From 4651e8d5627735cf371056b79de53e03a25d09a1 Mon Sep 17 00:00:00 2001
From: Paul Mathieu <paul@ponteilla.net>
Date: Sun, 19 Jun 2022 09:50:54 +0200
Subject: [PATCH] alchitry-loader: add bit2bin script

---
 alchitry-loader/bit2bin.py | 90 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 alchitry-loader/bit2bin.py

diff --git a/alchitry-loader/bit2bin.py b/alchitry-loader/bit2bin.py
new file mode 100644
index 0000000..55cc69b
--- /dev/null
+++ b/alchitry-loader/bit2bin.py
@@ -0,0 +1,90 @@
+#!/usr/bin/env python
+
+import argparse
+import struct
+
+
+def flip32(data: bytes):
+    sl = struct.Struct('<I')
+    sb = struct.Struct('>I')
+    d = bytearray(len(data))
+    for offset in range(0, len(data), 4):
+         sb.pack_into(d, offset, sl.unpack_from(data, offset)[0])
+    return d
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(description='Convert FPGA bit files to raw bin format suitable for flashing')
+    parser.add_argument('-f', '--flip', dest='flip', action='store_true', default=False, help='Flip 32-bit endianess (needed for Zynq)')
+    parser.add_argument("bitfiletemplate", help="Input bit file name from which the header is extracted")
+    parser.add_argument("binfile", help="Input bin file name from which the bitstream is extracted")
+    parser.add_argument("bitfile", help="Output bit file name")
+    return parser.parse_args()
+
+
+def main():
+    args = parse_args()
+    short = struct.Struct('>H')
+    ulong = struct.Struct('>I')
+
+    bitfile = open(args.bitfiletemplate, 'rb')
+    headerLength = 0
+    l = short.unpack(bitfile.read(2))[0]
+    headerLength = headerLength + 2
+    if l != 9:
+        raise Exception("Missing <0009> header (0x%x), not a bit file" % l)
+    bitfile.read(l)
+    headerLength = headerLength + l
+    l = short.unpack(bitfile.read(2))[0]
+    d = bitfile.read(l)
+    headerLength = headerLength + l + 2
+    if d != b'a':
+        raise Exception("Missing <a> header, not a bit file")
+
+    l = short.unpack(bitfile.read(2))[0]
+    d = bitfile.read(l)
+    headerLength = headerLength + l +2
+    print("Design name: %s" % d)
+
+    KEYNAMES = {b'b': "Partname", b'c': "Date", b'd': "Time"}
+
+    while 1:
+        k = bitfile.read(1)
+        headerLength = headerLength + 1
+        if not k:
+            bitfile.close()
+            raise Exception("unexpected EOF")
+        elif k == b'e':
+            l = ulong.unpack(bitfile.read(4))[0]
+            headerLength = headerLength + 4
+            print("Found header end: %d" % headerLength)
+            break
+        elif k in KEYNAMES:
+            l = short.unpack(bitfile.read(2))[0]
+            d = bitfile.read(l)
+            headerLength = headerLength + l + 2
+            print(KEYNAMES[k], d)
+        else:
+            print("Unexpected key: %s" % k)
+            l = short.unpack(bitfile.read(2))[0]
+            d = bitfile.read(l)
+            headerLength = headerLength + l + 2 
+
+    outputfile = open(args.bitfile, 'wb+')
+    bitfile.seek(0)
+    outputfile.write(bitfile.read(headerLength))
+    bitfile.close()
+
+    binfile = open( args.binfile, 'rb')
+    d = binfile.read()
+    binfile.close()
+    if args.flip:
+        print("Flipping data...")
+        d = flip32(d)
+
+    outputfile.write(d)
+    outputfile.close()
+
+
+if __name__ == "__main__":
+    main()