nextpnr/ecp5/pack.cc
David Shah 6c54d4f93c ecp5: FF packer
Signed-off-by: David Shah <davey1576@gmail.com>
2018-07-17 15:48:34 +02:00

405 lines
17 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()
{
log_info("Finding LUTFF pairs...\n");
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;
fflutPairs[ff->name] = ci->name;
}
}
}
}
}
// Return whether two FFs can be packed together in the same slice
bool can_pack_ffs(CellInfo *ff0, CellInfo *ff1)
{
if (str_or_default(ff0->params, ctx->id("GSR"), "DISABLED") !=
str_or_default(ff1->params, ctx->id("GSR"), "DISABLED"))
return false;
if (str_or_default(ff0->params, ctx->id("SRMODE"), "LSR_OVER_CE") !=
str_or_default(ff1->params, ctx->id("SRMODE"), "LSR_OVER_CE"))
return false;
if (str_or_default(ff0->params, ctx->id("CEMUX"), "1") != str_or_default(ff1->params, ctx->id("CEMUX"), "1"))
return false;
if (str_or_default(ff0->params, ctx->id("LSRMUX"), "LSR") !=
str_or_default(ff1->params, ctx->id("LSRMUX"), "LSR"))
return false;
if (str_or_default(ff0->params, ctx->id("CLKMUX"), "CLK") !=
str_or_default(ff1->params, ctx->id("CLKMUX"), "CLK"))
return false;
if (ff0->ports.at(ctx->id("CLK")).net != ff1->ports.at(ctx->id("CLK")).net)
return false;
if (ff0->ports.at(ctx->id("CE")).net != ff1->ports.at(ctx->id("CE")).net)
return false;
if (ff0->ports.at(ctx->id("LSR")).net != ff1->ports.at(ctx->id("LSR")).net)
return false;
return true;
}
// Return true if two LUTs can be paired considering FF compatibility
bool can_pack_lutff(IdString lut0, IdString lut1)
{
auto ff0 = lutffPairs.find(lut0), ff1 = lutffPairs.find(lut1);
if (ff0 != lutffPairs.end() && ff1 != lutffPairs.end()) {
return can_pack_ffs(ctx->cells.at(ff0->second).get(), ctx->cells.at(ff1->second).get());
} else {
return true;
}
}
// Find "closely connected" LUTs and pair them together
void pair_luts()
{
log_info("Finding LUT-LUT pairs...\n");
std::unordered_set<IdString> procdLuts;
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (is_lut(ctx, ci) && procdLuts.find(cell.first) == procdLuts.end()) {
NetInfo *znet = ci->ports.at(ctx->id("Z")).net;
if (znet != nullptr) {
for (auto user : znet->users) {
if (is_lut(ctx, user.cell) && procdLuts.find(user.cell->name) == procdLuts.end()) {
if (can_pack_lutff(ci->name, user.cell->name)) {
procdLuts.insert(ci->name);
procdLuts.insert(user.cell->name);
lutPairs[ci->name] = user.cell->name;
goto paired;
}
}
}
if (false) {
paired:
continue;
}
}
if (lutffPairs.find(ci->name) != lutffPairs.end()) {
NetInfo *qnet = ctx->cells.at(lutffPairs[ci->name])->ports.at(ctx->id("Q")).net;
if (qnet != nullptr) {
for (auto user : qnet->users) {
if (is_lut(ctx, user.cell) && procdLuts.find(user.cell->name) == procdLuts.end()) {
if (can_pack_lutff(ci->name, user.cell->name)) {
procdLuts.insert(ci->name);
procdLuts.insert(user.cell->name);
lutPairs[ci->name] = user.cell->name;
goto paired_ff;
}
}
}
if (false) {
paired_ff:
continue;
}
}
}
for (char inp : "ABCD") {
NetInfo *innet = ci->ports.at(ctx->id(std::string("") + inp)).net;
if (innet != nullptr && innet->driver.cell != nullptr) {
CellInfo *drv = innet->driver.cell;
if (is_lut(ctx, drv) && innet->driver.port == ctx->id("Z")) {
if (procdLuts.find(drv->name) == procdLuts.end()) {
if (can_pack_lutff(ci->name, drv->name)) {
procdLuts.insert(ci->name);
procdLuts.insert(drv->name);
lutPairs[ci->name] = drv->name;
goto paired_inlut;
}
}
} else if (is_ff(ctx, drv) && innet->driver.port == ctx->id("Q")) {
auto fflut = fflutPairs.find(drv->name);
if (fflut != fflutPairs.end() && procdLuts.find(fflut->second) == procdLuts.end()) {
if (can_pack_lutff(ci->name, fflut->second)) {
procdLuts.insert(ci->name);
procdLuts.insert(fflut->second);
lutPairs[ci->name] = fflut->second;
goto paired_inlut;
}
}
}
}
}
if (false) {
paired_inlut:
continue;
}
}
}
}
// 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 *lut0 = net_driven_by(ctx, f0, is_lut, ctx->id("Z"));
CellInfo *lut1 = net_driven_by(ctx, f1, is_lut, ctx->id("Z"));
if (lut0 == nullptr)
log_error("PFUMX '%s' has BLUT driven by cell other than a LUT\n", ci->name.c_str(ctx));
if (lut1 == nullptr)
log_error("PFUMX '%s' has ALUT driven by cell other than a LUT\n", ci->name.c_str(ctx));
replace_port(lut0, ctx->id("A"), packed.get(), ctx->id("A0"));
replace_port(lut0, ctx->id("B"), packed.get(), ctx->id("B0"));
replace_port(lut0, ctx->id("C"), packed.get(), ctx->id("C0"));
replace_port(lut0, ctx->id("D"), packed.get(), ctx->id("D0"));
replace_port(lut1, ctx->id("A"), packed.get(), ctx->id("A1"));
replace_port(lut1, ctx->id("B"), packed.get(), ctx->id("B1"));
replace_port(lut1, ctx->id("C"), packed.get(), ctx->id("C1"));
replace_port(lut1, 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"));
packed->params[ctx->id("LUT0_INITVAL")] = str_or_default(lut0->params, ctx->id("INIT"), "0");
packed->params[ctx->id("LUT1_INITVAL")] = str_or_default(lut1->params, ctx->id("INIT"), "0");
ctx->nets.erase(f0->name);
ctx->nets.erase(f1->name);
sliceUsage[packed->name].lut0_used = true;
sliceUsage[packed->name].lut1_used = true;
sliceUsage[packed->name].mux5_used = true;
if (lutffPairs.find(ci->name) != lutffPairs.end()) {
CellInfo *ff = ctx->cells.at(lutffPairs[ci->name]).get();
ff_to_slice(ctx, ff, packed.get(), 0, true);
packed_cells.insert(ff->name);
sliceUsage[packed->name].ff0_used = true;
}
new_cells.push_back(std::move(packed));
packed_cells.insert(lut0->name);
packed_cells.insert(lut1->name);
packed_cells.insert(ci->name);
}
}
flush_cells();
}
// Pack LUTs that have been paired together
void pack_lut_pairs()
{
log_info("Packing paired LUTs into a SLICE...\n");
for (auto pair : lutPairs) {
CellInfo *lut0 = ctx->cells.at(pair.first).get();
CellInfo *lut1 = ctx->cells.at(pair.second).get();
std::unique_ptr<CellInfo> slice =
create_ecp5_cell(ctx, ctx->id("TRELLIS_SLICE"), lut0->name.str(ctx) + "_SLICE");
lut_to_slice(ctx, lut0, slice.get(), 0);
lut_to_slice(ctx, lut1, slice.get(), 1);
auto ff0 = lutffPairs.find(lut0->name), ff1 = lutffPairs.find(lut1->name);
if (ff0 != lutffPairs.end()) {
ff_to_slice(ctx, ctx->cells.at(ff0->second).get(), slice.get(), 0, true);
packed_cells.insert(ff0->second);
}
if (ff1 != lutffPairs.end()) {
ff_to_slice(ctx, ctx->cells.at(ff1->second).get(), slice.get(), 1, true);
packed_cells.insert(ff1->second);
}
new_cells.push_back(std::move(slice));
packed_cells.insert(lut0->name);
packed_cells.insert(lut1->name);
}
flush_cells();
}
// Pack single LUTs that weren't paired into their own slice,
// with an optional FF also
void pack_remaining_luts()
{
log_info("Packing unpaired LUTs into a SLICE...\n");
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (is_lut(ctx, ci)) {
std::unique_ptr<CellInfo> slice =
create_ecp5_cell(ctx, ctx->id("TRELLIS_SLICE"), ci->name.str(ctx) + "_SLICE");
lut_to_slice(ctx, ci, slice.get(), 0);
auto ff = lutffPairs.find(ci->name);
if (ff != lutffPairs.end()) {
ff_to_slice(ctx, ctx->cells.at(ff->second).get(), slice.get(), 0, true);
packed_cells.insert(ff->second);
}
new_cells.push_back(std::move(slice));
packed_cells.insert(ci->name);
}
}
flush_cells();
}
// Pack flipflops that weren't paired with a LUT
void pack_remaining_ffs()
{
log_info("Packing unpaired FFs into a SLICE...\n");
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (is_ff(ctx, ci)) {
std::unique_ptr<CellInfo> slice =
create_ecp5_cell(ctx, ctx->id("TRELLIS_SLICE"), ci->name.str(ctx) + "_SLICE");
ff_to_slice(ctx, ci, slice.get(), 0, false);
new_cells.push_back(std::move(slice));
packed_cells.insert(ci->name);
}
}
flush_cells();
}
public:
void pack()
{
pack_io();
find_lutff_pairs();
pack_lut5s();
pair_luts();
pack_lut_pairs();
pack_remaining_luts();
pack_remaining_ffs();
}
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;
std::unordered_map<IdString, IdString> fflutPairs;
std::unordered_map<IdString, IdString> lutPairs;
};
// 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