litex/liteeth/generic/crossbar.py

from collections import OrderedDict

from liteeth.common import *
from liteeth.generic import *
from liteeth.generic.arbiter import Arbiter
from liteeth.generic.dispatcher import Dispatcher

class LiteEthCrossbar(Module):
	def __init__(self, master_port, dispatch_param):
		self.users = OrderedDict()
		self.master = master_port(8)
		self.dispatch_param = dispatch_param

	# overload this in derived classes
	def get_port(self, *args, **kwargs):
		pass

	def do_finalize(self):
		# TX arbitrate
		sinks = [port.sink for port in self.users.values()]
		self.submodules.arbiter = Arbiter(sinks, self.master.source)

		# RX dispatch
		sources = [port.source for port in self.users.values()]
		self.submodules.dispatcher = Dispatcher(self.master.sink, sources, one_hot=True)
		cases = {}
		cases["default"] = self.dispatcher.sel.eq(0)
		for i, (k, v) in enumerate(self.users.items()):
			cases[k] = self.dispatcher.sel.eq(2**i)
		self.comb += \
			Case(getattr(self.master.sink, self.dispatch_param), cases)