Merge remote-tracking branch 'origin/clifford/async2synclatch' into Sergey/tests_ice40

5 files changed, 423 insertions, 67 deletions

diff --git a/passes/techmap/Makefile.inc b/passes/techmap/Makefile.inc
index 56f05eca4..631a80aa5 100644
--- a/passes/techmap/Makefile.inc
+++ b/passes/techmap/Makefile.inc
@@ -16,6 +16,7 @@ endif
 
 ifneq ($(SMALL),1)
 OBJS += passes/techmap/iopadmap.o
+OBJS += passes/techmap/clkbufmap.o
 OBJS += passes/techmap/hilomap.o
 OBJS += passes/techmap/extract.o
 OBJS += passes/techmap/extract_fa.o
diff --git a/passes/techmap/abc9.cc b/passes/techmap/abc9.cc
index c1d4fff2d..84cb2c04f 100644
--- a/passes/techmap/abc9.cc
+++ b/passes/techmap/abc9.cc
@@ -76,12 +76,11 @@ inline std::string remap_name(RTLIL::IdString abc_name)
 	return stringf("$abc$%d$%s", map_autoidx, abc_name.c_str()+1);
 }
 
-void handle_loops(RTLIL::Design *design)
+void handle_loops(RTLIL::Design *design,
+		const dict<IdString,pool<IdString>> &scc_break_inputs)
 {
 	Pass::call(design, "scc -set_attr abc_scc_id {}");
 
-	dict<IdString, vector<IdString>> abc_scc_break;
-
 	// For every unique SCC found, (arbitrarily) find the first
 	// cell in the component, and select (and mark) all its output
 	// wires
@@ -116,44 +115,29 @@ void handle_loops(RTLIL::Design *design)
 			cell->attributes.erase(it);
 		}
 
-		auto jt = abc_scc_break.find(cell->type);
-		if (jt == abc_scc_break.end()) {
-			std::vector<IdString> ports;
-			RTLIL::Module* box_module = design->module(cell->type);
-			if (box_module) {
-				auto ports_csv = box_module->attributes.at(ID(abc_scc_break), RTLIL::Const::from_string("")).decode_string();
-				for (const auto &port_name : split_tokens(ports_csv, ",")) {
-					auto port_id = RTLIL::escape_id(port_name);
-					auto kt = cell->connections_.find(port_id);
-					if (kt == cell->connections_.end())
-						log_error("abc_scc_break attribute value '%s' does not exist as port on module '%s'\n", port_name.c_str(), log_id(box_module));
-					ports.push_back(port_id);
-				}
-			}
-			jt = abc_scc_break.insert(std::make_pair(cell->type, std::move(ports))).first;
-		}
-
-		for (auto port_name : jt->second) {
-			RTLIL::SigSpec sig;
-			auto &rhs = cell->connections_.at(port_name);
-			for (auto b : rhs) {
-				Wire *w = b.wire;
-				if (!w) continue;
-				w->port_output = true;
-				w->set_bool_attribute(ID(abc_scc_break));
-				w = module->wire(stringf("%s.abci", w->name.c_str()));
-				if (!w) {
-					w = module->addWire(stringf("%s.abci", b.wire->name.c_str()), GetSize(b.wire));
-					w->port_input = true;
-				}
-				else {
-					log_assert(b.offset < GetSize(w));
-					log_assert(w->port_input);
+		auto jt = scc_break_inputs.find(cell->type);
+		if (jt != scc_break_inputs.end())
+			for (auto port_name : jt->second) {
+				RTLIL::SigSpec sig;
+				auto &rhs = cell->connections_.at(port_name);
+				for (auto b : rhs) {
+					Wire *w = b.wire;
+					if (!w) continue;
+					w->port_output = true;
+					w->set_bool_attribute(ID(abc_scc_break));
+					w = module->wire(stringf("%s.abci", w->name.c_str()));
+					if (!w) {
+						w = module->addWire(stringf("%s.abci", b.wire->name.c_str()), GetSize(b.wire));
+						w->port_input = true;
+					}
+					else {
+						log_assert(b.offset < GetSize(w));
+						log_assert(w->port_input);
+					}
+					sig.append(RTLIL::SigBit(w, b.offset));
 				}
-				sig.append(RTLIL::SigBit(w, b.offset));
+				rhs = sig;
 			}
-			rhs = sig;
-		}
 	}
 
 	module->fixup_ports();
@@ -288,7 +272,9 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 		bool cleanup, vector<int> lut_costs, bool dff_mode, std::string clk_str,
 		bool /*keepff*/, std::string delay_target, std::string /*lutin_shared*/, bool fast_mode,
 		bool show_tempdir, std::string box_file, std::string lut_file,
-		std::string wire_delay, const dict<int,IdString> &box_lookup)
+		std::string wire_delay, const dict<int,IdString> &box_lookup,
+		const dict<IdString,pool<IdString>> &scc_break_inputs
+)
 {
 	module = current_module;
 	map_autoidx = autoidx++;
@@ -427,7 +413,7 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 		RTLIL::Selection& sel = design->selection_stack.back();
 		sel.select(module);
 
-		handle_loops(design);
+		handle_loops(design, scc_break_inputs);
 
 		Pass::call(design, "aigmap");
 
@@ -1081,6 +1067,7 @@ struct Abc9Pass : public Pass {
 		extra_args(args, argidx, design);
 
 		dict<int,IdString> box_lookup;
+		dict<IdString,pool<IdString>> scc_break_inputs;
 		for (auto m : design->modules()) {
 			auto it = m->attributes.find(ID(abc_box_id));
 			if (it == m->attributes.end())
@@ -1093,6 +1080,56 @@ struct Abc9Pass : public Pass {
 				log_error("Module '%s' has the same abc_box_id = %d value as '%s'.\n",
 						log_id(m), id, log_id(r.first->second));
 			log_assert(r.second);
+
+			RTLIL::Wire *carry_in = nullptr, *carry_out = nullptr;
+			for (auto p : m->ports) {
+				auto w = m->wire(p);
+				log_assert(w);
+				if (w->port_input) {
+					if (w->attributes.count(ID(abc_scc_break)))
+						scc_break_inputs[m->name].insert(p);
+					if (w->attributes.count(ID(abc_carry))) {
+						if (carry_in)
+							log_error("Module '%s' contains more than one 'abc_carry' input port.\n", log_id(m));
+						carry_in = w;
+					}
+				}
+				if (w->port_output) {
+					if (w->attributes.count(ID(abc_carry))) {
+						if (carry_out)
+							log_error("Module '%s' contains more than one 'abc_carry' input port.\n", log_id(m));
+						carry_out = w;
+					}
+				}
+			}
+			if (carry_in || carry_out) {
+				if (carry_in && !carry_out)
+					log_error("Module '%s' contains an 'abc_carry' input port but no output port.\n", log_id(m));
+				if (!carry_in && carry_out)
+					log_error("Module '%s' contains an 'abc_carry' output port but no input port.\n", log_id(m));
+				// Make carry_in the last PI, and carry_out the last PO
+				//   since ABC requires it this way
+				auto &ports = m->ports;
+				for (auto it = ports.begin(); it != ports.end(); ) {
+					RTLIL::Wire* w = m->wire(*it);
+					log_assert(w);
+					if (w == carry_in || w == carry_out) {
+						it = ports.erase(it);
+						continue;
+					}
+					if (w->port_id > carry_in->port_id)
+						--w->port_id;
+					if (w->port_id > carry_out->port_id)
+						--w->port_id;
+					log_assert(w->port_input || w->port_output);
+					log_assert(ports[w->port_id-1] == w->name);
+					++it;
+				}
+				ports.push_back(carry_in->name);
+				carry_in->port_id = ports.size();
+				ports.push_back(carry_out->name);
+				carry_out->port_id = ports.size();
+			}
 		}
 
 		for (auto mod : design->selected_modules())
@@ -1110,7 +1147,7 @@ struct Abc9Pass : public Pass {
 			if (!dff_mode || !clk_str.empty()) {
 				abc9_module(design, mod, script_file, exe_file, cleanup, lut_costs, dff_mode, clk_str, keepff,
 						delay_target, lutin_shared, fast_mode, show_tempdir,
-						box_file, lut_file, wire_delay, box_lookup);
+						box_file, lut_file, wire_delay, box_lookup, scc_break_inputs);
 				continue;
 			}
 
@@ -1256,7 +1293,7 @@ struct Abc9Pass : public Pass {
 				en_sig = assign_map(std::get<3>(it.first));
 				abc9_module(design, mod, script_file, exe_file, cleanup, lut_costs, !clk_sig.empty(), "$",
 						keepff, delay_target, lutin_shared, fast_mode, show_tempdir,
-						box_file, lut_file, wire_delay, box_lookup);
+						box_file, lut_file, wire_delay, box_lookup, scc_break_inputs);
 				assign_map.set(mod);
 			}
 		}
diff --git a/passes/techmap/clkbufmap.cc b/passes/techmap/clkbufmap.cc
new file mode 100644
index 000000000..246932d81
--- /dev/null
+++ b/passes/techmap/clkbufmap.cc
@@ -0,0 +1,298 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *  Copyright (C) 2019  Marcin Kościelnicki <mwk@0x04.net>
+ *
+ *  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
+
+void split_portname_pair(std::string &port1, std::string &port2)
+{
+	size_t pos = port1.find_first_of(':');
+	if (pos != std::string::npos) {
+		port2 = port1.substr(pos+1);
+		port1 = port1.substr(0, pos);
+	}
+}
+
+struct ClkbufmapPass : public Pass {
+	ClkbufmapPass() : Pass("clkbufmap", "insert global buffers on clock networks") { }
+	void help() YS_OVERRIDE
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    clkbufmap [options] [selection]\n");
+		log("\n");
+		log("Inserts global buffers between nets connected to clock inputs and their drivers.\n");
+		log("\n");
+		log("In the absence of any selection, all wires without the 'clkbuf_inhibit'\n");
+		log("attribute will be considered for global buffer insertion.\n");
+		log("Alternatively, to consider all wires without the 'buffer_type' attribute set to\n");
+		log("'none' or 'bufr' one would specify:\n");
+		log("  'w:* a:buffer_type=none a:buffer_type=bufr %%u %%d'\n");
+		log("as the selection.\n");
+		log("\n");
+		log("    -buf <celltype> <portname_out>:<portname_in>\n");
+		log("        Specifies the cell type to use for the global buffers\n");
+		log("        and its port names.  The first port will be connected to\n");
+		log("        the clock network sinks, and the second will be connected\n");
+		log("        to the actual clock source.  This option is required.\n");
+		log("\n");
+		log("    -inpad <celltype> <portname_out>:<portname_in>\n");
+		log("        If specified, a PAD cell of the given type is inserted on\n");
+		log("        clock nets that are also top module's inputs (in addition\n");
+		log("        to the global buffer).\n");
+		log("\n");
+	}
+
+	void module_queue(Design *design, Module *module, std::vector<Module *> &modules_sorted, pool<Module *> &modules_processed) {
+		if (modules_processed.count(module))
+			return;
+		for (auto cell : module->cells()) {
+			Module *submodule = design->module(cell->type);
+			if (!submodule)
+				continue;
+			module_queue(design, submodule, modules_sorted, modules_processed);
+		}
+		modules_sorted.push_back(module);
+		modules_processed.insert(module);
+	}
+
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	{
+		log_header(design, "Executing CLKBUFMAP pass (inserting global clock buffers).\n");
+
+		std::string buf_celltype, buf_portname, buf_portname2;
+		std::string inpad_celltype, inpad_portname, inpad_portname2;
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++)
+		{
+			std::string arg = args[argidx];
+			if (arg == "-buf" && argidx+2 < args.size()) {
+				buf_celltype = args[++argidx];
+				buf_portname = args[++argidx];
+				split_portname_pair(buf_portname, buf_portname2);
+				continue;
+			}
+			if (arg == "-inpad" && argidx+2 < args.size()) {
+				inpad_celltype = args[++argidx];
+				inpad_portname = args[++argidx];
+				split_portname_pair(inpad_portname, inpad_portname2);
+				continue;
+			}
+			break;
+		}
+
+		bool select = false;
+		if (argidx < args.size()) {
+			if (args[argidx].compare(0, 1, "-") != 0)
+				select = true;
+			extra_args(args, argidx, design);
+		}
+
+		if (buf_celltype.empty())
+			log_error("The -buf option is required.\n");
+
+		// Cell type, port name, bit index.
+		pool<pair<IdString, pair<IdString, int>>> sink_ports;
+		pool<pair<IdString, pair<IdString, int>>> buf_ports;
+
+		// Process submodules before module using them.
+		std::vector<Module *> modules_sorted;
+		pool<Module *> modules_processed;
+		for (auto module : design->selected_modules())
+			module_queue(design, module, modules_sorted, modules_processed);
+
+		for (auto module : modules_sorted)
+		{
+			if (module->get_blackbox_attribute()) {
+				for (auto port : module->ports) {
+					auto wire = module->wire(port);
+					if (wire->get_bool_attribute("\\clkbuf_driver"))
+						for (int i = 0; i < GetSize(wire); i++)
+							buf_ports.insert(make_pair(module->name, make_pair(wire->name, i)));
+					if (wire->get_bool_attribute("\\clkbuf_sink"))
+						for (int i = 0; i < GetSize(wire); i++)
+							sink_ports.insert(make_pair(module->name, make_pair(wire->name, i)));
+				}
+				continue;
+			}
+			pool<SigBit> sink_wire_bits;
+			pool<SigBit> buf_wire_bits;
+			pool<SigBit> driven_wire_bits;
+			SigMap sigmap(module);
+			// bit -> (buffer, buffer's input)
+			dict<SigBit, pair<Cell *, Wire *>> buffered_bits;
+
+			// First, collect nets that could use a clock buffer.
+			for (auto cell : module->cells())
+			for (auto port : cell->connections())
+			for (int i = 0; i < port.second.size(); i++)
+				if (sink_ports.count(make_pair(cell->type, make_pair(port.first, i))))
+					sink_wire_bits.insert(sigmap(port.second[i]));
+
+			// Second, collect ones that already have a clock buffer.
+			for (auto cell : module->cells())
+			for (auto port : cell->connections())
+			for (int i = 0; i < port.second.size(); i++)
+				if (buf_ports.count(make_pair(cell->type, make_pair(port.first, i))))
+					buf_wire_bits.insert(sigmap(port.second[i]));
+
+			// Collect all driven bits.
+			for (auto cell : module->cells())
+			for (auto port : cell->connections())
+				if (cell->output(port.first))
+					for (int i = 0; i < port.second.size(); i++)
+						driven_wire_bits.insert(port.second[i]);
+
+			// Insert buffers.
+			std::vector<pair<Wire *, Wire *>> input_queue;
+			// Copy current wire list, as we will be adding new ones during iteration.
+			std::vector<Wire *> wires(module->wires());
+			for (auto wire : wires)
+			{
+				// Should not happen.
+				if (wire->port_input && wire->port_output)
+					continue;
+				bool process_wire = module->selected(wire);
+				if (!select && wire->get_bool_attribute("\\clkbuf_inhibit"))
+					process_wire = false;
+				if (!process_wire) {
+					// This wire is supposed to be bypassed, so make sure we don't buffer it in
+					// some buffer higher up in the hierarchy.
+					if (wire->port_output)
+						for (int i = 0; i < GetSize(wire); i++)
+							buf_ports.insert(make_pair(module->name, make_pair(wire->name, i)));
+					continue;
+				}
+
+				pool<int> input_bits;
+
+				for (int i = 0; i < GetSize(wire); i++)
+				{
+					SigBit wire_bit(wire, i);
+					SigBit mapped_wire_bit = sigmap(wire_bit);
+					if (buf_wire_bits.count(mapped_wire_bit)) {
+						// Already buffered downstream.  If this is an output, mark it.
+						if (wire->port_output)
+							buf_ports.insert(make_pair(module->name, make_pair(wire->name, i)));
+					} else if (!sink_wire_bits.count(mapped_wire_bit)) {
+						// Nothing to do.
+					} else if (driven_wire_bits.count(wire_bit) || (wire->port_input && module->get_bool_attribute("\\top"))) {
+						// Clock network not yet buffered, driven by one of
+						// our cells or a top-level input -- buffer it.
+
+						log("Inserting %s on %s.%s[%d].\n", buf_celltype.c_str(), log_id(module), log_id(wire), i);
+						RTLIL::Cell *cell = module->addCell(NEW_ID, RTLIL::escape_id(buf_celltype));
+						Wire *iwire = module->addWire(NEW_ID);
+						cell->setPort(RTLIL::escape_id(buf_portname), mapped_wire_bit);
+						cell->setPort(RTLIL::escape_id(buf_portname2), iwire);
+						if (wire->port_input && !inpad_celltype.empty() && module->get_bool_attribute("\\top")) {
+							log("Inserting %s on %s.%s[%d].\n", inpad_celltype.c_str(), log_id(module), log_id(wire), i);
+							RTLIL::Cell *cell2 = module->addCell(NEW_ID, RTLIL::escape_id(inpad_celltype));
+							cell2->setPort(RTLIL::escape_id(inpad_portname), iwire);
+							iwire = module->addWire(NEW_ID);
+							cell2->setPort(RTLIL::escape_id(inpad_portname2), iwire);
+						}
+						buffered_bits[mapped_wire_bit] = make_pair(cell, iwire);
+
+						if (wire->port_input) {
+							input_bits.insert(i);
+						}
+					} else if (wire->port_input) {
+						// A clock input in a submodule -- mark it, let higher level
+						// worry about it.
+						if (wire->port_input)
+							sink_ports.insert(make_pair(module->name, make_pair(wire->name, i)));
+					}
+				}
+				if (!input_bits.empty()) {
+					// This is an input port and some buffers were inserted -- we need
+					// to create a new input wire and transfer attributes.
+					Wire *new_wire = module->addWire(NEW_ID, wire);
+
+					for (int i = 0; i < wire->width; i++) {
+						SigBit wire_bit(wire, i);
+						SigBit mapped_wire_bit = sigmap(wire_bit);
+						auto it = buffered_bits.find(mapped_wire_bit);
+						if (it != buffered_bits.end()) {
+
+							module->connect(it->second.second, SigSpec(new_wire, i));
+						} else {
+							module->connect(SigSpec(wire, i), SigSpec(new_wire, i));
+						}
+					}
+					input_queue.push_back(make_pair(wire, new_wire));
+				}
+			}
+
+			// Mark any newly-buffered output ports as such.
+			for (auto wire : module->selected_wires()) {
+				if (wire->port_input || !wire->port_output)
+					continue;
+				for (int i = 0; i < GetSize(wire); i++)
+				{
+					SigBit wire_bit(wire, i);
+					SigBit mapped_wire_bit = sigmap(wire_bit);
+					if (buffered_bits.count(mapped_wire_bit))
+						buf_ports.insert(make_pair(module->name, make_pair(wire->name, i)));
+				}
+			}
+
+			// Reconnect the drivers to buffer inputs.
+			for (auto cell : module->cells())
+			for (auto port : cell->connections()) {
+				if (!cell->output(port.first))
+					continue;
+				SigSpec sig = port.second;
+				bool newsig = false;
+				for (auto &bit : sig) {
+					const auto it = buffered_bits.find(sigmap(bit));
+					if (it == buffered_bits.end())
+						continue;
+					// Avoid substituting buffer's own output pin.
+					if (cell == it->second.first)
+						continue;
+					bit = it->second.second;
+					newsig = true;
+				}
+				if (newsig)
+					cell->setPort(port.first, sig);
+			}
+
+			// This has to be done last, to avoid upsetting sigmap before the port reconnections.
+			for (auto &it : input_queue) {
+				Wire *wire = it.first;
+				Wire *new_wire = it.second;
+				module->swap_names(new_wire, wire);
+				wire->attributes.clear();
+				wire->port_id = 0;
+				wire->port_input = false;
+				wire->port_output = false;
+			}
+
+			module->fixup_ports();
+		}
+	}
+} ClkbufmapPass;
+
+PRIVATE_NAMESPACE_END
diff --git a/passes/techmap/iopadmap.cc b/passes/techmap/iopadmap.cc
index a2551316f..c868b9a87 100644
--- a/passes/techmap/iopadmap.cc
+++ b/passes/techmap/iopadmap.cc
@@ -64,6 +64,11 @@ struct IopadmapPass : public Pass {
 		log("        of the tristate driver and the 2nd portname is the internal output\n");
 		log("        buffering the external signal.\n");
 		log("\n");
+		log("    -ignore <celltype> <portname>[:<portname>]*\n");
+		log("        Skips mapping inputs/outputs that are already connected to given\n");
+		log("        ports of the given cell.  Can be used multiple times.  This is in\n");
+		log("        addition to the cells specified as mapping targets.\n");
+		log("\n");
 		log("    -widthparam <param_name>\n");
 		log("        Use the specified parameter name to set the port width.\n");
 		log("\n");
@@ -88,6 +93,7 @@ struct IopadmapPass : public Pass {
 		std::string toutpad_celltype, toutpad_portname, toutpad_portname2, toutpad_portname3;
 		std::string tinoutpad_celltype, tinoutpad_portname, tinoutpad_portname2, tinoutpad_portname3, tinoutpad_portname4;
 		std::string widthparam, nameparam;
+		pool<pair<IdString, IdString>> ignore;
 		bool flag_bits = false;
 
 		size_t argidx;
@@ -127,6 +133,18 @@ struct IopadmapPass : public Pass {
 				split_portname_pair(tinoutpad_portname3, tinoutpad_portname4);
 				continue;
 			}
+			if (arg == "-ignore" && argidx+2 < args.size()) {
+				std::string ignore_celltype = args[++argidx];
+				std::string ignore_portname = args[++argidx];
+				std::string ignore_portname2;
+				while (!ignore_portname.empty()) {
+					split_portname_pair(ignore_portname, ignore_portname2);
+					ignore.insert(make_pair(RTLIL::escape_id(ignore_celltype), RTLIL::escape_id(ignore_portname)));
+
+					ignore_portname = ignore_portname2;
+				}
+				continue;
+			}
 			if (arg == "-widthparam" && argidx+1 < args.size()) {
 				widthparam = args[++argidx];
 				continue;
@@ -143,6 +161,23 @@ struct IopadmapPass : public Pass {
 		}
 		extra_args(args, argidx, design);
 
+		if (!inpad_portname2.empty())
+			ignore.insert(make_pair(RTLIL::escape_id(inpad_celltype), RTLIL::escape_id(inpad_portname2)));
+		if (!outpad_portname2.empty())
+			ignore.insert(make_pair(RTLIL::escape_id(outpad_celltype), RTLIL::escape_id(outpad_portname2)));
+		if (!inoutpad_portname2.empty())
+			ignore.insert(make_pair(RTLIL::escape_id(inoutpad_celltype), RTLIL::escape_id(inoutpad_portname2)));
+		if (!toutpad_portname3.empty())
+			ignore.insert(make_pair(RTLIL::escape_id(toutpad_celltype), RTLIL::escape_id(toutpad_portname3)));
+		if (!tinoutpad_portname4.empty())
+			ignore.insert(make_pair(RTLIL::escape_id(tinoutpad_celltype), RTLIL::escape_id(tinoutpad_portname4)));
+
+		for (auto module : design->modules())
+			if (module->get_blackbox_attribute())
+				for (auto wire : module->wires())
+					if (wire->get_bool_attribute("\\iopad_external_pin"))
+						ignore.insert(make_pair(module->name, wire->name));
+
 		for (auto module : design->selected_modules())
 		{
 			dict<IdString, pool<int>> skip_wires;
@@ -150,28 +185,11 @@ struct IopadmapPass : public Pass {
 			SigMap sigmap(module);
 
 			for (auto cell : module->cells())
-			{
-				if (cell->type == RTLIL::escape_id(inpad_celltype) && cell->hasPort(RTLIL::escape_id(inpad_portname2)))
-					for (auto bit : sigmap(cell->getPort(RTLIL::escape_id(inpad_portname2))))
-						skip_wire_bits.insert(bit);
-
-				if (cell->type == RTLIL::escape_id(outpad_celltype) && cell->hasPort(RTLIL::escape_id(outpad_portname2)))
-					for (auto bit : sigmap(cell->getPort(RTLIL::escape_id(outpad_portname2))))
+			for (auto port : cell->connections())
+				if (ignore.count(make_pair(cell->type, port.first)))
+					for (auto bit : sigmap(port.second))
 						skip_wire_bits.insert(bit);
 
-				if (cell->type == RTLIL::escape_id(inoutpad_celltype) && cell->hasPort(RTLIL::escape_id(inoutpad_portname2)))
-					for (auto bit : sigmap(cell->getPort(RTLIL::escape_id(inoutpad_portname2))))
-						skip_wire_bits.insert(bit);
-
-				if (cell->type == RTLIL::escape_id(toutpad_celltype) && cell->hasPort(RTLIL::escape_id(toutpad_portname3)))
-					for (auto bit : sigmap(cell->getPort(RTLIL::escape_id(toutpad_portname3))))
-						skip_wire_bits.insert(bit);
-
-				if (cell->type == RTLIL::escape_id(tinoutpad_celltype) && cell->hasPort(RTLIL::escape_id(tinoutpad_portname4)))
-					for (auto bit : sigmap(cell->getPort(RTLIL::escape_id(tinoutpad_portname4))))
-						skip_wire_bits.insert(bit);
-			}
-
 			if (!toutpad_celltype.empty() || !tinoutpad_celltype.empty())
 			{
 				dict<SigBit, pair<IdString, pool<IdString>>> tbuf_bits;
diff --git a/passes/techmap/techmap.cc b/passes/techmap/techmap.cc
index b271c8781..c4496f76f 100644
--- a/passes/techmap/techmap.cc
+++ b/passes/techmap/techmap.cc
@@ -943,7 +943,8 @@ struct TechmapPass : public Pass {
 		log("        instead of inlining them.\n");
 		log("\n");
 		log("    -max_iter <number>\n");
-		log("        only run the specified number of iterations.\n");
+		log("        only run the specified number of iterations on each module.\n");
+		log("        default: unlimited\n");
 		log("\n");
 		log("    -recursive\n");
 		log("        instead of the iterative breadth-first algorithm use a recursive\n");
@@ -1157,15 +1158,16 @@ struct TechmapPass : public Pass {
 			RTLIL::Module *module = *worker.module_queue.begin();
 			worker.module_queue.erase(module);
 
+			int module_max_iter = max_iter;
 			bool did_something = true;
 			std::set<RTLIL::Cell*> handled_cells;
 			while (did_something) {
 				did_something = false;
-					if (worker.techmap_module(design, module, map, handled_cells, celltypeMap, false))
-						did_something = true;
+				if (worker.techmap_module(design, module, map, handled_cells, celltypeMap, false))
+					did_something = true;
 				if (did_something)
 					module->check();
-				if (max_iter > 0 && --max_iter == 0)
+				if (module_max_iter > 0 && --module_max_iter == 0)
 					break;
 			}
 		}