1 files changed, 22 insertions, 37 deletions

diff --git a/machxo2/pack.cc b/machxo2/pack.cc
index 7c05b22a..ecf8b88d 100644
--- a/machxo2/pack.cc
+++ b/machxo2/pack.cc
@@ -176,48 +176,33 @@ static void pack_io(Context *ctx)
                 disconnect_port(ctx, ci, p.first);
             packed_cells.insert(ci->name);
         } else if(is_facade_iob(ctx, ci)) {
-            // If net attached to PAD port of FACADE_IO has a LOC attribute OR
-            // FACADE_IO has LOC attribute, convert the LOC (pin) to a BEL
-            // attribute and place FACADE_IO at resulting BEL location.
-
-            auto pad_net = ci->ports[id_PAD].net;
-            auto loc_attr_pad = pad_net->attrs.find(ctx->id("LOC"));
+            // If FACADE_IO has LOC attribute, convert the LOC (pin) to a BEL
+            // attribute and place FACADE_IO at resulting BEL location. A BEL
+            // attribute already on a FACADE_IO is an error. Attributes on
+            // the pin attached to the PAD of FACADE_IO are ignored by this
+            // packing phase.
             auto loc_attr_cell = ci->attrs.find(ctx->id("LOC"));
             auto bel_attr_cell = ci->attrs.find(ctx->id("BEL"));
 
-            // Handle errors
-            if(loc_attr_pad != pad_net->attrs.end() && loc_attr_cell != ci->attrs.end())
-                log_error("IO buffer %s and attached PAD net %s both have LOC attributes.\n",
-                    ci->name.c_str(ctx), pad_net->name.c_str(ctx));
-            else if(loc_attr_pad != pad_net->attrs.end() && bel_attr_cell != ci->attrs.end())
-                log_error("IO buffer %s has a BEL attribute and attached PAD net %s has a LOC attribute.\n",
-                    ci->name.c_str(ctx), pad_net->name.c_str(ctx));
-            else if(loc_attr_cell != ci->attrs.end() && bel_attr_cell != ci->attrs.end())
-                log_error("IO buffer %s has both a BEL attribute and LOC attribute.\n",
-                    ci->name.c_str(ctx));
-
-            std::string pin;
-            // At this point only PAD net or FACADE_IO has LOC attribute.
-            if(loc_attr_pad != pad_net->attrs.end()) {
-                pin = loc_attr_pad->second.as_string();
-                log_info("found LOC attribute on net %s. Will constrain IO buffer %s.\n",
-                    pad_net->name.c_str(ctx), ci->name.c_str(ctx));
-            } else if(loc_attr_cell != ci->attrs.end()) {
+            if(loc_attr_cell != ci->attrs.end()) {
+                if (bel_attr_cell != ci->attrs.end()) {
+                    log_error("IO buffer %s has both a BEL attribute and LOC attribute.\n",
+                        ci->name.c_str(ctx));
+                }
+
                 log_info("found LOC attribute on IO buffer %s.\n", ci->name.c_str(ctx));
-                pin = loc_attr_cell->second.as_string();
-            } else
-                // Nothing to do if no LOC attrs.
-                continue;
-
-            BelId pinBel = ctx->getPackagePinBel(pin);
-            if (pinBel == BelId()) {
-                log_error("IO buffer '%s' constrained to pin '%s', which does not exist for package '%s'.\n",
-                          ci->name.c_str(ctx), pin.c_str(), ctx->args.package.c_str());
-            } else {
-                log_info("pin '%s' constrained to Bel '%s'.\n", ci->name.c_str(ctx),
-                         ctx->getBelName(pinBel).c_str(ctx));
+                std::string pin = loc_attr_cell->second.as_string();
+
+                BelId pinBel = ctx->getPackagePinBel(pin);
+                if (pinBel == BelId()) {
+                    log_error("IO buffer '%s' constrained to pin '%s', which does not exist for package '%s'.\n",
+                              ci->name.c_str(ctx), pin.c_str(), ctx->args.package.c_str());
+                } else {
+                    log_info("pin '%s' constrained to Bel '%s'.\n", ci->name.c_str(ctx),
+                             ctx->getBelName(pinBel).c_str(ctx));
+                }
+                ci->attrs[ctx->id("BEL")] = ctx->getBelName(pinBel).str(ctx);
             }
-            ci->attrs[ctx->id("BEL")] = ctx->getBelName(pinBel).str(ctx);
         }
     }