fdt_util.py
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#!/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 sys
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
"""
if sys.version_info > (3, 0):
if isinstance(val, bytes):
val = val.decode('utf-8')
val = val.encode('raw_unicode_escape')
return struct.unpack('>I', val)[0]
def fdt_cells_to_cpu(val, cells):
"""Convert one or two cells to a long integer
Args:
Value to convert (array of one or more 4-character strings)
Return:
A native-endian long value
"""
if not cells:
return 0
out = long(fdt32_to_cpu(val[0]))
if cells == 2:
out = out << 32 | fdt32_to_cpu(val[1])
return out
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',
'-W', 'no-unit_address_vs_reg']
args.extend(search_list)
args.append(dts_input)
dtc = os.environ.get('DTC') or 'dtc'
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