201 lines
7.2 KiB
C++
201 lines
7.2 KiB
C++
/*
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* nextpnr -- Next Generation Place and Route
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*
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* Copyright (C) 2018 Clifford Wolf <clifford@clifford.at>
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* Copyright (C) 2018 David Shah <dave@ds0.me>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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*/
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#include "pack.h"
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#include <algorithm>
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#include <unordered_set>
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#include "cells.h"
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#include "design_utils.h"
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#include "log.h"
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NEXTPNR_NAMESPACE_BEGIN
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// Pack LUTs and LUT-FF pairs
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static void pack_lut_lutffs(Design *design)
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{
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std::unordered_set<IdString> packed_cells;
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std::vector<CellInfo *> new_cells;
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for (auto cell : design->cells) {
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CellInfo *ci = cell.second;
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log_info("cell '%s' is of type '%s'\n", ci->name.c_str(),
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ci->type.c_str());
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if (is_lut(ci)) {
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CellInfo *packed = create_ice_cell(design, "ICESTORM_LC",
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ci->name.str() + "_LC");
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std::copy(ci->attrs.begin(), ci->attrs.end(),
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std::inserter(packed->attrs, packed->attrs.begin()));
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packed_cells.insert(ci->name);
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new_cells.push_back(packed);
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log_info("packed cell %s into %s\n", ci->name.c_str(),
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packed->name.c_str());
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// See if we can pack into a DFF
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// TODO: LUT cascade
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NetInfo *o = ci->ports.at("O").net;
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CellInfo *dff = net_only_drives(o, is_ff, "D", true);
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auto lut_bel = ci->attrs.find("BEL");
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bool packed_dff = false;
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if (dff) {
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log_info("found attached dff %s\n", dff->name.c_str());
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auto dff_bel = dff->attrs.find("BEL");
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if (lut_bel != ci->attrs.end() && dff_bel != dff->attrs.end() &&
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lut_bel->second != dff_bel->second) {
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// Locations don't match, can't pack
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} else {
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lut_to_lc(ci, packed, false);
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dff_to_lc(dff, packed, false);
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design->nets.erase(o->name);
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if (dff_bel != dff->attrs.end())
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packed->attrs["BEL"] = dff_bel->second;
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packed_cells.insert(dff->name);
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log_info("packed cell %s into %s\n", dff->name.c_str(),
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packed->name.c_str());
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packed_dff = true;
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}
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}
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if (!packed_dff) {
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lut_to_lc(ci, packed, true);
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}
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}
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}
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for (auto pcell : packed_cells) {
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design->cells.erase(pcell);
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}
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for (auto ncell : new_cells) {
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design->cells[ncell->name] = ncell;
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}
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}
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// Pack FFs not packed as LUTFFs
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static void pack_nonlut_ffs(Design *design)
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{
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std::unordered_set<IdString> packed_cells;
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std::vector<CellInfo *> new_cells;
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for (auto cell : design->cells) {
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CellInfo *ci = cell.second;
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if (is_ff(ci)) {
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CellInfo *packed = create_ice_cell(design, "ICESTORM_LC",
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ci->name.str() + "_DFFLC");
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std::copy(ci->attrs.begin(), ci->attrs.end(),
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std::inserter(packed->attrs, packed->attrs.begin()));
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log_info("packed cell %s into %s\n", ci->name.c_str(),
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packed->name.c_str());
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packed_cells.insert(ci->name);
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new_cells.push_back(packed);
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dff_to_lc(ci, packed, true);
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}
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}
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for (auto pcell : packed_cells) {
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design->cells.erase(pcell);
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}
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for (auto ncell : new_cells) {
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design->cells[ncell->name] = ncell;
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}
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}
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// Pack constants (simple implementation)
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static void pack_constants(Design *design)
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{
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CellInfo *gnd_cell = create_ice_cell(design, "ICESTORM_LC", "$PACKER_GND");
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gnd_cell->attrs["LUT_INIT"] = "0";
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CellInfo *vcc_cell = create_ice_cell(design, "ICESTORM_LC", "$PACKER_VCC");
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vcc_cell->attrs["LUT_INIT"] = "1";
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for (auto net : design->nets) {
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NetInfo *ni = net.second;
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if (ni->driver.cell != nullptr && ni->driver.cell->type == "GND") {
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ni->driver.cell = gnd_cell;
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ni->driver.port = "O";
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design->cells[gnd_cell->name] = gnd_cell;
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} else if (ni->driver.cell != nullptr &&
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ni->driver.cell->type == "VCC") {
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ni->driver.cell = vcc_cell;
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ni->driver.port = "O";
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design->cells[vcc_cell->name] = vcc_cell;
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}
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}
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}
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static bool is_nextpnr_iob(CellInfo *cell)
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{
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return cell->type == "$nextpnr_ibuf" || cell->type == "$nextpnr_obuf" ||
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cell->type == "$nextpnr_iobuf";
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}
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// Pack IO buffers
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static void pack_io(Design *design)
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{
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std::unordered_set<IdString> packed_cells;
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std::vector<CellInfo *> new_cells;
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for (auto cell : design->cells) {
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CellInfo *ci = cell.second;
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if (is_nextpnr_iob(ci)) {
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CellInfo *sb = nullptr;
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if (ci->type == "$nextpnr_ibuf" || ci->type == "$nextpnr_iobuf") {
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sb = net_only_drives(ci->ports.at("O").net, is_sb_io,
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"PACKAGE_PIN", true, ci);
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} else if (ci->type == "$nextpnr_obuf") {
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sb = net_only_drives(ci->ports.at("I").net, is_sb_io,
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"PACKAGE_PIN", true, ci);
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}
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if (sb != nullptr) {
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// Trivial case, SB_IO used. Just destroy the net and the
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// iobuf
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log_info("%s feeds SB_IO %s, removing %s %s.\n",
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ci->name.c_str(), sb->name.c_str(), ci->type.c_str(),
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ci->name.c_str());
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NetInfo *net = sb->ports.at("PACKAGE_PIN").net;
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if (net != nullptr) {
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design->nets.erase(net->name);
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sb->ports.at("PACKAGE_PIN").net = nullptr;
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}
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} else {
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// Create a SB_IO buffer
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sb = create_ice_cell(design, "SB_IO");
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nxio_to_sb(ci, sb);
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new_cells.push_back(sb);
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}
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packed_cells.insert(ci->name);
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std::copy(ci->attrs.begin(), ci->attrs.end(),
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std::inserter(sb->attrs, sb->attrs.begin()));
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}
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}
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for (auto pcell : packed_cells) {
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design->cells.erase(pcell);
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}
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for (auto ncell : new_cells) {
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design->cells[ncell->name] = ncell;
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}
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}
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// Main pack function
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void pack_design(Design *design)
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{
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pack_constants(design);
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pack_io(design);
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pack_lut_lutffs(design);
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pack_nonlut_ffs(design);
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}
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NEXTPNR_NAMESPACE_END
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