mec1322: Update pack script

This includes:
  - Reference to the boot ROM document
  - Update flags usage from the document
  - Command line argument support

BUG=chrome-os-partner:24107, chrome-os-partner:24188
TEST=Pack and boot
BRANCH=None

Change-Id: I6f79ca94fbc10448e3a1c884a2d52fdf4abf266d
Signed-off-by: Vic (Chun-Ju) Yang <victoryang@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/180180
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

1 files changed, 77 insertions, 39 deletions

diff --git a/chip/mec1322/util/pack_ec.py b/chip/mec1322/util/pack_ec.py
index 6039b3c10b..46aebe5564 100755
--- a/chip/mec1322/util/pack_ec.py
+++ b/chip/mec1322/util/pack_ec.py
@@ -5,30 +5,19 @@
 # found in the LICENSE file.
 
 # A script to pack EC binary into SPI flash image for MEC1322
+# Based on MEC1322_ROM_Doc_Rev0.5.pdf.
 
-# TODO(crosbug.com/p/24107): Add reference to document on image format.
-
+import argparse
 import hashlib
 import os
 import struct
 import subprocess
 import tempfile
 
-# TODO(crosbug.com/p/24188): Make these options available as command line
-#                            arguments.
-SPI_SIZE = 4 * 1024 * 1024
-HEADER_PEM_FILE = 'rsakey_sign_header.pem'
-PAYLOAD_PEM_FILE = 'rsakey_sign_payload.pem'
-PAYLOAD_FILE = 'ec.bin' # Set to 'ec.RO.flat' for RO-only image
-HEADER_LOCATION = 0x170000
-HEADER_FLAG1 = 0x00
-HEADER_FLAG2 = 0x01
-SPI_READ_CMD = 0x01
 LOAD_ADDR = 0x100000
-SPI_CHIP_SELECT = 0
 HEADER_SIZE = 0x140
-PAYLOAD_OFFSET = 0x240
-OUTPUT_FILE = 'ec.4mb.bin'
+SPI_CLOCK_LIST = [48, 24, 12, 8]
+SPI_READ_CMD_LIST = [0x3, 0xb, 0x3b]
 
 CRC_TABLE = [0x00, 0x07, 0x0e, 0x09, 0x1c, 0x1b, 0x12, 0x15,
              0x38, 0x3f, 0x36, 0x31, 0x24, 0x23, 0x2a, 0x2d]
@@ -77,20 +66,35 @@ def GetPublicKey(pem_file):
                                   modulus_raw[0:256])))
   return struct.pack('<Q', exp), modulus
 
+def GetSpiClockParameter(args):
+  assert args.spi_clock in SPI_CLOCK_LIST, \
+         "Unsupported SPI clock speed %d MHz" % args.spi_clock
+  return SPI_CLOCK_LIST.index(args.spi_clock)
+
+def GetSpiReadCmdParameter(args):
+  assert args.spi_read_cmd in SPI_READ_CMD_LIST, \
+         "Unsupported SPI read command 0x%x" % args.spi_read_cmd
+  return SPI_READ_CMD_LIST.index(args.spi_read_cmd)
+
 def PadZeroTo(data, size):
   data.extend('\0' * (size - len(data)))
 
-def BuildHeader(payload_len):
+def BuildHeader(args, payload_len):
+  # Identifier and header version
   header = bytearray(['C', 'S', 'M', 'S', '\0'])
-  header.extend([HEADER_FLAG1, HEADER_FLAG2, SPI_READ_CMD])
+
+  PadZeroTo(header, 0x6)
+  header.append(GetSpiClockParameter(args))
+  header.append(GetSpiReadCmdParameter(args))
+
   header.extend(struct.pack('<I', LOAD_ADDR))
-  header.extend(struct.pack('<I', GetEntryPoint(PAYLOAD_FILE)))
+  header.extend(struct.pack('<I', GetEntryPoint(args.input)))
   header.append((payload_len >> 6) & 0xff)
   header.append((payload_len >> 14) & 0xff)
   PadZeroTo(header, 0x14)
-  header.extend(struct.pack('<I', PAYLOAD_OFFSET))
+  header.extend(struct.pack('<I', args.payload_offset))
 
-  exp, modulus = GetPublicKey(PAYLOAD_PEM_FILE)
+  exp, modulus = GetPublicKey(args.payload_key)
   PadZeroTo(header, 0x20)
   header.extend(exp)
   PadZeroTo(header, 0x30)
@@ -114,36 +118,70 @@ def SignByteArray(data, pem_file):
     signed.reverse()
     return bytearray(''.join(signed))
 
-def BuildTag(header_loc):
-  tag = bytearray([(header_loc >> 8) & 0xff,
-                   (header_loc >> 16) & 0xff,
-                   (header_loc >> 24) & 0xff])
-  if SPI_CHIP_SELECT != 0:
+def BuildTag(args):
+  tag = bytearray([(args.header_loc >> 8) & 0xff,
+                   (args.header_loc >> 16) & 0xff,
+                   (args.header_loc >> 24) & 0xff])
+  if args.chip_select != 0:
     tag[2] |= 0x80
   tag.append(Crc8(0, tag))
   return tag
 
 
 def main():
+  parser = argparse.ArgumentParser()
+  parser.add_argument("-i", "--input",
+                      help="EC binary to pack, usually ec.bin or ec.RO.flat.",
+                      metavar="EC_BIN", default="ec.bin")
+  parser.add_argument("-o", "--output",
+                      help="Output flash binary file",
+                      metavar="EC_SPI_FLASH", default="ec.packed.bin")
+  parser.add_argument("--header_key",
+                      help="PEM key file for signing header",
+                      default="rsakey_sign_header.pem")
+  parser.add_argument("--payload_key",
+                      help="PEM key file for signing payload",
+                      default="rsakey_sign_payload.pem")
+  parser.add_argument("-s", "--spi_size", type=int,
+                      help="Size of the SPI flash in MB",
+                      default=4)
+  parser.add_argument("-l", "--header_loc", type=int,
+                      help="Location of header in SPI flash",
+                      default=0x170000)
+  parser.add_argument("-p", "--payload_offset", type=int,
+                      help="The offset of payload from the header",
+                      default=0x240)
+  parser.add_argument("-c", "--chip_select", type=int,
+                      help="Chip select signal to use, either 0 or 1.",
+                      default=0)
+  parser.add_argument("--spi_clock", type=int,
+                      help="SPI clock speed. 8, 12, 24, or 48 MHz.",
+                      default=24)
+  parser.add_argument("--spi_read_cmd", type=int,
+                      help="SPI read command. 0x3, 0xB, or 0x3B.",
+                      default=0xb)
+  args = parser.parse_args()
+
+  spi_size = args.spi_size * 1024 * 1024
   spi_list = []
 
-  payload = GetPayload(PAYLOAD_FILE)
+  payload = GetPayload(args.input)
   payload_len = len(payload)
-  payload_signature = SignByteArray(payload, PAYLOAD_PEM_FILE)
-  header = BuildHeader(payload_len)
-  header_signature = SignByteArray(header, HEADER_PEM_FILE)
-  tag = BuildTag(HEADER_LOCATION)
-
-  spi_list.append((HEADER_LOCATION, header))
-  spi_list.append((HEADER_LOCATION + HEADER_SIZE, header_signature))
-  spi_list.append((HEADER_LOCATION + PAYLOAD_OFFSET, payload))
-  spi_list.append((HEADER_LOCATION + PAYLOAD_OFFSET + payload_len,
+  payload_signature = SignByteArray(payload, args.payload_key)
+  header = BuildHeader(args, payload_len)
+  header_signature = SignByteArray(header, args.header_key)
+  tag = BuildTag(args)
+
+  spi_list.append((args.header_loc, header))
+  spi_list.append((args.header_loc + HEADER_SIZE, header_signature))
+  spi_list.append((args.header_loc + args.payload_offset, payload))
+  spi_list.append((args.header_loc + args.payload_offset + payload_len,
                    payload_signature))
-  spi_list.append((SPI_SIZE - 256, tag))
+  spi_list.append((spi_size - 256, tag))
 
   spi_list = sorted(spi_list)
 
-  with open(OUTPUT_FILE, 'wb') as f:
+  with open(args.output, 'wb') as f:
     addr = 0
     for s in spi_list:
       assert addr <= s[0]
@@ -152,8 +190,8 @@ def main():
         addr = s[0]
       f.write(s[1])
       addr += len(s[1])
-    if addr < SPI_SIZE:
-      f.write('\xff' * (SPI_SIZE - addr))
+    if addr < spi_size:
+      f.write('\xff' * (spi_size - addr))
 
 if __name__ == '__main__':
   main()