gowin: Let the placer know about global networks

Refactor in order to detect networks that will be routed in a special
mode earlier. This makes it possible to mark the source of such networks
as a global buffer, thereby removing their influence on element
placement.

In addition, timing classes are set for some cells.

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

1 files changed, 65 insertions, 1 deletions

diff --git a/gowin/globals.h b/gowin/globals.h
index 41a8727a..69232d7c 100644
--- a/gowin/globals.h
+++ b/gowin/globals.h
@@ -18,10 +18,74 @@
  *
  */
 
+#ifndef GOWIN_GLOBALS_H
+#define GOWIN_GLOBALS_H
+
 #include "nextpnr.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
-void route_gowin_globals(Context *ctx);
+class GowinGlobalRouter
+{
+  public:
+    GowinGlobalRouter() {}
+
+  private:
+    // wire -> clock#
+    dict<WireId, int> used_wires;
+
+    // ordered nets
+    struct globalnet_t
+    {
+        IdString name;
+        int clock_ports;
+        BelId clock_io_bel;
+        WireId clock_io_wire; // IO wire if there is one
+        int clock;            // clock #
+
+        globalnet_t()
+        {
+            name = IdString();
+            clock_ports = 0;
+            clock_io_bel = BelId();
+            clock_io_wire = WireId();
+            clock = -1;
+        }
+        globalnet_t(IdString _name)
+        {
+            name = _name;
+            clock_ports = 0;
+            clock_io_bel = BelId();
+            clock_io_wire = WireId();
+            clock = -1;
+        }
+
+        // sort
+        bool operator<(const globalnet_t &other) const
+        {
+            if ((clock_io_wire != WireId()) ^ (other.clock_io_wire != WireId())) {
+                return !(clock_io_wire != WireId());
+            }
+            return clock_ports < other.clock_ports;
+        }
+        // search
+        bool operator==(const globalnet_t &other) const { return name == other.name; }
+    };
+
+    // discovered nets
+    std::vector<globalnet_t> nets;
+
+    bool is_clock_port(PortRef const &user);
+    std::pair<WireId, BelId> clock_io(Context *ctx, PortRef const &driver);
+    void gather_clock_nets(Context *ctx, std::vector<globalnet_t> &clock_nets);
+    IdString route_to_non_clock_port(Context *ctx, WireId const dstWire, int clock, pool<IdString> &used_pips,
+                                     pool<IdString> &undo_wires);
+    void route_net(Context *ctx, globalnet_t const &net);
+
+  public:
+    void mark_globals(Context *ctx);
+    void route_globals(Context *ctx);
+};
 
 NEXTPNR_NAMESPACE_END
+#endif // GOWIN_GLOBALS_H