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

   1 #!/usr/bin/python2.4
   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 parse_bitfield(line):
  53                 a = line.split(None, 1)
  54                 if len(a) != 2:
  55                         return None
  56                 (range_str, name) = a
  57
  58                 bits = []
  59                 for s in range_str.split(','):
  60                         if ':' in s:
  61                                 (start, end) = s.split(':')
  62                                 bits.extend(range(int(start), int(end) + 1, 1))
  63                         else:
  64                                 bits.append(int(s))
  65
  66                 return bitfield(bits, name)
  67
  68         @staticmethod
  69         def parse_value(line):
  70                 a = line.split(None, 1)
  71                 if len(a) != 2:
  72                         return None
  73                 return a
  74
  75 class register:
  76         def __init__(self, id, name, width):
  77                 self.id = id
  78                 self.name = name
  79                 self.width = width
  80                 self.fields = []
  81
  82         def add_field(self, field):
  83                 self.fields.append(field)
  84
  85         def decode(self, value, ignore_zero):
  86                 field_width = (self.width + 3) / 4
  87                 name_width = max(map(lambda f: len(f.name), self.fields))
  88
  89                 str = "0x%0*lx [%d]\n" % (field_width, value, value)
  90
  91                 for field in self.fields:
  92                         v = field.mask(self.width, value);
  93                         if ignore_zero and v == 0:
  94                                 continue
  95                         desc = field.value(v)
  96                         if desc is not None:
  97                                 str += "%*s: 0x%x [%s]\n" \
  98                                         % (name_width, field.name, v, desc)
  99                         else:
 100                                 str += "%*s: 0x%x\n" \
 101                                         % (name_width, field.name, v)
 102                 return str
 103
 104 def list_regs(regs):
 105         for (id, r) in regs.iteritems():
 106                 print "%18s : %s" % (id, r.name)
 107
 108 def search_regs(regs, str):
 109         return dict((k, regs[k]) for k in regs \
 110                         if str.lower() in regs[k].name.lower() + k.lower())
 111
 112 class ConfigurationError(Exception):
 113         def __init__(self, file, message):
 114                 self.file = file
 115                 self.message = message
 116
 117 def parse_config(bnf, regs, file):
 118         f = open(file)
 119
 120         tokens = bnf.parseString(f.read())
 121
 122         for tok in tokens:
 123                 ts = tok.asList()
 124                 id = ts.pop(0)
 125
 126                 if regs.has_key(id):
 127                         raise ConfigurationError(file,
 128                                 "Register %s is already defined" % id)
 129
 130                 # default to 64 bit registers
 131                 width = 64
 132                 name = None
 133                 alias_id = None
 134                 fields = []
 135
 136                 for t in ts:
 137                         if t[0] == 'name':
 138                                 name = t[1]
 139                                 name = name.strip()
 140                         elif t[0] == 'width':
 141                                 width = int(t[1])
 142                         elif t[0] == 'field':
 143                                 f = bitfield.parse_bitfield(t[1])
 144                                 if f is None:
 145                                         raise ConfigurationError(file,
 146                                                 "Invalid field in %s" % id)
 147                                 fields.append(f)
 148                         elif t[0] == 'value':
 149                                 if len(fields) == 0:
 150                                         raise ConfigurationError(file,
 151                                                 "No field for value in %s" % id)
 152                                 v = bitfield.parse_value(t[1])
 153                                 if v is None:
 154                                         raise ConfigurationError(file,
 155                                                 "Invalid value in %s" % id)
 156
 157                                 fields[-1].add_value(v[0], v[1])
 158                         elif t[0] == 'alias':
 159                                 alias_id = t[1].strip()
 160
 161                 if alias_id is not None:
 162                         if name is not None or fields != []:
 163                                 raise ConfigurationError(file, ("Definiton " \
 164                                         + "for %s is an alias, but has other " \
 165                                         + "attributes") % id)
 166
 167                         if not regs.has_key(alias_id):
 168                                 raise ConfigurationError(file, "Aliasing "
 169                                         "non-existent register %s (from %s)" \
 170                                         % (alias_id, id))
 171
 172                         regs[id] = regs[alias_id]
 173                         continue
 174
 175                 if name is None or name == '':
 176                         raise ConfigurationError(file,
 177                                 "No name for entry %s" % id)
 178
 179                 if len(fields) == 0:
 180                         raise ConfigurationError(file,
 181                                 "Register %s has no fields" % id)
 182
 183                 r = register(id, name, width)
 184                 for f in fields:
 185                         r.add_field(f)
 186
 187                 regs[id] = r
 188
 189 def parse_config_dir(data, dir, fnames):
 190         (bnf, regs) = data
 191         for fname in fnames:
 192                 full_fname = os.path.join(dir, fname)
 193
 194                 if os.path.isdir(full_fname):
 195                         continue
 196
 197                 if fname.endswith('.conf'):
 198                         parse_config(bnf, regs, full_fname)
 199
 200 def parse_all_configs(configs):
 201         regs = {}
 202
 203         # set up the bnf to be used for each file
 204         lbrack = Literal("[").suppress()
 205         rbrack = Literal("]").suppress()
 206         colon  = Literal(":").suppress()
 207         semi   = Literal(";")
 208
 209         comment = semi + Optional(restOfLine)
 210
 211         nonrbrack = "".join([c for c in printables if c != "]"]) + " \t"
 212         noncolon  = "".join([c for c in printables if c != ":"]) + " \t"
 213
 214         sectionDef = lbrack + Word(nonrbrack) + rbrack
 215         keyDef = ~lbrack + Word(noncolon) + colon + restOfLine
 216
 217         bnf = Dict(ZeroOrMore(Group(sectionDef + ZeroOrMore(Group(keyDef)))))
 218         bnf.ignore(comment)
 219
 220         # bundle into a single var that can be passed to os.path.walk
 221         conf_data = (bnf, regs)
 222
 223         for conf in configs:
 224                 if not os.path.exists(conf):
 225                         continue
 226                 if os.path.isdir(conf):
 227                         os.path.walk(conf, parse_config_dir, conf_data)
 228                 else:
 229                         parse_config(bnf, regs, conf)
 230         return regs
 231
 232 def usage(prog):
 233         print "Usage: %s <-l> | <-s pattern> | [-n] register [value...]" % prog
 234
 235 def decode_value(reg, value, options):
 236         try:
 237                 i = long(value, 0)
 238         except ValueError, e:
 239                 print "error: invalid value '%s'" % value
 240                 return
 241
 242         if i > ((1 << reg.width) - 1):
 243                 print ("error: value '%s' is too large " + \
 244                         "for %d-bit register '%s'") % (value, reg.width, reg.id)
 245                 return
 246
 247         print reg.decode(i, options['non-zero'])
 248
 249
 250 def main():
 251         try:
 252                 (opts, args) = getopt(sys.argv[1:], "hlns:", \
 253                         ["help", "list", "non-zero", "search="])
 254         except GetoptError:
 255                 usage(sys.argv[0])
 256                 return 1
 257
 258         try:
 259                 regs = parse_all_configs(configs)
 260         except ConfigurationError, e:
 261                 print "Error parsing configuration file %s:\n\t%s" % \
 262                         (e.file, e.message)
 263                 return 1
 264
 265         if regs == {}:
 266                 print "No configuration available"
 267                 return 1
 268
 269         options = {}
 270         options['non-zero'] = False
 271
 272         for o, a in opts:
 273                 if o in ("-h", "--help"):
 274                         usage(sys.argv[0])
 275                         return
 276
 277                 if o in ("-l", "--list"):
 278                         list_regs(regs)
 279                         return
 280
 281                 if o in ("-s", "--search"):
 282                         list_regs(search_regs(regs, a))
 283                         return
 284
 285                 if o in ("-n", "--non-zero"):
 286                         options['non-zero'] = True
 287
 288         if not args:
 289                 usage(sys.argv[0])
 290                 return 1
 291
 292         reg_id = args.pop(0)
 293         if not regs.has_key(reg_id):
 294                 print "No such register '%s'" % reg_id
 295                 return 1
 296
 297         reg = regs[reg_id]
 298         print "decoding as %s" % reg.name
 299
 300         if args:
 301                 value_iter = args.__iter__()
 302         else:
 303                 value_iter = iter(sys.stdin.readline, '')
 304
 305         try:
 306                 for value in value_iter:
 307                         decode_value(reg, value.strip(), options)
 308         except KeyboardInterrupt, e:
 309                 pass
 310
 311         return 0
 312
 313 if __name__ == "__main__":
 314         sys.exit(main())