ds2432: Add a Maxim DS2432 protocol decoder.

This fixes (parts of) bug #1019.

2 files changed, 273 insertions, 0 deletions

diff --git a/decoders/ds2432/__init__.py b/decoders/ds2432/__init__.py
new file mode 100644
index 0000000..7664b5b
--- /dev/null
+++ b/decoders/ds2432/__init__.py
@@ -0,0 +1,25 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2017 Kevin Redon <kingkevin@cuvoodoo.info>
+##
+## 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; either version 2 of the License, or
+## (at your option) any later version.
+##
+## 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.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+
+'''
+This decoder stacks on top of the 'onewire_network' PD and decodes the
+Maxim DS2432 (1-Wire 1Kbit protected EEPROM with SHA-1 engine) protocol.
+'''
+
+from .pd import Decoder
diff --git a/decoders/ds2432/pd.py b/decoders/ds2432/pd.py
new file mode 100644
index 0000000..269a23e
--- /dev/null
+++ b/decoders/ds2432/pd.py
@@ -0,0 +1,248 @@
+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2017 Kevin Redon <kingkevin@cuvoodoo.info>
+##
+## 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; either version 2 of the License, or
+## (at your option) any later version.
+##
+## 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.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+
+import sigrokdecode as srd
+
+# Dictionary of FUNCTION commands and their names.
+commands = {
+    0x0f: 'Write scratchpad',
+    0xaa: 'Read scratchpad',
+    0x55: 'Copy scratchpad',
+    0xf0: 'Read memory',
+    0x5a: 'Load first secret',
+    0x33: 'Compute next secret',
+    0xa5: 'Read authenticated page',
+}
+
+# Maxim DS2432 family code, present at the end of the ROM code.
+family_code = 0x33
+
+# Calculate the CRC-16 checksum.
+# Initial value: 0x0000, xor-in: 0x0000, polynom 0x8005, xor-out: 0xffff.
+def crc16(byte_array):
+    reverse = 0xa001 # Use the reverse polynom to make algo simpler.
+    crc = 0x0000 # Initial value.
+    # Reverse CRC calculation.
+    for byte in byte_array:
+        for bit in range(8):
+            if (byte ^ crc) & 1:
+                crc = (crc >> 1) ^ reverse
+            else:
+                crc >>= 1
+            byte >>= 1
+    crc ^= 0xffff # Invert CRC.
+    return crc
+
+class Decoder(srd.Decoder):
+    api_version = 3
+    id = 'ds2432'
+    name = 'DS2432'
+    longname = 'Maxim DS2432 1-Wire 1k-Bit Protected EEPROM with SHA-1 Engine'
+    desc = '1-Wire 1k-Bit Protected EEPROM with SHA-1 Engine.'
+    license = 'gplv2+'
+    inputs = ['onewire_network']
+    outputs = ['ds2432']
+    annotations = (
+        ('text', 'Human-readable text'),
+    )
+
+    def __init__(self):
+        # Bytes for function command.
+        self.bytes = []
+
+    def start(self):
+        self.out_ann = self.register(srd.OUTPUT_ANN)
+
+    def putx(self, data):
+        self.put(self.ss, self.es, self.out_ann, data)
+
+    def decode(self, ss, es, data):
+        code, val = data
+
+        if code == 'RESET/PRESENCE':
+            self.ss, self.es = ss, es
+            self.putx([0, ['Reset/presence: %s'
+                           % ('true' if val else 'false')]])
+            self.bytes = []
+        elif code == 'ROM':
+            self.ss, self.es = ss, es
+            self.putx([0, ['ROM: 0x%016x (family code %s to 0x%02x)'
+                           % (val, 'matches' if family_code == (val & 0xff)
+                               else 'does not match', family_code),
+                           'ROM: 0x%016x (family code %s)'
+                           % (val, 'match' if family_code == (val & 0xff)
+                               else 'mismatch')]])
+            self.bytes = []
+        elif code == 'DATA':
+            self.bytes.append(val)
+            if 1 == len(self.bytes):
+                self.ss, self.es = ss, es
+                if val not in commands:
+                    self.putx([0, ['Unrecognized command: 0x%02x' % val]])
+                else:
+                    self.putx([0, ['Function command: %s (0x%02x)'
+                                   % (commands[val], val)]])
+            elif 0x0f == self.bytes[0]: # Write scratchpad
+                if 2 == len(self.bytes):
+                    self.ss = ss
+                elif 3 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Target address: 0x%04x'
+                                   % ((self.bytes[2] << 8) + self.bytes[1])]])
+                elif 4 == len(self.bytes):
+                    self.ss = ss
+                elif 11 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Data: ' + (','.join(format(n, '#04x')
+                                       for n in self.bytes[3:11]))]])
+                elif 12 == len(self.bytes):
+                    self.ss = ss
+                elif 13 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['CRC: '
+                        + ('ok' if crc16(self.bytes[0:11]) == (self.bytes[11]
+                        + (self.bytes[12] << 8)) else 'error')]])
+            elif 0xaa == self.bytes[0]: # Read scratchpad
+                if 2 == len(self.bytes):
+                    self.ss = ss
+                elif 3 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Target address: 0x%04x'
+                                   % ((self.bytes[2] << 8) + self.bytes[1])]])
+                elif 4 == len(self.bytes):
+                    self.ss, self.es = ss, es
+                    self.putx([0, ['Data status (E/S): 0x%02x'
+                                   % (self.bytes[3])]])
+                elif 5 == len(self.bytes):
+                    self.ss = ss
+                elif 12 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Data: ' + (','.join(format(n, '#04x')
+                                       for n in self.bytes[4:12]))]])
+                elif 13 == len(self.bytes):
+                    self.ss = ss
+                elif 14 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['CRC: '
+                        + ('ok' if crc16(self.bytes[0:12]) == (self.bytes[12]
+                        + (self.bytes[13] << 8)) else 'error')]])
+            elif 0x5a == self.bytes[0]: # Load first secret
+                if 2 == len(self.bytes):
+                    self.ss = ss
+                elif 4 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Authorization pattern (TA1, TA2, E/S): '
+                        + (','.join(format(n, '#04x')
+                            for n in self.bytes[1:4]))]])
+                elif 4 < len(self.bytes):
+                    self.ss, self.es = ss, es
+                    if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
+                        self.putx([0, ['End of operation']])
+            elif 0x33 == self.bytes[0]: # Compute next secret
+                if 2 == len(self.bytes):
+                    self.ss = ss
+                elif 3 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Target address: 0x%04x'
+                                   % ((self.bytes[2] << 8) + self.bytes[1])]])
+                elif 3 < len(self.bytes):
+                    self.ss, self.es = ss, es
+                    if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
+                        self.putx([0, ['End of operation']])
+            elif 0x55 == self.bytes[0]: # Copy scratchpad
+                if 2 == len(self.bytes):
+                    self.ss = ss
+                elif 4 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Authorization pattern (TA1, TA2, E/S): '
+                        + (','.join(format(n, '#04x')
+                            for n in self.bytes[1:4]))]])
+                elif 5 == len(self.bytes):
+                    self.ss = ss
+                elif 24 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Message authentication code: '
+                                   + (','.join(format(n, '#04x')
+                                       for n in self.bytes[4:24])),
+                                   'MAC: '
+                                   + (','.join(format(n, '#04x')
+                                       for n in self.bytes[4:24])),
+                                   ]])
+                elif 24 < len(self.bytes):
+                    self.ss, self.es = ss, es
+                    if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
+                        self.putx([0, ['Operation succeeded']])
+                    elif (0 == self.bytes[-1]):
+                        self.putx([0, ['Operation failed']])
+            elif 0xa5 == self.bytes[0]: # Read authenticated page
+                if 2 == len(self.bytes):
+                    self.ss = ss
+                elif 3 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Target address: 0x%04x'
+                                   % ((self.bytes[2] << 8) + self.bytes[1])]])
+                elif 4 == len(self.bytes):
+                    self.ss = ss
+                elif 35 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Data: ' + (','.join(format(n, '#04x')
+                                       for n in self.bytes[3:35]))]])
+                elif 36 == len(self.bytes):
+                    self.ss, self.es = ss, es
+                    self.putx([0, ['Padding: '
+                        + ('ok' if 0xff == self.bytes[-1] else 'error')]])
+                elif 37 == len(self.bytes):
+                    self.ss = ss
+                elif 38 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['CRC: '
+                        + ('ok' if crc16(self.bytes[0:36]) == (self.bytes[36]
+                        + (self.bytes[37] << 8)) else 'error')]])
+                elif 39 == len(self.bytes):
+                    self.ss = ss
+                elif 58 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Message authentication code: '
+                                   + (','.join(format(n, '#04x')
+                                       for n in self.bytes[38:58])),
+                                   'MAC: '
+                                   + (','.join(format(n, '#04x')
+                                       for n in self.bytes[38:58])),
+                                   ]])
+                elif 59 == len(self.bytes):
+                    self.ss = ss
+                elif 60 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['MAC CRC: '
+                        + ('ok' if crc16(self.bytes[38:58]) == (self.bytes[58]
+                        + (self.bytes[59] << 8)) else 'error')]])
+                elif 60 < len(self.bytes):
+                    self.ss, self.es = ss, es
+                    if (0xaa == self.bytes[-1] or 0x55 == self.bytes[-1]):
+                        self.putx([0, ['Operation completed']])
+            elif 0xf0 == self.bytes[0]: # Read memory
+                if 2 == len(self.bytes):
+                    self.ss = ss
+                elif 3 == len(self.bytes):
+                    self.es = es
+                    self.putx([0, ['Target address: 0x%04x'
+                                   % ((self.bytes[2] << 8) + self.bytes[1])]])
+                elif 3 < len(self.bytes):
+                    self.ss, self.es = ss, es
+                    self.putx([0, ['Data: 0x%02x' % (self.bytes[-1])]])