diff --git a/common/fast_bels.h b/common/fast_bels.h
index 54ac97d9..bc8e39bf 100644
--- a/common/fast_bels.h
+++ b/common/fast_bels.h
@@ -30,7 +30,7 @@ NEXTPNR_NAMESPACE_BEGIN
 struct FastBels {
     struct TypeData {
         size_t type_index;
-        size_t number_of_possible_bels;
+        int number_of_possible_bels;
     };
 
     FastBels(Context *ctx, int minBelsForGridPick) : ctx(ctx), minBelsForGridPick(minBelsForGridPick) {}
@@ -133,7 +133,7 @@ struct FastBels {
 
     typedef std::vector<std::vector<std::vector<BelId>>> FastBelsData;
 
-    size_t getBelsForCellType(IdString cell_type, FastBelsData **data) {
+    int getBelsForCellType(IdString cell_type, FastBelsData **data) {
         auto iter = cell_types.find(cell_type);
         if(iter == cell_types.end()) {
             addCellType(cell_type);
diff --git a/gowin/arch.cc b/gowin/arch.cc
index b3a6a47d..cd4048ca 100644
--- a/gowin/arch.cc
+++ b/gowin/arch.cc
@@ -739,6 +739,15 @@ Arch::Arch(ArchArgs args) : args(args)
     }
     // Dummy for empty decals
     decal_graphics[IdString()];
+
+    std::unordered_set<IdString> bel_types;
+    for(BelId bel : getBels()) {
+        bel_types.insert(getBelType(bel));
+    }
+
+    for(IdString bel_type : bel_types) {
+        cell_types.push_back(bel_type);
+    }
 }
 
 void IdString::initialize_arch(const BaseCtx *ctx)
diff --git a/gowin/arch.h b/gowin/arch.h
index 100ba5ba..f7379a3c 100644
--- a/gowin/arch.h
+++ b/gowin/arch.h
@@ -425,6 +425,41 @@ struct Arch : BaseCtx
     bool isValidBelForCellType(IdString cell_type, BelId bel) const {
         return cell_type == getBelType(bel);
     }
+
+    const std::vector<IdString> &getCellTypes() const {
+        return cell_types;
+    }
+
+    std::vector<PartitionId> getPartitions() const {
+        return cell_types;
+    }
+
+    IdString getPartitionName(PartitionId partition) const {
+        return partition;
+    }
+
+    PartitionId getPartitionByName(IdString name) const {
+        return name;
+    }
+
+    PartitionId getPartitionForBel(BelId bel) const {
+        return getBelType(bel);
+    }
+
+    PartitionId getPartitionForCellType(IdString cell_type) const {
+        return cell_type;
+    }
+
+    std::vector<BelId> getBelsForPartition(PartitionId partition) const {
+        std::vector<BelId> bels;
+        for(BelId bel : getBels()) {
+            if(getBelType(bel) == partition) {
+                bels.push_back(bel);
+            }
+        }
+        return bels;
+    }
+
     bool isValidBelForCell(CellInfo *cell, BelId bel) const;
     bool isBelLocationValid(BelId bel) const;
 
@@ -437,6 +472,8 @@ struct Arch : BaseCtx
     // Internal usage
     void assignArchInfo();
     bool cellsCompatible(const CellInfo **cells, int count) const;
+
+    std::vector<IdString> cell_types;
 };
 
 NEXTPNR_NAMESPACE_END
diff --git a/gowin/archdefs.h b/gowin/archdefs.h
index adeb8a0d..96ab5c6d 100644
--- a/gowin/archdefs.h
+++ b/gowin/archdefs.h
@@ -72,6 +72,7 @@ typedef IdString WireId;
 typedef IdString PipId;
 typedef IdString GroupId;
 typedef IdString DecalId;
+typedef IdString PartitionId;
 
 struct ArchNetInfo
 {
diff --git a/ice40/arch.cc b/ice40/arch.cc
index e450e682..fcf6506d 100644
--- a/ice40/arch.cc
+++ b/ice40/arch.cc
@@ -115,6 +115,19 @@ Arch::Arch(ArchArgs args) : args(args)
     wire_to_net.resize(chip_info->wire_data.size());
     pip_to_net.resize(chip_info->pip_data.size());
     switches_locked.resize(chip_info->num_switches);
+
+    std::unordered_set<IdString> bel_types;
+    for(BelId bel : getBels()) {
+        bel_types.insert(getBelType(bel));
+    }
+
+    for(IdString bel_type : bel_types) {
+        cell_types.push_back(bel_type);
+
+        PartitionId partition;
+        partition.name = bel_type;
+        partitions.push_back(partition);
+    }
 }
 
 // -----------------------------------------------------------------------
diff --git a/ice40/arch.h b/ice40/arch.h
index 60171a4c..18fc3aeb 100644
--- a/ice40/arch.h
+++ b/ice40/arch.h
@@ -826,6 +826,46 @@ struct Arch : BaseCtx
         return cell_type == getBelType(bel);
     }
 
+    const std::vector<IdString> &getCellTypes() const {
+        return cell_types;
+    }
+
+    std::vector<PartitionId> getPartitions() const {
+        return partitions;
+    }
+
+    IdString getPartitionName(PartitionId partition) const {
+        return partition.name;
+    }
+
+    PartitionId getPartitionByName(IdString name) const {
+        PartitionId partition;
+        partition.name = name;
+        return partition;
+    }
+
+    PartitionId getPartitionForBel(BelId bel) const {
+        PartitionId partition;
+        partition.name = getBelType(bel);
+        return partition;
+    }
+
+    PartitionId getPartitionForCellType(IdString cell_type) const {
+        PartitionId partition;
+        partition.name = cell_type;
+        return partition;
+    }
+
+    std::vector<BelId> getBelsForPartition(PartitionId partition) const {
+        std::vector<BelId> bels;
+        for(BelId bel : getBels()) {
+            if(getBelType(bel) == partition.name) {
+                bels.push_back(bel);
+            }
+        }
+        return bels;
+    }
+
     // Whether or not a given cell can be placed at a given Bel
     // This is not intended for Bel type checks, but finer-grained constraints
     // such as conflicting set/reset signals, etc
@@ -867,6 +907,9 @@ struct Arch : BaseCtx
     static const std::vector<std::string> availablePlacers;
     static const std::string defaultRouter;
     static const std::vector<std::string> availableRouters;
+
+    std::vector<IdString> cell_types;
+    std::vector<PartitionId> partitions;
 };
 
 void ice40DelayFuzzerMain(Context *ctx);
diff --git a/ice40/archdefs.h b/ice40/archdefs.h
index e95953f1..1b7821b0 100644
--- a/ice40/archdefs.h
+++ b/ice40/archdefs.h
@@ -170,6 +170,17 @@ struct ArchCellInfo
     };
 };
 
+struct PartitionId {
+    IdString name;
+
+    bool operator==(const PartitionId &other) const { return (name == other.name); }
+    bool operator!=(const PartitionId &other) const { return (name != other.name); }
+    bool operator<(const PartitionId &other) const
+    {
+        return name < other.name;
+    }
+};
+
 NEXTPNR_NAMESPACE_END
 
 namespace std {
@@ -213,4 +224,15 @@ template <> struct hash<NEXTPNR_NAMESPACE_PREFIX DecalId>
         return seed;
     }
 };
+
+template <> struct hash<NEXTPNR_NAMESPACE_PREFIX PartitionId>
+{
+    std::size_t operator()(const NEXTPNR_NAMESPACE_PREFIX PartitionId &partition) const noexcept
+    {
+        std::size_t seed = 0;
+        boost::hash_combine(seed, hash<NEXTPNR_NAMESPACE_PREFIX IdString>()(partition.name));
+        return seed;
+    }
+};
+
 } // namespace std
diff --git a/nexus/arch.cc b/nexus/arch.cc
index eadfaa4b..659703de 100644
--- a/nexus/arch.cc
+++ b/nexus/arch.cc
@@ -171,6 +171,19 @@ Arch::Arch(ArchArgs args) : args(args)
     }
     if (!speed_grade)
         log_error("Unknown speed grade '%s'.\n", speed.c_str());
+
+    std::unordered_set<IdString> bel_types;
+    for(BelId bel : getBels()) {
+        bel_types.insert(getBelType(bel));
+    }
+
+    for(IdString bel_type : bel_types) {
+        cell_types.push_back(bel_type);
+
+        PartitionId partition;
+        partition.name = bel_type;
+        partitions.push_back(partition);
+    }
 }
 
 // -----------------------------------------------------------------------
@@ -635,8 +648,8 @@ bool Arch::place()
         cfg.ioBufTypes.insert(id_SEIO18_CORE);
         cfg.ioBufTypes.insert(id_OSC_CORE);
         cfg.cellGroups.emplace_back();
-        cfg.cellGroups.back().insert(id_OXIDE_COMB);
-        cfg.cellGroups.back().insert(id_OXIDE_FF);
+        cfg.cellGroups.back().insert({id_OXIDE_COMB});
+        cfg.cellGroups.back().insert({id_OXIDE_FF});
 
         cfg.beta = 0.5;
         cfg.criticalityExponent = 7;
diff --git a/nexus/arch.h b/nexus/arch.h
index 31bfa603..dfd00f90 100644
--- a/nexus/arch.h
+++ b/nexus/arch.h
@@ -1340,6 +1340,46 @@ struct Arch : BaseCtx
         return cell_type == getBelType(bel);
     }
 
+    const std::vector<IdString> &getCellTypes() const {
+        return cell_types;
+    }
+
+    std::vector<PartitionId> getPartitions() const {
+        return partitions;
+    }
+
+    IdString getPartitionName(PartitionId partition) const {
+        return partition.name;
+    }
+
+    PartitionId getPartitionByName(IdString name) const {
+        PartitionId partition;
+        partition.name = name;
+        return partition;
+    }
+
+    PartitionId getPartitionForBel(BelId bel) const {
+        PartitionId partition;
+        partition.name = getBelType(bel);
+        return partition;
+    }
+
+    PartitionId getPartitionForCellType(IdString cell_type) const {
+        PartitionId partition;
+        partition.name = cell_type;
+        return partition;
+    }
+
+    std::vector<BelId> getBelsForPartition(PartitionId partition) const {
+        std::vector<BelId> bels;
+        for(BelId bel : getBels()) {
+            if(getBelType(bel) == partition.name) {
+                bels.push_back(bel);
+            }
+        }
+        return bels;
+    }
+
     // Whether or not a given cell can be placed at a given Bel
     // This is not intended for Bel type checks, but finer-grained constraints
     // such as conflicting set/reset signals, etc
@@ -1541,6 +1581,9 @@ struct Arch : BaseCtx
 
     // -------------------------------------------------
     void write_fasm(std::ostream &out) const;
+
+    std::vector<IdString> cell_types;
+    std::vector<PartitionId> partitions;
 };
 
 NEXTPNR_NAMESPACE_END
diff --git a/nexus/archdefs.h b/nexus/archdefs.h
index adc1342c..12bbd228 100644
--- a/nexus/archdefs.h
+++ b/nexus/archdefs.h
@@ -114,6 +114,17 @@ struct PipId
     }
 };
 
+struct PartitionId {
+    IdString name;
+
+    bool operator==(const PartitionId &other) const { return (name == other.name); }
+    bool operator!=(const PartitionId &other) const { return (name != other.name); }
+    bool operator<(const PartitionId &other) const
+    {
+        return name < other.name;
+    }
+};
+
 struct GroupId
 {
     enum : int8_t
@@ -250,4 +261,15 @@ template <> struct hash<NEXTPNR_NAMESPACE_PREFIX DecalId>
         return seed;
     }
 };
+
+template <> struct hash<NEXTPNR_NAMESPACE_PREFIX PartitionId>
+{
+    std::size_t operator()(const NEXTPNR_NAMESPACE_PREFIX PartitionId &partition) const noexcept
+    {
+        std::size_t seed = 0;
+        boost::hash_combine(seed, hash<NEXTPNR_NAMESPACE_PREFIX IdString>()(partition.name));
+        return seed;
+    }
+};
+
 } // namespace std