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 DATA_SIZE 10 11Output: 12 13 IN padded out to DATA_SIZE, checksum at the end, written to OUT. 14""" 15 16import struct 17import sys 18 19def main(argv): 20 if len(argv) != 4: 21 exit('usage: %s IN OUT DATA_SIZE' % argv[0]) 22 23 in_name, out_name = argv[1:3] 24 size = int(argv[3], 0) 25 checksum_format = "<I" 26 with open(in_name, "rb") as in_file, open(out_name, "wb") as out_file: 27 data = in_file.read() 28 checksum_size = struct.calcsize(checksum_format) 29 data_size = size - checksum_size 30 assert len(data) <= data_size 31 checksum = struct.pack(checksum_format, sum(data)) 32 out_file.write(data + bytearray(data_size - len(data)) + checksum) 33 34 35if __name__ == '__main__': 36 main(sys.argv) 37