| #!/usr/bin/env python2 |
| # |
| # 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) |