#!/usr/bin/env python # # Copyright (C) 2013 Google Inc. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions # are met: # 1. Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # 2. Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in the # documentation and/or other materials provided with the distribution. # 3. The name of the author may not be used to endorse or promote products # derived from this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE # ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF # SUCH DAMAGE. """ This utility computes and fills Exynos ROM checksum (for BL1 or BL2). (Algorithm from U-Boot: tools/mkexynosspl.c) Input: IN OUT DATA_SIZE Output: IN padded out to DATA_SIZE, checksum at the end, written to OUT. """ import struct import sys def main(argv): if len(argv) != 4: exit('usage: %s IN OUT DATA_SIZE' % argv[0]) in_name, out_name = argv[1:3] size = int(argv[3], 0) checksum_format = "<I" with open(in_name, "rb") as in_file, open(out_name, "wb") as out_file: data = in_file.read() checksum_size = struct.calcsize(checksum_format) data_size = size - checksum_size assert len(data) <= data_size checksum = struct.pack(checksum_format, sum(map(ord, data))) out_file.write(data + bytearray(data_size - len(data)) + checksum) if __name__ == '__main__': main(sys.argv)