git.ozlabs.org Git - bitfield/blob - bitfield

   1 #!/usr/bin/env python3
   2 #
   3 # Utility to decode register values
   4 # Copyright (c) 2006 Jeremy Kerr <jk@ozlabs.org>
   5 # Released under the GNU General Public License version 2 or later
   6 #
   7 # Documentation and updates at: http://ozlabs.org/~jk/code/bitfield
   8
   9 import os
  10 import sys
  11 import pprint
  12 import math
  13 from pyparsing import Literal, Word, ZeroOrMore, Group, Dict, Optional, \
  14         printables, ParseException, restOfLine
  15 from getopt import getopt, GetoptError
  16
  17 # List of paths to look for configuration files. If a directory is specified,
  18 # it will be (recursively) scanned for .conf files.
  19 configs = ["/etc/bitfield.d", "/etc/bitfield",
  20                 os.path.join(os.getenv("HOME"), ".bitfield.d"),
  21                 os.path.join(os.getenv("HOME"), ".bitfield.conf")]
  22
  23 class bitfield:
  24         def __init__(self, bits, name):
  25                 self.bits = bits
  26                 self.name = name
  27                 self.values = {}
  28
  29         def width(self):
  30                 return len(self.bits)
  31
  32         def add_value(self, value, description):
  33                 self.values[int(value, 0)] = description
  34
  35         def mask(self, reg, value):
  36                 ret = 0
  37                 out_len = len(self.bits)
  38
  39                 if reg.bit_order == reg.bit_0_is_msb:
  40                         bit_pairs = zip(self.bits, range(0, out_len))
  41                 else:
  42                         bit_pairs = zip(self.bits, range(out_len - 1, -1, -1))
  43
  44                 for (in_bit, out_bit) in bit_pairs:
  45                         # shift this bit down to the LSB (and mask the rest)
  46                         i = (value >> (reg.width - in_bit - 1)) & 1
  47                         # shift back to the output position in the field
  48                         i <<= out_len - out_bit - 1
  49                         ret |= i
  50                 return ret
  51
  52         def value(self, value):
  53                 if value in self.values:
  54                         return self.values[value]
  55                 return None
  56
  57         @staticmethod
  58         def mask_and_shift_to_bits(width, mask, shift):
  59                 bits = []
  60                 val = mask << shift
  61                 for i in range(0, width):
  62                         if mask & (1 << i):
  63                                 bits.insert(0, width - i - 1 - shift)
  64                 return bits
  65
  66         @staticmethod
  67         def mask_to_bits(width, mask):
  68                 return bitfield.mask_and_shift_to_bits(width, mask, 0)
  69
  70         @staticmethod
  71         def parse_bitfield(line, reg):
  72                 a = line.split(None, 1)
  73                 if len(a) != 2:
  74                         return None
  75                 (range_str, name) = a
  76
  77                 bits = []
  78                 for s in range_str.split(','):
  79                         if ':' in s:
  80                                 (start, end) = map( \
  81                                         lambda s: reg.bit_number(int(s)),
  82                                         s.split(':'))
  83                                 bits.extend(range(start, end - 1, -1))
  84                         elif '<<' in s:
  85                                 (mask, shift) = map(lambda s: int(s.strip()),
  86                                         s.split('<<'))
  87                                 bits.extend(bitfield.mask_and_shift_to_bits( \
  88                                         reg.width, mask, shift))
  89                         elif s.startswith('&'):
  90                                 mask = int(s[1:], 0)
  91                                 bits.extend(bitfield.mask_to_bits(reg.width, \
  92                                                         mask))
  93                         else:
  94                                 bits.append(reg.bit_number(int(s)))
  95
  96                 return bitfield(bits, name)
  97
  98
  99
 100         @staticmethod
 101         def parse_value(line):
 102                 a = line.split(None, 1)
 103                 if len(a) != 2:
 104                         return None
 105                 return a
 106
 107 class register:
 108         bit_0_is_msb = 0
 109         bit_0_is_lsb = 1
 110
 111         def __init__(self, id):
 112                 self.id = id
 113                 self.fields = []
 114                 # set defaults
 115                 self.name = None
 116                 self.bit_order = self.bit_0_is_msb
 117                 self.width = 64
 118
 119         def add_field(self, field):
 120                 self.fields.append(field)
 121
 122         def decode(self, value, ignore_zero):
 123                 field_width = math.floor((self.width + 3) / 4)
 124                 name_width = max(map(lambda f: len(f.name), self.fields))
 125
 126                 str = "0x%0*lx [%d]\n" % (field_width, value, value)
 127
 128                 for field in self.fields:
 129                         v = field.mask(self, value);
 130                         if ignore_zero and v == 0:
 131                                 continue
 132                         desc = field.value(v)
 133                         if desc is not None:
 134                                 str += "%*s: 0x%x [%s]\n" \
 135                                         % (name_width, field.name, v, desc)
 136                         else:
 137                                 str += "%*s: 0x%x\n" \
 138                                         % (name_width, field.name, v)
 139                 return str
 140
 141         def bit_number(self, number):
 142                 if self.bit_order == self.bit_0_is_lsb:
 143                         number = self.width - number - 1
 144                 return number
 145
 146 def list_regs(regs):
 147         for (id, r) in regs.items():
 148                 print("%18s : %s" % (id, r.name))
 149
 150 def search_regs(regs, str):
 151         return dict((k, regs[k]) for k in regs \
 152                         if str.lower() in regs[k].name.lower() + k.lower())
 153
 154 class ConfigurationError(Exception):
 155         def __init__(self, file, message):
 156                 self.file = file
 157                 self.message = message
 158
 159 def parse_config(bnf, regs, file):
 160         f = open(file)
 161
 162         tokens = bnf.parseString(f.read())
 163
 164         order_map = {'bit-0-is-lsb':    register.bit_0_is_lsb,
 165                         'bit-0-is-msb': register.bit_0_is_msb,
 166                         'ibm':          register.bit_0_is_msb,
 167                         'default':      register.bit_0_is_msb}
 168
 169         for tok in tokens:
 170                 ts = tok.asList()
 171                 id = ts.pop(0)
 172
 173                 if id in regs:
 174                         raise ConfigurationError(file,
 175                                 "Register %s is already defined" % id)
 176
 177                 reg = register(id)
 178
 179                 alias_id = None
 180                 fields = []
 181
 182                 for t in ts:
 183                         if t[0] == 'name':
 184                                 name = t[1]
 185                                 reg.name = name.strip()
 186                         elif t[0] == 'width':
 187                                 reg.width = int(t[1])
 188                         elif t[0] == 'field':
 189                                 f = bitfield.parse_bitfield(t[1], reg)
 190                                 if f is None:
 191                                         raise ConfigurationError(file,
 192                                                 "Invalid field in %s" % id)
 193                                 fields.append(f)
 194                         elif t[0] == 'value':
 195                                 if len(fields) == 0:
 196                                         raise ConfigurationError(file,
 197                                                 "No field for value in %s" % id)
 198                                 v = bitfield.parse_value(t[1])
 199                                 if v is None:
 200                                         raise ConfigurationError(file,
 201                                                 "Invalid value in %s" % id)
 202
 203                                 fields[-1].add_value(v[0], v[1])
 204                         elif t[0] == 'order':
 205                                 if len(fields) != 0:
 206                                         raise ConfigurationError(file,
 207                                                 ("bit order defined after " \
 208                                                 + "fields in %s") % id)
 209
 210                                 order_str = t[1].strip().lower()
 211                                 order_str = order_str.replace(' ', '-')
 212
 213                                 if order_str not in order_map.keys():
 214                                         raise ConfigurationError(file,
 215                                                 "Invalid bit order %s in %s" % \
 216                                                 (order_str, id))
 217                                 reg.bit_order = order_map[order_str]
 218
 219                         elif t[0] == 'alias':
 220                                 alias_id = t[1].strip()
 221
 222                 if alias_id is not None:
 223                         if reg.name is not None or fields != []:
 224                                 raise ConfigurationError(file, ("Definiton " \
 225                                         + "for %s is an alias, but has other " \
 226                                         + "attributes") % id)
 227
 228                         if not regs.has_key(alias_id):
 229                                 raise ConfigurationError(file, "Aliasing "
 230                                         "non-existent register %s (from %s)" \
 231                                         % (alias_id, id))
 232
 233                         reg = regs[alias_id]
 234                         continue
 235
 236                 if reg.name is None or reg.name == '':
 237                         raise ConfigurationError(file,
 238                                 "No name for entry %s" % id)
 239
 240                 if len(fields) == 0:
 241                         raise ConfigurationError(file,
 242                                 "Register %s has no fields" % id)
 243
 244                 for f in fields:
 245                         reg.add_field(f)
 246
 247                 regs[id] = reg
 248
 249 def parse_config_dir(data, dir, fnames):
 250         (bnf, regs) = data
 251         for fname in fnames:
 252                 full_fname = os.path.join(dir, fname)
 253
 254                 if os.path.isdir(full_fname):
 255                         continue
 256
 257                 if fname.endswith('.conf'):
 258                         parse_config(bnf, regs, full_fname)
 259
 260 def parse_all_configs(configs):
 261         regs = {}
 262
 263         # set up the bnf to be used for each file
 264         lbrack = Literal("[").suppress()
 265         rbrack = Literal("]").suppress()
 266         colon  = Literal(":").suppress()
 267         semi   = Literal(";")
 268
 269         comment = semi + Optional(restOfLine)
 270
 271         nonrbrack = "".join([c for c in printables if c != "]"]) + " \t"
 272         noncolon  = "".join([c for c in printables if c != ":"]) + " \t"
 273
 274         sectionDef = lbrack + Word(nonrbrack) + rbrack
 275         keyDef = ~lbrack + Word(noncolon) + colon + restOfLine
 276
 277         bnf = Dict(ZeroOrMore(Group(sectionDef + ZeroOrMore(Group(keyDef)))))
 278         bnf.ignore(comment)
 279
 280         # bundle into a single var that can be passed to os.path.walk
 281         conf_data = (bnf, regs)
 282
 283         for conf in configs:
 284                 if not os.path.exists(conf):
 285                         continue
 286                 if os.path.isdir(conf):
 287                         for c in os.walk(conf):
 288                                 parse_config_dir(conf_data, c[0], c[2])
 289                 else:
 290                         parse_config(bnf, regs, conf)
 291         return regs
 292
 293 def usage(prog):
 294         print("Usage: %s <-l> | <-s pattern> | [-n] register [value...]" % prog)
 295
 296 def decode_value(reg, value, options):
 297         try:
 298                 i = int(value, 0)
 299         except ValueError:
 300                 print("error: invalid value '%s'" % value)
 301                 return
 302
 303         if i > ((1 << reg.width) - 1):
 304                 print("error: value '%s' is too large " + \
 305                         "for %d-bit register '%s'") % (value, reg.width, reg.id)
 306                 return
 307
 308         print(reg.decode(i, options['non-zero']))
 309
 310
 311 def main():
 312         try:
 313                 (opts, args) = getopt(sys.argv[1:], "hlns:", \
 314                         ["help", "list", "non-zero", "search="])
 315         except GetoptError:
 316                 usage(sys.argv[0])
 317                 return 1
 318
 319         try:
 320                 regs = parse_all_configs(configs)
 321         except ConfigurationError as e:
 322                 print("Error parsing configuration file %s:\n\t%s" % \
 323                         (e.file, e.message))
 324                 return 1
 325
 326         if regs == {}:
 327                 print("No configuration available")
 328                 return 1
 329
 330         options = {}
 331         options['non-zero'] = False
 332
 333         for o, a in opts:
 334                 if o in ("-h", "--help"):
 335                         usage(sys.argv[0])
 336                         return
 337
 338                 if o in ("-l", "--list"):
 339                         list_regs(regs)
 340                         return
 341
 342                 if o in ("-s", "--search"):
 343                         list_regs(search_regs(regs, a))
 344                         return
 345
 346                 if o in ("-n", "--non-zero"):
 347                         options['non-zero'] = True
 348
 349         if not args:
 350                 usage(sys.argv[0])
 351                 return 1
 352
 353         reg_id = args.pop(0)
 354         if reg_id not in regs:
 355                 print("No such register '%s'" % reg_id)
 356                 return 1
 357
 358         reg = regs[reg_id]
 359         print("decoding as %s" % reg.name)
 360
 361         if args:
 362                 value_iter = args.__iter__()
 363         else:
 364                 value_iter = iter(sys.stdin.readline, '')
 365
 366         try:
 367                 for value in value_iter:
 368                         decode_value(reg, value.strip(), options)
 369         except KeyboardInterrupt:
 370                 pass
 371
 372         return 0
 373
 374 if __name__ == "__main__":
 375         sys.exit(main())