litex/misoclib/liteeth/generic/dispatcher.py

from migen.fhdl.std import *
from migen.genlib.record import *

class Dispatcher(Module):
	def __init__(self, source, sinks, one_hot=False):
		if len(sinks) == 0:
			self.sel = Signal()
		elif len(sinks) == 1:
			self.comb += Record.connect(source, sinks.pop())
			self.sel = Signal()
		else:
			if one_hot:
				self.sel = Signal(len(sinks))
			else:
				self.sel = Signal(max=len(sinks))
			###
			sop = Signal()
			self.comb += sop.eq(source.stb & source.sop)
			sel = Signal(flen(self.sel))
			sel_r = Signal(flen(self.sel))
			self.sync += \
				If(sop,
					sel_r.eq(self.sel)
				)
			self.comb += \
				If(sop,
					sel.eq(self.sel)
				).Else(
					sel.eq(sel_r)
				)
			cases = {}
			for i, sink in enumerate(sinks):
				if one_hot:
					idx = 2**i
				else:
					idx = i
				cases[idx] = [Record.connect(source, sink)]
			cases["default"] = [source.ack.eq(1)]
			self.comb += Case(sel, cases)