Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 1 | #!/usr/bin/env python |
| 2 | # Fill in checksum/size of an option rom, and pad it to proper length. |
| 3 | # |
| 4 | # Copyright (C) 2009 Kevin O'Connor <kevin@koconnor.net> |
| 5 | # |
| 6 | # This file may be distributed under the terms of the GNU GPLv3 license. |
| 7 | |
| 8 | import sys |
| 9 | |
Johannes Krampf | 19f789b | 2014-01-19 16:03:49 +0100 | [diff] [blame] | 10 | from python23compat import as_bytes |
| 11 | |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 12 | def alignpos(pos, alignbytes): |
| 13 | mask = alignbytes - 1 |
| 14 | return (pos + mask) & ~mask |
| 15 | |
| 16 | def checksum(data): |
| 17 | ords = map(ord, data) |
| 18 | return sum(ords) |
| 19 | |
| 20 | def main(): |
| 21 | inname = sys.argv[1] |
| 22 | outname = sys.argv[2] |
| 23 | |
| 24 | # Read data in |
| 25 | f = open(inname, 'rb') |
| 26 | data = f.read() |
Kevin O'Connor | f31bff1 | 2013-05-20 21:39:56 -0400 | [diff] [blame] | 27 | f.close() |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 28 | count = len(data) |
| 29 | |
| 30 | # Pad to a 512 byte boundary |
Johannes Krampf | 19f789b | 2014-01-19 16:03:49 +0100 | [diff] [blame] | 31 | data += as_bytes("\0") * (alignpos(count, 512) - count) |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 32 | count = len(data) |
| 33 | |
Julian Pidancet | 65cfaa2 | 2011-12-19 05:07:57 +0000 | [diff] [blame] | 34 | # Check if a pci header is present |
| 35 | pcidata = ord(data[24:25]) + (ord(data[25:26]) << 8) |
| 36 | if pcidata != 0: |
Johannes Krampf | 9d7d044 | 2014-01-12 11:19:22 -0500 | [diff] [blame] | 37 | data = data[:pcidata + 16] + chr(int(count/512)) + chr(0) + data[pcidata + 18:] |
Julian Pidancet | 65cfaa2 | 2011-12-19 05:07:57 +0000 | [diff] [blame] | 38 | |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 39 | # Fill in size field; clear checksum field |
Johannes Krampf | 19f789b | 2014-01-19 16:03:49 +0100 | [diff] [blame] | 40 | data = data[:2] + chr(int(count/512)) + data[3:6] + as_bytes("\0") + data[7:] |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 41 | |
| 42 | # Checksum rom |
| 43 | newsum = (256 - checksum(data)) & 0xff |
| 44 | data = data[:6] + chr(newsum) + data[7:] |
| 45 | |
| 46 | # Write new rom |
| 47 | f = open(outname, 'wb') |
| 48 | f.write(data) |
Kevin O'Connor | f31bff1 | 2013-05-20 21:39:56 -0400 | [diff] [blame] | 49 | f.close() |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 50 | |
| 51 | if __name__ == '__main__': |
| 52 | main() |