hatch: automate creating a new variant in coreboot

To create a new variant of the hatch baseboard, we need to
add the variant's GBB_HWID and other information to Kconfig
and Kconfig.name, and set up a skeletal build based on the
hatch baseboard.

BUG=b:140261109
BRANCH=none
TEST=``./create_coreboot_variant.sh sushi && git show``
Kconfig will have three new lines for the SUSHI variant, and
Kconfig.name will have an entirely new section.
New files created are:
variants/sushi/Makefile.inc
variants/sushi/overridetree.cb
variants/sushi/include/ec.h
variants/sushi/include/gpio.h
variants/sushi/include/variant/acpi/dptf.asl

Also run the script with an existing board name to verify that you
can't create a variant that already exists.

Change-Id: I1a5b9c8735faafebb2e4e384cb3346867d64c556
Signed-off-by: Paul Fagerburg <pfagerburg@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35239
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

util/mainboard/google/hatch/kconfig.py

@@ -0,0 +1,156 @@
+#!/usr/bin/python3
+"""Add a new variant to the Kconfig and Kconfig.name for the baseboard
+
+To start a new variant of an existing baseboard, we need to add
+the variant into the Kconfig and Kconfig.name files for the
+baseboard. In Kconfig, we have three sections that need additional
+entries, GBB_HWID, MAINBOARD_PART_NUMBER, and VARIANT_DIR.
+
+In GBB_HWID, we need to add a HWID that includes a numeric suffix.
+The numeric suffix is the CRC-32 of the all-caps ASCII name,
+modulo 10000.
+For example, if the board name is "Fizz", we calculate the CRC of
+"FIZZ TEST", which is 0x598C492D. In decimal, the value is 1502365997,
+modulo 10000 is 5997. So the HWID string is "FIZZ TEST 5997"
+In the past, we have used an online CRC-32 calculator such as
+https://www.lammertbies.nl/comm/info/crc-calculation.html, and then
+used the calculator app to convert to decimal and take the last
+4 digits.
+
+The MAINBOARD_PART_NUMBER and VARIANT_DIR are simpler, just using
+various capitalizations of the variant name to create the strings.
+
+Kconfig.name adds an entire section for the new variant, and all
+of these use various capitalizations of the variant name. The strings
+in this section are SOC-specific, so we'll need versions for each
+SOC that we support.
+
+Copyright 2019 Google LLC.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; version 2 of the License.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+"""
+
+import argparse
+import zlib
+
+
+def main():
+  parser = argparse.ArgumentParser(
+    description="Add strings to coreboot Kconfig for a new board variant")
+  parser.add_argument('--name', type=str, required=True,
+    help='Name of the board variant')
+  args = parser.parse_args()
+
+  add_to_Kconfig(args.name)
+  add_to_Kconfig_name(args.name)
+
+
+def get_gbb_hwid(variant_name):
+  """Create the GBB_HWID for a variant
+
+  variant_name    The name of the board variant, e.g. 'kohaku'
+
+  Returns:
+    GBB_HWID string for the board variant, e.g. 'KOHAKU TEST 1953'
+
+  Note that the case of the variant name does not matter; it gets
+  converted to all uppercase as part of this function."""
+  hwid = variant_name + ' test'
+  upperhwid = hwid.upper()
+  suffix = zlib.crc32(upperhwid.encode('UTF-8')) % 10000
+  gbb_hwid = upperhwid + ' ' + str(suffix).zfill(4)
+  return gbb_hwid
+
+
+def add_to_Kconfig(variant_name):
+  """Add options for the variant to the Kconfig
+
+  Open the Kconfig file and read it line-by-line. When we detect that we're
+  in one of the sections of interest, wait until we get a blank line
+  (signalling the end of that section), and then add our new line before
+  the blank line. The updated lines are written out to Kconfig.new in the
+  same directory as Kconfig.
+
+  variant_name    The name of the board variant, e.g. 'kohaku'"""
+  # These are the part of the strings that we'll add to the sections
+  BOARD = 'BOARD_GOOGLE_' + variant_name.upper()
+  gbb_hwid = get_gbb_hwid(variant_name)
+  lowercase = variant_name.lower()
+  capitalized = lowercase.capitalize()
+
+  # These flags track whether we're in a section where we need to add an option
+  in_gbb_hwid = False
+  in_mainboard_part_number = False
+  in_variant_dir = False
+
+  inputname = 'Kconfig'
+  outputname = 'Kconfig.new'
+  with open(outputname, 'w') as outfile:
+    with open(inputname, 'r') as infile:
+      for rawline in infile:
+        line = rawline.rstrip('\r\n')
+
+        # Are we in one of the sections of interest?
+        if line == 'config GBB_HWID':
+          in_gbb_hwid = True
+        if line == 'config MAINBOARD_PART_NUMBER':
+          in_mainboard_part_number = True
+        if line == 'config VARIANT_DIR':
+          in_variant_dir = True
+
+        # Are we at the end of a section, and if so, is it one of the
+        # sections of interest?
+        if line == '':
+          if in_gbb_hwid:
+            print('\tdefault "' + gbb_hwid + '" if ' + BOARD, file=outfile)
+            in_gbb_hwid = False
+          if in_mainboard_part_number:
+            print('\tdefault "' + capitalized + '" if ' + BOARD, file=outfile)
+            in_mainboard_part_number = False
+          if in_variant_dir:
+            print('\tdefault "' + lowercase + '" if ' + BOARD, file=outfile)
+            in_variant_dir = False
+
+        print(line, file=outfile)
+
+
+def add_to_Kconfig_name(variant_name):
+  """Add a config section for the variant to the Kconfig.name
+
+  Kconfig.name is easier to modify than Kconfig; it only has a block at
+  the end with the new variant's details.
+
+  config BOARD_GOOGLE_${VARIANT}
+
+  variant_name    The name of the board variant, e.g. 'kohaku'"""
+  # Board name for the config section
+  uppercase = variant_name.upper()
+  BOARD = 'BOARD_GOOGLE_' + uppercase
+  capitalized = variant_name.lower().capitalize()
+
+  inputname = 'Kconfig.name'
+  outputname = 'Kconfig.name.new'
+  with open(outputname, 'w') as outfile:
+    with open(inputname, 'r') as infile:
+      # Copy all input lines to output
+      for rawline in infile:
+        line = rawline.rstrip('\r\n')
+        print(line, file=outfile)
+
+      # Now add the new section
+      print('\nconfig ' + BOARD, file=outfile)
+      print('\tbool "-> ' + capitalized + '"', file=outfile)
+      print('\tselect BOARD_GOOGLE_BASEBOARD_HATCH', file=outfile)
+      print('\tselect BOARD_ROMSIZE_KB_16384', file=outfile)
+      print('\tselect SOC_INTEL_COMETLAKE', file=outfile)
+
+
+if __name__ == '__main__':
+  main()