nextpnr/himbaechel/uarch/gatemate/route_clock.cc

232 lines
9.3 KiB
C++

/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2024 The Project Peppercorn Authors.
*
* 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 <functional>
#include <queue>
#include "gatemate.h"
#include "log.h"
#include "nextpnr_assertions.h"
#define HIMBAECHEL_CONSTIDS "uarch/gatemate/constids.inc"
#include "himbaechel_constids.h"
NEXTPNR_NAMESPACE_BEGIN
namespace {
struct QueuedWire
{
explicit QueuedWire(WireId wire, float delay = 0.0) : wire{wire}, delay{delay} {};
WireId wire;
float delay;
bool operator>(const QueuedWire &rhs) const { return this->delay > rhs.delay; }
};
} // namespace
void GateMateImpl::route_clock()
{
auto clk_nets = std::vector<NetInfo *>{};
auto reserved_wires = dict<WireId, IdString>{};
auto feeds_clk_port = [&](PortRef &port) {
return (ctx->getBelBucketForCellType(port.cell->type) == id_CPE_FF) && port.port.in(id_CLK);
};
auto feeds_ddr_port = [&](NetInfo *net, PortRef &port) {
return this->ddr_nets.find(net->name) != this->ddr_nets.end() && port.port == id_IN1;
};
auto pip_plane = [&](PipId pip) {
const auto &extra_data = *pip_extra_data(pip);
if (extra_data.type != PipExtra::PIP_EXTRA_MUX)
return uint8_t{0};
return extra_data.plane;
};
auto reserve = [&](WireId wire, NetInfo *net) {
if (ctx->debug) {
auto wire_name = "(uninitialized)";
if (wire != WireId())
wire_name = ctx->nameOfWire(wire);
log_info(" reserving wire %s\n", wire_name);
}
reserved_wires.insert({wire, net->name});
};
log_info("Routing clock nets...\n");
for (auto &net_pair : ctx->nets) {
NetInfo *net = net_pair.second.get();
if (!net->driver.cell)
continue;
bool is_clk_net = false;
for (auto &usr : net->users) {
if (feeds_clk_port(usr) || feeds_ddr_port(net, usr)) {
is_clk_net = true;
for (auto clk_sink_wire : ctx->getNetinfoSinkWires(net, usr))
reserve(clk_sink_wire, net);
auto reserve_port_if_needed = [&](IdString port_name) {
auto port = usr.cell->ports.find(port_name);
if (port != usr.cell->ports.end() && port->second.net != nullptr) {
auto sink_wire = ctx->getNetinfoSinkWire(port->second.net,
port->second.net->users.at(port->second.user_idx), 0);
reserve(sink_wire, port->second.net);
}
};
reserve_port_if_needed(id_EN);
reserve_port_if_needed(id_SR);
}
}
if (is_clk_net)
clk_nets.push_back(net);
}
for (auto clk_net : clk_nets) {
log_info(" routing net '%s'\n", clk_net->name.c_str(ctx));
ctx->bindWire(ctx->getNetinfoSourceWire(clk_net), clk_net, STRENGTH_LOCKED);
auto clk_plane = 0;
switch (clk_net->driver.port.index) {
case id_GLB0.index:
clk_plane = 9;
break;
case id_GLB1.index:
clk_plane = 10;
break;
case id_GLB2.index:
clk_plane = 11;
break;
case id_GLB3.index:
clk_plane = 12;
break;
}
for (auto &usr : clk_net->users) {
std::priority_queue<QueuedWire, std::vector<QueuedWire>, std::greater<QueuedWire>> visit;
dict<WireId, PipId> backtrace;
WireId dest = WireId();
if (!feeds_clk_port(usr) && !feeds_ddr_port(clk_net, usr))
continue;
auto cpe_loc = ctx->getBelLocation(usr.cell->bel);
auto is_glb_clk = clk_net->driver.cell->type == id_GLBOUT;
auto sink_wire = ctx->getNetinfoSinkWire(clk_net, usr, 0);
if (ctx->debug) {
auto sink_wire_name = "(uninitialized)";
if (sink_wire != WireId())
sink_wire_name = ctx->nameOfWire(sink_wire);
log_info(" routing arc to %s.%s (wire %s):\n", usr.cell->name.c_str(ctx), usr.port.c_str(ctx),
sink_wire_name);
}
visit.push(QueuedWire(sink_wire));
while (!visit.empty()) {
QueuedWire curr = visit.top();
visit.pop();
if (curr.wire == ctx->getNetinfoSourceWire(clk_net)) {
if (ctx->debug)
log_info(" (%.3fns)\n", curr.delay);
dest = curr.wire;
break;
}
PipId bound_pip;
auto fnd_wire = clk_net->wires.find(curr.wire);
if (fnd_wire != clk_net->wires.end()) {
bound_pip = fnd_wire->second.pip;
}
for (auto uh : ctx->getPipsUphill(curr.wire)) {
if (!ctx->checkPipAvailForNet(uh, clk_net))
continue;
WireId src = ctx->getPipSrcWire(uh);
if (backtrace.count(src))
continue;
if (!ctx->checkWireAvail(src) && ctx->getBoundWireNet(src) != clk_net)
continue;
if (bound_pip != PipId() && uh != bound_pip)
continue;
// Has this wire been reserved for another net?
auto reserved = reserved_wires.find(src);
if (reserved != reserved_wires.end() && reserved->second != clk_net->name)
continue;
auto pip_loc = ctx->getPipLocation(uh);
// Use only a specific plane to minimise congestion for global clocks.
if (is_glb_clk && (pip_loc.x != cpe_loc.x || pip_loc.y != cpe_loc.y)) {
// Plane 9 is the clock plane, so it should only ever use itself.
if (clk_plane == 9 && pip_plane(uh) != 9)
continue;
// Plane 10 is the enable plane.
// When there's a set/reset, we want to use the switchbox X23 pip to change directly to plane 9.
if (clk_plane == 10 && pip_plane(uh) != 9 && pip_plane(uh) != 10)
continue;
// Plane 11 is the set/reset plane; we want to use the switchbox X14 pip to go to plane 12, then
// use the IM to switch to plane 9.
if (clk_plane == 11 && pip_plane(uh) == 10)
continue;
// Plane 12 is the spare plane; we can use the IM to change directly to plane 9.
if (clk_plane == 12 && pip_plane(uh) != 9 && pip_plane(uh) != 12)
continue;
}
backtrace[src] = uh;
auto delay = ctx->getDelayNS(ctx->getPipDelay(uh).maxDelay() + ctx->getWireDelay(src).maxDelay() +
ctx->getDelayEpsilon());
visit.push(QueuedWire(src, curr.delay + delay));
}
}
if (dest == WireId()) {
log_info(" failed to find a route using dedicated resources. %s -> %s\n",
clk_net->driver.cell->name.c_str(ctx), usr.cell->name.c_str(ctx));
}
while (backtrace.count(dest)) {
auto uh = backtrace[dest];
dest = ctx->getPipDstWire(uh);
if (ctx->getBoundWireNet(dest) == clk_net) {
NPNR_ASSERT(clk_net->wires.at(dest).pip == uh);
if (ctx->debug)
log_info(" pip %s --> %s (plane %hhd)\n", ctx->nameOfPip(uh),
ctx->nameOfWire(dest), pip_plane(uh));
} else if (ctx->getBoundWireNet(dest) == nullptr) {
ctx->bindPip(uh, clk_net, STRENGTH_LOCKED);
if (ctx->debug)
log_info(" bind pip %s --> %s (plane %hhd)\n", ctx->nameOfPip(uh),
ctx->nameOfWire(dest), pip_plane(uh));
} else {
log_error("Can't bind pip %s because wire %s is already bound\n", ctx->nameOfPip(uh),
ctx->nameOfWire(dest));
}
if (dest == sink_wire)
break;
}
}
}
}
NEXTPNR_NAMESPACE_END