litex/milkymist/dfii/__init__.py

from migen.fhdl.structure import *
from migen.fhdl.module import Module
from migen.bus import dfi
from migen.bank.description import *

class PhaseInjector(Module, AutoCSR):
	def __init__(self, phase):
		self._command = CSRStorage(6) # cs, we, cas, ras, wren, rden
		self._command_issue = CSR()
		self._address = CSRStorage(len(phase.address))
		self._baddress = CSRStorage(len(phase.bank))
		self._wrdata = CSRStorage(len(phase.wrdata))
		self._rddata = CSRStatus(len(phase.rddata))
	
		###

		self.comb += [
			If(self._command_issue.re,
				phase.cs_n.eq(~self._command.storage[0]),
				phase.we_n.eq(~self._command.storage[1]),
				phase.cas_n.eq(~self._command.storage[2]),
				phase.ras_n.eq(~self._command.storage[3])
			).Else(
				phase.cs_n.eq(1),
				phase.we_n.eq(1),
				phase.cas_n.eq(1),
				phase.ras_n.eq(1)
			),
			phase.address.eq(self._address.storage),
			phase.bank.eq(self._baddress.storage),
			phase.wrdata_en.eq(self._command_issue.re & self._command.storage[4]),
			phase.rddata_en.eq(self._command_issue.re & self._command.storage[5]),
			phase.wrdata.eq(self._wrdata.storage),
			phase.wrdata_mask.eq(0)
		]
		self.sync += If(phase.rddata_valid, self._rddata.status.eq(phase.rddata))

class DFIInjector(Module, AutoCSR):
	def __init__(self, a, ba, d, nphases=1):
		inti = dfi.Interface(a, ba, d, nphases)
		self.slave = dfi.Interface(a, ba, d, nphases)
		self.master = dfi.Interface(a, ba, d, nphases)
		
		self._control = CSRStorage(2) # sel, cke
		
		for n, phase in enumerate(inti.phases):
			setattr(self.submodules, "pi" + str(n), PhaseInjector(phase))
	
		###
	
		self.comb += If(self._control.storage[0],
				self.slave.connect(self.master)
			).Else(
				inti.connect(self.master)
			)
		self.comb += [phase.cke.eq(self._control.storage[1]) for phase in inti.phases]