[ot] scripts/opentitan: cfggen.py: define a list of supported tops

QEMU only supports a known list of OT machine, ensure the specified top
matches one of the supported machine.

Signed-off-by: Emmanuel Blot <eblot@rivosinc.com>

Author: rivos-eblot

docs/opentitan/cfggen.md

@@ -11,8 +11,8 @@ the QEMU binary.
 ## Usage
 
 ````text
-usage: cfggen.py [-h] [-o CFG] [-T TOP] [-c SV] [-l SV] [-t HJSON] [-s SOCID]
-                 [-C COUNT] [-v] [-d]
+usage: cfggen.py [-h] -T {Darjeeling,EarlGrey} [-o CFG] [-c SV] [-l SV]
+                 [-t HJSON] [-s SOCID] [-C COUNT] [-v] [-d]
                  TOPDIR
 
 OpenTitan QEMU configuration file generator.
@@ -22,26 +22,22 @@ options:
 
 Files:
   TOPDIR                OpenTitan top directory
-  -o CFG, --out CFG     Filename of the config file to generate
-  -T TOP, --top TOP     OpenTitan Top name (default: darjeeling)
-  -c SV, --otpconst SV  OTP Constant SV file (default: auto)
-  -l SV, --lifecycle SV
-                        LifeCycle SV file (default: auto)
-  -t HJSON, --topcfg HJSON
-                        OpenTitan top HJSON config file (default: auto)
+  -T, --top {Darjeeling,EarlGrey}
+                        OpenTitan top name
+  -o, --out CFG         Filename of the config file to generate
+  -c, --otpconst SV     OTP Constant SV file (default: auto)
+  -l, --lifecycle SV    LifeCycle SV file (default: auto)
+  -t, --topcfg HJSON    OpenTitan top HJSON config file (default: auto)
 
 Modifiers:
-  -s SOCID, --socid SOCID
-                        SoC identifier, if any
-  -C COUNT, --count COUNT
-                        SoC count (default: 1)
+  -s, --socid SOCID     SoC identifier, if any
+  -C, --count COUNT     SoC count (default: 1)
 
 Extras:
   -v, --verbose         increase verbosity
   -d, --debug           enable debug mode
 ````
 
-
 ### Arguments
 
 `TOPDIR` is a required positional argument which should point to the top-level directory of the
@@ -62,7 +58,7 @@ parse, each of which can be overidden with options `-c`, `-l` and `-t`.
 * `-s` specify a SoC identifier for OT platforms with mulitple SoCs
 
 * `-T` specify the OpenTitan _top_ name, such as `Darjeeling`, `EarlGrey`, ... This option is
-  case-insensitive.
+  mandatory.
 
 * `-t` alternative path to the `top_<top>.gen.hjson` file
 
@@ -72,5 +68,5 @@ parse, each of which can be overidden with options `-c`, `-l` and `-t`.
 ### Examples
 
 ````sh
-./scripts/opentitan/cfggen.py ../opentitan-integrated -o opentitan.cfg
+./scripts/opentitan/cfggen.py ../opentitan -T EarlGrey -o opentitan.cfg
 ````

scripts/opentitan/cfggen.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 
 # Copyright (c) 2024 Rivos, Inc.
+# Copyright (c) 2025 lowRISC contributors.
 # SPDX-License-Identifier: Apache2
 
 """OpenTitan QEMU configuration file generator.
@@ -223,17 +224,20 @@ def _generate_life_cycle(self, cfg: ConfigParser,
 def main():
     """Main routine"""
     debug = True
-    default_top = 'Darjeeling'
+    top_map = {
+        'Darjeeling': 'dj',
+        'EarlGrey': 'eg',
+    }
     try:
         desc = sys.modules[__name__].__doc__.split('.', 1)[0].strip()
         argparser = ArgumentParser(description=f'{desc}.')
         files = argparser.add_argument_group(title='Files')
         files.add_argument('opentitan', nargs=1, metavar='TOPDIR',
                            help='OpenTitan top directory')
+        files.add_argument('-T', '--top', choices=top_map.keys(), required=True,
+                           help='OpenTitan top name')
         files.add_argument('-o', '--out', metavar='CFG',
                            help='Filename of the config file to generate')
-        files.add_argument('-T', '--top', default=default_top,
-                           help=f'OpenTitan Top name (default: {default_top})')
         files.add_argument('-c', '--otpconst', metavar='SV',
                            help='OTP Constant SV file (default: auto)')
         files.add_argument('-l', '--lifecycle', metavar='SV',
@@ -263,13 +267,9 @@ def main():
         if not isdir(topdir):
             argparser.error('Invalid OpenTitan top directory')
         ot_dir = normpath(topdir)
-        top = f'top_{args.top.lower()}'
-        if args.top.lower() != default_top.lower():
-            var = ''.join(w[0]
-                          for w in camel_to_snake_case(args.top).split('_'))
-        else:
-            var = 'dj'
-
+        ltop = args.top.lower()
+        top = f'top_{ltop}'
+        var = top_map[args.top]
         if not args.topcfg:
             cfgpath = joinpath(ot_dir, f'hw/{top}/data/autogen/{top}.gen.hjson')
         else: