ecp5: Add support for pin name constraints using 'LOC' attributes

Signed-off-by: David Shah <davey1576@gmail.com>

ecp5/arch.cc

@@ -118,6 +118,16 @@ Arch::Arch(ArchArgs args) : args(args)
         log_error("Unsupported ECP5 chip type.\n");
     }
 #endif
+    package_info = nullptr;
+    for (int i = 0; i < chip_info->num_packages; i++) {
+        if (args.package == chip_info->package_info[i].name.get()) {
+            package_info = &(chip_info->package_info[i]);
+            break;
+        }
+    }
+
+    if (!package_info)
+        log_error("Unsupported package '%s' for '%s'.\n", args.package.c_str(), getChipName().c_str());
 
     id_trellis_slice = id("TRELLIS_SLICE");
     id_clk = id("CLK");
@@ -282,9 +292,28 @@ IdString Arch::getPipName(PipId pip) const
 
 // -----------------------------------------------------------------------
 
-BelId Arch::getPackagePinBel(const std::string &pin) const { return BelId(); }
+BelId Arch::getPackagePinBel(const std::string &pin) const
+{
+    for (int i = 0; i < package_info->num_pins; i++) {
+        if (package_info->pin_data[i].name.get() == pin) {
+            BelId bel;
+            bel.location = package_info->pin_data[i].abs_loc;
+            bel.index = package_info->pin_data[i].bel_index;
+            return bel;
+        }
+    }
+    return BelId();
+}
 
-std::string Arch::getBelPackagePin(BelId bel) const { return ""; }
+std::string Arch::getBelPackagePin(BelId bel) const
+{
+    for (int i = 0; i < package_info->num_pins; i++) {
+        if (package_info->pin_data[i].abs_loc == bel.location && package_info->pin_data[i].bel_index == bel.index) {
+            return package_info->pin_data[i].name.get();
+        }
+    }
+    return "";
+}
 // -----------------------------------------------------------------------
 
 void Arch::estimatePosition(BelId bel, int &x, int &y, bool &gb) const

ecp5/arch.h

@@ -363,6 +363,7 @@ struct ArchArgs
 struct Arch : BaseCtx
 {
     const ChipInfoPOD *chip_info;
+    const PackageInfoPOD *package_info;
 
     mutable std::unordered_map<IdString, BelId> bel_by_name;
     mutable std::unordered_map<IdString, WireId> wire_by_name;

ecp5/main.cc

@@ -68,6 +68,8 @@ int main(int argc, char *argv[])
         options.add_options()("45k", "set device type to LFE5U-45F");
         options.add_options()("85k", "set device type to LFE5U-85F");
 
+        options.add_options()("package", po::value<std::string>(), "select device package (defaults to CABGA381)");
+
         options.add_options()("json", po::value<std::string>(), "JSON design file to ingest");
         options.add_options()("seed", po::value<int>(), "seed value for random number generator");
 
@@ -123,8 +125,10 @@ int main(int argc, char *argv[])
             args.type = ArchArgs::LFE5U_45F;
         if (vm.count("85k"))
             args.type = ArchArgs::LFE5U_85F;
-
+        if (vm.count("package"))
-        args.package = "CABGA381";
+            args.package = vm["package"].as<std::string>();
+        else
+            args.package = "CABGA381";
         args.speed = 6;
         std::unique_ptr<Context> ctx = std::unique_ptr<Context>(new Context(args));
 

ecp5/pack.cc

@@ -232,8 +232,23 @@ class Ecp5Packer
                 } else {
                     log_error("TRELLIS_IO required on all top level IOs...\n");
                 }
+
                 packed_cells.insert(ci->name);
                 std::copy(ci->attrs.begin(), ci->attrs.end(), std::inserter(trio->attrs, trio->attrs.begin()));
+
+                auto loc_attr = trio->attrs.find(ctx->id("LOC"));
+                if (loc_attr != trio->attrs.end()) {
+                    std::string pin = loc_attr->second;
+                    BelId pinBel = ctx->getPackagePinBel(pin);
+                    if (pinBel == BelId()) {
+                        log_error("IO pin '%s' constrained to pin '%s', which does not exist for package '%s'.\n",
+                                  trio->name.c_str(ctx), pin.c_str(), ctx->args.package.c_str());
+                    } else {
+                        log_info("pin '%s' constrained to Bel '%s'.\n", trio->name.c_str(ctx),
+                                 ctx->getBelName(pinBel).c_str(ctx));
+                    }
+                    trio->attrs[ctx->id("BEL")] = ctx->getBelName(pinBel).str(ctx);
+                }
             }
         }
         flush_cells();

ecp5/synth/blinky.v

@@ -5,32 +5,32 @@ module top(input clk_pin, input btn_pin, output [7:0] led_pin, output gpio0_pin)
     wire btn;
     wire gpio0;
 
-	(* BEL="X0/Y35/PIOA" *) (* IO_TYPE="LVCMOS33" *)
+	(* LOC="G2" *) (* IO_TYPE="LVCMOS33" *)
 	TRELLIS_IO #(.DIR("INPUT")) clk_buf (.B(clk_pin), .O(clk));
 
-	(* BEL="X4/Y71/PIOA" *) (* IO_TYPE="LVCMOS33" *)
+	(* LOC="R1" *) (* IO_TYPE="LVCMOS33" *)
 	TRELLIS_IO #(.DIR("INPUT")) btn_buf (.B(btn_pin), .O(btn));
 
-	(* BEL="X0/Y23/PIOC" *) (* IO_TYPE="LVCMOS33" *)
+	(* LOC="B2" *) (* IO_TYPE="LVCMOS33" *)
 	TRELLIS_IO #(.DIR("OUTPUT")) led_buf_0 (.B(led_pin[0]), .I(led[0]));
-	(* BEL="X0/Y23/PIOD" *) (* IO_TYPE="LVCMOS33" *)
+	(* LOC="C2" *) (* IO_TYPE="LVCMOS33" *)
 	TRELLIS_IO #(.DIR("OUTPUT")) led_buf_1 (.B(led_pin[1]), .I(led[1]));
-	(* BEL="X0/Y26/PIOA" *) (* IO_TYPE="LVCMOS33" *)
+	(* LOC="C1" *) (* IO_TYPE="LVCMOS33" *)
 	TRELLIS_IO #(.DIR("OUTPUT")) led_buf_2 (.B(led_pin[2]), .I(led[2]));
-    (* BEL="X0/Y26/PIOC" *) (* IO_TYPE="LVCMOS33" *)
+    (* LOC="D2" *) (* IO_TYPE="LVCMOS33" *)
 	TRELLIS_IO #(.DIR("OUTPUT")) led_buf_3 (.B(led_pin[3]), .I(led[3]));
 
-	(* BEL="X0/Y26/PIOB" *) (* IO_TYPE="LVCMOS33" *)
+	(* LOC="D1" *) (* IO_TYPE="LVCMOS33" *)
 	TRELLIS_IO #(.DIR("OUTPUT")) led_buf_4 (.B(led_pin[4]), .I(led[4]));
-	(* BEL="X0/Y32/PIOD" *) (* IO_TYPE="LVCMOS33" *)
+	(* LOC="E2" *) (* IO_TYPE="LVCMOS33" *)
 	TRELLIS_IO #(.DIR("OUTPUT")) led_buf_5 (.B(led_pin[5]), .I(led[5]));
-	(* BEL="X0/Y26/PIOD" *) (* IO_TYPE="LVCMOS33" *)
+	(* LOC="E1" *) (* IO_TYPE="LVCMOS33" *)
 	TRELLIS_IO #(.DIR("OUTPUT")) led_buf_6 (.B(led_pin[6]), .I(led[6]));
-    (* BEL="X0/Y29/PIOD" *) (* IO_TYPE="LVCMOS33" *)
+    (* LOC="H3" *) (* IO_TYPE="LVCMOS33" *)
 	TRELLIS_IO #(.DIR("OUTPUT")) led_buf_7 (.B(led_pin[7]), .I(led[7]));
 
 
-	(* BEL="X0/Y62/PIOD" *) (* IO_TYPE="LVCMOS33" *)
+	(* LOC="L2" *) (* IO_TYPE="LVCMOS33" *)
 	TRELLIS_IO #(.DIR("OUTPUT")) gpio0_buf (.B(gpio0_pin), .I(gpio0));
 
     localparam ctr_width = 24;