bus: CSR initiator

migen/bus/csr.py

@@ -1,5 +1,7 @@
 from migen.fhdl.structure import *
 from migen.bus.simple import *
+from migen.bus.transactions import *
+from migen.sim.generic import PureSimulable
 
 _desc = Description(
 	(M_TO_S,	"adr",		14),
@@ -14,3 +16,28 @@ class Interface(SimpleInterface):
 
 class Interconnect(SimpleInterconnect):
 	pass
+
+class Initiator(PureSimulable):
+	def __init__(self, generator):
+		self.generator = generator
+		self.bus = Interface()
+		self.transaction = None
+		self.done = False
+		
+	def do_simulation(self, s):
+		if not self.done:
+			if self.transaction is not None:
+				if isinstance(self.transaction, TRead):
+					self.transaction.data = s.rd(self.bus.dat_r)
+				else:
+					s.wr(self.bus.we, 0)
+			try:
+				self.transaction = next(self.generator)
+			except StopIteration:
+				self.transaction = None
+				self.done = True
+			if self.transaction is not None:
+				s.wr(self.bus.adr, self.transaction.address)
+				if isinstance(self.transaction, TWrite):
+					s.wr(self.bus.we, 1)
+					s.wr(self.bus.dat_w, self.transaction.data)