litex/misoc/interconnect/stream.py

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from migen import *
from migen.genlib.record import *
from migen.genlib import fifo
def _make_m2s(layout):
r = []
for f in layout:
if isinstance(f[1], (int, tuple)):
r.append((f[0], f[1], DIR_M_TO_S))
else:
r.append((f[0], _make_m2s(f[1])))
return r
class EndpointDescription:
def __init__(self, payload_layout, packetized=False):
self.payload_layout = payload_layout
self.packetized = packetized
def get_full_layout(self):
reserved = {"stb", "ack", "payload", "sop", "eop", "description"}
attributed = set()
for f in self.payload_layout:
if f[0] in attributed:
raise ValueError(f[0] + " already attributed in payload layout")
if f[0] in reserved:
raise ValueError(f[0] + " cannot be used in endpoint layout")
attributed.add(f[0])
full_layout = [
("payload", _make_m2s(self.payload_layout)),
("stb", 1, DIR_M_TO_S),
("ack", 1, DIR_S_TO_M)
]
if self.packetized:
full_layout += [
("sop", 1, DIR_M_TO_S),
("eop", 1, DIR_M_TO_S)
]
return full_layout
class _Endpoint(Record):
def __init__(self, description_or_layout):
if isinstance(description_or_layout, EndpointDescription):
self.description = description_or_layout
else:
self.description = EndpointDescription(description_or_layout)
Record.__init__(self, self.description.get_full_layout())
def __getattr__(self, name):
return getattr(object.__getattribute__(self, "payload"), name)
class Source(_Endpoint):
def connect(self, sink):
return Record.connect(self, sink)
class Sink(_Endpoint):
def connect(self, source):
return source.connect(self)
class _FIFOWrapper(Module):
def __init__(self, fifo_class, layout, depth):
self.sink = Sink(layout)
self.source = Source(layout)
self.busy = Signal()
###
description = self.sink.description
fifo_layout = [("payload", description.payload_layout)]
if description.packetized:
fifo_layout += [("sop", 1), ("eop", 1)]
self.submodules.fifo = fifo_class(layout_len(fifo_layout), depth)
fifo_in = Record(fifo_layout)
fifo_out = Record(fifo_layout)
self.comb += [
self.fifo.din.eq(fifo_in.raw_bits()),
fifo_out.raw_bits().eq(self.fifo.dout)
]
self.comb += [
self.sink.ack.eq(self.fifo.writable),
self.fifo.we.eq(self.sink.stb),
fifo_in.payload.eq(self.sink.payload),
self.source.stb.eq(self.fifo.readable),
self.source.payload.eq(fifo_out.payload),
self.fifo.re.eq(self.source.ack)
]
if description.packetized:
self.comb += [
fifo_in.sop.eq(self.sink.sop),
fifo_in.eop.eq(self.sink.eop),
self.source.sop.eq(fifo_out.sop),
self.source.eop.eq(fifo_out.eop)
]
class SyncFIFO(_FIFOWrapper):
def __init__(self, layout, depth, buffered=False):
_FIFOWrapper.__init__(
self,
fifo.SyncFIFOBuffered if buffered else fifo.SyncFIFO,
layout, depth)
class AsyncFIFO(_FIFOWrapper):
def __init__(self, layout, depth):
_FIFOWrapper.__init__(self, fifo.AsyncFIFO, layout, depth)
class Multiplexer(Module):
def __init__(self, layout, n):
self.source = Source(layout)
sinks = []
for i in range(n):
sink = Sink(layout)
setattr(self, "sink"+str(i), sink)
sinks.append(sink)
self.sel = Signal(max=n)
# # #
cases = {}
for i, sink in enumerate(sinks):
cases[i] = Record.connect(sink, self.source)
self.comb += Case(self.sel, cases)
class Demultiplexer(Module):
def __init__(self, layout, n):
self.sink = Sink(layout)
sources = []
for i in range(n):
source = Source(layout)
setattr(self, "source"+str(i), source)
sources.append(source)
self.sel = Signal(max=n)
# # #
cases = {}
for i, source in enumerate(sources):
cases[i] = Record.connect(self.sink, source)
self.comb += Case(self.sel, cases)