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#!/usr/bin/python
# SPDX-License-Identifier: GPL-2.0+
#
# Copyright (C) 2016 Google, Inc
# Written by Simon Glass <sjg@chromium.org>
#
# Utility functions for reading from a device tree. Once the upstream pylibfdt
# implementation advances far enough, we should be able to drop these.
import os
import struct
import sys
import tempfile
import command
import tools
VERSION3 = sys.version_info > (3, 0)
def get_plain_bytes(val):
"""Handle Python 3 strings"""
if isinstance(val, bytes):
val = val.decode('utf-8')
return val.encode('raw_unicode_escape')
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 VERSION3:
# This code is not reached in Python 2
val = get_plain_bytes(val) # pragma: no cover
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, capture_stderr=False):
"""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, capture_stderr=capture_stderr)
return dtb_output
def GetInt(node, propname, default=None):
"""Get an integer from a property
Args:
node: Node object to read from
propname: property name to read
default: Default value to use if the node/property do not exist
Returns:
Integer value read, or default if none
"""
prop = node.props.get(propname)
if not prop:
return default
if isinstance(prop.value, list):
raise ValueError("Node '%s' property '%s' has list value: expecting "
"a single integer" % (node.name, propname))
value = fdt32_to_cpu(prop.value)
return value
def GetString(node, propname, default=None):
"""Get a string from a property
Args:
node: Node object to read from
propname: property name to read
default: Default value to use if the node/property do not exist
Returns:
String value read, or default if none
"""
prop = node.props.get(propname)
if not prop:
return default
value = prop.value
if isinstance(value, list):
raise ValueError("Node '%s' property '%s' has list value: expecting "
"a single string" % (node.name, propname))
return value
def GetBool(node, propname, default=False):
"""Get an boolean from a property
Args:
node: Node object to read from
propname: property name to read
default: Default value to use if the node/property do not exist
Returns:
Boolean value read, or default if none (if you set this to True the
function will always return True)
"""
if propname in node.props:
return True
return default
def GetByte(node, propname, default=None):
"""Get an byte from a property
Args:
node: Node object to read from
propname: property name to read
default: Default value to use if the node/property do not exist
Returns:
Byte value read, or default if none
"""
prop = node.props.get(propname)
if not prop:
return default
value = prop.value
if isinstance(value, list):
raise ValueError("Node '%s' property '%s' has list value: expecting "
"a single byte" % (node.name, propname))
if len(value) != 1:
raise ValueError("Node '%s' property '%s' has length %d, expecting %d" %
(node.name, propname, len(value), 1))
return ord(value[0])
def GetPhandleList(node, propname):
"""Get a list of phandles from a property
Args:
node: Node object to read from
propname: property name to read
Returns:
List of phandles read, each an integer
"""
prop = node.props.get(propname)
if not prop:
return None
value = prop.value
if not isinstance(value, list):
value = [value]
return [fdt32_to_cpu(v) for v in value]
def GetDatatype(node, propname, datatype):
"""Get a value of a given type from a property
Args:
node: Node object to read from
propname: property name to read
datatype: Type to read (str or int)
Returns:
value read, or None if none
Raises:
ValueError if datatype is not str or int
"""
if datatype == str:
return GetString(node, propname)
elif datatype == int:
return GetInt(node, propname)
raise ValueError("fdt_util internal error: Unknown data type '%s'" %
datatype)
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