bus: CSR initiator

diff --git a/migen/bus/csr.py b/migen/bus/csr.py
index af6064dac8af555bc2cb6a99ea6ae838fddc06df..417501036b3a94df859db12b22963885c382970e 100644 (file)
--- a/migen/bus/csr.py
+++ b/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)