Merge pull request #144 from azonenberg/master

Added COUNT_EXTRACT constraint to greenpak4_counters pass. Added support for inferring level-resettable counters. Fixed use-after-free.

techlibs/greenpak4/cells_map.v

@@ -33,8 +33,13 @@ module \$lut (A, Y);
 
   generate
     if (WIDTH == 1) begin
-      GP_2LUT #(.INIT({2'b00, LUT})) _TECHMAP_REPLACE_ (.OUT(Y),
-      	.IN0(A[0]), .IN1(1'b0));
+		if(LUT == 2'b01) begin
+			GP_INV _TECHMAP_REPLACE_ (.OUT(Y), .IN(A[0]) );
+		end
+		else begin
+			GP_2LUT #(.INIT({2'b00, LUT})) _TECHMAP_REPLACE_ (.OUT(Y),
+				.IN0(A[0]), .IN1(1'b0));
+		end
     end else
     if (WIDTH == 2) begin
       GP_2LUT #(.INIT(LUT)) _TECHMAP_REPLACE_ (.OUT(Y),

techlibs/greenpak4/cells_sim.v

@@ -40,6 +40,10 @@ module GP_DFFSR(input D, CLK, nSR, output reg Q);
 	end
 endmodule
 
+module GP_INV(input IN, output OUT);
+	assign OUT = ~IN;
+endmodule
+
 module GP_2LUT(input IN0, IN1, output OUT);
 	parameter [3:0] INIT = 0;
 	assign OUT = INIT[{IN1, IN0}];

techlibs/greenpak4/greenpak4_counters.cc

@@ -87,70 +87,84 @@ bool is_unconnected(const RTLIL::SigSpec& port, ModIndex& index)
 	return true;
 }
 
-void greenpak4_counters_worker(ModIndex& index, Module *module, Cell *cell, unsigned int& total_counters)
+struct CounterExtraction
+{
+	int width;					//counter width
+	RTLIL::Wire* rwire;			//the register output
+	bool has_reset;				//true if we have a reset
+	RTLIL::SigSpec rst;			//reset pin
+	int count_value;			//value we count from
+	RTLIL::SigSpec clk;			//clock signal
+	RTLIL::SigSpec outsig;		//counter output signal
+	RTLIL::Cell* count_mux;		//counter mux
+	RTLIL::Cell* count_reg;		//counter register
+	RTLIL::Cell* underflow_inv;	//inverter reduction for output-underflow detect
+};
+
+//attempt to extract a counter centered on the given cell
+int greenpak4_counters_tryextract(ModIndex& index, Cell *cell, CounterExtraction& extract)
 {
 	SigMap& sigmap = index.sigmap;
 	
-	//Core of the counter must be an ALU
-	if (cell->type != "$alu")
-		return;
-	
 	//GreenPak does not support counters larger than 14 bits so immediately skip anything bigger
 	int a_width = cell->getParam("\\A_WIDTH").as_int();
+	extract.width = a_width;
 	if(a_width > 14)
-		return;
+		return 1;
 		
 	//Second input must be a single bit
 	int b_width = cell->getParam("\\B_WIDTH").as_int();
 	if(b_width != 1)
-		return;
+		return 2;
 		
 	//Both inputs must be unsigned, so don't extract anything with a signed input
 	bool a_sign = cell->getParam("\\A_SIGNED").as_bool();
 	bool b_sign = cell->getParam("\\B_SIGNED").as_bool();
 	if(a_sign || b_sign)
-		return;
+		return 3;
 
 	//To be a counter, one input of the ALU must be a constant 1
 	//TODO: can A or B be swapped in synthesized RTL or is B always the 1?
 	const RTLIL::SigSpec b_port = sigmap(cell->getPort("\\B"));
 	if(!b_port.is_fully_const() || (b_port.as_int() != 1) )
-		return;
+		return 4;
 		
 	//BI and CI must be constant 1 as well
 	const RTLIL::SigSpec bi_port = sigmap(cell->getPort("\\BI"));
 	if(!bi_port.is_fully_const() || (bi_port.as_int() != 1) )
-		return;
+		return 5;
 	const RTLIL::SigSpec ci_port = sigmap(cell->getPort("\\CI"));
 	if(!ci_port.is_fully_const() || (ci_port.as_int() != 1) )
-		return;
+		return 6;
 				
 	//CO and X must be unconnected (exactly one connection to each port)
 	if(!is_unconnected(sigmap(cell->getPort("\\CO")), index))
-		return;
+		return 7;
 	if(!is_unconnected(sigmap(cell->getPort("\\X")), index))
-		return;
+		return 8;
 		
 	//Y must have exactly one connection, and it has to be a $mux cell.
 	//We must have a direct bus connection from our Y to their A.
 	const RTLIL::SigSpec aluy = sigmap(cell->getPort("\\Y"));
 	pool<Cell*> y_loads = get_other_cells(aluy, index, cell);
 	if(y_loads.size() != 1)
-		return;
+		return 9;
 	Cell* count_mux = *y_loads.begin();
+	extract.count_mux = count_mux;
 	if(count_mux->type != "$mux")
-		return;
+		return 10;
 	if(!is_full_bus(aluy, index, cell, "\\Y", count_mux, "\\A"))
-		return;
+		return 11;
 
 	//B connection of the mux is our underflow value
 	const RTLIL::SigSpec underflow = sigmap(count_mux->getPort("\\B"));
 	if(!underflow.is_fully_const())
-		return;
-	int count_value = underflow.as_int();
+		return 12;
+	extract.count_value = underflow.as_int();
 	
 	//S connection of the mux must come from an inverter (need not be the only load)
 	const RTLIL::SigSpec muxsel = sigmap(count_mux->getPort("\\S"));
+	extract.outsig = muxsel;
 	pool<Cell*> muxsel_conns = get_other_cells(muxsel, index, count_mux);
 	Cell* underflow_inv = NULL;
 	for(auto c : muxsel_conns)
@@ -164,54 +178,175 @@ void greenpak4_counters_worker(ModIndex& index, Module *module, Cell *cell, unsi
 		break;
 	}
 	if(underflow_inv == NULL)
-		return;
+		return 13;
+	extract.underflow_inv = underflow_inv;
 	
 	//Y connection of the mux must have exactly one load, the counter's internal register
 	const RTLIL::SigSpec muxy = sigmap(count_mux->getPort("\\Y"));
 	pool<Cell*> muxy_loads = get_other_cells(muxy, index, count_mux);
 	if(muxy_loads.size() != 1)
-		return;
+		return 14;
 	Cell* count_reg = *muxy_loads.begin();
-	if(count_reg->type != "$dff")			//TODO: support dffr/dffs?
-		return;
+	extract.count_reg = count_reg;
+	if(count_reg->type == "$dff")
+		extract.has_reset = false;
+	else if(count_reg->type == "$adff")
+	{
+		extract.has_reset = true;
+		
+		//Verify ARST_VALUE is zero and ARST_POLARITY is 1
+		//TODO: infer an inverter to make it 1 if necessary, so we can support negative level resets?
+		if(count_reg->getParam("\\ARST_POLARITY").as_int() != 1)
+			return 22;
+		if(count_reg->getParam("\\ARST_VALUE").as_int() != 0)
+			return 23;
+			
+		//Save the reset
+		extract.rst = sigmap(count_reg->getPort("\\ARST"));
+	}
+	//TODO: support synchronous reset
+	else
+		return 15;
 	if(!is_full_bus(muxy, index, count_mux, "\\Y", count_reg, "\\D"))
-		return;
+		return 16;
+		
+	//TODO: Verify count_reg CLK_POLARITY is 1
 		
 	//Register output must have exactly two loads, the inverter and ALU
 	const RTLIL::SigSpec cnout = sigmap(count_reg->getPort("\\Q"));
 	pool<Cell*> cnout_loads = get_other_cells(cnout, index, count_reg);
 	if(cnout_loads.size() != 2)
-		return;
+		return 17;
 	if(!is_full_bus(cnout, index, count_reg, "\\Q", underflow_inv, "\\A", true))
-		return;
+		return 18;
 	if(!is_full_bus(cnout, index, count_reg, "\\Q", cell, "\\A", true))
-		return;
+		return 19;
 		
 	//Look up the clock from the register
-	const RTLIL::SigSpec clk = sigmap(count_reg->getPort("\\CLK"));
+	extract.clk = sigmap(count_reg->getPort("\\CLK"));
 	
 	//Register output net must have an INIT attribute equal to the count value
-	auto rwire = cnout.as_wire();
-	if(rwire->attributes.find("\\init") == rwire->attributes.end())
+	extract.rwire = cnout.as_wire();
+	if(extract.rwire->attributes.find("\\init") == extract.rwire->attributes.end())
+		return 20;
+	int rinit = extract.rwire->attributes["\\init"].as_int();
+	if(rinit != extract.count_value)
+		return 21;
+		
+	return 0;
+}
+
+void greenpak4_counters_worker(
+	ModIndex& index,
+	Cell *cell,
+	unsigned int& total_counters,
+	pool<Cell*>& cells_to_remove)
+{
+	SigMap& sigmap = index.sigmap;
+	
+	//Core of the counter must be an ALU
+	if (cell->type != "$alu")
 		return;
-	int rinit = rwire->attributes["\\init"].as_int();
-	if(rinit != count_value)
+	
+	//A input is the count value. Check if it has COUNT_EXTRACT set
+	RTLIL::Wire* a_wire = sigmap(cell->getPort("\\A")).as_wire();
+	bool force_extract = false;
+	bool never_extract = false;
+	string count_reg_src = a_wire->attributes["\\src"].decode_string().c_str();
+	if(a_wire->attributes.find("\\COUNT_EXTRACT") != a_wire->attributes.end())
+	{
+		pool<string> sa = a_wire->get_strpool_attribute("\\COUNT_EXTRACT");
+		string extract_value;
+		if(sa.size() >= 1)
+		{
+			extract_value = *sa.begin();
+			log("  Signal %s declared at %s has COUNT_EXTRACT = %s\n",
+				log_id(a_wire),
+				count_reg_src.c_str(),
+				extract_value.c_str());
+				
+			if(extract_value == "FORCE")
+				force_extract = true;
+			else if(extract_value == "NO")
+				never_extract = true;
+			else if(extract_value == "AUTO")
+			{}	//default
+			else
+				log_error("  Illegal COUNT_EXTRACT value %s (must be one of FORCE, NO, AUTO)\n",
+					extract_value.c_str());
+		}
+	}
+	
+	//If we're explicitly told not to extract, don't infer a counter
+	if(never_extract)
 		return;
 	
+	//Attempt to extract a counter
+	CounterExtraction extract;
+	int reason = greenpak4_counters_tryextract(index, cell, extract);
+	
+	//Nonzero code - we could not find a matchable counter.
+	//Do nothing, unless extraction was forced in which case give an error
+	if(reason != 0)
+	{
+		static const char* reasons[24]=
+		{
+			"no problem",									//0
+			"counter is larger than 14 bits",				//1
+			"counter does not count by one",				//2
+			"counter uses signed math",						//3
+			"counter does not count by one",				//4
+			"ALU is not a subtractor",						//5
+			"ALU is not a subtractor",						//6
+			"ALU ports used outside counter",				//7
+			"ALU ports used outside counter",				//8
+			"ALU output used outside counter",				//9
+			"ALU output is not a mux",						//10
+			"ALU output is not full bus",					//11
+			"Underflow value is not constant",				//12
+			"No underflow detector found",					//13
+			"Mux output is used outside counter",			//14
+			"Counter reg is not DFF/ADFF",					//15
+			"Counter input is not full bus",				//16
+			"Count register is used outside counter",		//17
+			"Register output is not full bus",				//18
+			"Register output is not full bus",				//19
+			"No init value found",							//20
+			"Underflow value is not equal to init value",	//21
+			"Reset polarity is not positive",				//22
+			"Reset is not to zero"							//23
+		};
+		
+		if(force_extract)
+		{
+			log_error(
+			"Counter extraction is set to FORCE on register %s, but a counter could not be inferred (%s)\n",
+			log_id(a_wire),
+			reasons[reason]);
+		}
+		return;
+	}
+	
 	//Figure out the final cell type based on the counter size
 	string celltype = "\\GP_COUNT8";
-	if(a_width > 8)
+	if(extract.width > 8)
 		celltype = "\\GP_COUNT14";
 	
 	//Log it
 	total_counters ++;
-	string count_reg_src = rwire->attributes["\\src"].decode_string().c_str();
-	log("  Found %d-bit non-resettable down counter (from %d) for register %s declared at %s\n",
-		a_width,
-		count_value,
-		log_id(rwire->name),
+	string reset_type = "non-resettable";
+	if(extract.has_reset)
+	{
+		//TODO: support other kind of reset
+		reset_type = "async resettable";
+	}
+	log("  Found %d-bit %s down counter (from %d) for register %s declared at %s\n",
+		extract.width,
+		reset_type.c_str(),
+		extract.count_value,
+		log_id(extract.rwire->name),
 		count_reg_src.c_str());
-		
+	
 	//Wipe all of the old connections to the ALU
 	cell->unsetPort("\\A");
 	cell->unsetPort("\\B");
@@ -225,22 +360,34 @@ void greenpak4_counters_worker(ModIndex& index, Module *module, Cell *cell, unsi
 	cell->unsetParam("\\B_SIGNED");
 	cell->unsetParam("\\B_WIDTH");
 	cell->unsetParam("\\Y_WIDTH");
-	
+
 	//Change the cell type
 	cell->type = celltype;
 	
-	//Hook it up to everything
-	cell->setParam("\\RESET_MODE", RTLIL::Const("RISING"));
+	//Hook up resets
+	if(extract.has_reset)
+	{
+		//TODO: support other kinds of reset
+		cell->setParam("\\RESET_MODE", RTLIL::Const("LEVEL"));
+		cell->setPort("\\RST", extract.rst);
+	}
+	else
+	{
+		cell->setParam("\\RESET_MODE", RTLIL::Const("RISING"));
+		cell->setPort("\\RST", RTLIL::SigSpec(false));
+	}
+	
+	//Hook up other stuff
 	cell->setParam("\\CLKIN_DIVIDE", RTLIL::Const(1));
-	cell->setParam("\\COUNT_TO", RTLIL::Const(count_value));
-	cell->setPort("\\CLK", clk);
-	cell->setPort("\\RST", RTLIL::SigSpec(false));
-	cell->setPort("\\OUT", muxsel);
+	cell->setParam("\\COUNT_TO", RTLIL::Const(extract.count_value));
+	
+	cell->setPort("\\CLK", extract.clk);
+	cell->setPort("\\OUT", extract.outsig);
 	
 	//Delete the cells we've replaced (let opt_clean handle deleting the now-redundant wires)
-	module->remove(count_mux);
-	module->remove(count_reg);
-	module->remove(underflow_inv);
+	cells_to_remove.insert(extract.count_mux);
+	cells_to_remove.insert(extract.count_reg);
+	cells_to_remove.insert(extract.underflow_inv);
 }
 
 struct Greenpak4CountersPass : public Pass {
@@ -251,8 +398,8 @@ struct Greenpak4CountersPass : public Pass {
 		log("\n");
 		log("    greenpak4_counters [options] [selection]\n");
 		log("\n");
-		log("This pass converts non-resettable down counters to GreenPak4 counter cells\n");
-		log("(All other GreenPak4 counter modes must be instantiated manually for now.)\n");
+		log("This pass converts non-resettable or async resettable down counters to GreenPak4\n");
+		log("counter cells (All other GreenPak4 counter modes must be instantiated manually.)\n");
 		log("\n");
 	}
 	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
@@ -269,17 +416,22 @@ struct Greenpak4CountersPass : public Pass {
 		}
 		extra_args(args, argidx, design);
 		
+		//Extract all of the counters we could find
 		unsigned int total_counters = 0;
 		for (auto module : design->selected_modules())
 		{
+			pool<Cell*> cells_to_remove;
+			
 			ModIndex index(module);
 			for (auto cell : module->selected_cells())
-				greenpak4_counters_worker(index, module, cell, total_counters);
+				greenpak4_counters_worker(index, cell, total_counters, cells_to_remove);
+				
+			for(auto cell : cells_to_remove)
+				module->remove(cell);
 		}
 		
 		if(total_counters)
 			log("Extracted %u counters\n", total_counters);
-		
 	}
 } Greenpak4CountersPass;
 

techlibs/greenpak4/synth_greenpak4.cc

@@ -207,8 +207,8 @@ struct SynthGreenPAK4Pass : public Pass {
 		if (check_label(active, run_from, run_to, "map_luts"))
 		{
 			if (part == "SLG46140V") Pass::call(design, "nlutmap -luts 0,6,8,2");
-			if (part == "SLG46620V") Pass::call(design, "nlutmap -luts 0,8,16,2");
-			if (part == "SLG46621V") Pass::call(design, "nlutmap -luts 0,8,16,2");
+			if (part == "SLG46620V") Pass::call(design, "nlutmap -luts 2,8,16,2");
+			if (part == "SLG46621V") Pass::call(design, "nlutmap -luts 2,8,16,2");
 			Pass::call(design, "clean");
 		}