blob: f4f77eacca8f7f3df5da3719c98db6983c4769c2 [file] [log] [blame]
#!/usr/bin/env python
# Copyright 2018 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.
"""Lock/unlock the u-boot console."""
import argparse
import binascii
import logging
import mmap
import os
import struct
SD_PATH = '/dev/mmcblk0'
BOOTDELAY = 'bootdelay'
ENV_OFFSET = 0x200
LOCK = '0'
UNLOCK = '5'
def main():
"""The Main program."""
parser = argparse.ArgumentParser(
description='Lock/unlock the u-boot console',
parser.add_argument('-l', '--lock', dest='lock', action='store_true',
help='lock the u-boot console')
parser.add_argument('-u', '--unlock', dest='unlock', action='store_true',
help='unlock the u-boot console')
parser.add_argument('-v', '--verbose', action='count', dest='verbose',
help='increase message verbosity')
options = parser.parse_args()
verbosity_map = {0: logging.INFO, 1: logging.DEBUG}
verbosity = verbosity_map.get(options.verbose or 0, logging.NOTSET)
log_format = '%(asctime)s %(levelname)s '
if options.verbose > 0:
log_format += '(%(filename)s:%(lineno)d) '
log_format += '%(message)s'
log_config = {'level': verbosity,
'format': log_format}
if options.lock and options.unlock:
logging.error('Lock and unlock at the same time?')
# Mmap the SD card image, for the first 5K area.
# The u-boot environment variables are stored at 0x200, size: 4K.
fd =, os.O_RDWR)
mm = mmap.mmap(fd, 5 * 1024, access=mmap.ACCESS_WRITE)
# Find bootdelay, i.e. how long to wait to skip u-boot console.
pattern = BOOTDELAY + '='
index = mm.find(pattern, ENV_OFFSET)
logging.debug('index found: %d', index)
if index == -1:
logging.error('Pattern %s not found', pattern)
index += len(pattern)
is_changed = False
value = mm[index]
if value not in (LOCK, UNLOCK):
logging.error('The boot_delay value not expected: %r', value)
# Original bootdelay value is 5, meaning unlocked. Change it to 0 for
# locking the console.
logging.debug('original value: %d', int(value))
if options.unlock:
if value != UNLOCK:
mm[index] = UNLOCK'Unlocked the u-boot console')
is_changed = True
else:'Already in unlocked state; nothing to do')
elif options.lock:
if value != LOCK:
mm[index] = LOCK'Locked the u-boot console')
is_changed = True
else:'Already in locked state; nothing to do')
else:'Current lock state: %s',
'locked' if value == LOCK else 'unlocked')
if is_changed:
value = mm[index]
logging.debug('new value: %d', int(value))
# Update the crc32 of the data, starting from the 0x204 to the end
# (0x200+4K), and keep it in 0x200.
crc = binascii.crc32(mm[ENV_OFFSET+4:ENV_OFFSET+4096])
mm[ENV_OFFSET:ENV_OFFSET+4] = struct.pack('<i', crc)
if __name__ == '__main__':