u-boot/tools/dtoc/fdt_util.py
Simon Glass 8f224b3734 dtoc: Add methods for reading data from properties
Provide easy helpers for reading integer, string and boolean values from
device-tree properties.

Signed-off-by: Simon Glass <sjg@chromium.org>
2016-09-18 21:04:39 -06:00

87 lines
2.3 KiB
Python

#!/usr/bin/python
#
# Copyright (C) 2016 Google, Inc
# Written by Simon Glass <sjg@chromium.org>
#
# SPDX-License-Identifier: GPL-2.0+
#
import os
import struct
import tempfile
import command
import tools
def fdt32_to_cpu(val):
"""Convert a device tree cell to an integer
Args:
Value to convert (4-character string representing the cell value)
Return:
A native-endian integer value
"""
return struct.unpack('>I', val)[0]
def EnsureCompiled(fname):
"""Compile an fdt .dts source file into a .dtb binary blob if needed.
Args:
fname: Filename (if .dts it will be compiled). It not it will be
left alone
Returns:
Filename of resulting .dtb file
"""
_, ext = os.path.splitext(fname)
if ext != '.dts':
return fname
dts_input = tools.GetOutputFilename('source.dts')
dtb_output = tools.GetOutputFilename('source.dtb')
search_paths = [os.path.join(os.getcwd(), 'include')]
root, _ = os.path.splitext(fname)
args = ['-E', '-P', '-x', 'assembler-with-cpp', '-D__ASSEMBLY__']
args += ['-Ulinux']
for path in search_paths:
args.extend(['-I', path])
args += ['-o', dts_input, fname]
command.Run('cc', *args)
# If we don't have a directory, put it in the tools tempdir
search_list = []
for path in search_paths:
search_list.extend(['-i', path])
args = ['-I', 'dts', '-o', dtb_output, '-O', 'dtb']
args.extend(search_list)
args.append(dts_input)
command.Run('dtc', *args)
return dtb_output
def GetInt(node, propname, default=None):
prop = node.props.get(propname)
if not prop:
return default
value = fdt32_to_cpu(prop.value)
if type(value) == type(list):
raise ValueError("Node '%s' property '%' has list value: expecting"
"a single integer" % (node.name, propname))
return value
def GetString(node, propname, default=None):
prop = node.props.get(propname)
if not prop:
return default
value = prop.value
if type(value) == type(list):
raise ValueError("Node '%s' property '%' has list value: expecting"
"a single string" % (node.name, propname))
return value
def GetBool(node, propname, default=False):
if propname in node.props:
return True
return default