SDC expansion with OpenSTA

kernel/ff.h

@@ -78,31 +78,20 @@ YOSYS_NAMESPACE_BEGIN
 // - has_arst [does not correspond to a native cell, represented as dlatch with const D input]
 // - empty set [not a cell — will be emitted as a simple direct connection]
 
-struct FfData {
-	Module *module;
-	FfInitVals *initvals;
-	Cell *cell;
-	IdString name;
-	// The FF output.
-	SigSpec sig_q;
-	// The sync data input, present if has_clk or has_gclk.
-	SigSpec sig_d;
-	// The async data input, present if has_aload.
-	SigSpec sig_ad;
-	// The sync clock, present if has_clk.
-	SigSpec sig_clk;
-	// The clock enable, present if has_ce.
-	SigSpec sig_ce;
-	// The async load enable, present if has_aload.
-	SigSpec sig_aload;
-	// The async reset, preset if has_arst.
-	SigSpec sig_arst;
-	// The sync reset, preset if has_srst.
-	SigSpec sig_srst;
-	// The async clear (per-lane), present if has_sr.
-	SigSpec sig_clr;
-	// The async set (per-lane), present if has_sr.
-	SigSpec sig_set;
+struct FfTypeData {
+	FfTypeData(IdString type);
+	FfTypeData() {
+		has_clk = false;
+		has_gclk = false;
+		has_ce = false;
+		has_aload = false;
+		has_srst = false;
+		has_arst = false;
+		has_sr = false;
+		ce_over_srst = false;
+		is_fine = false;
+		is_anyinit = false;
+	}
 	// True if this is a clocked (edge-sensitive) flip-flop.
 	bool has_clk;
 	// True if this is a $ff, exclusive with every other has_*.
@@ -143,9 +132,38 @@ struct FfData {
 	bool pol_clr;
 	bool pol_set;
 	// The value loaded by sig_arst.
+	// Zero length if unknowable from just type
 	Const val_arst;
 	// The value loaded by sig_srst.
+	// Zero length if unknowable from just type
 	Const val_srst;
+};
+
+struct FfData : FfTypeData {
+	Module *module;
+	FfInitVals *initvals;
+	Cell *cell;
+	IdString name;
+	// The FF output.
+	SigSpec sig_q;
+	// The sync data input, present if has_clk or has_gclk.
+	SigSpec sig_d;
+	// The async data input, present if has_aload.
+	SigSpec sig_ad;
+	// The sync clock, present if has_clk.
+	SigSpec sig_clk;
+	// The clock enable, present if has_ce.
+	SigSpec sig_ce;
+	// The async load enable, present if has_aload.
+	SigSpec sig_aload;
+	// The async reset, preset if has_arst.
+	SigSpec sig_arst;
+	// The sync reset, preset if has_srst.
+	SigSpec sig_srst;
+	// The async clear (per-lane), present if has_sr.
+	SigSpec sig_clr;
+	// The async set (per-lane), present if has_sr.
+	SigSpec sig_set;
 	// The initial value at power-up.
 	Const val_init;
 	// The FF data width in bits.
@@ -154,16 +172,6 @@ struct FfData {
 
 	FfData(Module *module = nullptr, FfInitVals *initvals = nullptr, IdString name = IdString()) : module(module), initvals(initvals), cell(nullptr), name(name) {
 		width = 0;
-		has_clk = false;
-		has_gclk = false;
-		has_ce = false;
-		has_aload = false;
-		has_srst = false;
-		has_arst = false;
-		has_sr = false;
-		ce_over_srst = false;
-		is_fine = false;
-		is_anyinit = false;
 		pol_clk = false;
 		pol_aload = false;
 		pol_ce = false;

kernel/rtlil.h

@@ -728,7 +728,6 @@
 namespace RTLIL {
 	extern dict<std::string, std::string> constpad;
 
-	[[deprecated("Call cell->is_builtin_ff() instead")]]
 	const pool<IdString> &builtin_ff_cell_types();
 
 	static inline std::string escape_id(const std::string &str) {
@@ -1272,7 +1271,7 @@
 	RTLIL::IdString name;
 };
 
 struct RTLIL::SigChunk
 {
 	RTLIL::Wire *wire;
 	std::vector<RTLIL::State> data; // only used if wire == NULL, LSB at index 0

passes/cmds/Makefile.inc

@@ -58,5 +58,6 @@ OBJS += passes/cmds/test_select.o
 OBJS += passes/cmds/timeest.o
 OBJS += passes/cmds/linecoverage.o
 OBJS += passes/cmds/sort.o
+OBJS += passes/cmds/icell_liberty.o
 
 include $(YOSYS_SRC)/passes/cmds/sdc/Makefile.inc

passes/cmds/icell_liberty.cc

@@ -0,0 +1,207 @@
+#include "kernel/yosys.h"
+#include "kernel/celltypes.h"
+#include "kernel/ff.h"
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+struct LibertyStubber {
+	CellTypes ct;
+	LibertyStubber() {
+		ct.setup();
+		ct.setup_internals_ff();
+	}
+	void liberty_prefix(std::ostream& f)
+	{
+		f << "/*\n";
+		f << stringf("\tModels interfaces of select Yosys internal cell.\n");
+		f << stringf("\tLikely contains INCORRECT POLARITIES.\n");
+		f << stringf("\tImpractical for any simulation, synthesis, or timing.\n");
+		f << stringf("\tIntended purely for SDC expansion.\n");
+		f << stringf("\tDo not microwave or tumble dry.\n");
+		f << stringf("\tGenerated by %s\n", yosys_maybe_version());
+		f << "*/\n";
+		f << "library (yosys) {\n";
+		f << "\tinput_threshold_pct_fall : 50;\n";
+		f << "\tinput_threshold_pct_rise : 50;\n";
+		f << "\toutput_threshold_pct_fall : 50;\n";
+		f << "\toutput_threshold_pct_rise : 50;\n";
+		f << "\tslew_lower_threshold_pct_fall : 1;\n";
+		f << "\tslew_lower_threshold_pct_rise : 1;\n";
+		f << "\tslew_upper_threshold_pct_fall : 99;\n";
+		f << "\tslew_upper_threshold_pct_rise : 99;\n";
+	}
+	void liberty_suffix(std::ostream& f)
+	{
+		f << "}\n";
+	}
+	struct LibertyItemizer {
+		std::ostream& f;
+		int indent;
+		LibertyItemizer(std::ostream& f) : f(f), indent(0) {};
+		void item(std::string key, std::string val)
+		{
+			f << std::string(indent, '\t') << key << " : \"" << val << "\";\n";
+		}
+	};
+	void liberty_flop(Module* base, Module* derived, std::ostream& f)
+	{
+		auto base_name = base->name.str().substr(1);
+		auto derived_name = derived->name.str().substr(1);
+
+		FfTypeData ffType(base_name);
+		LibertyItemizer i(f);
+
+		if (ffType.has_gclk) {
+			log_warning("Formal flip flop %s can't be modeled\n", base_name.c_str());
+			return;
+		}
+		if (ffType.has_ce) {
+			log_warning("DFFE %s can't be modeled\n", base_name.c_str());
+			return;
+		}
+
+		f << "\tcell (\"" << derived_name << "\") {\n";
+		auto& base_type = ct.cell_types[base_name];
+		i.indent = 3;
+		auto sorted_ports = derived->ports;
+		// Hack for CLK and C coming before Q does
+		auto cmp = [](IdString l, IdString r) { return l.str() < r.str(); };
+		std::sort(sorted_ports.begin(), sorted_ports.end(), cmp);
+		std::string clock_pin_name = "";
+		for (auto x : sorted_ports) {
+			std::string port_name = RTLIL::unescape_id(x);
+			bool is_input = base_type.inputs.count(x);
+			bool is_output = base_type.outputs.count(x);
+			f << "\t\tpin (" << RTLIL::unescape_id(x.str()) << ") {\n";
+			if (is_input && !is_output) {
+				i.item("direction", "input");
+			} else if (!is_input && is_output) {
+				i.item("direction", "output");
+			} else {
+				i.item("direction", "inout");
+			}
+			if (port_name == "CLK" || port_name == "C") {
+				i.item("clock", "true");
+				clock_pin_name = port_name;
+			}
+			if (port_name == "Q") {
+				i.item("function", "IQ");
+				f << "\t\t\ttiming () {\n";
+				i.indent++;
+				log_assert(clock_pin_name.size());
+				i.item("related_pin", clock_pin_name);
+				i.indent--;
+            	f << "\t\t\t}\n";
+			}
+			f << "\t\t}\n";
+		}
+
+		f << "\t\tff (\"IQ\",\"IQ_N\") {\n";
+		i.indent = 3;
+		// TODO polarities?
+		if (ffType.has_clk) {
+			auto pin = ffType.is_fine ? "C" : "CLK";
+			i.item("clocked_on", pin);
+		}
+		if (ffType.has_arst) {
+			auto meaning = (ffType.val_arst == State::S1) ? "preset" : "clear";
+			auto pin = ffType.is_fine ? "R" : "ARST";
+			i.item(meaning, pin);
+		}
+		auto next_state = ffType.has_ce ? "D & EN" : "D";
+		i.item("next_state", next_state);
+		f << "\t\t}\n";
+		f << "\t}\n";
+	}
+	void liberty_cell(Module* base, Module* derived, std::ostream& f)
+	{
+		auto base_name = base->name.str().substr(1);
+		auto derived_name = derived->name.str().substr(1);
+		if (!ct.cell_types.count(base_name)) {
+			log_debug("skip skeleton for %s\n", base_name.c_str());
+			return;
+		}
+
+		if (RTLIL::builtin_ff_cell_types().count(base_name))
+			return liberty_flop(base, derived, f);
+
+		auto& base_type = ct.cell_types[base_name];
+		f << "\tcell (\"" << derived_name << "\") {\n";
+		for (auto x : derived->ports) {
+			bool is_input = base_type.inputs.count(x);
+			bool is_output = base_type.outputs.count(x);
+			f << "\t\tpin (" << RTLIL::unescape_id(x.str()) << ") {\n";
+			if (is_input && !is_output) {
+				f << "\t\t\tdirection : input;\n";
+			} else if (!is_input && is_output) {
+				f << "\t\t\tdirection : output;\n";
+			} else {
+				f << "\t\t\tdirection : inout;\n";
+			}
+			f << "\t\t}\n";
+		}
+		f << "\t}\n";
+	}
+};
+
+struct IcellLiberty : Pass {
+	IcellLiberty() : Pass("icell_liberty", "write Liberty interfaces for used internal cells") {}
+	void help() override
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    icell_liberty <liberty_file>\n");
+		log("\n");
+		log("Write Liberty files modeling the interfaces of used internal cells.\n");
+		log("\n");
+		log("Models are not guaranteed to be logically sound.\n");
+		log("\n");
+	}
+	void execute(std::vector<std::string> args, RTLIL::Design *d) override
+	{
+		log_header(d, "Executing ICELL_LIBERTY pass.\n");
+
+		size_t argidx;
+		IdString naming_attr;
+		std::string liberty_filename;
+		auto liberty_file = std::make_unique<std::ofstream>();
+
+		for (argidx = 1; argidx < args.size(); argidx++) {
+			break;
+		}
+		if (argidx < args.size())
+			liberty_filename = args[argidx++];
+		else
+			log_cmd_error("no Liberty filename specified\n");
+
+		if (liberty_filename.size()) {
+			liberty_file->open(liberty_filename.c_str());
+			if (liberty_file->fail()) {
+				log_cmd_error("Can't open file `%s' for writing: %s\n", liberty_filename.c_str(), strerror(errno));
+			}
+		}
+
+		pool<RTLIL::IdString> done;
+		LibertyStubber stubber = {};
+
+		stubber.liberty_prefix(*liberty_file);
+
+		for (auto module : d->selected_modules()) {
+			for (auto cell : module->selected_cells()) {
+				Module *inst_module = d->module(cell->type);
+				if (!inst_module || !inst_module->get_blackbox_attribute())
+					continue;
+				Module *base = inst_module;
+				if (!done.count(base->name)) {
+					stubber.liberty_cell(base, base, *liberty_file);
+					done.insert(base->name);
+				}
+			}
+		}
+
+		stubber.liberty_suffix(*liberty_file);
+	}
+} IcellLiberty;
+
+PRIVATE_NAMESPACE_END

techlibs/common/Makefile.inc

@@ -2,6 +2,8 @@
 ifneq ($(SMALL),1)
 OBJS += techlibs/common/synth.o
 OBJS += techlibs/common/prep.o
+OBJS += techlibs/common/opensta.o
+OBJS += techlibs/common/sdc_expand.o
 endif
 
 GENFILES += techlibs/common/simlib_help.inc