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pack.cc
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pack.cc
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/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2020 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 "design_utils.h"
#include "log.h"
#include "nextpnr.h"
#include "util.h"
#include <boost/algorithm/string.hpp>
#include <queue>
#include <set>
NEXTPNR_NAMESPACE_BEGIN
namespace {
bool is_enabled(CellInfo *ci, IdString prop) { return str_or_default(ci->params, prop, "") == "ENABLED"; }
} // namespace
Property Arch::parse_lattice_param_from_cell(const CellInfo *ci, IdString prop, int width, int64_t defval) const
{
auto fnd = ci->params.find(prop);
if (fnd == ci->params.end())
return Property(defval, width);
return this->parse_lattice_param(fnd->second, prop, width, nameOf(ci));
}
// Parse a possibly-Lattice-style (C literal in Verilog string) style parameter
Property Arch::parse_lattice_param(const Property &val, IdString prop, int width, const char *ci) const
{
if (val.is_string && !prop.in(id_CSDECODE_A, id_CSDECODE_B, id_CSDECODE_R, id_CSDECODE_W)) {
const std::string &s = val.str;
Property temp;
if (boost::starts_with(s, "0b")) {
for (int i = int(s.length()) - 1; i >= 2; i--) {
char c = s.at(i);
if (c != '0' && c != '1' && c != 'x')
log_error("Invalid binary digit '%c' in property %s.%s\n", c, ci, nameOf(prop));
temp.str.push_back(c);
}
} else if (boost::starts_with(s, "0x")) {
for (int i = int(s.length()) - 1; i >= 2; i--) {
char c = s.at(i);
int nibble;
if (c >= '0' && c <= '9')
nibble = (c - '0');
else if (c >= 'a' && c <= 'f')
nibble = (c - 'a') + 10;
else if (c >= 'A' && c <= 'F')
nibble = (c - 'A') + 10;
else
log_error("Invalid hex digit '%c' in property %s.%s\n", c, ci, nameOf(prop));
for (int j = 0; j < 4; j++)
temp.str.push_back(((nibble >> j) & 0x1) ? Property::S1 : Property::S0);
}
} else {
int64_t ival = 0;
try {
if (boost::starts_with(s, "0d"))
ival = std::stoll(s.substr(2));
else
ival = std::stoll(s);
} catch (std::runtime_error &e) {
log_error("Invalid decimal value for property %s.%s", ci, nameOf(prop));
}
temp = Property(ival);
}
if (int(temp.size()) > width) {
for (auto b : temp.str.substr(width)) {
if (b == Property::S1)
log_error("Found value for property %s.%s with width greater than %d\n", ci, nameOf(prop), width);
}
}
temp.update_intval();
return temp.extract(0, width);
} else {
if (int(val.str.size()) > width) {
for (auto b : val.str.substr(width)) {
if (b == Property::S1)
log_error("Found bitvector value for property %s.%s with width greater than %d - perhaps a string "
"was "
"converted to bits?\n",
ci, nameOf(prop), width);
}
}
return val.extract(0, width);
}
}
struct NexusPacker
{
Context *ctx;
// Generic cell transformation
// Given cell name map and port map
// If port name is not found in port map; it will be copied as-is but stripping []
struct XFormRule
{
IdString new_type;
dict<IdString, IdString> port_xform;
dict<IdString, std::vector<IdString>> port_multixform;
dict<IdString, IdString> param_xform;
std::vector<std::pair<IdString, std::string>> set_attrs;
std::vector<std::pair<IdString, Property>> set_params;
std::vector<std::pair<IdString, Property>> default_params;
std::vector<std::tuple<IdString, IdString, int, int64_t>> parse_params;
};
void xform_cell(const dict<IdString, XFormRule> &rules, CellInfo *ci)
{
auto &rule = rules.at(ci->type);
ci->type = rule.new_type;
std::vector<IdString> orig_port_names;
for (auto &port : ci->ports)
orig_port_names.push_back(port.first);
for (auto pname : orig_port_names) {
if (rule.port_multixform.count(pname)) {
auto old_port = ci->ports.at(pname);
ci->disconnectPort(pname);
ci->ports.erase(pname);
for (auto new_name : rule.port_multixform.at(pname)) {
ci->ports[new_name].name = new_name;
ci->ports[new_name].type = old_port.type;
ci->connectPort(new_name, old_port.net);
}
} else {
IdString new_name;
if (rule.port_xform.count(pname)) {
new_name = rule.port_xform.at(pname);
} else {
std::string stripped_name;
for (auto c : pname.str(ctx))
if (c != '[' && c != ']')
stripped_name += c;
new_name = ctx->id(stripped_name);
}
if (new_name != pname) {
ci->renamePort(pname, new_name);
}
}
}
std::vector<IdString> xform_params;
for (auto ¶m : ci->params)
if (rule.param_xform.count(param.first))
xform_params.push_back(param.first);
for (auto param : xform_params)
ci->params[rule.param_xform.at(param)] = ci->params[param];
for (auto &attr : rule.set_attrs)
ci->attrs[attr.first] = attr.second;
for (auto ¶m : rule.default_params)
if (!ci->params.count(param.first))
ci->params[param.first] = param.second;
{
IdString old_param, new_param;
int width;
int64_t def;
for (const auto &p : rule.parse_params) {
std::tie(old_param, new_param, width, def) = p;
ci->params[new_param] = ctx->parse_lattice_param_from_cell(ci, old_param, width, def);
}
}
for (auto ¶m : rule.set_params)
ci->params[param.first] = param.second;
}
void generic_xform(const dict<IdString, XFormRule> &rules, bool print_summary = false)
{
std::map<std::string, int> cell_count;
std::map<std::string, int> new_types;
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (rules.count(ci->type)) {
cell_count[ci->type.str(ctx)]++;
xform_cell(rules, ci);
new_types[ci->type.str(ctx)]++;
}
}
if (print_summary) {
for (auto &nt : new_types) {
log_info(" Created %d %s cells from:\n", nt.second, nt.first.c_str());
for (auto &cc : cell_count) {
if (rules.at(ctx->id(cc.first)).new_type != ctx->id(nt.first))
continue;
log_info(" %6dx %s\n", cc.second, cc.first.c_str());
}
}
}
}
void pack_luts()
{
log_info("Packing LUTs...\n");
dict<IdString, XFormRule> lut_rules;
lut_rules[id_LUT4].new_type = id_OXIDE_COMB;
lut_rules[id_LUT4].port_xform[id_Z] = id_F;
lut_rules[id_LUT4].parse_params.emplace_back(id_INIT, id_INIT, 16, 0);
lut_rules[id_INV].new_type = id_OXIDE_COMB;
lut_rules[id_INV].port_xform[id_Z] = id_F;
lut_rules[id_INV].port_xform[id_A] = id_A;
lut_rules[id_INV].set_params.emplace_back(id_INIT, 0x5555);
lut_rules[id_VHI].new_type = id_OXIDE_COMB;
lut_rules[id_VHI].port_xform[id_Z] = id_F;
lut_rules[id_VHI].set_params.emplace_back(id_INIT, 0xFFFF);
lut_rules[id_VLO].new_type = id_OXIDE_COMB;
lut_rules[id_VLO].port_xform[id_Z] = id_F;
lut_rules[id_VLO].set_params.emplace_back(id_INIT, 0x0000);
generic_xform(lut_rules);
}
void pack_ffs()
{
log_info("Packing FFs...\n");
dict<IdString, XFormRule> ff_rules;
for (auto type : {id_FD1P3BX, id_FD1P3DX, id_FD1P3IX, id_FD1P3JX}) {
ff_rules[type].new_type = id_OXIDE_FF;
ff_rules[type].port_xform[id_CK] = id_CLK;
ff_rules[type].port_xform[id_D] = id_M; // will be rerouted to DI later if applicable
ff_rules[type].port_xform[id_SP] = id_CE;
ff_rules[type].port_xform[id_Q] = id_Q;
ff_rules[type].default_params.emplace_back(id_CLKMUX, std::string("CLK"));
ff_rules[type].default_params.emplace_back(id_CEMUX, std::string("CE"));
ff_rules[type].default_params.emplace_back(id_LSRMUX, std::string("LSR"));
ff_rules[type].set_params.emplace_back(id_LSRMODE, std::string("LSR"));
}
// Async preload
ff_rules[id_FD1P3BX].set_params.emplace_back(id_SRMODE, std::string("ASYNC"));
ff_rules[id_FD1P3BX].set_params.emplace_back(id_REGSET, std::string("SET"));
ff_rules[id_FD1P3BX].port_xform[id_PD] = id_LSR;
// Async clear
ff_rules[id_FD1P3DX].set_params.emplace_back(id_SRMODE, std::string("ASYNC"));
ff_rules[id_FD1P3DX].set_params.emplace_back(id_REGSET, std::string("RESET"));
ff_rules[id_FD1P3DX].port_xform[id_CD] = id_LSR;
// Sync preload
ff_rules[id_FD1P3JX].set_params.emplace_back(id_SRMODE, std::string("LSR_OVER_CE"));
ff_rules[id_FD1P3JX].set_params.emplace_back(id_REGSET, std::string("SET"));
ff_rules[id_FD1P3JX].port_xform[id_PD] = id_LSR;
// Sync clear
ff_rules[id_FD1P3IX].set_params.emplace_back(id_SRMODE, std::string("LSR_OVER_CE"));
ff_rules[id_FD1P3IX].set_params.emplace_back(id_REGSET, std::string("RESET"));
ff_rules[id_FD1P3IX].port_xform[id_CD] = id_LSR;
generic_xform(ff_rules, true);
}
dict<IdString, BelId> reference_bels;
void autocreate_ports(CellInfo *cell)
{
// Automatically create ports for all inputs, and maybe outputs, of a cell; even if they were left off the
// instantiation so we can tie them to constants as appropriate This also checks for any cells that don't have
// corresponding bels
if (!reference_bels.count(cell->type)) {
// We need to look up a corresponding bel to get the list of input ports
BelId ref_bel;
for (BelId bel : ctx->getBels()) {
if (ctx->getBelType(bel) != cell->type)
continue;
ref_bel = bel;
break;
}
if (ref_bel == BelId())
log_error("Cell type '%s' instantiated as '%s' is not supported by this device.\n",
ctx->nameOf(cell->type), ctx->nameOf(cell));
reference_bels[cell->type] = ref_bel;
}
BelId bel = reference_bels.at(cell->type);
for (IdString pin : ctx->getBelPins(bel)) {
PortType dir = ctx->getBelPinType(bel, pin);
if (dir != PORT_IN)
continue;
if (cell->ports.count(pin))
continue;
if (cell->type == id_OXIDE_COMB && pin == id_SEL)
continue; // doesn't always exist and not needed
cell->ports[pin].name = pin;
cell->ports[pin].type = dir;
}
}
NetInfo *get_const_net(IdString type)
{
// Gets a constant net, given the driver type (VHI or VLO)
// If one doesn't exist already; then create it
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (ci->type != type)
continue;
NetInfo *z = ci->getPort(id_Z);
if (z == nullptr)
continue;
return z;
}
NetInfo *new_net = ctx->createNet(ctx->idf("$CONST_%s_NET_", type.c_str(ctx)));
CellInfo *new_cell = ctx->createCell(ctx->idf("$CONST_%s_DRV_", type.c_str(ctx)), type);
new_cell->addOutput(id_Z);
new_cell->connectPort(id_Z, new_net);
if (type == id_VCC_DRV)
new_net->constant_value = id_VCC_DRV;
return new_net;
}
CellPinMux get_pin_needed_muxval(CellInfo *cell, IdString port)
{
NetInfo *net = cell->getPort(port);
if (net == nullptr || net->driver.cell == nullptr) {
// Pin is disconnected
// If a mux value exists already, honour it
CellPinMux exist_mux = ctx->get_cell_pinmux(cell, port);
if (exist_mux != PINMUX_SIG)
return exist_mux;
// Otherwise, look up the default value and use that
CellPinStyle pin_style = ctx->get_cell_pin_style(cell, port);
if ((pin_style & PINDEF_MASK) == PINDEF_0)
return PINMUX_0;
else if ((pin_style & PINDEF_MASK) == PINDEF_1)
return PINMUX_1;
else
return PINMUX_SIG;
}
// Look to see if the driver is an inverter or constant
IdString drv_type = net->driver.cell->type;
if (drv_type == id_INV)
return PINMUX_INV;
else if (drv_type == id_VLO)
return PINMUX_0;
else if (drv_type == id_VHI)
return PINMUX_1;
else
return PINMUX_SIG;
}
void uninvert_port(CellInfo *cell, IdString port)
{
// Rewire a port so it is driven by the input to an inverter
NetInfo *net = cell->getPort(port);
NPNR_ASSERT(net != nullptr && net->driver.cell != nullptr && net->driver.cell->type == id_INV);
CellInfo *inv = net->driver.cell;
cell->disconnectPort(port);
NetInfo *inv_a = inv->getPort(id_A);
if (inv_a != nullptr) {
cell->connectPort(port, inv_a);
}
}
void trim_design()
{
// Remove unused inverters and high/low drivers
std::vector<IdString> trim_cells;
std::vector<IdString> trim_nets;
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (ci->type != id_INV && ci->type != id_VLO && ci->type != id_VHI && ci->type != id_VCC_DRV)
continue;
NetInfo *z = ci->getPort(id_Z);
if (z == nullptr) {
trim_cells.push_back(ci->name);
continue;
}
if (!z->users.empty())
continue;
ci->disconnectPort(id_A);
trim_cells.push_back(ci->name);
trim_nets.push_back(z->name);
}
for (IdString rem_net : trim_nets)
ctx->nets.erase(rem_net);
for (IdString rem_cell : trim_cells)
ctx->cells.erase(rem_cell);
}
std::string remove_brackets(const std::string &name)
{
std::string new_name;
new_name.reserve(name.size());
for (char c : name)
if (c != '[' && c != ']')
new_name.push_back(c);
return new_name;
}
void prim_to_core(CellInfo *cell, IdString new_type = {})
{
// Convert a primitive to a '_CORE' variant
if (new_type == IdString())
new_type = ctx->id(cell->type.str(ctx) + "_CORE");
cell->type = new_type;
std::set<IdString> port_names;
for (auto port : cell->ports)
port_names.insert(port.first);
for (IdString port : port_names) {
IdString new_name = ctx->id(remove_brackets(port.str(ctx)));
if (new_name != port)
cell->renamePort(port, new_name);
}
}
NetInfo *gnd_net = nullptr, *vcc_net = nullptr, *dedi_vcc_net = nullptr;
void process_inv_constants(CellInfo *cell)
{
// Automatically create any extra inputs needed; so we can set them accordingly
autocreate_ports(cell);
for (auto &port : cell->ports) {
// Iterate over all inputs
if (port.second.type != PORT_IN)
continue;
IdString port_name = port.first;
CellPinMux req_mux = get_pin_needed_muxval(cell, port_name);
if (req_mux == PINMUX_SIG) {
// No special setting required, ignore
continue;
}
CellPinStyle pin_style = ctx->get_cell_pin_style(cell, port_name);
if (req_mux == PINMUX_INV) {
// Pin is inverted. If there is a hard inverter; then use it
if (pin_style & PINOPT_INV) {
uninvert_port(cell, port_name);
ctx->set_cell_pinmux(cell, port_name, PINMUX_INV);
}
} else if (req_mux == PINMUX_0 || req_mux == PINMUX_1) {
// Pin is tied to a constant
// If there is a hard constant option; use it
if ((pin_style & int(req_mux)) == req_mux) {
if ((cell->type == id_OXIDE_COMB) && (req_mux == PINMUX_1)) {
// We need to add a connection to the dedicated Vcc resource that can feed these cell ports
cell->disconnectPort(port_name);
cell->connectPort(port_name, dedi_vcc_net);
continue;
}
cell->disconnectPort(port_name);
ctx->set_cell_pinmux(cell, port_name, req_mux);
} else if (port.second.net == nullptr) {
// If the port is disconnected; and there is no hard constant
// then we need to connect it to the relevant soft-constant net
cell->connectPort(port_name, (req_mux == PINMUX_1) ? vcc_net : gnd_net);
}
}
}
}
void prepare_io()
{
// Find the actual IO buffer corresponding to a port; and copy attributes across to it
// Note that this relies on Yosys to do IO buffer inference, to match vendor tooling behaviour
// In all cases the nextpnr-inserted IO buffers are removed as redundant.
for (auto &port : ctx->ports) {
if (!ctx->cells.count(port.first))
log_error("Port '%s' doesn't seem to have a corresponding top level IO\n", ctx->nameOf(port.first));
CellInfo *ci = ctx->cells.at(port.first).get();
PortRef top_port;
top_port.cell = nullptr;
bool is_npnr_iob = false;
if (ci->type == ctx->id("$nextpnr_ibuf") || ci->type == ctx->id("$nextpnr_iobuf")) {
// Might have an input buffer (IB etc) connected to it
is_npnr_iob = true;
NetInfo *o = ci->getPort(id_O);
if (o == nullptr)
;
else if (o->users.entries() > 1)
log_error("Top level pin '%s' has multiple input buffers\n", ctx->nameOf(port.first));
else if (o->users.entries() == 1)
top_port = *o->users.begin();
}
if (ci->type == ctx->id("$nextpnr_obuf") || ci->type == ctx->id("$nextpnr_iobuf")) {
// Might have an output buffer (OB etc) connected to it
is_npnr_iob = true;
NetInfo *i = ci->getPort(id_I);
if (i != nullptr && i->driver.cell != nullptr) {
if (top_port.cell != nullptr)
log_error("Top level pin '%s' has multiple input/output buffers\n", ctx->nameOf(port.first));
top_port = i->driver;
}
// Edge case of a bidirectional buffer driving an output pin
if (i->users.entries() > 2) {
log_error("Top level pin '%s' has illegal buffer configuration\n", ctx->nameOf(port.first));
} else if (i->users.entries() == 2) {
if (top_port.cell != nullptr)
log_error("Top level pin '%s' has illegal buffer configuration\n", ctx->nameOf(port.first));
for (auto &usr : i->users) {
if (usr.cell->type == ctx->id("$nextpnr_obuf") || usr.cell->type == ctx->id("$nextpnr_iobuf"))
continue;
top_port = usr;
break;
}
}
}
if (!is_npnr_iob)
log_error("Port '%s' doesn't seem to have a corresponding top level IO (internal cell type mismatch)\n",
ctx->nameOf(port.first));
if (top_port.cell == nullptr) {
log_info("Trimming port '%s' as it is unused.\n", ctx->nameOf(port.first));
} else {
// Copy attributes to real IO buffer
if (ctx->io_attr.count(port.first)) {
for (auto &kv : ctx->io_attr.at(port.first)) {
top_port.cell->attrs[kv.first] = kv.second;
}
}
// Make sure that top level net is set correctly
port.second.net = top_port.cell->ports.at(top_port.port).net;
}
// Now remove the nextpnr-inserted buffer
ci->disconnectPort(id_I);
ci->disconnectPort(id_O);
ctx->cells.erase(port.first);
}
}
BelId get_bel_attr(const CellInfo *ci)
{
if (!ci->attrs.count(id_BEL))
return BelId();
return ctx->getBelByNameStr(ci->attrs.at(id_BEL).as_string());
}
void pack_io()
{
pool<IdString> iob_types = {id_IB, id_OB, id_OBZ, id_BB, id_BB_I3C_A, id_SEIO33,
id_SEIO18, id_DIFFIO18, id_SEIO33_CORE, id_SEIO18_CORE, id_DIFFIO18_CORE};
dict<IdString, XFormRule> io_rules;
// For the low level primitives, make sure we always preserve their type
io_rules[id_SEIO33_CORE].new_type = id_SEIO33_CORE;
io_rules[id_SEIO18_CORE].new_type = id_SEIO18_CORE;
io_rules[id_DIFFIO18_CORE].new_type = id_DIFFIO18_CORE;
// Some IO buffer types need a bit of pin renaming, too
io_rules[id_SEIO33].new_type = id_SEIO33_CORE;
io_rules[id_SEIO33].port_xform[id_PADDI] = id_O;
io_rules[id_SEIO33].port_xform[id_PADDO] = id_I;
io_rules[id_SEIO33].port_xform[id_PADDT] = id_T;
io_rules[id_SEIO33].port_xform[id_IOPAD] = id_B;
io_rules[id_BB_I3C_A] = XFormRule(io_rules[id_SEIO33]);
io_rules[id_SEIO18] = XFormRule(io_rules[id_SEIO33]);
io_rules[id_SEIO18].new_type = id_SEIO18_CORE;
io_rules[id_DIFFIO18] = XFormRule(io_rules[id_SEIO33]);
io_rules[id_DIFFIO18].new_type = id_DIFFIO18_CORE;
// Stage 0: deal with top level inserted IO buffers
prepare_io();
// Stage 1: setup constraints
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
// Iterate through all IO buffer primitives
if (!iob_types.count(ci->type))
continue;
// We need all IO constrained so we can pick the right IO bel type
// An improvement would be to allocate unconstrained IO here
if (!ci->attrs.count(id_LOC))
log_error("Found unconstrained IO '%s', these are currently unsupported\n", ctx->nameOf(ci));
// Convert package pin constraint to bel constraint
std::string loc = ci->attrs.at(id_LOC).as_string();
auto pad_info = ctx->get_pkg_pin_data(loc);
if (pad_info == nullptr)
log_error("IO '%s' is constrained to invalid pin '%s'\n", ctx->nameOf(ci), loc.c_str());
auto func = ctx->get_pad_functions(pad_info);
BelId bel = ctx->get_pad_pio_bel(pad_info);
if (bel == BelId()) {
log_error("IO '%s' is constrained to pin %s (%s) which is not a general purpose IO pin.\n",
ctx->nameOf(ci), loc.c_str(), func.c_str());
} else {
// Get IO type for reporting purposes
std::string io_type = str_or_default(ci->attrs, id_IO_TYPE, "LVCMOS33");
bool is_wr_bel = (ctx->getBelType(bel) == id_SEIO33_CORE);
if (!ctx->io_types.count(io_type))
log_error("IO '%s' has an unsupported IO type '%s'\n", ctx->nameOf(ci), io_type.c_str());
bool is_wr_io = (ctx->io_types.at(io_type).style & IOBANK_WR);
if (is_wr_io != is_wr_bel) {
log_error("%s IO '%s' requires a %s bank but is placed on pin %s in a %s bank.\n", io_type.c_str(),
ctx->nameOf(ci), (is_wr_io ? "wide-range" : "high-performance"), loc.c_str(),
(is_wr_bel ? "wide-range" : "high-performance"));
}
if (ctx->is_io_type_diff(io_type)) {
// Convert from SEIO18 to DIFFIO18
if (ctx->getBelType(bel) != id_SEIO18_CORE)
log_error("IO '%s' uses differential type '%s' but is placed on wide range pin '%s'\n",
ctx->nameOf(ci), io_type.c_str(), loc.c_str());
Loc bel_loc = ctx->getBelLocation(bel);
if (bel_loc.z != 0)
log_error("IO '%s' uses differential type '%s' but is placed on 'B' side pin '%s'\n",
ctx->nameOf(ci), io_type.c_str(), loc.c_str());
bel_loc.z = 2;
bel = ctx->getBelByLocation(bel_loc);
}
log_info("Constraining %s IO '%s' to pin %s (%s%sbel %s)\n", io_type.c_str(), ctx->nameOf(ci),
loc.c_str(), func.c_str(), func.empty() ? "" : "; ", ctx->nameOfBel(bel));
ci->attrs[id_BEL] = ctx->getBelName(bel).str(ctx);
}
}
// Stage 2: apply rules for primitives that need them
generic_xform(io_rules, false);
// Stage 3: all other IO primitives become their bel type
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
// Iterate through all IO buffer primitives
if (!iob_types.count(ci->type))
continue;
// Skip those dealt with in stage 2
if (io_rules.count(ci->type))
continue;
// For non-bidirectional IO, we also need to configure tristate and rename B
if (ci->type == id_IB) {
ctx->set_cell_pinmux(ci, id_T, PINMUX_1);
ci->renamePort(id_I, id_B);
} else if (ci->type == id_OB) {
ctx->set_cell_pinmux(ci, id_T, PINMUX_0);
ci->renamePort(id_O, id_B);
} else if (ci->type == id_OBZ) {
ctx->set_cell_pinmux(ci, id_T, PINMUX_SIG);
ci->renamePort(id_O, id_B);
}
// Get the IO bel
BelId bel = get_bel_attr(ci);
// Set the cell type to the bel type
IdString type = ctx->getBelType(bel);
NPNR_ASSERT(type != IdString());
ci->type = type;
}
}
void pack_constants()
{
// Make sure we have high and low nets available
vcc_net = get_const_net(id_VHI);
gnd_net = get_const_net(id_VLO);
dedi_vcc_net = get_const_net(id_VCC_DRV);
// Iterate through cells
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
// Skip certain cells at this point
if (ci->type != id_LUT4 && ci->type != id_INV && ci->type != id_VHI && ci->type != id_VLO &&
ci->type != id_VCC_DRV)
process_inv_constants(ci);
}
// Remove superfluous inverters and constant drivers
trim_design();
}
// Using a BFS, search for bels of a given type either upstream or downstream of another cell
void find_connected_bels(const CellInfo *cell, IdString port, IdString dest_type, IdString dest_pin, int iter_limit,
std::vector<BelId> &candidates)
{
int iter = 0;
std::queue<WireId> visit;
pool<WireId> seen_wires;
pool<BelId> seen_bels;
BelId bel = get_bel_attr(cell);
if (bel == BelId())
return;
WireId start_wire = ctx->getBelPinWire(bel, port);
NPNR_ASSERT(start_wire != WireId());
PortType dir = ctx->getBelPinType(bel, port);
visit.push(start_wire);
while (!visit.empty() && (iter++ < iter_limit)) {
WireId cursor = visit.front();
visit.pop();
// Check to see if we have reached a valid bel pin
for (auto bp : ctx->getWireBelPins(cursor)) {
if (ctx->getBelType(bp.bel) != dest_type)
continue;
if (dest_pin != IdString() && bp.pin != dest_pin)
continue;
if (seen_bels.count(bp.bel))
continue;
seen_bels.insert(bp.bel);
candidates.push_back(bp.bel);
}
// Search in the appropriate direction up/downstream of the cursor
if (dir == PORT_OUT) {
for (PipId p : ctx->getPipsDownhill(cursor))
if (ctx->checkPipAvail(p)) {
WireId dst = ctx->getPipDstWire(p);
if (seen_wires.count(dst))
continue;
seen_wires.insert(dst);
visit.push(dst);
}
} else {
for (PipId p : ctx->getPipsUphill(cursor))
if (ctx->checkPipAvail(p)) {
WireId src = ctx->getPipSrcWire(p);
if (seen_wires.count(src))
continue;
seen_wires.insert(src);
visit.push(src);
}
}
}
}
// Find the nearest bel of a given type; matching a closure predicate
template <typename Tpred> BelId find_nearest_bel(const CellInfo *cell, IdString dest_type, Tpred predicate)
{
BelId origin = get_bel_attr(cell);
if (origin == BelId())
return BelId();
Loc origin_loc = ctx->getBelLocation(origin);
int best_distance = std::numeric_limits<int>::max();
BelId best_bel = BelId();
for (BelId bel : ctx->getBels()) {
if (ctx->getBelType(bel) != dest_type)
continue;
if (!predicate(bel))
continue;
Loc bel_loc = ctx->getBelLocation(bel);
int dist = std::abs(origin_loc.x - bel_loc.x) + std::abs(origin_loc.y - bel_loc.y);
if (dist < best_distance) {
best_distance = dist;
best_bel = bel;
}
}
return best_bel;
}
pool<BelId> used_bels;
// Pre-place a primitive based on routeability first and distance second
bool preplace_prim(CellInfo *cell, IdString pin, bool strict_routing)
{
std::vector<BelId> routeability_candidates;
if (cell->attrs.count(id_BEL))
return false;
NetInfo *pin_net = cell->getPort(pin);
if (pin_net == nullptr)
return false;
CellInfo *pin_drv = pin_net->driver.cell;
if (pin_drv == nullptr)
return false;
// Check based on routeability
find_connected_bels(pin_drv, pin_net->driver.port, cell->type, pin, 25000, routeability_candidates);
for (BelId cand : routeability_candidates) {
if (used_bels.count(cand))
continue;
log_info(" constraining %s '%s' to bel '%s' based on dedicated routing\n", ctx->nameOf(cell),
ctx->nameOf(cell->type), ctx->nameOfBel(cand));
cell->attrs[id_BEL] = ctx->getBelName(cand).str(ctx);
used_bels.insert(cand);
return true;
}
// Unless in strict mode; check based on simple distance too
BelId nearest = find_nearest_bel(pin_drv, cell->type, [&](BelId bel) { return !used_bels.count(bel); });
if (nearest != BelId()) {
log_info(" constraining %s '%s' to bel '%s'\n", ctx->nameOf(cell), ctx->nameOf(cell->type),
ctx->nameOfBel(nearest));
cell->attrs[id_BEL] = ctx->getBelName(nearest).str(ctx);
used_bels.insert(nearest);
return true;
}
return false;
}
// Pre-place a singleton primitive; so decisions can be made on routeability downstream of it
bool preplace_singleton(CellInfo *cell)
{
if (cell->attrs.count(id_BEL))
return false;
bool did_something = false;
for (BelId bel : ctx->getBels()) {
if (ctx->getBelType(bel) != cell->type)
continue;
// Check that the bel really is a singleton...
NPNR_ASSERT(!cell->attrs.count(id_BEL));
cell->attrs[id_BEL] = ctx->getBelName(bel).str(ctx);
log_info(" constraining %s '%s' to bel '%s'\n", ctx->nameOf(cell), ctx->nameOf(cell->type),
ctx->nameOfBel(bel));
did_something = true;
}
return did_something;
}
// Insert a buffer primitive in a signal; moving all users that match a predicate behind it
template <typename Tpred>
CellInfo *insert_buffer(NetInfo *net, IdString buffer_type, std::string name_postfix, IdString i, IdString o,
Tpred pred)
{
// Create the buffered net
NetInfo *buffered_net = ctx->createNet(ctx->idf("%s$%s", ctx->nameOf(net), name_postfix.c_str()));
// Create the buffer cell
CellInfo *buffer = ctx->createCell(ctx->idf("%s$drv_%s", ctx->nameOf(buffered_net), ctx->nameOf(buffer_type)),
buffer_type);
buffer->addInput(i);
buffer->addOutput(o);
// Drive the buffered net with the buffer
buffer->connectPort(o, buffered_net);
// Filter users
std::vector<PortRef> remaining_users;
for (auto &usr : net->users) {
if (pred(usr)) {
usr.cell->ports[usr.port].net = buffered_net;
usr.cell->ports[usr.port].user_idx = buffered_net->users.add(usr);
} else {
remaining_users.push_back(usr);
}
}
net->users.clear();
for (auto &usr : remaining_users)
usr.cell->ports.at(usr.port).user_idx = net->users.add(usr);
// Connect buffer input to original net
buffer->connectPort(i, net);
return buffer;
}
// Insert global buffers
void promote_globals()
{
std::vector<std::pair<int, IdString>> clk_fanout;
int available_globals = 16;
for (auto &net : ctx->nets) {
NetInfo *ni = net.second.get();
// Skip undriven nets; and nets that are already global
if (ni->driver.cell == nullptr)
continue;
if (ni->driver.cell->type == id_DCS) {
continue;
}
if (ni->driver.cell->type == id_DCC) {
--available_globals;
continue;
}
// Count the number of clock ports
int clk_count = 0;
for (const auto &usr : ni->users) {
auto port_style = ctx->get_cell_pin_style(usr.cell, usr.port);
if (port_style & PINGLB_CLK)
++clk_count;
}
if (clk_count > 0)
clk_fanout.emplace_back(clk_count, ni->name);
}
if (available_globals <= 0)
return;
// Sort clocks by max fanout
std::sort(clk_fanout.begin(), clk_fanout.end(), std::greater<std::pair<int, IdString>>());
log_info("Promoting globals...\n");
// Promote the N highest fanout clocks
for (size_t i = 0; i < std::min<size_t>(clk_fanout.size(), available_globals); i++) {
NetInfo *net = ctx->nets.at(clk_fanout.at(i).second).get();
log_info(" promoting clock net '%s'\n", ctx->nameOf(net));
insert_buffer(net, id_DCC, "glb_clk", id_CLKI, id_CLKO,
[&](const PortRef &port) { return port.cell->type != id_DCC; });
}
}
// Place certain global cells
void place_globals()
{
// Keep running until we reach a fixed point
log_info("Placing globals...\n");
TopoSort<IdString> sorter;
auto is_glb_cell = [&](const CellInfo *cell) {
return cell->type.in(id_OSC_CORE, id_DCC, id_PLL_CORE, id_DCS);
};
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (is_glb_cell(ci)) {
sorter.node(ci->name);
auto do_pin = [&](IdString pin) {
NetInfo *net = ci->getPort(pin);
if (!net || !net->driver.cell || !is_glb_cell(net->driver.cell))
return;
sorter.edge(net->driver.cell->name, ci->name);
};
if (ci->type == id_PLL_CORE) {
do_pin(id_REFCK);
} else if (ci->type == id_DCC) {
do_pin(id_CLKI);
} else if (ci->type == id_DCS) {
do_pin(id_CLK0);
do_pin(id_CLK1);
}
}
}
sorter.sort();
for (IdString cell_name : sorter.sorted) {
CellInfo *ci = ctx->cells.at(cell_name).get();
if (ci->type == id_OSC_CORE)
preplace_singleton(ci);
else if (ci->type == id_DCC)
preplace_prim(ci, id_CLKI, false);
else if (ci->type == id_PLL_CORE)
preplace_prim(ci, id_REFCK, false);
else if (ci->type == id_DCS)
preplace_prim(ci, id_CLK0, false);
}
}
// Get a bus port name
IdString bus(const std::string &base, int i) { return ctx->idf("%s[%d]", base.c_str(), i); }
IdString bus_flat(const std::string &base, int i) { return ctx->idf("%s%d", base.c_str(), i); }
// Pack a LUTRAM into COMB and RAMW cells
void pack_lutram()
{
// Do this so we don't have an iterate-and-modfiy situation
std::vector<CellInfo *> lutrams;
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (ci->type != id_DPR16X4)
continue;
lutrams.push_back(ci);
}
// Port permutation vectors
IdString ramw_wdo[4] = {id_D1, id_C1, id_A1, id_B1};
IdString ramw_wado[4] = {id_D0, id_B0, id_C0, id_A0};
IdString comb0_rad[4] = {id_D, id_B, id_C, id_A};
IdString comb1_rad[4] = {id_C, id_B, id_D, id_A};
for (CellInfo *ci : lutrams) {
// Create constituent cells
CellInfo *ramw = ctx->createCell(ctx->idf("%s$lutram_ramw$", ctx->nameOf(ci)), id_RAMW);
std::vector<CellInfo *> combs;
for (int i = 0; i < 4; i++)
combs.push_back(ctx->createCell(ctx->idf("%s$lutram_comb[%d]$", ctx->nameOf(ci), i), id_OXIDE_COMB));
// Rewiring - external WCK and WRE
ci->movePortTo(id_WCK, ramw, id_CLK);
ci->movePortTo(id_WRE, ramw, id_LSR);
// Internal WCK and WRE signals
ramw->addOutput(id_WCKO);
ramw->addOutput(id_WREO);
NetInfo *int_wck = ctx->createNet(ctx->idf("%s$lutram_wck$", ctx->nameOf(ci)));
NetInfo *int_wre = ctx->createNet(ctx->idf("%s$lutram_wre$", ctx->nameOf(ci)));
ramw->connectPort(id_WCKO, int_wck);