litex/migen/actorlib/fifo.py

from migen.fhdl.std import *
from migen.flow.actor import *
from migen.genlib import fifo


class _FIFOActor(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),
            # Note : Can be optimized by passing parameters
            #        in another fifo. We will only have one
            #        data per packet.
            ("param", description.param_layout)
        ]
        if description.packetized:
            fifo_layout += [("sop", 1), ("eop", 1)]

        self.submodules.fifo = fifo_class(fifo_layout, depth)

        self.comb += [
            self.sink.ack.eq(self.fifo.writable),
            self.fifo.we.eq(self.sink.stb),
            self.fifo.din.payload.eq(self.sink.payload),
            self.fifo.din.param.eq(self.sink.param),

            self.source.stb.eq(self.fifo.readable),
            self.source.payload.eq(self.fifo.dout.payload),
            self.source.param.eq(self.fifo.dout.param),
            self.fifo.re.eq(self.source.ack)
        ]
        if description.packetized:
            self.comb += [
                self.fifo.din.sop.eq(self.sink.sop),
                self.fifo.din.eop.eq(self.sink.eop),
                self.source.sop.eq(self.fifo.dout.sop),
                self.source.eop.eq(self.fifo.dout.eop)
            ]


class SyncFIFO(_FIFOActor):
    def __init__(self, layout, depth, buffered=False):
        _FIFOActor.__init__(
            self,
            fifo.SyncFIFOBuffered if buffered else fifo.SyncFIFO,
            layout, depth)


class AsyncFIFO(_FIFOActor):
    def __init__(self, layout, depth):
        _FIFOActor.__init__(self, fifo.AsyncFIFO, layout, depth)