From 8624a48bcf8912966aea2b1d72ae96ea4d1e4fba Mon Sep 17 00:00:00 2001
From: gatecat <gatecat@ds0.me>
Date: Thu, 16 Jul 2026 12:10:35 +0200
Subject: [PATCH] ecp5: Make fabric routed ECLK an error

Signed-off-by: gatecat <gatecat@ds0.me>
---
 ecp5/globals.cc | 9 ++++++++-
 ecp5/main.cc    | 4 ++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/ecp5/globals.cc b/ecp5/globals.cc
index 4a439eaf..7c13a734 100644
--- a/ecp5/globals.cc
+++ b/ecp5/globals.cc
@@ -671,7 +671,14 @@ class Ecp5GlobalRouter
                             cursor = ctx->getPipDstWire(pip);
                         }
                     } else {
-                        log_info("        no route found, general routing will be used.\n");
+                        if (bool_or_default(ctx->settings, ctx->id("arch.fabric_eclk"))) {
+                            log_info("        no route found, general routing will be used.\n");
+                        } else {
+                            log_error("Unable to route edge clock source '%s' to pin '%s.%s' using dedicated routing.\n"
+                                      "Use --allow-fabric-eclk to use fabric routing with indeterminate skew, or "
+                                      "consider using an ECLKBRIDGECS to cross the device.\n",
+                                      ctx->nameOf(ni), ctx->nameOf(ci), ctx->nameOf(pin));
+                        }
                     }
                 }
             }
diff --git a/ecp5/main.cc b/ecp5/main.cc
index c08cebb1..1501efb5 100644
--- a/ecp5/main.cc
+++ b/ecp5/main.cc
@@ -86,6 +86,8 @@ po::options_description ECP5CommandHandler::getArchOptions()
             "disable IO buffer insertion and global promotion/routing, for building pre-routed blocks (experimental)");
     specific.add_options()("disable-router-lutperm", "don't allow the router to permute LUT inputs");
 
+    specific.add_options()("allow-fabric-eclk", "allow fabric routing of ECLKs");
+
     return specific;
 }
 void ECP5CommandHandler::validate()
@@ -258,6 +260,8 @@ std::unique_ptr<Context> ECP5CommandHandler::createContext(dict<std::string, Pro
         ctx->settings[ctx->id("arch.ooc")] = 1;
     if (vm.count("disable-router-lutperm"))
         ctx->settings[ctx->id("arch.disable_router_lutperm")] = 1;
+    if (vm.count("allow-fabric-eclk"))
+        ctx->settings[ctx->id("arch.fabric_eclk")] = 1;
     return ctx;
 }