Add getBelPinsForCellPin to Arch API

This is a basic implementation, without considering "M of N"
arrangements (e.g. for LUT permuation where you only want to route to 1
out of 4/6 sinks) or using a type other than IdString to identify bel
pins.

But this is also enough to start working out where in nextpnr will break
due to removing the 1:1 cell:bel pin cardinality, as a next step.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/gowin/arch.h b/gowin/arch.h
index c5ef0a2e..eab75899 100644
--- a/gowin/arch.h
+++ b/gowin/arch.h
@@ -251,6 +251,7 @@ struct ArchRanges
     using TileBelsRangeT = const std::vector<BelId> &;
     using BelAttrsRangeT = const std::map<IdString, std::string> &;
     using BelPinsRangeT = std::vector<IdString>;
+    using CellBelPinRangeT = std::array<IdString, 1>;
     // Wires
     using AllWiresRangeT = const std::vector<WireId> &;
     using DownhillPipRangeT = const std::vector<PipId> &;
@@ -375,6 +376,7 @@ struct Arch : BaseArch<ArchRanges>
     WireId getBelPinWire(BelId bel, IdString pin) const override;
     PortType getBelPinType(BelId bel, IdString pin) const override;
     std::vector<IdString> getBelPins(BelId bel) const override;
+    std::array<IdString, 1> getBelPinsForCellPin(CellInfo *cell_info, IdString pin) const override;
 
     WireId getWireByName(IdStringList name) const override;
     IdStringList getWireName(WireId wire) const override;