actorlib/dma_asmi: out-of-order reader and class factory

migen/actorlib/dma_asmi.py

@@ -1,5 +1,6 @@
 from migen.fhdl.structure import *
 from migen.flow.actor import *
+from migen.corelogic.buffers import ReorderBuffer
 
 class SequentialReader(Actor):
 	def __init__(self, port):
@@ -42,3 +43,49 @@ class SequentialReader(Actor):
 		]
 		
 		return Fragment(comb, sync)
+
+class OOOReader(Actor):
+	def __init__(self, port):
+		self.port = port
+		assert(len(self.port.slots) > 1)
+		super().__init__(
+			("address", Sink, [("a", BV(self.port.hub.aw))]),
+			("data", Source, [("d", BV(self.port.hub.dw))]))
+	
+	def get_fragment(self):
+		tag_width = len(self.port.tag_call)
+		data_width = self.port.hub.dw
+		depth = len(self.port.slots)
+		rob = ReorderBuffer(tag_width, data_width, depth)
+		
+		comb = [
+			self.port.adr.eq(self.token("address").a),
+			self.port.we.eq(0),
+			self.port.stb.eq(self.endpoints["address"].stb & rob.can_issue),
+			self.endpoints["address"].ack.eq(self.port.ack & rob.can_issue),
+			rob.issue.eq(self.endpoints["address"].stb & self.port.ack),
+			rob.tag_issue.eq(self.port.base + self.port.tag_issue),
+			
+			rob.data_call.eq(self.port.dat_r),
+			
+			self.endpoints["data"].stb.eq(rob.can_read),
+			rob.read.eq(self.endpoints["data"].ack),
+			self.token("data").d.eq(rob.data_read)
+		]
+		sync = [
+			# Data is announced one cycle in advance.
+			# Register the call to synchronize it with the data signal.
+			rob.call.eq(self.port.call),
+			rob.tag_call.eq(self.port.tag_call)
+		]
+		
+		return Fragment(comb, sync) + rob.get_fragment()
+
+class Reader:
+	def __init__(self, port):
+		if len(port.slots) == 1:
+			self.__class__ = SequentialReader
+			SequentialReader.__init__(self, port)
+		else:
+			self.__class__ = OOOReader
+			OOOReader.__init__(self, port)