decoders/parallel/pd.py

   1 ##
   2 ## This file is part of the libsigrokdecode project.
   3 ##
   4 ## Copyright (C) 2013-2016 Uwe Hermann <uwe@hermann-uwe.de>
   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 from common.srdhelper import bitpack
  22
  23 '''
  24 OUTPUT_PYTHON format:
  25
  26 Packet:
  27 [<ptype>, <pdata>]
  28
  29 <ptype>, <pdata>
  30  - 'ITEM', [<item>, <itembitsize>]
  31  - 'WORD', [<word>, <wordbitsize>, <worditemcount>]
  32
  33 <item>:
  34  - A single item (a number). It can be of arbitrary size. The max. number
  35    of bits in this item is specified in <itembitsize>.
  36
  37 <itembitsize>:
  38  - The size of an item (in bits). For a 4-bit parallel bus this is 4,
  39    for a 16-bit parallel bus this is 16, and so on.
  40
  41 <word>:
  42  - A single word (a number). It can be of arbitrary size. The max. number
  43    of bits in this word is specified in <wordbitsize>. The (exact) number
  44    of items in this word is specified in <worditemcount>.
  45
  46 <wordbitsize>:
  47  - The size of a word (in bits). For a 2-item word with 8-bit items
  48    <wordbitsize> is 16, for a 3-item word with 4-bit items <wordbitsize>
  49    is 12, and so on.
  50
  51 <worditemcount>:
  52  - The size of a word (in number of items). For a 4-item word (no matter
  53    how many bits each item consists of) <worditemcount> is 4, for a 7-item
  54    word <worditemcount> is 7, and so on.
  55 '''
  56
  57 NUM_CHANNELS = 16
  58
  59 class Pin:
  60     CLOCK = 0
  61     DATA_0 = CLOCK + 1
  62     DATA_N = DATA_0 + NUM_CHANNELS
  63     # BEWARE! DATA_N points _beyond_ the data partition (Python range(3)
  64     # semantics, useful to have to simplify other code locations).
  65     RESET = DATA_N
  66
  67 class Ann:
  68     ITEM, WORD, WARN = range(3)
  69
  70 class ChannelError(Exception):
  71     pass
  72
  73 class Decoder(srd.Decoder):
  74     api_version = 3
  75     id = 'parallel'
  76     name = 'Parallel'
  77     longname = 'Parallel sync bus'
  78     desc = 'Generic parallel synchronous bus.'
  79     license = 'gplv2+'
  80     inputs = ['logic']
  81     outputs = ['parallel']
  82     tags = ['Util']
  83     optional_channels = tuple(
  84         [{'id': 'clk', 'name': 'CLK', 'desc': 'Clock line'}] +
  85         [
  86             {'id': 'd%d' % i, 'name': 'D%d' % i, 'desc': 'Data line %d' % i}
  87             for i in range(NUM_CHANNELS)
  88         ] +
  89         [{'id': 'rst', 'name': 'RST', 'desc': 'RESET line'}]
  90     )
  91     options = (
  92         {'id': 'clock_edge', 'desc': 'Clock edge to sample on',
  93             'default': 'rising', 'values': ('rising', 'falling', 'either')},
  94         {'id': 'reset_polarity', 'desc': 'Reset line polarity',
  95             'default': 'low-active', 'values': ('low-active', 'high-active')},
  96         {'id': 'wordsize', 'desc': 'Data wordsize (# bus cycles)',
  97             'default': 0},
  98         {'id': 'endianness', 'desc': 'Data endianness',
  99             'default': 'little', 'values': ('little', 'big')},
 100     )
 101     annotations = (
 102         ('item', 'Item'),
 103         ('word', 'Word'),
 104         ('warning', 'Warning'),
 105     )
 106     annotation_rows = (
 107         ('items', 'Items', (Ann.ITEM,)),
 108         ('words', 'Words', (Ann.WORD,)),
 109         ('warnings', 'Warnings', (Ann.WARN,)),
 110     )
 111     binary = (
 112         ('binary', 'Binary'),
 113     )
 114
 115     def __init__(self):
 116         self.reset()
 117
 118     def reset(self):
 119         self.pend_item = None
 120         self.word_items = []
 121
 122     def start(self):
 123         self.out_python = self.register(srd.OUTPUT_PYTHON)
 124         self.out_binary = self.register(srd.OUTPUT_BINARY)
 125         self.out_ann = self.register(srd.OUTPUT_ANN)
 126
 127     def putg(self, ss, es, ann, txts):
 128         self.put(ss, es, self.out_ann, [ann, txts])
 129
 130     def putpy(self, ss, es, ann, data):
 131         self.put(ss, es, self.out_python, [ann, data])
 132
 133     def putbin(self, ss, es, ann_class, data):
 134         self.put(ss, es, self.out_binary, [ann_class, data])
 135
 136     def flush_word(self, bus_width):
 137         if not self.word_items:
 138             return
 139         word_size = self.options['wordsize']
 140
 141         items = self.word_items
 142         ss, es = items[0][0], items[-1][1]
 143         items = [i[2] for i in items]
 144         if self.options['endianness'] == 'big':
 145             items.reverse()
 146         word = sum([d << (i * bus_width) for i, d in enumerate(items)])
 147
 148         txts = [self.fmt_word.format(word)]
 149         self.putg(ss, es, Ann.WORD, txts)
 150         self.putpy(ss, es, 'WORD', (word, bus_width, word_size))
 151
 152         if len(items) != word_size:
 153             txts = ['incomplete word size', 'word size', 'ws']
 154             self.putg(ss, es, Ann.WARN, txts)
 155
 156         self.word_items.clear()
 157
 158     def queue_word(self, now, item, bus_width):
 159         wordsize = self.options['wordsize']
 160         if not wordsize:
 161             return
 162
 163         # Terminate a previously seen item of a word first. Emit the
 164         # word's annotation when the last item's end was seen.
 165         if self.word_items:
 166             ss, _, data = self.word_items[-1]
 167             es = now
 168             self.word_items[-1] = (ss, es, data)
 169             if len(self.word_items) == wordsize:
 170                 self.flush_word(bus_width)
 171
 172         # Start tracking the currently seen item (yet unknown end time).
 173         if item is not None:
 174             pend = (now, None, item)
 175             self.word_items.append(pend)
 176
 177     def handle_bits(self, now, item, bus_width):
 178
 179         # Optionally flush a previously started item.
 180         if self.pend_item:
 181             ss, _, data = self.pend_item
 182             self.pend_item = None
 183             es = now
 184             txts = [self.fmt_item.format(data)]
 185             self.putg(ss, es, Ann.ITEM, txts)
 186             self.putpy(ss, es, 'ITEM', (data, bus_width))
 187             self.putbin(ss, es, 0, data.to_bytes(1, byteorder='big'))
 188
 189         # Optionally queue the currently seen item.
 190         if item is not None:
 191             self.pend_item = (now, None, item)
 192
 193         # Pass the current item to the word accumulation logic.
 194         self.queue_word(now, item, bus_width)
 195
 196     def decode(self):
 197         # Determine which (optional) channels have input data. Insist in
 198         # a non-empty input data set. Cope with sparse connection maps.
 199         # Store enough state to later "compress" sampled input data.
 200         data_indices = [
 201             idx if self.has_channel(idx) else None
 202             for idx in range(Pin.DATA_0, Pin.DATA_N)
 203         ]
 204         has_data = [idx for idx in data_indices if idx is not None]
 205         if not has_data:
 206             raise ChannelError('Need at least one data channel.')
 207         max_connected = max(has_data)
 208
 209         # Pre-determine which input data to strip off, the width of
 210         # individual items and multiplexed words, as well as format
 211         # strings here. This simplifies call sites which run in tight
 212         # loops later.
 213         upper_data_bound = max_connected + 1
 214         num_item_bits = upper_data_bound - Pin.DATA_0
 215         num_word_items = self.options['wordsize']
 216         num_word_bits = num_item_bits * num_word_items
 217         num_digits = (num_item_bits + 4 - 1) // 4
 218         self.fmt_item = "{{:0{}x}}".format(num_digits)
 219         num_digits = (num_word_bits + 4 - 1) // 4
 220         self.fmt_word = "{{:0{}x}}".format(num_digits)
 221
 222         # Determine .wait() conditions, depending on the presence of a
 223         # clock signal. Either inspect samples on the configured edge of
 224         # the clock, or inspect samples upon ANY edge of ANY of the pins
 225         # which provide input data.
 226         conds = []
 227         cond_idx_clock = None
 228         cond_idx_data_0 = None
 229         cond_idx_data_N = None
 230         cond_idx_reset = None
 231         has_clock = self.has_channel(Pin.CLOCK)
 232         if has_clock:
 233             cond_idx_clock = len(conds)
 234             edge = {
 235                 'rising': 'r',
 236                 'falling': 'f',
 237                 'either': 'e',
 238             }.get(self.options['clock_edge'])
 239             conds.append({Pin.CLOCK: edge})
 240         else:
 241             cond_idx_data_0 = len(conds)
 242             conds.extend([{idx: 'e'} for idx in has_data])
 243             cond_idx_data_N = len(conds)
 244         has_reset = self.has_channel(Pin.RESET)
 245         if has_reset:
 246             cond_idx_reset = len(conds)
 247             conds.append({Pin.RESET: 'e'})
 248             reset_active = {
 249                 'low-active': 0,
 250                 'high-active': 1,
 251             }.get(self.options['reset_polarity'])
 252
 253         # Keep processing the input stream. Assume "always zero" for
 254         # not-connected input lines. Pass data bits (all inputs except
 255         # clock and reset) to the handle_bits() method. Handle reset
 256         # edges first and data changes then, within the same iteration.
 257         # This results in robust operation for low-oversampled input.
 258         in_reset = False
 259         while True:
 260             try:
 261                 pins = self.wait(conds)
 262             except EOFError as e:
 263                 break
 264             clock_edge = cond_idx_clock is not None and self.matched[cond_idx_clock]
 265             data_edge = cond_idx_data_0 is not None and [idx for idx in range(cond_idx_data_0, cond_idx_data_N) if self.matched[idx]]
 266             reset_edge = cond_idx_reset is not None and self.matched[cond_idx_reset]
 267
 268             if reset_edge:
 269                 in_reset = pins[Pin.RESET] == reset_active
 270                 if in_reset:
 271                     self.handle_bits(self.samplenum, None, num_item_bits)
 272                     self.flush_word(num_item_bits)
 273             if in_reset:
 274                 continue
 275
 276             if clock_edge or data_edge:
 277                 data_bits = [0 if idx is None else pins[idx] for idx in data_indices]
 278                 data_bits = data_bits[:num_item_bits]
 279                 item = bitpack(data_bits)
 280                 self.handle_bits(self.samplenum, item, num_item_bits)
 281
 282         self.handle_bits(self.samplenum, None, num_item_bits)
 283         # TODO Determine whether a WARN annotation needs to get emitted.
 284         # The decoder has not seen the end of the last accumulated item.
 285         # Instead it just ran out of input data.