nextpnr/generic/viaduct/fabulous/pack.cc
gatecat 3826a31ad3 fabulous: Pack, validity check and FASM support for muxes
Signed-off-by: gatecat <gatecat@ds0.me>
2022-09-30 13:27:51 +02:00

302 lines
12 KiB
C++

/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2021-22 gatecat <gatecat@ds0.me>
*
* 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 "pack.h"
#include "log.h"
#include "util.h"
#define VIADUCT_CONSTIDS "viaduct/fabulous/constids.inc"
#include "viaduct_constids.h"
#include "viaduct_helpers.h"
NEXTPNR_NAMESPACE_BEGIN
namespace {
struct FabulousPacker
{
Context *ctx;
const FabricConfig &cfg;
ViaductHelpers h;
dict<IdString, unsigned> lut_types;
std::vector<IdString> lut_inputs;
FabulousPacker(Context *ctx, const FabricConfig &cfg) : ctx(ctx), cfg(cfg)
{
// Set up some structures for faster lookups
for (unsigned i = 0; i < cfg.clb.lut_k; i++) {
lut_types[ctx->idf("LUT%d", i + 1)] = i + 1;
lut_inputs.push_back(ctx->idf("I%d", i));
}
h.init(ctx);
}
void pack_luts()
{
// Pack LUTs into FABULOUS_COMB (split-LUTFF mode) or FABULOUS_LC (packed-LUTFF mode)
// TODO: fracturable LUT handling
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
auto fnd_lut = lut_types.find(ci->type);
if (fnd_lut == lut_types.end())
continue;
unsigned lut_n = fnd_lut->second;
// convert to the necessary type
ci->type = cfg.clb.split_lc ? id_FABULOUS_COMB : id_FABULOUS_LC;
// add disconnected unused inputs
for (unsigned i = 0; i < cfg.clb.lut_k; i++)
if (!ci->ports.count(lut_inputs.at(i)))
ci->addInput(lut_inputs.at(i));
// replicate the INIT value so the unused MSBs become don't-cares
auto inst_init = get_or_default(ci->params, id_INIT, Property(0));
unsigned orig_init_len = 1U << lut_n, prim_len = 1U << cfg.clb.lut_k;
Property new_init(0, prim_len);
for (unsigned i = 0; i < prim_len; i += orig_init_len) {
auto chunk = inst_init.extract(0, orig_init_len);
for (unsigned j = 0; j < orig_init_len; j++)
new_init.str.at(i + j) = chunk.str.at(j);
}
new_init.update_intval();
ci->params[id_INIT] = new_init;
}
}
// Two-stage flipflop packing. First convert all the random primitives into a much easier-to-handle FABULOUS_FF
// Then for split-LC mode, cluster it to connected LUTs; separate-LC mode, pack it into a connected or new LC
void prepare_ffs()
{
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
const std::string &type_str = ci->type.str(ctx);
if (type_str.size() < 5 || type_str.substr(0, 5) != "LUTFF")
continue;
ci->type = id_FABULOUS_FF;
// parse config string and unify
size_t idx = 5;
if (idx < type_str.size() && type_str.at(idx) == '_')
++idx;
// clock inversion
if (idx < type_str.size() && type_str.at(idx) == 'N') {
ci->params[id_NEG_CLK] = 1;
++idx;
} else {
ci->params[id_NEG_CLK] = 0;
}
// clock enable
if (idx < type_str.size() && type_str.at(idx) == 'E')
++idx;
if (ci->ports.count(id_E))
ci->renamePort(id_E, id_EN);
else
ci->addInput(id_EN); // autocreate emtpy enable port if enable missing or unused
// sr presence and type
std::string srt = type_str.substr(idx);
if (srt == "S") {
ci->params[id_SET_NORESET] = 1;
ci->params[id_ASYNC_SR] = 1;
} else if (srt == "R") {
ci->params[id_SET_NORESET] = 0;
ci->params[id_ASYNC_SR] = 1;
} else if (srt == "SS") {
ci->params[id_SET_NORESET] = 1;
ci->params[id_ASYNC_SR] = 0;
} else if (srt == "SR" || srt == "") {
ci->params[id_SET_NORESET] = 0;
ci->params[id_ASYNC_SR] = 0;
} else {
NPNR_ASSERT_FALSE("unhandled FF type");
}
if (ci->ports.count(id_S))
ci->renamePort(id_S, id_SR);
else if (ci->ports.count(id_R))
ci->renamePort(id_R, id_SR);
if (!ci->ports.count(id_SR))
ci->addInput(id_SR); // autocreate emtpy enable port if enable missing or unused
}
}
void pack_muxes()
{
// TODO: don't hardcode z-offset -- we should come up with our own constraint structure
int lut_muxes_dz = 9;
int lut_lut_dz = 1;
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
unsigned k = 0;
if (ci->type == id_FABULOUS_MUX2)
k = 1;
else if (ci->type == id_FABULOUS_MUX4)
k = 2;
else if (ci->type == id_FABULOUS_MUX8)
k = 3;
else
continue;
unsigned m = (1U << k);
std::vector<CellInfo *> luts;
for (unsigned i = 0; i < m; i++) {
NetInfo *ii = ci->getPort(ctx->idf("I%d", i));
if (!ii || !ii->driver.cell || !ii->driver.cell->type.in(id_FABULOUS_LC, id_FABULOUS_COMB) ||
ii->driver.port != id_O)
log_error("mux %s input I%d net %s is not driven by a LUT!\n", ctx->nameOf(ci), i, ctx->nameOf(ii));
CellInfo *lut = ii->driver.cell;
NPNR_ASSERT(lut->cluster == ClusterId());
luts.push_back(lut);
}
luts.at(0)->cluster = luts.at(0)->name;
for (unsigned i = 0; i < m; i++) {
luts.at(i)->cluster = luts.at(0)->name;
luts.at(i)->constr_x = 0;
luts.at(i)->constr_y = 0;
luts.at(i)->constr_z = i * lut_lut_dz;
luts.at(i)->constr_abs_z = false;
if (i > 0)
luts.at(0)->constr_children.push_back(luts.at(i));
}
int extra_mux_dz = (m == 8) ? 7 : (m == 4) ? 1 : 0;
ci->cluster = luts.at(0)->name;
ci->constr_x = 0;
ci->constr_y = 0;
ci->constr_z = lut_muxes_dz + extra_mux_dz;
ci->constr_abs_z = false;
luts.at(0)->constr_children.push_back(ci);
}
}
void pack_ffs()
{
pool<IdString> to_delete;
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (ci->type != id_FABULOUS_FF)
continue;
NetInfo *d = ci->getPort(id_D);
if (!d || !d->driver.cell)
continue;
CellInfo *drv = d->driver.cell;
if (drv->type != (cfg.clb.split_lc ? id_FABULOUS_COMB : id_FABULOUS_LC) || d->driver.port != id_O)
continue;
if (!cfg.clb.split_lc && d->users.entries() > 1)
continue; // TODO: could also resolve by duplicating LUT
if (drv->cluster != ClusterId()) {
// TODO: actually we can pack these often, we just have to be more careful to check control sets
continue;
}
// we can pack them together
if (cfg.clb.split_lc) {
// create/modify cluster and add constraints. copy from an arch where we do this already...
NPNR_ASSERT_FALSE("unimplemented");
} else {
to_delete.insert(ci->name);
// this connection is packed inside the LC
ci->disconnectPort(id_D);
drv->disconnectPort(id_O);
// move other ports/params
ci->movePortTo(id_CLK, drv, id_CLK);
ci->movePortTo(id_SR, drv, id_SR);
ci->movePortTo(id_EN, drv, id_EN);
ci->movePortTo(id_O, drv, id_Q);
drv->params[id_NEG_CLK] = ci->params[id_NEG_CLK];
drv->params[id_ASYNC_SR] = ci->params[id_ASYNC_SR];
drv->params[id_SET_NORESET] = ci->params[id_SET_NORESET];
drv->params[id_FF] = 1;
for (auto &attr : ci->attrs)
drv->attrs[attr.first] = attr.second;
}
}
for (auto del : to_delete)
ctx->cells.erase(del);
if (!cfg.clb.split_lc) {
// convert remaining ffs to their own lc
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (ci->type != id_FABULOUS_FF)
continue;
ci->type = id_FABULOUS_LC;
ci->renamePort(id_D, lut_inputs.at(0));
ci->renamePort(id_O, id_Q);
// configure LUT as a thru
Property init(1U << cfg.clb.lut_k);
for (unsigned i = 0; i < (1U << cfg.clb.lut_k); i += 2) {
init.str[i] = Property::S0;
init.str[i + 1] = Property::S1;
}
init.update_intval();
ci->params[id_INIT] = init;
ci->params[id_FF] = 1;
}
}
}
void update_bel_attrs()
{
// This new arch uses the new IdStringList system with a / separator
// old fabulous arches used a dot separator in bel names
// update old attributes for maximum cross-compat
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (!ci->attrs.count(id_BEL))
continue;
std::string &bel = ci->attrs.at(id_BEL).str;
if (bel.find('/') != std::string::npos) // new style
continue;
size_t dot_pos = bel.find('.');
if (dot_pos != std::string::npos)
bel[dot_pos] = '/';
}
}
void handle_constants()
{
const dict<IdString, Property> vcc_params = {{id_INIT, Property(0x3, 2)}};
const dict<IdString, Property> gnd_params = {{id_INIT, Property(0x0, 2)}};
h.replace_constants(CellTypePort(id_LUT1, id_O), CellTypePort(id_LUT1, id_O), vcc_params, gnd_params);
}
void handle_io()
{
// As per the preferred approach for new nextpnr flows, we require IO to be inserted by Yosys
// pre-place-and-route, or just manually instantiated
const pool<CellTypePort> top_ports{
CellTypePort(id_IO_1_bidirectional_frame_config_pass, id_PAD),
};
h.remove_nextpnr_iobs(top_ports);
}
void run()
{
update_bel_attrs();
handle_constants();
handle_io();
pack_luts();
pack_muxes();
prepare_ffs();
pack_ffs();
}
};
} // namespace
void fabulous_pack(Context *ctx, const FabricConfig &cfg)
{
FabulousPacker packer(ctx, cfg);
packer.run();
}
NEXTPNR_NAMESPACE_END