static: Allow a custom delay prediction function

Signed-off-by: gatecat <gatecat@ds0.me>

common/place/placer_static.cc

@@ -1295,8 +1295,8 @@ class StaticPlacer
             RealPair drv_loc = cell_loc(ni->driver.cell, false);
             for (auto usr : ni->users.enumerate()) {
                 RealPair usr_loc = cell_loc(usr.value.cell, false);
-                delay_t est_delay = cfg.timing_c + cfg.timing_mx * std::abs(drv_loc.x - usr_loc.x) +
-                                    cfg.timing_my * std::abs(drv_loc.y - usr_loc.y);
+                delay_t est_delay = cfg.predict_delay(ctx, cfg, Loc(drv_loc.x, drv_loc.y, 0), ni->driver.port,
+                                                      Loc(usr_loc.x, usr_loc.y, 0), usr.value.port);
                 tmg.set_route_delay(CellPortKey(usr.value), DelayPair(est_delay));
             }
         }
@@ -1721,6 +1721,12 @@ PlacerStaticCfg::PlacerStaticCfg(Context *ctx)
 
     hpwl_scale_x = 1;
     hpwl_scale_y = 1;
+
+    predict_delay = [](Context *ctx, const PlacerStaticCfg &cfg, Loc src_loc, IdString /*src_pin*/, Loc dst_loc,
+                       IdString /*dst_pin*/) -> delay_t {
+        return cfg.timing_c + delay_t(cfg.timing_mx * std::abs(dst_loc.x - src_loc.x)) +
+               delay_t(cfg.timing_my * std::abs(dst_loc.y - src_loc.y));
+    };
 }
 
 NEXTPNR_NAMESPACE_END

common/place/placer_static.h

@@ -72,6 +72,9 @@ struct PlacerStaticCfg
     // this is an optional callback to override the area of a cell e.g. based on configuration
     std::function<std::optional<StaticRect>(Context *, const CellInfo *)> get_cell_area_override =
             [](Context *, const CellInfo *) { return std::optional<StaticRect>{}; };
+
+    // override the default delay estimation formula (we can't use predictDelay because we don't have concrete bels)
+    std::function<delay_t(Context *, const PlacerStaticCfg &, Loc, IdString, Loc, IdString)> predict_delay;
 };
 
 extern bool placer_static(Context *ctx, PlacerStaticCfg cfg);

ecp5/arch.cc

@@ -630,6 +630,18 @@ void configure_static(Arch *arch, PlacerStaticCfg &cfg)
     cfg.timing_c = (120 - 22 * arch->args.speed) * 6;
     cfg.timing_mx = (120 - 22 * arch->args.speed);
     cfg.timing_my = (120 - 22 * arch->args.speed);
+
+    cfg.predict_delay = [](Context *ctx, const PlacerStaticCfg &cfg, Loc src_loc, IdString src_pin, Loc dst_loc,
+                           IdString dst_pin) -> delay_t {
+        if ((src_pin == id_FCO && dst_pin == id_FCI) || dst_pin.in(id_FXA, id_FXB) ||
+            (src_pin == id_F && dst_pin == id_DI))
+            return 0;
+
+        int dx = abs(src_loc.x - dst_loc.x), dy = abs(src_loc.y - dst_loc.y);
+
+        return (80 - 9 * ctx->args.speed) *
+               (6 + std::max(dx - 5, 0) + std::max(dy - 5, 0) + 2 * (std::min(dx, 5) + std::min(dy, 5)));
+    };
 }
 } // namespace
 

himbaechel/uarch/xilinx/xilinx.cc

@@ -362,6 +362,16 @@ void XilinxImpl::configurePlacerStatic(PlacerStaticCfg &cfg)
     cfg.timing_mx = 25;
     cfg.timing_my = 50;
 
+    cfg.predict_delay = [](Context *ctx, const PlacerStaticCfg &cfg, Loc src_loc, IdString src_pin, Loc dst_loc,
+                           IdString dst_pin) -> delay_t {
+        if (dst_pin == id_CIN && src_pin == id_CO3)
+            return 0;
+        // TODO: improve sophistication here based on old nextpnr-xilinx code
+        int dist_x = std::abs(dst_loc.x - src_loc.x), dist_y = std::abs(dst_loc.y - src_loc.y);
+        return 500 + 12 * (2 * std::max(dist_y - 6, 0) + 4 * std::min(dist_y, 6) + std::max(dist_x - 12, 0) +
+                           2 * std::min(dist_x, 12));
+    };
+
     {
         cfg.cell_groups.emplace_back();
         auto &comb = cfg.cell_groups.back();