nmigen/build/dsl.py

   1 __all__ = ["Pins", "Subsignal", "DiffPairs", "Resource"]
   2
   3
   4 class Pins:
   5     def __init__(self, names, dir="io"):
   6         if not isinstance(names, str):
   7             raise TypeError("Names must be a whitespace-separated string, not {!r}"
   8                             .format(names))
   9         self.names = names.split()
  10
  11         if dir not in ("i", "o", "io"):
  12             raise TypeError("Direction must be one of \"i\", \"o\" or \"io\", not {!r}"
  13                             .format(dir))
  14         self.dir = dir
  15
  16     def __repr__(self):
  17         return "(pins {} {})".format(" ".join(self.names), self.dir)
  18
  19
  20 class DiffPairs:
  21     def __init__(self, p, n, dir="io"):
  22         self.p = Pins(p, dir=dir)
  23         self.n = Pins(n, dir=dir)
  24
  25         if len(self.p.names) != len(self.n.names):
  26             raise TypeError("Positive and negative pins must have the same width, but {!r} "
  27                             "and {!r} do not"
  28                             .format(self.p, self.n))
  29
  30         self.dir = self.p.dir
  31
  32     def __repr__(self):
  33         return "(diffpairs {} {})".format(self.p, self.n)
  34
  35
  36 class Subsignal:
  37     def __init__(self, name, *io, extras=()):
  38         self.name = name
  39
  40         if not io:
  41             raise TypeError("Missing I/O constraints")
  42         for c in io:
  43             if not isinstance(c, (Pins, DiffPairs, Subsignal)):
  44                 raise TypeError("I/O constraint must be one of Pins, DiffPairs or Subsignal, "
  45                                 "not {!r}"
  46                                 .format(c))
  47         if isinstance(io[0], (Pins, DiffPairs)) and len(io) > 1:
  48             raise TypeError("Pins and DiffPairs cannot be followed by more I/O constraints, but "
  49                             "{!r} is followed by {!r}"
  50                             .format(io[0], io[1]))
  51         if isinstance(io[0], Subsignal):
  52             for c in io[1:]:
  53                 if not isinstance(c, Subsignal):
  54                     raise TypeError("A Subsignal can only be followed by more Subsignals, but "
  55                                     "{!r} is followed by {!r}"
  56                                     .format(io[0], c))
  57         self.io = io
  58
  59         for c in extras:
  60             if not isinstance(c, str):
  61                 raise TypeError("Extra constraint must be a string, not {!r}".format(c))
  62         self.extras = list(extras)
  63
  64         if isinstance(self.io[0], Subsignal):
  65             for sub in self.io:
  66                 sub.extras += self.extras
  67
  68     def __repr__(self):
  69         return "(subsignal {} {} {})".format(self.name,
  70                                              " ".join(map(repr, self.io)),
  71                                              " ".join(self.extras))
  72
  73
  74 class Resource(Subsignal):
  75     def __init__(self, name, number, *io, extras=()):
  76         self.number = number
  77         super().__init__(name, *io, extras=extras)
  78
  79     def __repr__(self):
  80         return "(resource {} {} {} {})".format(self.name, self.number,
  81                                                " ".join(map(repr, self.io)),
  82                                                " ".join(self.extras))