remove the direct connected IPIN/OPIN from RR GSB builder

openfpga/src/annotation/annotate_rr_graph.cpp

@@ -12,6 +12,7 @@
 
 /* Headers from vpr library */
 #include "rr_graph_obj_util.h"
+#include "openfpga_rr_graph_utils.h"
 
 #include "annotate_rr_graph.h"
 
@@ -264,9 +265,18 @@ RRGSB build_rr_gsb(const DeviceContext& vpr_device_ctx,
                              vpr_device_ctx.rr_graph.node_configurable_out_edges(inode).end())) {
         continue;
       }
+
+      /* Do not consider OPINs that directly drive an IPIN
+       * they are supposed to be handled by direct connection
+       */
+      if (true == is_opin_direct_connected_ipin(vpr_device_ctx.rr_graph, inode)) { 
+        continue;
+      }
+
       /* Grid[x+1][y+1] Bottom side outputs pins */
       rr_gsb.add_opin_node(inode, side_manager.get_side());
     }
+
     for (const RRNodeId& inode : temp_opin_rr_nodes[1]) {
       /* Skip those has no configurable outgoing, they should NOT appear in the GSB connection
        * This is for those grid output pins used by direct connections
@@ -276,6 +286,13 @@ RRGSB build_rr_gsb(const DeviceContext& vpr_device_ctx,
         continue;
       }
 
+      /* Do not consider OPINs that directly drive an IPIN
+       * they are supposed to be handled by direct connection
+       */
+      if (true == is_opin_direct_connected_ipin(vpr_device_ctx.rr_graph, inode)) { 
+        continue;
+      }
+
       /* Grid[x+1][y] TOP side outputs pins */
       rr_gsb.add_opin_node(inode, side_manager.get_side());
     }
@@ -356,6 +373,13 @@ RRGSB build_rr_gsb(const DeviceContext& vpr_device_ctx,
                                                   ix, iy, IPIN, ipin_rr_node_grid_side);
     /* Fill the ipin nodes of RRGSB */ 
     for (const RRNodeId& inode : temp_ipin_rr_nodes) {
+      /* Do not consider IPINs that are directly connected by an OPIN
+       * they are supposed to be handled by direct connection
+       */
+      if (true == is_ipin_direct_connected_opin(vpr_device_ctx.rr_graph, inode)) { 
+        continue;
+      }
+ 
       rr_gsb.add_ipin_node(inode, side_manager.get_side());
     }
     /* Clear the temp data */

openfpga/src/tile_direct/build_tile_direct.cpp

@@ -674,6 +674,9 @@ TileDirect build_device_tile_direct(const DeviceContext& device_ctx,
                                        arch_direct_id);
   } 
 
+  VTR_LOG("Built %lu tile-to-tile direct connections\n",
+          std::distance(tile_direct.directs().begin(), tile_direct.directs().end()));
+
   return tile_direct;
 }
 

openfpga/test_vpr_arch/k6_frac_N10_adder_chain_40nm.xml

@@ -159,7 +159,7 @@
   </tiles>
   <!-- ODIN II specific config ends -->
   <!-- Physical descriptions begin -->
-  <layout tileable="true">
+  <layout tileable="false">
     <!--auto_layout aspect_ratio="1.0"-->
     <fixed_layout name="2x2" width="4" height="4">
       <!--Perimeter of 'io' blocks with 'EMPTY' blocks at corners-->

vpr/src/tileable_rr_graph/openfpga_rr_graph_utils.cpp

@@ -128,4 +128,56 @@ std::vector<RRNodeId> get_rr_graph_non_configurable_driver_nodes(const RRGraph&
   return driver_nodes;
 }
 
+/************************************************************************
+ * Check if an OPIN of a rr_graph is directly driving an IPIN
+ * To meet this requirement, the OPIN must:
+ *   - Have only 1 fan-out
+ *   - The only fan-out is an IPIN
+ ***********************************************************************/
+bool is_opin_direct_connected_ipin(const RRGraph& rr_graph,
+                                   const RRNodeId& node) {
+  /* We only accept OPIN */
+  VTR_ASSERT(OPIN == rr_graph.node_type(node));
+
+  if (1 != rr_graph.node_out_edges(node).size()) {
+    return false;
+  }
+
+  VTR_ASSERT(1 == rr_graph.node_out_edges(node).size());
+  for (const RREdgeId& edge: rr_graph.node_out_edges(node)) {
+    const RRNodeId& sink_node = rr_graph.edge_sink_node(edge);
+    if (IPIN != rr_graph.node_type(sink_node)) {
+      return false;
+    }
+  }
+  
+  return true;
+}
+
+/************************************************************************
+ * Check if an IPIN of a rr_graph is directly connected to an OPIN
+ * To meet this requirement, the IPIN must:
+ *   - Have only 1 fan-in
+ *   - The only fan-in is an OPIN
+ ***********************************************************************/
+bool is_ipin_direct_connected_opin(const RRGraph& rr_graph,
+                                   const RRNodeId& node) {
+  /* We only accept IPIN */
+  VTR_ASSERT(IPIN == rr_graph.node_type(node));
+
+  if (1 != rr_graph.node_in_edges(node).size()) {
+    return false;
+  }
+
+  VTR_ASSERT(1 == rr_graph.node_in_edges(node).size());
+  for (const RREdgeId& edge: rr_graph.node_in_edges(node)) {
+    const RRNodeId& src_node = rr_graph.edge_src_node(edge);
+    if (OPIN != rr_graph.node_type(src_node)) {
+      return false;
+    }
+  }
+  
+  return true;
+}
+
 } /* end namespace openfpga */

vpr/src/tileable_rr_graph/openfpga_rr_graph_utils.h

@@ -35,6 +35,12 @@ std::vector<RRNodeId> get_rr_graph_configurable_driver_nodes(const RRGraph& rr_g
 std::vector<RRNodeId> get_rr_graph_non_configurable_driver_nodes(const RRGraph& rr_graph,
                                                                  const RRNodeId& node);
 
+bool is_opin_direct_connected_ipin(const RRGraph& rr_graph,
+                                   const RRNodeId& node);
+
+bool is_ipin_direct_connected_opin(const RRGraph& rr_graph,
+                                   const RRNodeId& node);
+
 } /* end namespace openfpga */
 
 #endif

vpr/src/tileable_rr_graph/rr_gsb.cpp

@@ -445,7 +445,8 @@ bool RRGSB::is_sb_node_passing_wire(const RRGraph& rr_graph,
    * we should be able to find the node on the opposite side of the GSB!
    */
   if (true != is_sb_node_exist_opposite_side(rr_graph, track_node, node_side)) {
-    VTR_LOG("GSB[%lu][%lu] track node:\n", get_x(), get_y());
+    VTR_LOG("GSB[%lu][%lu] track node[%lu] at %s:\n",
+            get_x(), get_y(), track_id, SIDE_STRING[node_side]);
     rr_graph.print_node(track_node);
   }
   VTR_ASSERT (true == is_sb_node_exist_opposite_side(rr_graph, track_node, node_side));