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| 1 #!/usr/bin/python | |
| 2 | |
| 3 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved. | |
| 4 # Use of this source code is governed by a BSD-style license that can be | |
| 5 # found in the LICENSE file. | |
| 6 | |
| 7 """A script to manipulate ChromeOS CMOS reboot Field. | |
| 8 | |
| 9 A few bits in a byte in CMOS (called RDB, short for 'Reboot Data Byte' | |
| 10 hereafter) are dedicated to information exchange between Linux and BIOS. | |
| 11 | |
| 12 The CMOS contents are available through /dev/nvrom. The location of RDB is | |
| 13 reported by BIOS through ACPI. The few bits in RDB operated on by this script | |
| 14 are defined in the all_mode_fields dictionary below along with their | |
| 15 functions. | |
| 16 | |
| 17 When invoked without parameters this script prints values of the fields. When | |
| 18 invoked with any of the bit field names as parameter(s), the script sets the | |
| 19 bit(s) as required. | |
| 20 | |
| 21 Additional parameters allow to specify alternative ACPI and NVRAM files for | |
| 22 testing. | |
| 23 """ | |
| 24 | |
| 25 __author__ = 'The Chromium OS Authors' | |
| 26 | |
| 27 import optparse | |
| 28 import sys | |
| 29 | |
| 30 class RebootModeError(Exception): | |
| 31 pass | |
| 32 | |
| 33 # global variables | |
| 34 parser = optparse.OptionParser() | |
| 35 acpi_file = '/sys/devices/platform/chromeos_acpi/CHNV' | |
| 36 nvram_file = '/dev/nvram' | |
| 37 | |
| 38 # Offset of RDB in NVRAM | |
| 39 rdb_offset = 0 | |
| 40 | |
| 41 # NVRAM contents read on startup | |
| 42 rdb_value = '' | |
| 43 | |
| 44 # All bitfields in RDB this script provides access to. Field names prepended | |
| 45 # by `--' become this script's command line options | |
| 46 all_mode_fields = { | |
| 47 'recovery' : 0x80, | |
| 48 'debug_reset' : 0x40, | |
| 49 'try_firmware_b': 0x20 | |
| 50 } | |
| 51 | |
| 52 # A dictionary of fields to be updated as requested by the command line | |
| 53 # parameters | |
| 54 fields_to_set = {} | |
| 55 | |
| 56 | |
| 57 def OptionHandler(option, opt_str, value, p): | |
| 58 """Process bit field name command line parameter. | |
| 59 | |
| 60 Verifies that the value is in range (0 or 1) and adds the appropriate | |
| 61 element to fields_to_set dictionary. Should the same field specified in the | |
| 62 command line more than once, only the last value will be used. | |
| 63 | |
| 64 Raises: | |
| 65 RebootModeError in case the parameter value is out of range. | |
| 66 """ | |
| 67 | |
| 68 global fields_to_set | |
| 69 key = opt_str[2:] | |
| 70 if value < 0 or value > 1: | |
| 71 raise RebootModeError('--%s should be either 0 or 1' % key) | |
| 72 | |
| 73 fields_to_set[key] = value | |
| 74 | |
| 75 | |
| 76 def PrepareOptions(): | |
| 77 global parser | |
| 78 for field in all_mode_fields: | |
| 79 parser.add_option('--' + field, action='callback', type='int', | |
| 80 callback=OptionHandler) | |
| 81 parser.add_option('--acpi_file', dest='acpi_file') | |
| 82 parser.add_option('--nvram_file', dest='nvram_file') | |
| 83 | |
| 84 | |
| 85 def ParseOptions(): | |
| 86 global acpi_file | |
| 87 global nvram_file | |
| 88 (opts, args) = parser.parse_args() | |
| 89 | |
| 90 if opts.acpi_file is not None: | |
| 91 acpi_file = opts.acpi_file | |
| 92 | |
| 93 if opts.nvram_file is not None: | |
| 94 nvram_file = opts.nvram_file | |
| 95 | |
| 96 | |
| 97 def GetRDBOffset(): | |
| 98 global rdb_offset | |
| 99 try: | |
| 100 f = open(acpi_file, 'r') | |
| 101 rdb_offset = int(f.read()) | |
| 102 f.close() | |
| 103 except IOError, e: | |
| 104 raise RebootModeError('Trying to read %s got this: %s' % (acpi_file, e)) | |
| 105 except ValueError: | |
| 106 raise RebootModeError('%s contents are corrupted' % acpi_file) | |
| 107 | |
| 108 | |
| 109 def ReadNvram(): | |
| 110 global rdb_value | |
| 111 try: | |
| 112 f = open(nvram_file, 'rb') | |
| 113 f.seek(rdb_offset) | |
| 114 rdb_value = ord(f.read(1)[0]) | |
| 115 f.close() | |
| 116 except IOError, e: | |
| 117 if e[0] == 2: | |
| 118 raise RebootModeError( | |
| 119 '%s does not exist. Is nvram module installed?' % nvram_file) | |
| 120 if e[0] == 13: | |
| 121 raise RebootModeError('Access to %s denied. Are you root?' % nvram_file) | |
| 122 raise RebootModeError(e[1]) | |
| 123 except IndexError, e: | |
| 124 raise RebootModeError('Failed reading mode byte from %s' % nvram_file) | |
| 125 | |
| 126 | |
| 127 def PrintCurrentMode(): | |
| 128 print 'Current reboot mode settings:' | |
| 129 for (field, mask) in all_mode_fields.iteritems(): | |
| 130 print '%-15s: %d' % (field, int(not not (rdb_value & mask))) | |
| 131 | |
| 132 | |
| 133 def SetNewMode(): | |
| 134 new_mode = 0 | |
| 135 updated_bits_mask = 0 | |
| 136 | |
| 137 for (opt, value) in fields_to_set.iteritems(): | |
| 138 mask = all_mode_fields[opt] | |
| 139 if value: | |
| 140 new_mode |= mask | |
| 141 updated_bits_mask |= mask | |
| 142 | |
| 143 if (rdb_value & updated_bits_mask) == new_mode: | |
| 144 print 'No update required' | |
| 145 return | |
| 146 | |
| 147 f = open(nvram_file, 'rb+') | |
| 148 f.seek(rdb_offset) | |
| 149 new_mode |= (rdb_value & ~updated_bits_mask) | |
| 150 f.write('%c' % new_mode) | |
| 151 f.close() | |
| 152 | |
| 153 | |
| 154 def DoRebootMode(): | |
| 155 PrepareOptions() | |
| 156 ParseOptions() | |
| 157 GetRDBOffset() | |
| 158 ReadNvram() | |
| 159 if fields_to_set: | |
| 160 SetNewMode() | |
| 161 else: | |
| 162 PrintCurrentMode() | |
| 163 | |
| 164 | |
| 165 if __name__ == '__main__': | |
| 166 try: | |
| 167 DoRebootMode() | |
| 168 except RebootModeError, e: | |
| 169 print >> sys.stderr, '%s: %s' % (sys.argv[0].split('/')[-1], e) | |
| 170 sys.exit(1) | |
| 171 sys.exit(0) | |
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Chromium Code Reviews
Issue 2656004:
add c++ version of the firmware utilities (Closed)
Base URL: ssh://gitrw.chromium.org/firmware-utils.git