biod: Add fptool.py that will replace flash_fp_mcu

This is similar to gsctool, but this tool would only be in the
test image.

This comes from the effort to move away from shell script.
See http://go/deshell.

The idea is that you start with a simple wrapper for the given shell
script. Over time, features are transplanted or added-new to the python
wrapper, until the shell script is no longer needed.

BRANCH=none
BUG=b:172020576
TEST=./util/fptool.py
     ./util/fptool.py --help
     ./util/fptool.py flash --help
     ./util/fptool.py flash
     # Error about flash_fp_mcu not existing
TEST=scp util/fptool.py $DUT:/usr/local/bin
     ssh $DUT fptool.py flash /root/doesnotexist
     ssh $DUT fptool.py flash
     ssh $DUT fptool.py flash /opt/google/biod/fw/$(cros_config /fingerprint board)*.bin

Change-Id: I8774bda4a057ee09f70bf474ce3ba2fa0bbcf92d
Signed-off-by: Craig Hesling <hesling@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3060744
Reviewed-by: Josie Nordrum <josienordrum@google.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/util/fptool.py b/util/fptool.py
new file mode 100755
index 0000000000..9c59c1014c
--- /dev/null
+++ b/util/fptool.py
@@ -0,0 +1,56 @@
+#!/usr/bin/env python3
+# Copyright 2021 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""A tool to manage the fingerprint system on Chrome OS."""
+
+import argparse
+import os
+import shutil
+import subprocess
+import sys
+
+
+def cmd_flash(args: argparse.Namespace) -> int:
+    """
+    Flash the entire firmware FPMCU using the native bootloader.
+
+    This requires the Chromebook to be in dev mode with hardware write protect
+    disabled.
+    """
+
+    if not shutil.which('flash_fp_mcu'):
+        print('Error - The flash_fp_mcu utility does not exist.')
+        return 1
+
+    cmd = ['flash_fp_mcu']
+    if args.image:
+        if not os.path.isfile(args.image):
+            print(f'Error - image {args.image} is not a file.')
+            return 1
+        cmd.append(args.image)
+
+    print(f'Running {" ".join(cmd)}.')
+    sys.stdout.flush()
+    p = subprocess.run(cmd)
+    return p.returncode
+
+
+def main(argv: list) -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    subparsers = parser.add_subparsers(dest='subcommand', title='subcommands')
+    # This method of setting required is more compatible with older python.
+    subparsers.required = True
+
+    # Parser for "flash" subcommand.
+    parser_decrypt = subparsers.add_parser('flash', help=cmd_flash.__doc__)
+    parser_decrypt.add_argument(
+        'image', nargs='?', help='Path to the firmware image')
+    parser_decrypt.set_defaults(func=cmd_flash)
+    opts = parser.parse_args(argv)
+    return opts.func(opts)
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv[1:]))