diff options
Diffstat (limited to 'passes/techmap')
-rw-r--r-- | passes/techmap/Makefile.inc | 1 | ||||
-rw-r--r-- | passes/techmap/extract_counter.cc | 513 |
2 files changed, 514 insertions, 0 deletions
diff --git a/passes/techmap/Makefile.inc b/passes/techmap/Makefile.inc index 3f8a6feb5..140a9f892 100644 --- a/passes/techmap/Makefile.inc +++ b/passes/techmap/Makefile.inc @@ -17,6 +17,7 @@ OBJS += passes/techmap/iopadmap.o OBJS += passes/techmap/hilomap.o OBJS += passes/techmap/extract.o OBJS += passes/techmap/extract_fa.o +OBJS += passes/techmap/extract_counter.o OBJS += passes/techmap/extract_reduce.o OBJS += passes/techmap/alumacc.o OBJS += passes/techmap/dff2dffe.o diff --git a/passes/techmap/extract_counter.cc b/passes/techmap/extract_counter.cc new file mode 100644 index 000000000..54584b6f3 --- /dev/null +++ b/passes/techmap/extract_counter.cc @@ -0,0 +1,513 @@ +/* + * yosys -- Yosys Open SYnthesis Suite + * + * Copyright (C) 2017 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" +#include "kernel/modtools.h" + +USING_YOSYS_NAMESPACE +PRIVATE_NAMESPACE_BEGIN + +//get the list of cells hooked up to at least one bit of a given net +pool<Cell*> get_other_cells(const RTLIL::SigSpec& port, ModIndex& index, Cell* src) +{ + pool<Cell*> rval; + for(auto b : port) + { + pool<ModIndex::PortInfo> ports = index.query_ports(b); + for(auto x : ports) + { + if(x.cell == src) + continue; + rval.insert(x.cell); + } + } + return rval; +} + +//return true if there is a full-width bus connection from cell a port ap to cell b port bp +//if other_conns_allowed is false, then we require a strict point to point connection (no other links) +bool is_full_bus( + const RTLIL::SigSpec& sig, + ModIndex& index, + Cell* a, + RTLIL::IdString ap, + Cell* b, + RTLIL::IdString bp, + bool other_conns_allowed = false) +{ + for(auto s : sig) + { + pool<ModIndex::PortInfo> ports = index.query_ports(s); + bool found_a = false; + bool found_b = false; + for(auto x : ports) + { + if( (x.cell == a) && (x.port == ap) ) + found_a = true; + else if( (x.cell == b) && (x.port == bp) ) + found_b = true; + else if(!other_conns_allowed) + return false; + } + + if( (!found_a) || (!found_b) ) + return false; + } + + return true; +} + +//return true if the signal connects to one port only (nothing on the other end) +bool is_unconnected(const RTLIL::SigSpec& port, ModIndex& index) +{ + for(auto b : port) + { + pool<ModIndex::PortInfo> ports = index.query_ports(b); + if(ports.size() > 1) + return false; + } + + return true; +} + +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 + pool<ModIndex::PortInfo> pouts; //Ports that take a parallel output from us +}; + +//attempt to extract a counter centered on the given adder cell +int counter_tryextract(ModIndex& index, Cell *cell, CounterExtraction& extract) +{ + SigMap& sigmap = index.sigmap; + + //GreenPak does not support counters larger than 14 bits so immediately skip anything bigger + //TODO: infer cascaded counters? + int a_width = cell->getParam("\\A_WIDTH").as_int(); + extract.width = a_width; + if(a_width > 14) + return 1; + + //Second input must be a single bit + int b_width = cell->getParam("\\B_WIDTH").as_int(); + if(b_width != 1) + 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 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 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 5; + const RTLIL::SigSpec ci_port = sigmap(cell->getPort("\\CI")); + if(!ci_port.is_fully_const() || (ci_port.as_int() != 1) ) + return 6; + + //CO and X must be unconnected (exactly one connection to each port) + if(!is_unconnected(sigmap(cell->getPort("\\CO")), index)) + return 7; + if(!is_unconnected(sigmap(cell->getPort("\\X")), index)) + return 8; + + //Y must have exactly one connection, and it has to be a $mux cell. + //We must have a direct bus connection from our Y to their A. + const RTLIL::SigSpec aluy = sigmap(cell->getPort("\\Y")); + pool<Cell*> y_loads = get_other_cells(aluy, index, cell); + if(y_loads.size() != 1) + return 9; + Cell* count_mux = *y_loads.begin(); + extract.count_mux = count_mux; + if(count_mux->type != "$mux") + return 10; + if(!is_full_bus(aluy, index, cell, "\\Y", count_mux, "\\A")) + 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 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) + { + if(c->type != "$logic_not") + continue; + if(!is_full_bus(muxsel, index, c, "\\Y", count_mux, "\\S", true)) + continue; + + underflow_inv = c; + break; + } + if(underflow_inv == NULL) + return 13; + extract.underflow_inv = underflow_inv; + + //Y connection of the mux must have exactly one load, the counter's internal register + const RTLIL::SigSpec muxy = sigmap(count_mux->getPort("\\Y")); + pool<Cell*> muxy_loads = get_other_cells(muxy, index, count_mux); + if(muxy_loads.size() != 1) + return 14; + Cell* count_reg = *muxy_loads.begin(); + extract.count_reg = count_reg; + if(count_reg->type == "$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 16; + + //TODO: Verify count_reg CLK_POLARITY is 1 + + //Register output must have exactly two loads, the inverter and ALU + //(unless we have a parallel output!) + const RTLIL::SigSpec qport = count_reg->getPort("\\Q"); + const RTLIL::SigSpec cnout = sigmap(qport); + pool<Cell*> cnout_loads = get_other_cells(cnout, index, count_reg); + if(cnout_loads.size() > 2) + { + //It's OK to have other loads iff they go to a DAC or DCMP (these are POUT) + for(auto c : cnout_loads) + { + if(c == underflow_inv) + continue; + if(c == cell) + continue; + + //If the cell is not a DAC or DCMP, complain + if( (c->type != "\\GP_DCMP") && (c->type != "\\GP_DAC") ) + return 17; + + //Figure out what port(s) are driven by it + //TODO: this can probably be done more efficiently w/o multiple iterations over our whole net? + RTLIL::IdString portname; + for(auto b : qport) + { + pool<ModIndex::PortInfo> ports = index.query_ports(b); + for(auto x : ports) + { + if(x.cell != c) + continue; + if(portname == "") + portname = x.port; + + //somehow our counter output is going to multiple ports + //this makes no sense, don't allow inference + else if(portname != x.port) + return 17; + } + } + + //Save the other loads + extract.pouts.insert(ModIndex::PortInfo(c, portname, 0)); + } + } + if(!is_full_bus(cnout, index, count_reg, "\\Q", underflow_inv, "\\A", true)) + return 18; + if(!is_full_bus(cnout, index, count_reg, "\\Q", cell, "\\A", true)) + return 19; + + //Look up the clock from the register + extract.clk = sigmap(count_reg->getPort("\\CLK")); + + //Register output net must have an INIT attribute equal to the count value + 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 counter_worker( + ModIndex& index, + Cell *cell, + unsigned int& total_counters, + pool<Cell*>& cells_to_remove, + pool<pair<Cell*, string>>& cells_to_rename) +{ + SigMap& sigmap = index.sigmap; + + //Core of the counter must be an ALU + if (cell->type != "$alu") + return; + + //A input is the count value. Check if it has COUNT_EXTRACT set. + //If it's not a wire, don't even try + auto port = sigmap(cell->getPort("\\A")); + if(!port.is_wire()) + return; + RTLIL::Wire* a_wire = port.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 = counter_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, but not by a DCMP or DAC", //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(extract.width > 8) + celltype = "\\GP_COUNT14"; + + //Get new cell name + string countname = string("$auto$GP_COUNTx$") + log_id(extract.rwire->name.str()); + + //Log it + total_counters ++; + 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 %s (counting from %d) for register %s declared at %s\n", + extract.width, + reset_type.c_str(), + countname.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"); + cell->unsetPort("\\BI"); + cell->unsetPort("\\CI"); + cell->unsetPort("\\CO"); + cell->unsetPort("\\X"); + cell->unsetPort("\\Y"); + cell->unsetParam("\\A_SIGNED"); + cell->unsetParam("\\A_WIDTH"); + cell->unsetParam("\\B_SIGNED"); + cell->unsetParam("\\B_WIDTH"); + cell->unsetParam("\\Y_WIDTH"); + + //Change the cell type + cell->type = celltype; + + //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(extract.count_value)); + + cell->setPort("\\CLK", extract.clk); + cell->setPort("\\OUT", extract.outsig); + + //Hook up any parallel outputs + for(auto load : extract.pouts) + { + log(" Counter has parallel output to cell %s port %s\n", log_id(load.cell->name), log_id(load.port)); + + //Find the wire hooked to the old port + auto sig = load.cell->getPort(load.port); + + //Connect it to our parallel output + //(this is OK to do more than once b/c they all go to the same place) + cell->setPort("\\POUT", sig); + } + + //Delete the cells we've replaced (let opt_clean handle deleting the now-redundant wires) + cells_to_remove.insert(extract.count_mux); + cells_to_remove.insert(extract.count_reg); + cells_to_remove.insert(extract.underflow_inv); + + //Finally, rename the cell + cells_to_rename.insert(pair<Cell*, string>(cell, countname)); +} + +struct ExtractCounterPass : public Pass { + ExtractCounterPass() : Pass("extract_counter", "Extract GreenPak4 counter cells") { } + virtual void help() + { + // |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---| + log("\n"); + log(" extract_counter [options] [selection]\n"); + log("\n"); + log("This pass converts non-resettable or async resettable down counters to\n"); + log("counter cells\n"); + log("\n"); + } + virtual void execute(std::vector<std::string> args, RTLIL::Design *design) + { + log_header(design, "Executing EXTRACT_COUNTER pass (find counters in netlist).\n"); + + size_t argidx; + for (argidx = 1; argidx < args.size(); argidx++) + { + // if (args[argidx] == "-v") { + // continue; + // } + break; + } + 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; + pool<pair<Cell*, string>> cells_to_rename; + + ModIndex index(module); + for (auto cell : module->selected_cells()) + counter_worker(index, cell, total_counters, cells_to_remove, cells_to_rename); + + for(auto cell : cells_to_remove) + { + //log("Removing cell %s\n", log_id(cell->name)); + module->remove(cell); + } + + for(auto cpair : cells_to_rename) + { + //log("Renaming cell %s to %s\n", log_id(cpair.first->name), cpair.second.c_str()); + module->rename(cpair.first, cpair.second); + } + } + + if(total_counters) + log("Extracted %u counters\n", total_counters); + } +} ExtractCounterPass; + +PRIVATE_NAMESPACE_END |