nextpnr/ecp5/pack.cc
David Shah 7c89aed70e ecp5: Infrastructure for FF packing
Signed-off-by: David Shah <davey1576@gmail.com>
2018-07-17 14:19:21 +02:00

202 lines
7.6 KiB
C++

/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2018 David Shah <david@symbioticeda.com>
*
* 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 <algorithm>
#include <iterator>
#include <unordered_set>
#include "cells.h"
#include "design_utils.h"
#include "log.h"
#include "util.h"
NEXTPNR_NAMESPACE_BEGIN
static bool is_nextpnr_iob(Context *ctx, CellInfo *cell)
{
return cell->type == ctx->id("$nextpnr_ibuf") || cell->type == ctx->id("$nextpnr_obuf") ||
cell->type == ctx->id("$nextpnr_iobuf");
}
class Ecp5Packer
{
public:
Ecp5Packer(Context *ctx) : ctx(ctx){};
private:
// Process the contents of packed_cells and new_cells
void flush_cells()
{
for (auto pcell : packed_cells) {
ctx->cells.erase(pcell);
}
for (auto &ncell : new_cells) {
ctx->cells[ncell->name] = std::move(ncell);
}
packed_cells.clear();
new_cells.clear();
}
// Find FFs associated with LUTs, or LUT expansion muxes
void find_lutff_pairs()
{
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (is_lut(ctx, ci) || is_pfumx(ctx, ci) || is_l6mux(ctx, ci)) {
NetInfo *znet = ci->ports.at(ctx->id("Z")).net;
if (znet != nullptr) {
CellInfo *ff = net_only_drives(ctx, znet, is_ff, ctx->id("DI"), false);
if (ff != nullptr) {
lutffPairs[ci->name] = ff->name;
}
}
}
}
}
// Simple "packer" to remove nextpnr IOBUFs, this assumes IOBUFs are manually instantiated
void pack_io()
{
log_info("Packing IOs..\n");
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (is_nextpnr_iob(ctx, ci)) {
CellInfo *trio = nullptr;
if (ci->type == ctx->id("$nextpnr_ibuf") || ci->type == ctx->id("$nextpnr_iobuf")) {
trio = net_only_drives(ctx, ci->ports.at(ctx->id("O")).net, is_trellis_io, ctx->id("B"), true, ci);
} else if (ci->type == ctx->id("$nextpnr_obuf")) {
trio = net_only_drives(ctx, ci->ports.at(ctx->id("I")).net, is_trellis_io, ctx->id("B"), true, ci);
}
if (trio != nullptr) {
// Trivial case, TRELLIS_IO used. Just destroy the net and the
// iobuf
log_info("%s feeds TRELLIS_IO %s, removing %s %s.\n", ci->name.c_str(ctx), trio->name.c_str(ctx),
ci->type.c_str(ctx), ci->name.c_str(ctx));
NetInfo *net = trio->ports.at(ctx->id("B")).net;
if (net != nullptr) {
ctx->nets.erase(net->name);
trio->ports.at(ctx->id("B")).net = nullptr;
}
if (ci->type == ctx->id("$nextpnr_iobuf")) {
NetInfo *net2 = ci->ports.at(ctx->id("I")).net;
if (net2 != nullptr) {
ctx->nets.erase(net2->name);
}
}
} else {
log_error("TRELLIS_IO required on all top level IOs...\n");
}
packed_cells.insert(ci->name);
std::copy(ci->attrs.begin(), ci->attrs.end(), std::inserter(trio->attrs, trio->attrs.begin()));
}
}
flush_cells();
}
// Pass to pack LUT5s into a newly created slice
void pack_lut5s()
{
log_info("Packing LUT5s...\n");
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (is_pfumx(ctx, ci)) {
std::unique_ptr<CellInfo> packed =
create_ecp5_cell(ctx, ctx->id("TRELLIS_SLICE"), ci->name.str(ctx) + "_SLICE");
NetInfo *f0 = ci->ports.at(ctx->id("BLUT")).net;
if (f0 == nullptr)
log_error("PFUMX '%s' has disconnected port 'BLUT'\n", ci->name.c_str(ctx));
NetInfo *f1 = ci->ports.at(ctx->id("ALUT")).net;
if (f1 == nullptr)
log_error("PFUMX '%s' has disconnected port 'ALUT'\n", ci->name.c_str(ctx));
CellInfo *lc0 = net_driven_by(ctx, f0, is_lut, ctx->id("Z"));
CellInfo *lc1 = net_driven_by(ctx, f1, is_lut, ctx->id("Z"));
if (lc0 == nullptr)
log_error("PFUMX '%s' has BLUT driven by cell other than a LUT\n", ci->name.c_str(ctx));
if (lc1 == nullptr)
log_error("PFUMX '%s' has ALUT driven by cell other than a LUT\n", ci->name.c_str(ctx));
replace_port(lc0, ctx->id("A"), packed.get(), ctx->id("A0"));
replace_port(lc0, ctx->id("B"), packed.get(), ctx->id("B0"));
replace_port(lc0, ctx->id("C"), packed.get(), ctx->id("C0"));
replace_port(lc0, ctx->id("D"), packed.get(), ctx->id("D0"));
replace_port(lc1, ctx->id("A"), packed.get(), ctx->id("A1"));
replace_port(lc1, ctx->id("B"), packed.get(), ctx->id("B1"));
replace_port(lc1, ctx->id("C"), packed.get(), ctx->id("C1"));
replace_port(lc1, ctx->id("D"), packed.get(), ctx->id("D1"));
replace_port(ci, ctx->id("C0"), packed.get(), ctx->id("M0"));
replace_port(ci, ctx->id("Z"), packed.get(), ctx->id("OFX0"));
ctx->nets.erase(f0->name);
ctx->nets.erase(f1->name);
if (lutffPairs.find(ci->name) != lutffPairs.end()) {
CellInfo *ff = ctx->cells.at(lutffPairs[ci->name]).get();
ff_to_lc(ctx, ff, packed.get(), 0, true);
packed_cells.insert(ff->name);
}
new_cells.push_back(std::move(packed));
packed_cells.insert(lc0->name);
packed_cells.insert(lc1->name);
packed_cells.insert(ci->name);
}
}
flush_cells();
}
public:
void pack()
{
pack_io();
pack_lut5s();
}
private:
Context *ctx;
std::unordered_set<IdString> packed_cells;
std::vector<std::unique_ptr<CellInfo>> new_cells;
struct SliceUsage
{
bool lut0_used = false, lut1_used = false;
bool ccu2_used = false, dpram_used = false, ramw_used = false;
bool ff0_used = false, ff1_used = false;
bool mux5_used = false, muxx_used = false;
};
std::unordered_map<IdString, SliceUsage> sliceUsage;
std::unordered_map<IdString, IdString> lutffPairs;
};
// Main pack function
bool Arch::pack()
{
Context *ctx = getCtx();
try {
log_break();
Ecp5Packer(ctx).pack();
log_info("Checksum: 0x%08x\n", ctx->checksum());
return true;
} catch (log_execution_error_exception) {
return false;
}
}
NEXTPNR_NAMESPACE_END