tools: romtool.py: fix a bug with VMEM file parsing and add Digest report option.

docs/opentitan/romtool.md

@@ -12,8 +12,8 @@ Supported input formats:
 ## Usage
 
 ````text
-usage: romtool.py [-h] -c CFG [-o OUTPUT] [-i ROM_ID] [-z SIZE]
-                  [-f {HEX,BIN,SVMEM,VMEM}] [-s] [-v] [-d]
+usage: romtool.py [-h] -c CFG [-o OUTPUT] [-D] [-f {HEX,BIN,SVMEM,VMEM}]
+                  [-i ROM_ID] [-s] [-z SIZE] [-v] [-d]
                   rom
 
 QEMU OT tool to generate a scrambled ROM image.
@@ -27,11 +27,12 @@ Files:
   -o, --output OUTPUT   output ROM image file
 
 Parameters:
-  -i, --rom-id ROM_ID   ROM image identifier
-  -z, --rom-size SIZE   ROM image size in bytes (accepts Ki suffix)
+  -D, --digest          Show the ROM digest
   -f, --output-format {HEX,BIN,SVMEM,VMEM}
                         Output file format (default: HEX)
+  -i, --rom-id ROM_ID   ROM image identifier
   -s, --subst-perm      Enable legacy mode with S&P mode
+  -z, --rom-size SIZE   ROM image size in bytes (accepts Ki suffix)
 
 Extras:
   -v, --verbose         increase verbosity
@@ -43,6 +44,8 @@ Extras:
 * `-c` specify a QEMU [configuration file](otcfg.md) from which to read all the cryptographic
   constants. See [`cfggen.py`](cfggen.md) tool to generate such a file.
 
+* `-D` show the loaded or computed ROM digest as an hexadecimal string
+
 * `-d` only useful to debug the script, reports any Python traceback to the standard error stream.
 
 * `-f` output file format. `HEX` format always output scrambled/SEC-DED data, `SVMEM` specifies a

python/qemu/ot/rom/image.py

@@ -185,6 +185,16 @@ def digest(self) -> bytes:
             self._make_digest()
         return self._digest
 
+    @property
+    def hexdigest(self) -> str:
+        """Return the current digest of the ROM image.
+
+           Digest is computed on-the-fly if not already known.
+
+           :return: the digest as a hexa string.
+        """
+        return hexlify(self.digest).decode()
+
     @property
     def key(self) -> Optional[int]:
         """Key observer."""
@@ -395,7 +405,7 @@ def _load_vmem(self, rfp: BinaryIO, size: Optional[int]) -> None:
             line = line.strip()
             if not line.startswith(b'@'):
                 continue
-            parts = re.split(r'\s+', line[1:])
+            parts = re.split(rb'\s+', line[1:])
             address_str = parts[0]
             data_str = parts[1:]
             scrambled_data = all(len(d) in (9, 10) for d in data_str)

scripts/opentitan/romtool.py

@@ -47,17 +47,19 @@ def main():
                            help='output ROM image file')
 
         params = argparser.add_argument_group(title='Parameters')
-        params.add_argument('-i', '--rom-id', type=int,
-                            help='ROM image identifier')
-        params.add_argument('-z', '--rom-size', metavar='SIZE',
-                            type=HexInt.xparse,
-                            help='ROM image size in bytes (accepts Ki suffix)')
+        params.add_argument('-D', '--digest', action='store_true',
+                            help='Show the ROM digest')
         params.add_argument('-f', '--output-format', choices=out_formats,
                             default=out_formats[0],
                             help=f'Output file format '
                                  f'(default: {out_formats[0]})')
+        params.add_argument('-i', '--rom-id', type=int,
+                            help='ROM image identifier')
         params.add_argument('-s', '--subst-perm', action='store_true',
                             help='Enable legacy mode with S&P mode')
+        params.add_argument('-z', '--rom-size', metavar='SIZE',
+                            type=HexInt.xparse,
+                            help='ROM image size in bytes (accepts Ki suffix)')
 
         extra = argparser.add_argument_group(title='Extras')
         extra.add_argument('-v', '--verbose', action='count',
@@ -74,6 +76,9 @@ def main():
         rom_img.load_config(args.config, args.rom_id)
         rom_img.load(args.rom[0], args.rom_size)
 
+        if args.digest:
+            print('Digest:', rom_img.hexdigest)
+
         with open(args.output, 'wb') if args.output else \
                 sys.stdout.buffer as wfp:
             rom_img.save(wfp, args.output_format)