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

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