From 1698202ccc2f62d581673fd1320c3ab137f0261a Mon Sep 17 00:00:00 2001
From: Jannis Harder <me@jix.one>
Date: Mon, 13 Feb 2023 12:26:06 +0100
Subject: [PATCH] sim: For yw cosim, drive parent module's signals for input
 ports

---
 passes/sat/sim.cc | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/passes/sat/sim.cc b/passes/sat/sim.cc
index cfe31968dd3..7c209f51674 100644
--- a/passes/sat/sim.cc
+++ b/passes/sat/sim.cc
@@ -139,6 +139,8 @@ struct SimInstance
 	dict<SigBit, pool<Cell*>> upd_cells;
 	dict<SigBit, pool<Wire*>> upd_outports;
 
+	dict<SigBit, SigBit> in_parent_drivers;
+
 	pool<SigBit> dirty_bits;
 	pool<Cell*> dirty_cells;
 	pool<IdString> dirty_memories;
@@ -218,6 +220,12 @@ struct SimInstance
 						dirty_bits.insert(sig[i]);
 					}
 			}
+
+			if (wire->port_input && instance != nullptr && parent != nullptr) {
+				for (int i = 0; i < GetSize(sig); i++) {
+					in_parent_drivers.emplace(sig[i], parent->sigmap(instance->getPort(wire->name)[i]));
+				}
+			}
 		}
 
 		memories = Mem::get_all_memories(module);
@@ -372,6 +380,22 @@ struct SimInstance
 		return did_something;
 	}
 
+	void set_state_parent_drivers(SigSpec sig, Const value)
+	{
+		sigmap.apply(sig);
+
+		for (int i = 0; i < GetSize(sig); i++) {
+			auto sigbit = sig[i];
+			auto sigval = value[i];
+
+			auto in_parent_driver = in_parent_drivers.find(sigbit);
+			if (in_parent_driver == in_parent_drivers.end())
+				set_state(sigbit, sigval);
+			else
+				parent->set_state_parent_drivers(in_parent_driver->second, sigval);
+		}
+	}
+
 	void set_memory_state(IdString memid, Const addr, Const data)
 	{
 		set_memory_state(memid, addr.as_int(), data);
@@ -1760,7 +1784,7 @@ struct SimWorker : SimShared
 				log("yw: set %s to %s\n", signal.path.str().c_str(), log_const(value));
 
 			if (found_path.wire != nullptr) {
-				found_path.instance->set_state(
+				found_path.instance->set_state_parent_drivers(
 						SigChunk(found_path.wire, signal.offset, signal.width),
 						value);
 			} else if (!found_path.memid.empty()) {