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