decoders/ds2432/pd.py

   1 ##
   2 ## This file is part of the libsigrokdecode project.
   3 ##
   4 ## Copyright (C) 2017 Kevin Redon <kingkevin@cuvoodoo.info>
   5 ##
   6 ## This program is free software; you can redistribute it and/or modify
   7 ## it under the terms of the GNU General Public License as published by
   8 ## the Free Software Foundation; either version 2 of the License, or
   9 ## (at your option) any later version.
  10 ##
  11 ## This program is distributed in the hope that it will be useful,
  12 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ## GNU General Public License for more details.
  15 ##
  16 ## You should have received a copy of the GNU General Public License
  17 ## along with this program; if not, see <http://www.gnu.org/licenses/>.
  18 ##
  19
  20 import sigrokdecode as srd
  21
  22 # Dictionary of FUNCTION commands and their names.
  23 commands = {
  24     0x0f: 'Write scratchpad',
  25     0xaa: 'Read scratchpad',
  26     0x55: 'Copy scratchpad',
  27     0xf0: 'Read memory',
  28     0x5a: 'Load first secret',
  29     0x33: 'Compute next secret',
  30     0xa5: 'Read authenticated page',
  31 }
  32
  33 # Maxim DS2432 family code, present at the end of the ROM code.
  34 family_code = 0x33
  35
  36 # Calculate the CRC-16 checksum.
  37 # Initial value: 0x0000, xor-in: 0x0000, polynom 0x8005, xor-out: 0xffff.
  38 def crc16(byte_array):
  39     reverse = 0xa001 # Use the reverse polynom to make algo simpler.
  40     crc = 0x0000 # Initial value.
  41     # Reverse CRC calculation.
  42     for byte in byte_array:
  43         for bit in range(8):
  44             if (byte ^ crc) & 1:
  45                 crc = (crc >> 1) ^ reverse
  46             else:
  47                 crc >>= 1
  48             byte >>= 1
  49     crc ^= 0xffff # Invert CRC.
  50     return crc
  51
  52 class Decoder(srd.Decoder):
  53     api_version = 3
  54     id = 'ds2432'
  55     name = 'DS2432'
  56     longname = 'Maxim DS2432 1-Wire 1k-Bit Protected EEPROM with SHA-1 Engine'
  57     desc = '1-Wire 1k-Bit Protected EEPROM with SHA-1 Engine.'
  58     license = 'gplv2+'
  59     inputs = ['onewire_network']
  60     outputs = ['ds2432']
  61     annotations = (
  62         ('text', 'Human-readable text'),
  63     )
  64
  65     def __init__(self):
  66         # Bytes for function command.
  67         self.bytes = []
  68
  69     def start(self):
  70         self.out_ann = self.register(srd.OUTPUT_ANN)
  71
  72     def putx(self, data):
  73         self.put(self.ss, self.es, self.out_ann, data)
  74
  75     def decode(self, ss, es, data):
  76         code, val = data
  77
  78         if code == 'RESET/PRESENCE':
  79             self.ss, self.es = ss, es
  80             self.putx([0, ['Reset/presence: %s'
  81                            % ('true' if val else 'false')]])
  82             self.bytes = []
  83         elif code == 'ROM':
  84             self.ss, self.es = ss, es
  85             self.putx([0, ['ROM: 0x%016x (family code %s to 0x%02x)'
  86                            % (val, 'matches' if family_code == (val & 0xff)
  87                                else 'does not match', family_code),
  88                            'ROM: 0x%016x (family code %s)'
  89                            % (val, 'match' if family_code == (val & 0xff)
  90                                else 'mismatch')]])
  91             self.bytes = []
  92         elif code == 'DATA':
  93             self.bytes.append(val)
  94             if 1 == len(self.bytes):
  95                 self.ss, self.es = ss, es
  96                 if val not in commands:
  97                     self.putx([0, ['Unrecognized command: 0x%02x' % val]])
  98                 else:
  99                     self.putx([0, ['Function command: %s (0x%02x)'
 100                                    % (commands[val], val)]])
 101             elif 0x0f == self.bytes[0]: # Write scratchpad
 102                 if 2 == len(self.bytes):
 103                     self.ss = ss
 104                 elif 3 == len(self.bytes):
 105                     self.es = es
 106                     self.putx([0, ['Target address: 0x%04x'
 107                                    % ((self.bytes[2] << 8) + self.bytes[1])]])
 108                 elif 4 == len(self.bytes):
 109                     self.ss = ss
 110                 elif 11 == len(self.bytes):
 111                     self.es = es
 112                     self.putx([0, ['Data: ' + (','.join(format(n, '#04x')
 113                                        for n in self.bytes[3:11]))]])
 114                 elif 12 == len(self.bytes):
 115                     self.ss = ss
 116                 elif 13 == len(self.bytes):
 117                     self.es = es
 118                     self.putx([0, ['CRC: '
 119                         + ('ok' if crc16(self.bytes[0:11]) == (self.bytes[11]
 120                         + (self.bytes[12] << 8)) else 'error')]])
 121             elif 0xaa == self.bytes[0]: # Read scratchpad
 122                 if 2 == len(self.bytes):
 123                     self.ss = ss
 124                 elif 3 == len(self.bytes):
 125                     self.es = es
 126                     self.putx([0, ['Target address: 0x%04x'
 127                                    % ((self.bytes[2] << 8) + self.bytes[1])]])
 128                 elif 4 == len(self.bytes):
 129                     self.ss, self.es = ss, es
 130                     self.putx([0, ['Data status (E/S): 0x%02x'
 131                                    % (self.bytes[3])]])
 132                 elif 5 == len(self.bytes):
 133                     self.ss = ss
 134                 elif 12 == len(self.bytes):
 135                     self.es = es
 136                     self.putx([0, ['Data: ' + (','.join(format(n, '#04x')
 137                                        for n in self.bytes[4:12]))]])
 138                 elif 13 == len(self.bytes):
 139                     self.ss = ss
 140                 elif 14 == len(self.bytes):
 141                     self.es = es
 142                     self.putx([0, ['CRC: '
 143                         + ('ok' if crc16(self.bytes[0:12]) == (self.bytes[12]
 144                         + (self.bytes[13] << 8)) else 'error')]])
 145             elif 0x5a == self.bytes[0]: # Load first secret
 146                 if 2 == len(self.bytes):
 147                     self.ss = ss
 148                 elif 4 == len(self.bytes):
 149                     self.es = es
 150                     self.putx([0, ['Authorization pattern (TA1, TA2, E/S): '
 151                         + (','.join(format(n, '#04x')
 152                             for n in self.bytes[1:4]))]])
 153                 elif 4 < len(self.bytes):
 154                     self.ss, self.es = ss, es
 155                     if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
 156                         self.putx([0, ['End of operation']])
 157             elif 0x33 == self.bytes[0]: # Compute next secret
 158                 if 2 == len(self.bytes):
 159                     self.ss = ss
 160                 elif 3 == len(self.bytes):
 161                     self.es = es
 162                     self.putx([0, ['Target address: 0x%04x'
 163                                    % ((self.bytes[2] << 8) + self.bytes[1])]])
 164                 elif 3 < len(self.bytes):
 165                     self.ss, self.es = ss, es
 166                     if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
 167                         self.putx([0, ['End of operation']])
 168             elif 0x55 == self.bytes[0]: # Copy scratchpad
 169                 if 2 == len(self.bytes):
 170                     self.ss = ss
 171                 elif 4 == len(self.bytes):
 172                     self.es = es
 173                     self.putx([0, ['Authorization pattern (TA1, TA2, E/S): '
 174                         + (','.join(format(n, '#04x')
 175                             for n in self.bytes[1:4]))]])
 176                 elif 5 == len(self.bytes):
 177                     self.ss = ss
 178                 elif 24 == len(self.bytes):
 179                     self.es = es
 180                     self.putx([0, ['Message authentication code: '
 181                                    + (','.join(format(n, '#04x')
 182                                        for n in self.bytes[4:24])),
 183                                    'MAC: '
 184                                    + (','.join(format(n, '#04x')
 185                                        for n in self.bytes[4:24])),
 186                                    ]])
 187                 elif 24 < len(self.bytes):
 188                     self.ss, self.es = ss, es
 189                     if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
 190                         self.putx([0, ['Operation succeeded']])
 191                     elif (0 == self.bytes[-1]):
 192                         self.putx([0, ['Operation failed']])
 193             elif 0xa5 == self.bytes[0]: # Read authenticated page
 194                 if 2 == len(self.bytes):
 195                     self.ss = ss
 196                 elif 3 == len(self.bytes):
 197                     self.es = es
 198                     self.putx([0, ['Target address: 0x%04x'
 199                                    % ((self.bytes[2] << 8) + self.bytes[1])]])
 200                 elif 4 == len(self.bytes):
 201                     self.ss = ss
 202                 elif 35 == len(self.bytes):
 203                     self.es = es
 204                     self.putx([0, ['Data: ' + (','.join(format(n, '#04x')
 205                                        for n in self.bytes[3:35]))]])
 206                 elif 36 == len(self.bytes):
 207                     self.ss, self.es = ss, es
 208                     self.putx([0, ['Padding: '
 209                         + ('ok' if 0xff == self.bytes[-1] else 'error')]])
 210                 elif 37 == len(self.bytes):
 211                     self.ss = ss
 212                 elif 38 == len(self.bytes):
 213                     self.es = es
 214                     self.putx([0, ['CRC: '
 215                         + ('ok' if crc16(self.bytes[0:36]) == (self.bytes[36]
 216                         + (self.bytes[37] << 8)) else 'error')]])
 217                 elif 39 == len(self.bytes):
 218                     self.ss = ss
 219                 elif 58 == len(self.bytes):
 220                     self.es = es
 221                     self.putx([0, ['Message authentication code: '
 222                                    + (','.join(format(n, '#04x')
 223                                        for n in self.bytes[38:58])),
 224                                    'MAC: '
 225                                    + (','.join(format(n, '#04x')
 226                                        for n in self.bytes[38:58])),
 227                                    ]])
 228                 elif 59 == len(self.bytes):
 229                     self.ss = ss
 230                 elif 60 == len(self.bytes):
 231                     self.es = es
 232                     self.putx([0, ['MAC CRC: '
 233                         + ('ok' if crc16(self.bytes[38:58]) == (self.bytes[58]
 234                         + (self.bytes[59] << 8)) else 'error')]])
 235                 elif 60 < len(self.bytes):
 236                     self.ss, self.es = ss, es
 237                     if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
 238                         self.putx([0, ['Operation completed']])
 239             elif 0xf0 == self.bytes[0]: # Read memory
 240                 if 2 == len(self.bytes):
 241                     self.ss = ss
 242                 elif 3 == len(self.bytes):
 243                     self.es = es
 244                     self.putx([0, ['Target address: 0x%04x'
 245                                    % ((self.bytes[2] << 8) + self.bytes[1])]])
 246                 elif 3 < len(self.bytes):
 247                     self.ss, self.es = ss, es
 248                     self.putx([0, ['Data: 0x%02x' % (self.bytes[-1])]])