diff options
Diffstat (limited to 'tools/dtoc/fdt_util.py')
-rw-r--r-- | tools/dtoc/fdt_util.py | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/tools/dtoc/fdt_util.py b/tools/dtoc/fdt_util.py new file mode 100644 index 0000000000..929b524fcf --- /dev/null +++ b/tools/dtoc/fdt_util.py @@ -0,0 +1,86 @@ +#!/usr/bin/python +# +# Copyright (C) 2016 Google, Inc +# Written by Simon Glass <sjg@chromium.org> +# +# SPDX-License-Identifier: GPL-2.0+ +# + +import struct + +# A list of types we support +(TYPE_BYTE, TYPE_INT, TYPE_STRING, TYPE_BOOL) = range(4) + +def BytesToValue(bytes): + """Converts a string of bytes into a type and value + + Args: + A string containing bytes + + Return: + A tuple: + Type of data + Data, either a single element or a list of elements. Each element + is one of: + TYPE_STRING: string value from the property + TYPE_INT: a byte-swapped integer stored as a 4-byte string + TYPE_BYTE: a byte stored as a single-byte string + """ + size = len(bytes) + strings = bytes.split('\0') + is_string = True + count = len(strings) - 1 + if count > 0 and not strings[-1]: + for string in strings[:-1]: + if not string: + is_string = False + break + for ch in string: + if ch < ' ' or ch > '~': + is_string = False + break + else: + is_string = False + if is_string: + if count == 1: + return TYPE_STRING, strings[0] + else: + return TYPE_STRING, strings[:-1] + if size % 4: + if size == 1: + return TYPE_BYTE, bytes[0] + else: + return TYPE_BYTE, list(bytes) + val = [] + for i in range(0, size, 4): + val.append(bytes[i:i + 4]) + if size == 4: + return TYPE_INT, val[0] + else: + return TYPE_INT, val + +def GetEmpty(type): + """Get an empty / zero value of the given type + + Returns: + A single value of the given type + """ + if type == TYPE_BYTE: + return chr(0) + elif type == TYPE_INT: + return struct.pack('<I', 0); + elif type == TYPE_STRING: + return '' + else: + return True + +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] |