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 | |
Kevin O'Connor | e51488c | 2014-05-22 16:59:16 -0400 | [diff] [blame] | 8 | import sys, struct |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 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): |
Kevin O'Connor | e51488c | 2014-05-22 16:59:16 -0400 | [diff] [blame] | 17 | if (sys.version_info > (3, 0)): |
| 18 | cksum = sum(data) |
| 19 | else: |
| 20 | cksum = sum(map(ord, data)) |
| 21 | return struct.pack('<B', (0x100 - cksum) & 0xff) |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 22 | |
| 23 | def main(): |
| 24 | inname = sys.argv[1] |
| 25 | outname = sys.argv[2] |
| 26 | |
| 27 | # Read data in |
| 28 | f = open(inname, 'rb') |
| 29 | data = f.read() |
Kevin O'Connor | f31bff1 | 2013-05-20 21:39:56 -0400 | [diff] [blame] | 30 | f.close() |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 31 | count = len(data) |
| 32 | |
| 33 | # Pad to a 512 byte boundary |
Johannes Krampf | 19f789b | 2014-01-19 16:03:49 +0100 | [diff] [blame] | 34 | data += as_bytes("\0") * (alignpos(count, 512) - count) |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 35 | count = len(data) |
| 36 | |
Julian Pidancet | 65cfaa2 | 2011-12-19 05:07:57 +0000 | [diff] [blame] | 37 | # Check if a pci header is present |
| 38 | pcidata = ord(data[24:25]) + (ord(data[25:26]) << 8) |
| 39 | if pcidata != 0: |
Kevin O'Connor | e51488c | 2014-05-22 16:59:16 -0400 | [diff] [blame] | 40 | blocks = struct.pack('<H', int(count/512)) |
| 41 | data = data[:pcidata + 16] + blocks + data[pcidata + 18:] |
Julian Pidancet | 65cfaa2 | 2011-12-19 05:07:57 +0000 | [diff] [blame] | 42 | |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 43 | # Fill in size field; clear checksum field |
Kevin O'Connor | e51488c | 2014-05-22 16:59:16 -0400 | [diff] [blame] | 44 | blocks = struct.pack('<B', int(count/512)) |
| 45 | data = data[:2] + blocks + data[3:6] + as_bytes("\0") + data[7:] |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 46 | |
| 47 | # Checksum rom |
Kevin O'Connor | e51488c | 2014-05-22 16:59:16 -0400 | [diff] [blame] | 48 | data = data[:6] + checksum(data) + data[7:] |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 49 | |
| 50 | # Write new rom |
| 51 | f = open(outname, 'wb') |
| 52 | f.write(data) |
Kevin O'Connor | f31bff1 | 2013-05-20 21:39:56 -0400 | [diff] [blame] | 53 | f.close() |
Kevin O'Connor | 32da6a6 | 2009-05-14 19:01:39 -0400 | [diff] [blame] | 54 | |
| 55 | if __name__ == '__main__': |
| 56 | main() |