Add SF2 IO buffer insertion

Signed-off-by: Clifford Wolf <clifford@clifford.at>

examples/igloo2/example.v

@@ -1,5 +1,6 @@
 module example (
 	input  clk,
+	input  EN,
 	output LED1,
 	output LED2,
 	output LED3,
@@ -14,7 +15,7 @@ module example (
 	reg [BITS-1:0] outcnt;
 
 	always @(posedge clk) begin
-		counter <= counter + 1;
+		counter <= counter + EN;
 		outcnt <= counter >> LOG2DELAY;
 	end
 

examples/igloo2/libero.tcl

@@ -5,7 +5,7 @@ file delete -force proj
 new_project \
     -name example \
     -location proj \
-    -block_mode 1 \
+    -block_mode 0 \
     -hdl "VERILOG" \
     -family IGLOO2 \
     -die PA4MGL500 \

techlibs/sf2/Makefile.inc

@@ -1,5 +1,6 @@
 
 OBJS += techlibs/sf2/synth_sf2.o
+OBJS += techlibs/sf2/sf2_iobs.o
 
 $(eval $(call add_share_file,share/sf2,techlibs/sf2/arith_map.v))
 $(eval $(call add_share_file,share/sf2,techlibs/sf2/cells_map.v))

techlibs/sf2/cells_sim.v

@@ -73,3 +73,24 @@ module CFG4 (
 	parameter [15:0] INIT = 16'h0;
 	assign Y = INIT >> {D, C, B, A};
 endmodule
+
+module CLKBUF (
+	input PAD,
+	output Y
+);
+	assign Y = PAD;
+endmodule
+
+module INBUF (
+	input PAD,
+	output Y
+);
+	assign Y = PAD;
+endmodule
+
+module OUTBUF (
+	input D,
+	output PAD
+);
+	assign PAD = D;
+endmodule

techlibs/sf2/sf2_iobs.cc

@@ -0,0 +1,130 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "kernel/yosys.h"
+#include "kernel/sigtools.h"
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+struct Sf2IobsPass : public Pass {
+	Sf2IobsPass() : Pass("sf2_iobs", "SF2: insert IO buffers") { }
+	void help() YS_OVERRIDE
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    sf2_iobs [options] [selection]\n");
+		log("\n");
+		log("Add SF2 I/O buffers to top module IOs as needed.\n");
+		log("\n");
+	}
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	{
+		log_header(design, "Executing sf2_iobs pass (insert IO buffers).\n");
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++)
+		{
+			// if (args[argidx] == "-singleton") {
+			// 	singleton_mode = true;
+			// 	continue;
+			// }
+			break;
+		}
+		extra_args(args, argidx, design);
+
+		Module *module = design->top_module();
+
+		if (module == nullptr)
+			log_cmd_error("No top module found.\n");
+
+		SigMap sigmap(module);
+
+		pool<SigBit> clk_bits;
+		pool<SigBit> handled_io_bits;
+		dict<SigBit, SigBit> rewrite_bits;
+		vector<pair<Cell*, SigBit>> pad_bits;
+
+		for (auto cell : module->cells())
+		{
+			if (cell->type == "\\SLE") {
+				for (auto bit : sigmap(cell->getPort("\\CLK")))
+					clk_bits.insert(bit);
+			}
+			if (cell->type.in("\\INBUF", "\\OUTBUF", "\\CLKBUF")) {
+				for (auto bit : sigmap(cell->getPort("\\PAD")))
+					handled_io_bits.insert(bit);
+			}
+		}
+
+		for (auto wire : vector<Wire*>(module->wires()))
+		{
+			if (!wire->port_input && !wire->port_output)
+				continue;
+
+			for (int index = 0; index < GetSize(wire); index++)
+			{
+				SigBit bit(wire, index);
+				SigBit canonical_bit = sigmap(bit);
+
+				if (handled_io_bits.count(canonical_bit))
+					continue;
+
+				if (wire->port_input && wire->port_output)
+					log_error("Failed to add buffer for inout port bit %s.\n", log_signal(bit));
+
+				IdString buf_type, buf_port;
+
+				if (wire->port_output) {
+					buf_type = "\\OUTBUF";
+					buf_port = "\\D";
+				} else if (clk_bits.count(canonical_bit)) {
+					buf_type = "\\CLKBUF";
+					buf_port = "\\Y";
+				} else {
+					buf_type = "\\INBUF";
+					buf_port = "\\Y";
+				}
+
+				Cell *c = module->addCell(NEW_ID, buf_type);
+				SigBit new_bit = module->addWire(NEW_ID);
+				c->setPort(buf_port, new_bit);
+				pad_bits.push_back(make_pair(c, bit));
+				rewrite_bits[canonical_bit] = new_bit;
+
+				log("Added %s cell %s for port bit %s.\n", log_id(c->type), log_id(c), log_signal(bit));
+			}
+		}
+
+		auto rewrite_function = [&](SigSpec &s) {
+			for (auto &bit : s) {
+				SigBit canonical_bit = sigmap(bit);
+				if (rewrite_bits.count(canonical_bit))
+					bit = rewrite_bits.at(canonical_bit);
+			}
+		};
+
+		module->rewrite_sigspecs(rewrite_function);
+
+		for (auto &it : pad_bits)
+			it.first->setPort("\\PAD", it.second);
+	}
+} Sf2IobsPass;
+
+PRIVATE_NAMESPACE_END

techlibs/sf2/synth_sf2.cc

@@ -60,6 +60,9 @@ struct SynthSf2Pass : public ScriptPass
 		log("    -noflatten\n");
 		log("        do not flatten design before synthesis\n");
 		log("\n");
+		log("    -noiobs\n");
+		log("        run synthesis in \"block mode\", i.e. do not insert IO buffers\n");
+		log("\n");
 		log("    -retime\n");
 		log("        run 'abc' with -dff option\n");
 		log("\n");
@@ -70,7 +73,7 @@ struct SynthSf2Pass : public ScriptPass
 	}
 
 	string top_opt, edif_file, vlog_file, json_file;
-	bool flatten, retime;
+	bool flatten, retime, iobs;
 
 	void clear_flags() YS_OVERRIDE
 	{
@@ -80,6 +83,7 @@ struct SynthSf2Pass : public ScriptPass
 		json_file = "";
 		flatten = true;
 		retime = false;
+		iobs = true;
 	}
 
 	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
@@ -122,6 +126,10 @@ struct SynthSf2Pass : public ScriptPass
 				retime = true;
 				continue;
 			}
+			if (args[argidx] == "-noiobs") {
+				iobs = false;
+				continue;
+			}
 			break;
 		}
 		extra_args(args, argidx, design);
@@ -191,6 +199,13 @@ struct SynthSf2Pass : public ScriptPass
 			run("clean");
 		}
 
+		if (check_label("map_iobs"))
+		{
+			if (iobs || help_mode)
+				run("sf2_iobs", "(unless -noiobs)");
+			run("clean");
+		}
+
 		if (check_label("check"))
 		{
 			run("hierarchy -check");