xref: /aosp_15_r20/external/coreboot/util/exynos/variable_cksum.py (revision b9411a12aaaa7e1e6a6fb7c5e057f44ee179a49c)
1#!/usr/bin/env python3
2#
3# SPDX-License-Identifier: BSD-3-Clause
4
5"""
6This utility computes and fills Exynos ROM checksum (for BL1 or BL2).
7(Algorithm from U-Boot: tools/mkexynosspl.c)
8
9Input: IN OUT
10
11Output:
12
13  Checksum header added to IN and written to OUT.
14  Header: uint32_t size, checksum, reserved[2].
15"""
16
17import struct
18import sys
19
20def main(argv):
21  if len(argv) != 3:
22    exit('usage: %s IN OUT' % argv[0])
23
24  in_name, out_name = argv[1:3]
25  header_format = "<IIII"
26  with open(in_name, "rb") as in_file, open(out_name, "wb") as out_file:
27    data = in_file.read()
28    header = struct.pack(header_format,
29                         struct.calcsize(header_format) + len(data),
30                         sum(data),
31                         0, 0)
32    out_file.write(header + data)
33
34
35if __name__ == '__main__':
36  main(sys.argv)
37