Use env to find python
[bitfield] / bitfield
index d470c7ce2958d5f7a22eff2e7f42ba4aba31d064..ae5b1380b48ced412f579c13566f07164df08edf 100644 (file)
--- a/bitfield
+++ b/bitfield
@@ -1,4 +1,4 @@
-#!/usr/bin/python2.4
+#!/usr/bin/env python
 #
 # Utility to decode register values
 # Copyright (c) 2006 Jeremy Kerr <jk@ozlabs.org>
@@ -13,56 +13,77 @@ from pyparsing import Literal, Word, ZeroOrMore, Group, Dict, Optional, \
         printables, ParseException, restOfLine
 from getopt import getopt, GetoptError
 
-conf = os.path.join(os.getenv("HOME"), ".bitfields.conf")
+# List of paths to look for configuration files. If a directory is specified,
+# it will be (recursively) scanned for .conf files.
+configs = ["/etc/bitfield.d", "/etc/bitfield",
+               os.path.join(os.getenv("HOME"), ".bitfield.d"),
+               os.path.join(os.getenv("HOME"), ".bitfield.conf")]
 
 class bitfield:
-       def __init__(self, start_bit, end_bit, name):
-               self.start_bit = start_bit
-               self.end_bit = end_bit
+       def __init__(self, bits, name):
+               self.bits = bits
                self.name = name
                self.values = {}
 
-       def start_bit(self):
-               return self.start_bit
-
-       def end_bit(self):
-               return self.end_bit
-
        def width(self):
-               return 1 + self.end_bit - self.start_bit
+               return len(self.bits)
 
        def add_value(self, value, description):
                self.values[int(value)] = description
 
        def mask(self, reg_width, value):
-               shift = (reg_width - 1) - self.end_bit
-               return (((2 ** self.width() - 1) << (shift))
-                       & value) >> shift
+               ret = 0
+               out_len = len(self.bits)
+               for out_bit in range(0, out_len):
+                       in_bit = self.bits[out_bit]
+                       # shift this bit down to the LSB (and mask the rest)
+                       i = (value >> (reg_width - in_bit - 1)) & 1
+                       # shift back to the output position in the field
+                       i <<= out_len - out_bit - 1
+                       ret |= i
+               return ret
 
        def value(self, value):
                if value in self.values:
                        return self.values[value]
                return None
 
-       def __str__(self):
-               return "[%2d:%-2d] %s 0x%x" % (int(self.start_bit),
-                       int(self.end_bit), self.name, self.mask())
+       @staticmethod
+       def mask_and_shift_to_bits(width, mask, shift):
+               bits = []
+               val = mask << shift
+               for i in range(0, width):
+                       if mask & (1 << i):
+                               bits.append(width - i - 1 - shift)
+               return bits
 
        @staticmethod
-       def parse_bitfield(line):
+       def parse_bitfield(line, reg):
                a = line.split(None, 1)
                if len(a) != 2:
                        return None
                (range_str, name) = a
 
-               range = (None,None)
-               if range_str.find(':') != -1:
-                       r = range_str.split(":")
-                       range = (int(r[0]),int(r[1]))
-               else:
-                       range = (int(range_str),int(range_str))
+               bits = []
+               for s in range_str.split(','):
+                       if ':' in s:
+                               (start, end) = map( \
+                                       lambda s: reg.bit_number(int(s)),
+                                       s.split(':'))
+                               start = reg.bit_number(int(start))
+                               end = reg.bit_number(int(end))
+                               bits.extend(range(start, end + 1, 1))
+                       elif '<<' in s:
+                               (mask, shift) = map(lambda s: int(s.strip()),
+                                       s.split('<<'))
+                               bits.extend(bitfield.mask_and_shift_to_bits( \
+                                       reg.width, mask, shift))
+                       else:
+                               bits.append(reg.bit_number(int(s)))
+
+               return bitfield(bits, name)
+
 
-               return bitfield(range[0], range[1], name)
 
        @staticmethod
        def parse_value(line):
@@ -72,34 +93,43 @@ class bitfield:
                return a
 
 class register:
-       def __init__(self, name, width):
-               self.name = name
-               self.width = width
+       bit_0_is_msb = 0
+       bit_0_is_lsb = 1
+
+       def __init__(self, id):
+               self.id = id
                self.fields = []
+               # set defaults
+               self.name = None
+               self.bit_order = self.bit_0_is_msb
+               self.width = 64
 
-       def add_field(self, field,):
+       def add_field(self, field):
                self.fields.append(field)
 
-       def decode(self, value):
+       def decode(self, value, ignore_zero):
                field_width = (self.width + 3) / 4
                name_width = max(map(lambda f: len(f.name), self.fields))
+
                str = "0x%0*lx [%d]\n" % (field_width, value, value)
+
                for field in self.fields:
                        v = field.mask(self.width, value);
+                       if ignore_zero and v == 0:
+                               continue
                        desc = field.value(v)
                        if desc is not None:
-                               str += "%*s: 0x%s [%s]\n" \
+                               str += "%*s: 0x%x [%s]\n" \
                                        % (name_width, field.name, v, desc)
                        else:
                                str += "%*s: 0x%x\n" \
                                        % (name_width, field.name, v)
                return str
 
-       def __str__(self):
-               str = self.name + "\n"
-               for f in self.fields:
-                       str += "\t%s\n" % f
-               return str
+       def bit_number(self, number):
+               if self.bit_order == self.bit_0_is_lsb:
+                       number = self.width - 1 - number
+               return number
 
 def list_regs(regs):
        for (id, r) in regs.iteritems():
@@ -114,97 +144,179 @@ class ConfigurationError(Exception):
                self.file = file
                self.message = message
 
-def parse_config(file):
-       lbrack = Literal("[").suppress()
-       rbrack = Literal("]").suppress()
-       colon  = Literal(":").suppress()
-       semi   = Literal(";")
-
-       comment = semi + Optional( restOfLine )
-
-       nonrbrack = "".join( [ c for c in printables if c != "]" ] ) + " \t"
-       nonequals = "".join( [ c for c in printables if c != ":" ] ) + " \t"
-
-       sectionDef = lbrack + Word( nonrbrack ) + rbrack
-       keyDef = ~lbrack + Word( nonequals ) + colon + restOfLine
-
-       bnf = Dict(ZeroOrMore(Group(sectionDef + ZeroOrMore(Group(keyDef)))))
-       bnf.ignore(comment)
-
+def parse_config(bnf, regs, file):
        f = open(file)
 
-       tokens = bnf.parseString("".join(f.readlines()))
+       tokens = bnf.parseString(f.read())
 
-       regs = {}
+       order_map = {'bit-0-is-lsb':    register.bit_0_is_lsb,
+                       'bit-0-is-msb': register.bit_0_is_msb,
+                       'ibm':          register.bit_0_is_msb,
+                       'default':      register.bit_0_is_msb}
 
        for tok in tokens:
                ts = tok.asList()
                id = ts.pop(0)
 
-               # default to 64 bit registers
-               width = 64
-               name = None
+               if regs.has_key(id):
+                       raise ConfigurationError(file,
+                               "Register %s is already defined" % id)
+
+               reg = register(id)
+
+               alias_id = None
                fields = []
 
                for t in ts:
                        if t[0] == 'name':
                                name = t[1]
-                               name = name.strip()
+                               reg.name = name.strip()
                        elif t[0] == 'width':
-                               width = int(t[1])
+                               reg.width = int(t[1])
                        elif t[0] == 'field':
-                               f = bitfield.parse_bitfield(t[1])
+                               f = bitfield.parse_bitfield(t[1], reg)
                                if f is None:
                                        raise ConfigurationError(file,
                                                "Invalid field in %s" % id)
                                fields.append(f)
                        elif t[0] == 'value':
-                               f = fields[-1]
-                               if f is None:
+                               if len(fields) == 0:
                                        raise ConfigurationError(file,
                                                "No field for value in %s" % id)
                                v = bitfield.parse_value(t[1])
                                if v is None:
                                        raise ConfigurationError(file,
                                                "Invalid value in %s" % id)
-                               f.add_value(v[0], v[1])
 
-               if name is None or name == '':
+                               fields[-1].add_value(v[0], v[1])
+                       elif t[0] == 'order':
+                               if len(fields) != 0:
+                                       raise ConfigurationError(file,
+                                               ("bit order defined after " \
+                                               + "fields in %s") % id)
+
+                               order_str = t[1].strip().lower()
+                               order_str = order_str.replace(' ', '-')
+
+                               if order_str not in order_map.keys():
+                                       raise ConfigurationError(file,
+                                               "Invalid bit order %s in %s" % \
+                                               (order_str, id))
+                               reg.bit_order = order_map[order_str]
+
+                       elif t[0] == 'alias':
+                               alias_id = t[1].strip()
+
+               if alias_id is not None:
+                       if reg.name is not None or fields != []:
+                               raise ConfigurationError(file, ("Definiton " \
+                                       + "for %s is an alias, but has other " \
+                                       + "attributes") % id)
+
+                       if not regs.has_key(alias_id):
+                               raise ConfigurationError(file, "Aliasing "
+                                       "non-existent register %s (from %s)" \
+                                       % (alias_id, id))
+
+                       reg = regs[alias_id]
+                       continue
+
+               if reg.name is None or reg.name == '':
                        raise ConfigurationError(file,
-                               "No name for entry %s" %id)
+                               "No name for entry %s" % id)
 
                if len(fields) == 0:
                        raise ConfigurationError(file,
                                "Register %s has no fields" % id)
 
-               r = register(name, width)
                for f in fields:
-                       r.add_field(f)
+                       reg.add_field(f)
 
-               regs[id] = r
+               regs[id] = reg
 
-       return regs
+def parse_config_dir(data, dir, fnames):
+       (bnf, regs) = data
+       for fname in fnames:
+               full_fname = os.path.join(dir, fname)
+
+               if os.path.isdir(full_fname):
+                       continue
 
+               if fname.endswith('.conf'):
+                       parse_config(bnf, regs, full_fname)
+
+def parse_all_configs(configs):
+       regs = {}
+
+       # set up the bnf to be used for each file
+       lbrack = Literal("[").suppress()
+       rbrack = Literal("]").suppress()
+       colon  = Literal(":").suppress()
+       semi   = Literal(";")
+
+       comment = semi + Optional(restOfLine)
+
+       nonrbrack = "".join([c for c in printables if c != "]"]) + " \t"
+       noncolon  = "".join([c for c in printables if c != ":"]) + " \t"
+
+       sectionDef = lbrack + Word(nonrbrack) + rbrack
+       keyDef = ~lbrack + Word(noncolon) + colon + restOfLine
+
+       bnf = Dict(ZeroOrMore(Group(sectionDef + ZeroOrMore(Group(keyDef)))))
+       bnf.ignore(comment)
+
+       # bundle into a single var that can be passed to os.path.walk
+       conf_data = (bnf, regs)
+
+       for conf in configs:
+               if not os.path.exists(conf):
+                       continue
+               if os.path.isdir(conf):
+                       os.path.walk(conf, parse_config_dir, conf_data)
+               else:
+                       parse_config(bnf, regs, conf)
+       return regs
 
 def usage(prog):
-       print "Usage: %s <-l> | <-s pattern> | register [value...]" % prog
+       print "Usage: %s <-l> | <-s pattern> | [-n] register [value...]" % prog
+
+def decode_value(reg, value, options):
+       try:
+               i = long(value, 0)
+       except ValueError, e:
+               print "error: invalid value '%s'" % value
+               return
+
+       if i > ((1 << reg.width) - 1):
+               print ("error: value '%s' is too large " + \
+                       "for %d-bit register '%s'") % (value, reg.width, reg.id)
+               return
+
+       print reg.decode(i, options['non-zero'])
+
 
 def main():
        try:
-               (opts, args) = getopt(sys.argv[1:], "hls:", \
-                       ["help", "list", "search="])
+               (opts, args) = getopt(sys.argv[1:], "hlns:", \
+                       ["help", "list", "non-zero", "search="])
        except GetoptError:
                usage(sys.argv[0])
                return 1
 
        try:
-               regs = parse_config(conf)
-
+               regs = parse_all_configs(configs)
        except ConfigurationError, e:
                print "Error parsing configuration file %s:\n\t%s" % \
                        (e.file, e.message)
                return 1
 
+       if regs == {}:
+               print "No configuration available"
+               return 1
+
+       options = {}
+       options['non-zero'] = False
+
        for o, a in opts:
                if o in ("-h", "--help"):
                        usage(sys.argv[0])
@@ -218,31 +330,31 @@ def main():
                        list_regs(search_regs(regs, a))
                        return
 
+               if o in ("-n", "--non-zero"):
+                       options['non-zero'] = True
 
        if not args:
                usage(sys.argv[0])
                return 1
 
-       a = args.pop(0)
-       if not regs.has_key(a):
-               print "No such register '%s'. Valid regs are:" % a
-               list_regs(regs)
+       reg_id = args.pop(0)
+       if not regs.has_key(reg_id):
+               print "No such register '%s'" % reg_id
                return 1
 
-       r = regs[a]
-       print "decoding as %s" % r.name
+       reg = regs[reg_id]
+       print "decoding as %s" % reg.name
 
        if args:
-               values = args
+               value_iter = args.__iter__()
        else:
-               try:
-                       values = sys.stdin.readlines()
-               except KeyboardInterrupt, e:
-                       return
+               value_iter = iter(sys.stdin.readline, '')
 
-       for value in values:
-               i = long(value.strip(), 0)
-               print r.decode(i)
+       try:
+               for value in value_iter:
+                       decode_value(reg, value.strip(), options)
+       except KeyboardInterrupt, e:
+               pass
 
        return 0