milkymist/dfii/__init__.py

   1 from migen.fhdl.structure import *
   2 from migen.bus import dfi
   3 from migen.bank.description import *
   4 from migen.bank import csrgen
   5
   6 class PhaseInjector:
   7         def __init__(self, phase):
   8                 self.phase = phase
   9
  10                 self._cs = Field("cs", 1, WRITE_ONLY, READ_ONLY)
  11                 self._we = Field("we", 1, WRITE_ONLY, READ_ONLY)
  12                 self._cas = Field("cas", 1, WRITE_ONLY, READ_ONLY)
  13                 self._ras = Field("ras", 1, WRITE_ONLY, READ_ONLY)
  14                 self._wren = Field("wren", 1, WRITE_ONLY, READ_ONLY)
  15                 self._rden = Field("rden", 1, WRITE_ONLY, READ_ONLY)
  16                 self._command = RegisterFields("command",
  17                         [self._cs, self._we, self._cas, self._ras, self._wren, self._rden])
  18
  19                 self._address = RegisterField("address", len(self.phase.address))
  20                 self._baddress = RegisterField("baddress", len(self.phase.bank))
  21
  22                 self._wrdata = RegisterField("wrdata", len(self.phase.wrdata))
  23                 self._rddata = RegisterField("rddata", len(self.phase.rddata), READ_ONLY, WRITE_ONLY)
  24
  25         def get_registers(self):
  26                 return [self._command,
  27                         self._address, self._baddress,
  28                         self._wrdata, self._rddata]
  29
  30         def get_fragment(self):
  31                 comb = [
  32                         If(self._command.re,
  33                                 self.phase.cs_n.eq(~self._cs.r),
  34                                 self.phase.we_n.eq(~self._we.r),
  35                                 self.phase.cas_n.eq(~self._cas.r),
  36                                 self.phase.ras_n.eq(~self._ras.r)
  37                         ).Else(
  38                                 self.phase.cs_n.eq(1),
  39                                 self.phase.we_n.eq(1),
  40                                 self.phase.cas_n.eq(1),
  41                                 self.phase.ras_n.eq(1)
  42                         ),
  43                         self.phase.address.eq(self._address.field.r),
  44                         self.phase.bank.eq(self._baddress.field.r),
  45                         self.phase.wrdata_en.eq(self._command.re & self._wren.r),
  46                         self.phase.rddata_en.eq(self._command.re & self._rden.r),
  47                         self.phase.wrdata.eq(self._wrdata.field.r),
  48                         self.phase.wrdata_mask.eq(0)
  49                 ]
  50                 sync = [
  51                         If(self.phase.rddata_valid, self._rddata.field.w.eq(self.phase.rddata))
  52                 ]
  53                 return Fragment(comb, sync)
  54
  55 class DFIInjector:
  56         def __init__(self, csr_address, a, ba, d, nphases=1):
  57                 self._int = dfi.Interface(a, ba, d, nphases)
  58                 self.slave = dfi.Interface(a, ba, d, nphases)
  59                 self.master = dfi.Interface(a, ba, d, nphases)
  60
  61                 self._sel = Field("sel")
  62                 self._cke = Field("cke")
  63                 self._control = RegisterFields("control", [self._sel, self._cke])
  64
  65                 self._phase_injectors = [PhaseInjector(phase) for phase in self._int.phases]
  66
  67                 registers = sum([pi.get_registers() for pi in self._phase_injectors], [self._control])
  68                 self.bank = csrgen.Bank(registers, address=csr_address)
  69
  70         def get_fragment(self):
  71                 connect_int = dfi.interconnect_stmts(self._int, self.master)
  72                 connect_slave = dfi.interconnect_stmts(self.slave, self.master)
  73                 comb = [
  74                         If(self._sel.r, *connect_slave).Else(*connect_int)
  75                 ]
  76                 comb += [phase.cke.eq(self._cke.r) for phase in self._int.phases]
  77
  78                 return Fragment(comb) \
  79                         + sum([pi.get_fragment() for pi in self._phase_injectors], Fragment()) \
  80                         + self.bank.get_fragment()