATH=../pylibfdt python
>>> import libfdt
>>> fdt = libfdt.Fdt(open('test_tree1.dtb').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=%r' % (prop.name, prop.value)
compatible=bytearray(b'subnode1\x00')
>>> print '%s=%s' % (prop.name, prop.value)
compatible=subnode1
>>> node2 = fdt.path_offset('/')
>>> print fdt.getprop(node2, 'compatible')
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
$ python -c "import libfdt; help(libfdt)"
If you add new features, please check code coverage:
$ sudo apt-get install python-pip python-pytest
$ sudo pip install coverage
$ cd tests
$ coverage run pylibfdt_tests.py
$ coverage html
# Open 'htmlcov/index.html' in your browser
To install the library via the normal setup.py method, use:
./pylibfdt/setup.py [--prefix=/path/to/install_dir]
If --prefix is not provided, the default prefix is used, typically '/usr'
or '/usr/local'. See Python's distutils documentation for details. You can
also install via the Makefile if you like, but the above is more common.
To install both libfdt and pylibfdt you can use:
make install [SETUP_PREFIX=/path/to/install_dir] \
[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.
Tests
-----
Test files are kept in the tests/ directory. Use 'make check' to build and run
all tests.
If you want to adjust a test file, be aware that tree_tree1.dts is compiled
and checked against a binary tree from assembler macros in trees.S. So
if you change that file you must change tree.S also.
Mailing list
------------
The following list is for discussion about dtc and libfdt implementation
mailto:devicetree-compiler@vger.kernel.org
Core device tree bindings are discussed on the devicetree-spec list:
mailto:devicetree-spec@vger.kernel.org