memory_map.cc

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/*
 *  yosys -- Yosys Open SYnthesis Suite
 *
 *  Copyright (C) 2012  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/register.h"
#include "kernel/log.h"
#include <sstream>
#include <set>
#include <stdlib.h>

USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN

struct MemoryMapWorker
{
    RTLIL::Design *design;
    RTLIL::Module *module;

    std::map<std::pair<RTLIL::SigSpec, RTLIL::SigSpec>, RTLIL::SigBit> decoder_cache;

    std::string genid(RTLIL::IdString name, std::string token1 = "", int i = -1, std::string token2 = "", int j = -1, std::string token3 = "", int k = -1, std::string token4 = "")
    {
        std::stringstream sstr;
        sstr << "$memory" << name.str() << token1;
        
        if (i >= 0)
            sstr << "[" << i << "]";

        sstr << token2;

        if (j >= 0)
            sstr << "[" << j << "]";

        sstr << token3;

        if (k >= 0)
            sstr << "[" << k << "]";

        sstr << token4 << "$" << (autoidx++);
        return sstr.str();
    }

    RTLIL::Wire *addr_decode(RTLIL::SigSpec addr_sig, RTLIL::SigSpec addr_val)
    {
        std::pair<RTLIL::SigSpec, RTLIL::SigSpec> key(addr_sig, addr_val);
        log_assert(GetSize(addr_sig) == GetSize(addr_val));

        if (decoder_cache.count(key) == 0) {
            if (GetSize(addr_sig) < 2) {
                decoder_cache[key] = module->Eq(NEW_ID, addr_sig, addr_val);
            } else {
                int split_at = GetSize(addr_sig) / 2;
                RTLIL::SigBit left_eq = addr_decode(addr_sig.extract(0, split_at), addr_val.extract(0, split_at));
                RTLIL::SigBit right_eq = addr_decode(addr_sig.extract(split_at, GetSize(addr_sig) - split_at), addr_val.extract(split_at, GetSize(addr_val) - split_at));
                decoder_cache[key] = module->And(NEW_ID, left_eq, right_eq);
            }
        }

        RTLIL::SigBit bit = decoder_cache.at(key);
        log_assert(bit.wire != nullptr && GetSize(bit.wire) == 1);
        return bit.wire;
    }

    void handle_cell(RTLIL::Cell *cell)
    {
        std::set<int> static_ports;
        std::map<int, RTLIL::SigSpec> static_cells_map;
        int mem_size = cell->parameters["\\SIZE"].as_int();
        int mem_width = cell->parameters["\\WIDTH"].as_int();
        int mem_offset = cell->parameters["\\OFFSET"].as_int();
        int mem_abits = cell->parameters["\\ABITS"].as_int();

        // delete unused memory cell
        if (cell->parameters["\\RD_PORTS"].as_int() == 0 && cell->parameters["\\WR_PORTS"].as_int() == 0) {
            module->remove(cell);
            return;
        }

        // all write ports must share the same clock
        RTLIL::SigSpec clocks = cell->getPort("\\WR_CLK");
        RTLIL::Const clocks_pol = cell->parameters["\\WR_CLK_POLARITY"];
        RTLIL::Const clocks_en = cell->parameters["\\WR_CLK_ENABLE"];
        RTLIL::SigSpec refclock;
        RTLIL::State refclock_pol = RTLIL::State::Sx;
        for (int i = 0; i < clocks.size(); i++) {
            RTLIL::SigSpec wr_en = cell->getPort("\\WR_EN").extract(i * mem_width, mem_width);
            if (wr_en.is_fully_const() && !wr_en.as_bool()) {
                static_ports.insert(i);
                continue;
            }
            if (clocks_en.bits[i] != RTLIL::State::S1) {
                RTLIL::SigSpec wr_addr = cell->getPort("\\WR_ADDR").extract(i*mem_abits, mem_abits);
                RTLIL::SigSpec wr_data = cell->getPort("\\WR_DATA").extract(i*mem_width, mem_width);
                if (wr_addr.is_fully_const()) {
                    // FIXME: Actually we should check for wr_en.is_fully_const() also and
                    // create a $adff cell with this ports wr_en input as reset pin when wr_en
                    // is not a simple static 1.
                    static_cells_map[wr_addr.as_int()] = wr_data;
                    static_ports.insert(i);
                    continue;
                }
                log("Not mapping memory cell %s in module %s (write port %d has no clock).\n",
                        cell->name.c_str(), module->name.c_str(), i);
                return;
            }
            if (refclock.size() == 0) {
                refclock = clocks.extract(i, 1);
                refclock_pol = clocks_pol.bits[i];
            }
            if (clocks.extract(i, 1) != refclock || clocks_pol.bits[i] != refclock_pol) {
                log("Not mapping memory cell %s in module %s (write clock %d is incompatible with other clocks).\n",
                        cell->name.c_str(), module->name.c_str(), i);
                return;
            }
        }

        log("Mapping memory cell %s in module %s:\n", cell->name.c_str(), module->name.c_str());

        std::vector<RTLIL::SigSpec> data_reg_in;
        std::vector<RTLIL::SigSpec> data_reg_out;

        int count_static = 0;

        for (int i = 0; i < mem_size; i++)
        {
            if (static_cells_map.count(i) > 0)
            {
                data_reg_in.push_back(RTLIL::SigSpec(RTLIL::State::Sz, mem_width));
                data_reg_out.push_back(static_cells_map[i]);
                count_static++;
            }
            else
            {
                RTLIL::Cell *c = module->addCell(genid(cell->name, "", i), "$dff");
                c->parameters["\\WIDTH"] = cell->parameters["\\WIDTH"];
                if (clocks_pol.bits.size() > 0) {
                    c->parameters["\\CLK_POLARITY"] = RTLIL::Const(clocks_pol.bits[0]);
                    c->setPort("\\CLK", clocks.extract(0, 1));
                } else {
                    c->parameters["\\CLK_POLARITY"] = RTLIL::Const(RTLIL::State::S1);
                    c->setPort("\\CLK", RTLIL::SigSpec(RTLIL::State::S0));
                }

                RTLIL::Wire *w_in = module->addWire(genid(cell->name, "", i, "$d"), mem_width);
                data_reg_in.push_back(RTLIL::SigSpec(w_in));
                c->setPort("\\D", data_reg_in.back());

                std::string w_out_name = stringf("%s[%d]", cell->parameters["\\MEMID"].decode_string().c_str(), i);
                if (module->wires_.count(w_out_name) > 0)
                    w_out_name = genid(cell->name, "", i, "$q");

                RTLIL::Wire *w_out = module->addWire(w_out_name, mem_width);
                w_out->start_offset = mem_offset;

                data_reg_out.push_back(RTLIL::SigSpec(w_out));
                c->setPort("\\Q", data_reg_out.back());
            }
        }

        log("  created %d $dff cells and %d static cells of width %d.\n", mem_size-count_static, count_static, mem_width);

        int count_dff = 0, count_mux = 0, count_wrmux = 0;

        for (int i = 0; i < cell->parameters["\\RD_PORTS"].as_int(); i++)
        {
            RTLIL::SigSpec rd_addr = cell->getPort("\\RD_ADDR").extract(i*mem_abits, mem_abits);

            std::vector<RTLIL::SigSpec> rd_signals;
            rd_signals.push_back(cell->getPort("\\RD_DATA").extract(i*mem_width, mem_width));

            if (cell->parameters["\\RD_CLK_ENABLE"].bits[i] == RTLIL::State::S1)
            {
                if (cell->parameters["\\RD_TRANSPARENT"].bits[i] == RTLIL::State::S1)
                {
                    RTLIL::Cell *c = module->addCell(genid(cell->name, "$rdreg", i), "$dff");
                    c->parameters["\\WIDTH"] = RTLIL::Const(mem_abits);
                    c->parameters["\\CLK_POLARITY"] = RTLIL::Const(cell->parameters["\\RD_CLK_POLARITY"].bits[i]);
                    c->setPort("\\CLK", cell->getPort("\\RD_CLK").extract(i, 1));
                    c->setPort("\\D", rd_addr);
                    count_dff++;

                    RTLIL::Wire *w = module->addWire(genid(cell->name, "$rdreg", i, "$q"), mem_abits);

                    c->setPort("\\Q", RTLIL::SigSpec(w));
                    rd_addr = RTLIL::SigSpec(w);
                }
                else
                {
                    RTLIL::Cell *c = module->addCell(genid(cell->name, "$rdreg", i), "$dff");
                    c->parameters["\\WIDTH"] = cell->parameters["\\WIDTH"];
                    c->parameters["\\CLK_POLARITY"] = RTLIL::Const(cell->parameters["\\RD_CLK_POLARITY"].bits[i]);
                    c->setPort("\\CLK", cell->getPort("\\RD_CLK").extract(i, 1));
                    c->setPort("\\Q", rd_signals.back());
                    count_dff++;

                    RTLIL::Wire *w = module->addWire(genid(cell->name, "$rdreg", i, "$d"), mem_width);

                    rd_signals.clear();
                    rd_signals.push_back(RTLIL::SigSpec(w));
                    c->setPort("\\D", rd_signals.back());
                }
            }

            for (int j = 0; j < mem_abits; j++)
            {
                std::vector<RTLIL::SigSpec> next_rd_signals;

                for (size_t k = 0; k < rd_signals.size(); k++)
                {
                    RTLIL::Cell *c = module->addCell(genid(cell->name, "$rdmux", i, "", j, "", k), "$mux");
                    c->parameters["\\WIDTH"] = cell->parameters["\\WIDTH"];
                    c->setPort("\\Y", rd_signals[k]);
                    c->setPort("\\S", rd_addr.extract(mem_abits-j-1, 1));
                    count_mux++;

                    c->setPort("\\A", module->addWire(genid(cell->name, "$rdmux", i, "", j, "", k, "$a"), mem_width));
                    c->setPort("\\B", module->addWire(genid(cell->name, "$rdmux", i, "", j, "", k, "$b"), mem_width));

                    next_rd_signals.push_back(c->getPort("\\A"));
                    next_rd_signals.push_back(c->getPort("\\B"));
                }

                next_rd_signals.swap(rd_signals);
            }

            for (int j = 0; j < mem_size; j++)
                module->connect(RTLIL::SigSig(rd_signals[j], data_reg_out[j]));
        }

        log("  read interface: %d $dff and %d $mux cells.\n", count_dff, count_mux);

        for (int i = 0; i < mem_size; i++)
        {
            if (static_cells_map.count(i) > 0)
                continue;

            RTLIL::SigSpec sig = data_reg_out[i];

            for (int j = 0; j < cell->parameters["\\WR_PORTS"].as_int(); j++)
            {
                RTLIL::SigSpec wr_addr = cell->getPort("\\WR_ADDR").extract(j*mem_abits, mem_abits);
                RTLIL::SigSpec wr_data = cell->getPort("\\WR_DATA").extract(j*mem_width, mem_width);
                RTLIL::SigSpec wr_en = cell->getPort("\\WR_EN").extract(j*mem_width, mem_width);
                RTLIL::Wire *w_seladdr = addr_decode(wr_addr, RTLIL::SigSpec(i, mem_abits));

                int wr_offset = 0;
                while (wr_offset < wr_en.size())
                {
                    int wr_width = 1;
                    RTLIL::SigSpec wr_bit = wr_en.extract(wr_offset, 1);

                    while (wr_offset + wr_width < wr_en.size()) {
                        RTLIL::SigSpec next_wr_bit = wr_en.extract(wr_offset + wr_width, 1);
                        if (next_wr_bit != wr_bit)
                            break;
                        wr_width++;
                    }

                    RTLIL::Wire *w = w_seladdr;

                    if (wr_bit != RTLIL::SigSpec(1, 1))
                    {
                        RTLIL::Cell *c = module->addCell(genid(cell->name, "$wren", i, "", j, "", wr_offset), "$and");
                        c->parameters["\\A_SIGNED"] = RTLIL::Const(0);
                        c->parameters["\\B_SIGNED"] = RTLIL::Const(0);
                        c->parameters["\\A_WIDTH"] = RTLIL::Const(1);
                        c->parameters["\\B_WIDTH"] = RTLIL::Const(1);
                        c->parameters["\\Y_WIDTH"] = RTLIL::Const(1);
                        c->setPort("\\A", w);
                        c->setPort("\\B", wr_bit);

                        w = module->addWire(genid(cell->name, "$wren", i, "", j, "", wr_offset, "$y"));
                        c->setPort("\\Y", RTLIL::SigSpec(w));
                    }

                    RTLIL::Cell *c = module->addCell(genid(cell->name, "$wrmux", i, "", j, "", wr_offset), "$mux");
                    c->parameters["\\WIDTH"] = wr_width;
                    c->setPort("\\A", sig.extract(wr_offset, wr_width));
                    c->setPort("\\B", wr_data.extract(wr_offset, wr_width));
                    c->setPort("\\S", RTLIL::SigSpec(w));

                    w = module->addWire(genid(cell->name, "$wrmux", i, "", j, "", wr_offset, "$y"), wr_width);
                    c->setPort("\\Y", w);

                    sig.replace(wr_offset, w);
                    wr_offset += wr_width;
                    count_wrmux++;
                }
            }

            module->connect(RTLIL::SigSig(data_reg_in[i], sig));
        }

        log("  write interface: %d write mux blocks.\n", count_wrmux);

        module->remove(cell);
    }

    MemoryMapWorker(RTLIL::Design *design, RTLIL::Module *module) : design(design), module(module)
    {
        std::vector<RTLIL::Cell*> cells;
        for (auto cell : module->selected_cells())
            if (cell->type == "$mem" && design->selected(module, cell))
                cells.push_back(cell);
        for (auto cell : cells)
            handle_cell(cell);
    }
};

struct MemoryMapPass : public Pass {
    MemoryMapPass() : Pass("memory_map", "translate multiport memories to basic cells") { }
    virtual void help()
    {
        //   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
        log("\n");
        log("    memory_map [selection]\n");
        log("\n");
        log("This pass converts multiport memory cells as generated by the memory_collect\n");
        log("pass to word-wide DFFs and address decoders.\n");
        log("\n");
    }
    virtual void execute(std::vector<std::string> args, RTLIL::Design *design) {
        log_header("Executing MEMORY_MAP pass (converting $mem cells to logic and flip-flops).\n");
        extra_args(args, 1, design);
        for (auto mod : design->selected_modules())
            MemoryMapWorker(design, mod);
    }
} MemoryMapPass;
 
PRIVATE_NAMESPACE_END