From a67f483f0fcdfaa8d00ee4cb706d3e11b6ada8b2 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sebastien@milkymist.org>
Date: Fri, 14 Dec 2012 19:16:22 +0100
Subject: [PATCH] Token: support idle_wait

---
 examples/dataflow/dma.py   |  2 +-
 migen/actorlib/sim.py      |  8 +++++++-
 migen/flow/transactions.py |  4 ++--
 migen/pytholite/io.py      | 10 ++++++++--
 4 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/examples/dataflow/dma.py b/examples/dataflow/dma.py
index dad3d47a7..98a3a2e18 100644
--- a/examples/dataflow/dma.py
+++ b/examples/dataflow/dma.py
@@ -29,7 +29,7 @@ def adrgen_gen():
 
 def dumper_gen():
 	while True:
-		t = Token("data")
+		t = Token("data", idle_wait=True)
 		yield t
 		print("Received: " + str(t.value["d"]))
 
diff --git a/migen/actorlib/sim.py b/migen/actorlib/sim.py
index 153dbe13f..67f8689eb 100644
--- a/migen/actorlib/sim.py
+++ b/migen/actorlib/sim.py
@@ -14,6 +14,7 @@ class TokenExchanger(PureSimulable):
 		self.generator = generator
 		self.actor = actor
 		self.active = set()
+		self.busy = True
 		self.done = False
 
 	def _process_transactions(self, s):
@@ -39,12 +40,15 @@ class TokenExchanger(PureSimulable):
 			else:
 				raise TypeError
 		self.active -= completed
+		if not self.active:
+			self.busy = True
 	
 	def _next_transactions(self):
 		try:
 			transactions = next(self.generator)
 		except StopIteration:
 			self.done = True
+			self.busy = False
 			transactions = None
 		if isinstance(transactions, Token):
 			self.active = {transactions}
@@ -56,6 +60,8 @@ class TokenExchanger(PureSimulable):
 			self.active = set()
 		else:
 			raise TypeError
+		if all(transaction.idle_wait for transaction in self.active):
+			self.busy = False
 	
 	def do_simulation(self, s):
 		if not self.done:
@@ -70,7 +76,7 @@ class SimActor(Actor):
 		self.token_exchanger = TokenExchanger(generator, self)
 	
 	def update_busy(self, s):
-		s.wr(self.busy, not self.token_exchanger.done)
+		s.wr(self.busy, self.token_exchanger.busy)
 	
 	def get_fragment(self):
 		return self.token_exchanger.get_fragment() + Fragment(sim=[self.update_busy])
diff --git a/migen/flow/transactions.py b/migen/flow/transactions.py
index 5c3ceab8b..b9c1bc1d7 100644
--- a/migen/flow/transactions.py
+++ b/migen/flow/transactions.py
@@ -1,5 +1,5 @@
 class Token:
-	def __init__(self, endpoint, value=None):
+	def __init__(self, endpoint, value=None, idle_wait=False):
 		self.endpoint = endpoint
 		self.value = value
- 
+		self.idle_wait = idle_wait
diff --git a/migen/pytholite/io.py b/migen/pytholite/io.py
index 66efa6e23..dbaa5613e 100644
--- a/migen/pytholite/io.py
+++ b/migen/pytholite/io.py
@@ -13,6 +13,8 @@ from migen.pytholite.expr import ExprCompiler
 class Pytholite(UnifiedIOObject):
 	def __init__(self, dataflow=None, buses={}):
 		super().__init__(dataflow, buses)
+		if dataflow is not None:
+			self.busy.reset = 1
 		self.memory_ports = dict((mem, mem.get_port(write_capable=True, we_granularity=8))
 			for mem in self._memories)
 	
@@ -43,14 +45,18 @@ class _TokenPullExprCompiler(ExprCompiler):
 def _gen_df_io(compiler, modelname, to_model, from_model):
 	epname = ast.literal_eval(to_model["endpoint"])
 	values = to_model["value"]
+	idle_wait = ast.literal_eval(to_model["idle_wait"])
 	ep = compiler.ioo.endpoints[epname]
+	if idle_wait:
+		state = [compiler.ioo.busy.eq(0)]
+	else:
+		state = []
 	
 	if isinstance(values, ast.Name) and values.id == "None":
 		# token pull from sink
 		if not isinstance(ep, Sink):
 			raise TypeError("Attempted to pull from source")
 		ec = _TokenPullExprCompiler(compiler.symdict, modelname, ep)
-		state = []
 		for target_regs, expr in from_model:
 			cexpr = ec.visit_expr(expr)
 			state += [reg.load(cexpr) for reg in target_regs]
@@ -67,7 +73,6 @@ def _gen_df_io(compiler, modelname, to_model, from_model):
 			raise TypeError("Attempted to read from pushed token")
 		if not isinstance(values, ast.Dict):
 			raise NotImplementedError
-		state = []
 		for akey, value in zip(values.keys, values.values):
 			key = ast.literal_eval(akey)
 			signal = getattr(ep.token, key)
@@ -190,6 +195,7 @@ def gen_io(compiler, modelname, model, to_model, to_model_kw, from_model):
 		desc = [
 			"endpoint",
 			("value", ast.Name("None", ast.Load())),
+			("idle_wait", ast.Name("False", ast.Load()))
 		]
 		args = _decode_args(desc, to_model, to_model_kw)
 		return _gen_df_io(compiler, modelname, args, from_model)