Mirroring from commit 106549a4362f6b499da522f8f8f5ed9f98388f87 from Coreboot upstream

scripts/buildrom.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python
+# Fill in checksum/size of an option rom, and pad it to proper length.
+#
+# Copyright (C) 2009  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+
+import sys, struct
+
+def alignpos(pos, alignbytes):
+    mask = alignbytes - 1
+    return (pos + mask) & ~mask
+
+def checksum(data):
+    if (sys.version_info > (3, 0)):
+        cksum = sum(data)
+    else:
+        cksum = sum(map(ord, data))
+    return struct.pack('<B', (0x100 - cksum) & 0xff)
+
+def main():
+    inname = sys.argv[1]
+    outname = sys.argv[2]
+
+    # Read data in
+    f = open(inname, 'rb')
+    data = f.read()
+    f.close()
+    count = len(data)
+
+    # Pad to a 512 byte boundary
+    data += b"\0" * (alignpos(count, 512) - count)
+    count = len(data)
+
+    # Check if a pci header is present
+    pcidata = ord(data[24:25]) + (ord(data[25:26]) << 8)
+    if pcidata != 0:
+        blocks = struct.pack('<H', int(count/512))
+        data = data[:pcidata + 16] + blocks + data[pcidata + 18:]
+
+    # Fill in size field; clear checksum field
+    blocks = struct.pack('<B', int(count/512))
+    data = data[:2] + blocks + data[3:6] + b"\0" + data[7:]
+
+    # Checksum rom
+    data = data[:6] + checksum(data) + data[7:]
+
+    # Write new rom
+    f = open(outname, 'wb')
+    f.write(data)
+    f.close()
+
+if __name__ == '__main__':
+    main()