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