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+/*
+ * yosys -- Yosys Open SYnthesis Suite
+ *
+ * Copyright (C) 2016 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
+};
+
+//attempt to extract a counter centered on the given cell
+int greenpak4_counters_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
+ 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 == "$adff")
+ {
+ extract.has_reset = true;
+
+ //Verify ARST_VALUE is zero and ARST_POLARITY is 1
+ //TODO: infer an inverter to make it 1 if necessary, so we can support negative level resets?
+ if(count_reg->getParam("\\ARST_POLARITY").as_int() != 1)
+ return 22;
+ if(count_reg->getParam("\\ARST_VALUE").as_int() != 0)
+ return 23;
+
+ //Save the reset
+ extract.rst = sigmap(count_reg->getPort("\\ARST"));
+ }
+ //TODO: support synchronous reset
+ else
+ return 15;
+ if(!is_full_bus(muxy, index, count_mux, "\\Y", count_reg, "\\D"))
+ return 16;
+
+ //TODO: Verify count_reg CLK_POLARITY is 1
+
+ //Register output must have exactly two loads, the inverter and ALU
+ const RTLIL::SigSpec cnout = sigmap(count_reg->getPort("\\Q"));
+ pool<Cell*> cnout_loads = get_other_cells(cnout, index, count_reg);
+ if(cnout_loads.size() != 2)
+ return 17;
+ if(!is_full_bus(cnout, index, count_reg, "\\Q", underflow_inv, "\\A", true))
+ return 18;
+ if(!is_full_bus(cnout, index, count_reg, "\\Q", cell, "\\A", true))
+ return 19;
+
+ //Look up the clock from the register
+ extract.clk = sigmap(count_reg->getPort("\\CLK"));
+
+ //Register output net must have an INIT attribute equal to the count value
+ extract.rwire = cnout.as_wire();
+ if(extract.rwire->attributes.find("\\init") == extract.rwire->attributes.end())
+ return 20;
+ int rinit = extract.rwire->attributes["\\init"].as_int();
+ if(rinit != extract.count_value)
+ return 21;
+
+ return 0;
+}
+
+void greenpak4_counters_worker(
+ ModIndex& index,
+ Cell *cell,
+ unsigned int& total_counters,
+ pool<Cell*>& cells_to_remove)
+{
+ SigMap& sigmap = index.sigmap;
+
+ //Core of the counter must be an ALU
+ if (cell->type != "$alu")
+ return;
+
+ //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 = 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(extract.width > 8)
+ celltype = "\\GP_COUNT14";
+
+ //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 (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");
+ 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);
+
+ //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);
+}
+
+struct Greenpak4CountersPass : public Pass {
+ Greenpak4CountersPass() : Pass("greenpak4_counters", "Extract GreenPak4 counter cells") { }
+ virtual void help()
+ {
+ // |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+ log("\n");
+ log(" greenpak4_counters [options] [selection]\n");
+ log("\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)
+ {
+ log_header(design, "Executing GREENPAK4_COUNTERS pass (mapping counters to hard IP blocks).\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;
+
+ ModIndex index(module);
+ for (auto cell : module->selected_cells())
+ 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;
+
+PRIVATE_NAMESPACE_END
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