fhdl/simplify: add FullMemoryWE decorator that splits memories to remove partial WEs

migen/fhdl/simplify.py

@@ -0,0 +1,41 @@
+from migen.fhdl.std import *
+from migen.fhdl.specials import _MemoryPort
+from migen.fhdl.decorators import ModuleDecorator
+from migen.util.misc import gcd_multiple
+
+class FullMemoryWE(ModuleDecorator):
+	def transform_fragment(self, f):
+		newspecials = set()
+
+		for orig in f.specials:
+			if not isinstance(orig, Memory):
+				newspecials.add(orig)
+				continue
+			global_granularity = gcd_multiple([p.we_granularity if p.we_granularity else orig.width for p in orig.ports])
+			if global_granularity == orig.width:
+				newspecials.add(orig) # nothing to do
+			else:
+				for i in range(orig.width//global_granularity):
+					if orig.init is None:
+						newinit = None
+					else:
+						newinit = [(v >> i*global_granularity) & (2**global_granularity - 1) for v in orig.init]
+					newmem = Memory(global_granularity, orig.depth, newinit, orig.name_override + "_grain" + str(i))
+					newspecials.add(newmem)
+					for port in orig.ports:
+						port_granularity = port.we_granularity if port.we_granularity else orig.width
+						newport = _MemoryPort(adr=port.adr,
+							
+							dat_r=port.dat_r[i*global_granularity:(i+1)*global_granularity] if port.dat_r is not None else None,
+							we=port.we[i*port_granularity//global_granularity] if port.we is not None else None,
+							dat_w=port.dat_w[i*global_granularity:(i+1)*global_granularity] if port.dat_w is not None else None,
+
+	  						async_read=port.async_read,
+	  						re=port.re,
+	  						we_granularity=0,
+	  						mode=port.mode,
+	  						clock_domain=port.clock)
+						newmem.ports.append(newport)
+						newspecials.add(newport)
+
+		f.specials = newspecials