gowin: improve clock wire routing

The dedicated router for clock wires now understands not only the IO
pins but also the rPLL outputs as clock sources.

This simple router sets an optimal route, so it is now the default
router. It can be disabled with the --disable-globals command line flag
if desired, but this is not recommended due to possible clock skew.

Still for GW1N-4C there is no good router for clock wires as there
external quartz resonator is connected via PLL.

Signed-off-by: YRabbit <rabbit@yrabbit.cyou>

1 files changed, 5 insertions, 5 deletions

diff --git a/gowin/main.cc b/gowin/main.cc
index 36bd8656..ccf4d190 100644
--- a/gowin/main.cc
+++ b/gowin/main.cc
@@ -51,7 +51,8 @@ po::options_description GowinCommandHandler::getArchOptions()
     specific.add_options()("device", po::value<std::string>(), "device name");
     specific.add_options()("family", po::value<std::string>(), "family name");
     specific.add_options()("cst", po::value<std::string>(), "physical constraints file");
-    specific.add_options()("enable-globals", "separate routing of the clocks");
+    specific.add_options()("enable-globals", "enable separate routing of the clocks");
+    specific.add_options()("disable-globals", "disable separate routing of the clocks");
     specific.add_options()("enable-auto-longwires", "automatic detection and routing of long wires");
     return specific;
 }
@@ -84,11 +85,10 @@ std::unique_ptr<Context> GowinCommandHandler::createContext(dict<std::string, Pr
 
     auto ctx = std::unique_ptr<Context>(new Context(chipArgs));
     // routing options
-    // the default values will change in the future
-    ctx->settings[ctx->id("arch.enable-globals")] = 0;
+    ctx->settings[ctx->id("arch.enable-globals")] = 1;
     ctx->settings[ctx->id("arch.enable-auto-longwires")] = 0;
-    if (vm.count("enable-globals")) {
-        ctx->settings[ctx->id("arch.enable-globals")] = 1;
+    if (vm.count("disable-globals")) {
+        ctx->settings[ctx->id("arch.enable-globals")] = 0;
     }
     if (vm.count("enable-auto-longwires")) {
         ctx->settings[ctx->id("arch.enable-auto-longwires")] = 1;