ecp5: Small DRAM routing fixes

Signed-off-by: David Shah <davey1576@gmail.com>

2 files changed, 25 insertions, 7 deletions

diff --git a/ecp5/globals.cc b/ecp5/globals.cc
index e5627b66..364e4bca 100644
--- a/ecp5/globals.cc
+++ b/ecp5/globals.cc
@@ -302,6 +302,14 @@ class Ecp5GlobalRouter
         ctx->nets[glbnet->name] = std::move(glbnet);
         return glbptr;
     }
+
+    int global_route_priority(const PortRef &load)
+    {
+        if (load.port == id_WCK || load.port == id_WRE)
+            return 90;
+        return 99;
+    }
+
     Context *ctx;
 
   public:
@@ -333,7 +341,13 @@ class Ecp5GlobalRouter
             NetInfo *global = insert_dcc(clock);
             bool routed = route_onto_global(global, glbid);
             NPNR_ASSERT(routed);
-            for (const auto &user : global->users) {
+
+            // WCK must have routing priority
+            auto sorted_users = global->users;
+            std::sort(sorted_users.begin(), sorted_users.end(), [this](const PortRef &a, const PortRef &b) {
+                return global_route_priority(a) < global_route_priority(b);
+            });
+            for (const auto &user : sorted_users) {
                 route_logic_tile_global(global, glbid, user);
             }
         }
diff --git a/ecp5/pack.cc b/ecp5/pack.cc
index 8e33356e..60ac55f6 100644
--- a/ecp5/pack.cc
+++ b/ecp5/pack.cc
@@ -598,9 +598,11 @@ class Ecp5Packer
                     if (f0net != nullptr) {
                         ff0 = net_only_drives(ctx, f0net, is_ff, ctx->id("DI"), false);
                         if (ff0 != nullptr && can_add_ff_to_tile(tile_ffs, ff0)) {
-                            ff_packing.push_back(std::make_tuple(ff0, slice, 0));
-                            tile_ffs.push_back(ff0);
-                            packed_cells.insert(ff0->name);
+                            if (net_or_nullptr(ff0, ctx->id("CLK")) == net_or_nullptr(slice, ctx->id("WCK"))) {
+                                ff_packing.push_back(std::make_tuple(ff0, slice, 0));
+                                tile_ffs.push_back(ff0);
+                                packed_cells.insert(ff0->name);
+                            }
                         }
                     }
 
@@ -610,9 +612,11 @@ class Ecp5Packer
                         ff1 = net_only_drives(ctx, f1net, is_ff, ctx->id("DI"), false);
                         if (ff1 != nullptr && (ff0 == nullptr || can_pack_ffs(ff0, ff1)) &&
                             can_add_ff_to_tile(tile_ffs, ff1)) {
-                            ff_packing.push_back(std::make_tuple(ff1, slice, 1));
-                            tile_ffs.push_back(ff1);
-                            packed_cells.insert(ff1->name);
+                            if (net_or_nullptr(ff1, ctx->id("CLK")) == net_or_nullptr(slice, ctx->id("WCK"))) {
+                                ff_packing.push_back(std::make_tuple(ff1, slice, 1));
+                                tile_ffs.push_back(ff1);
+                                packed_cells.insert(ff1->name);
+                            }
                         }
                     }
                 }