445 lines
14 KiB
C++
445 lines
14 KiB
C++
/*
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* nextpnr -- Next Generation Place and Route
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*
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* Copyright (C) 2018 Clifford Wolf <clifford@clifford.at>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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*/
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#include <cmath>
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#include <queue>
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#include "log.h"
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#include "route.h"
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namespace {
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USING_NEXTPNR_NAMESPACE
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struct QueuedWire
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{
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WireId wire;
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PipId pip;
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float delay = 0, togo = 0;
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struct Greater
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{
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bool operator()(const QueuedWire &lhs, const QueuedWire &rhs) const
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noexcept
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{
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return (lhs.delay + lhs.togo) > (rhs.delay + rhs.togo);
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}
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};
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};
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void ripup_net(Design *design, IdString net_name)
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{
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auto &chip = design->chip;
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auto net_info = design->nets.at(net_name);
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for (auto &it : net_info->wires) {
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if (it.second != PipId())
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chip.unbindPip(it.second);
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chip.unbindWire(it.first);
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}
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net_info->wires.clear();
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}
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struct Router
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{
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std::unordered_set<IdString> rippedNets;
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int visitCnt = 0, revisitCnt = 0;
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bool routedOkay = false;
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float maxDelay = 0.0;
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Router(Design *design, IdString net_name, bool verbose, bool ripup = false,
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float ripup_pip_penalty = 5.0, float ripup_wire_penalty = 5.0)
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{
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auto &chip = design->chip;
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auto net_info = design->nets.at(net_name);
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if (verbose)
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log("Routing net %s.\n", net_name.c_str());
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if (verbose)
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log(" Source: %s.%s.\n", net_info->driver.cell->name.c_str(),
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net_info->driver.port.c_str());
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auto src_bel = net_info->driver.cell->bel;
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if (src_bel == BelId())
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log_error("Source cell %s (%s) is not mapped to a bel.\n",
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net_info->driver.cell->name.c_str(),
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net_info->driver.cell->type.c_str());
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if (verbose)
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log(" Source bel: %s\n", chip.getBelName(src_bel).c_str());
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IdString driver_port = net_info->driver.port;
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auto driver_port_it = net_info->driver.cell->pins.find(driver_port);
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if (driver_port_it != net_info->driver.cell->pins.end())
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driver_port = driver_port_it->second;
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auto src_wire = chip.getWireBelPin(src_bel, portPinFromId(driver_port));
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if (src_wire == WireId())
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log_error("No wire found for port %s (pin %s) on source cell %s "
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"(bel %s).\n",
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net_info->driver.port.c_str(), driver_port.c_str(),
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net_info->driver.cell->name.c_str(),
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chip.getBelName(src_bel).c_str());
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if (verbose)
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log(" Source wire: %s\n", chip.getWireName(src_wire).c_str());
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std::unordered_map<WireId, DelayInfo> src_wires;
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src_wires[src_wire] = DelayInfo();
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net_info->wires[src_wire] = PipId();
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chip.bindWire(src_wire, net_name);
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for (auto &user_it : net_info->users) {
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if (verbose)
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log(" Route to: %s.%s.\n", user_it.cell->name.c_str(),
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user_it.port.c_str());
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auto dst_bel = user_it.cell->bel;
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if (dst_bel == BelId())
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log_error("Destination cell %s (%s) is not mapped to a bel.\n",
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user_it.cell->name.c_str(),
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user_it.cell->type.c_str());
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if (verbose)
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log(" Destination bel: %s\n",
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chip.getBelName(dst_bel).c_str());
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IdString user_port = user_it.port;
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auto user_port_it = user_it.cell->pins.find(user_port);
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if (user_port_it != user_it.cell->pins.end())
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user_port = user_port_it->second;
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auto dst_wire =
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chip.getWireBelPin(dst_bel, portPinFromId(user_port));
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if (dst_wire == WireId())
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log_error("No wire found for port %s (pin %s) on destination "
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"cell %s (bel %s).\n",
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user_it.port.c_str(), user_port.c_str(),
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user_it.cell->name.c_str(),
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chip.getBelName(dst_bel).c_str());
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if (verbose) {
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log(" Destination wire: %s\n",
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chip.getWireName(dst_wire).c_str());
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log(" Path delay estimate: %.2f\n",
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chip.estimateDelay(src_wire, dst_wire));
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}
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std::unordered_map<WireId, QueuedWire> visited;
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std::priority_queue<QueuedWire, std::vector<QueuedWire>,
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QueuedWire::Greater>
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queue;
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for (auto &it : src_wires) {
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QueuedWire qw;
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qw.wire = it.first;
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qw.pip = PipId();
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qw.delay = it.second.avgDelay();
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qw.togo = chip.estimateDelay(qw.wire, dst_wire);
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queue.push(qw);
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visited[qw.wire] = qw;
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}
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while (!queue.empty() && !visited.count(dst_wire)) {
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QueuedWire qw = queue.top();
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queue.pop();
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for (auto pip : chip.getPipsDownhill(qw.wire)) {
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float next_delay = qw.delay;
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visitCnt++;
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if (!chip.checkPipAvail(pip)) {
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if (!ripup || net_name == chip.getPipNet(pip, true))
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continue;
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next_delay += ripup_pip_penalty;
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}
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WireId next_wire = chip.getPipDstWire(pip);
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next_delay += chip.getPipDelay(pip).avgDelay();
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if (visited.count(next_wire)) {
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if (visited.at(next_wire).delay <= next_delay + 1e-3)
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continue;
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#if 0 // FIXME
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if (verbose)
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log("Found better route to %s. Old vs new delay "
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"estimate: %.2f %.2f\n",
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chip.getWireName(next_wire).c_str(),
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visited.at(next_wire).delay, next_delay);
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#endif
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revisitCnt++;
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}
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if (!chip.checkWireAvail(next_wire)) {
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if (!ripup ||
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net_name == chip.getWireNet(next_wire, true))
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continue;
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next_delay += ripup_wire_penalty;
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}
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QueuedWire next_qw;
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next_qw.wire = next_wire;
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next_qw.pip = pip;
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next_qw.delay = next_delay;
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next_qw.togo = chip.estimateDelay(next_wire, dst_wire);
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visited[next_qw.wire] = next_qw;
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queue.push(next_qw);
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}
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}
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if (visited.count(dst_wire) == 0) {
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if (verbose)
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log("Failed to route %s -> %s.\n",
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chip.getWireName(src_wire).c_str(),
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chip.getWireName(dst_wire).c_str());
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else if (ripup)
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log_info("Failed to route %s -> %s.\n",
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chip.getWireName(src_wire).c_str(),
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chip.getWireName(dst_wire).c_str());
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ripup_net(design, net_name);
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return;
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}
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if (verbose)
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log(" Final path delay: %.2f\n", visited[dst_wire].delay);
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maxDelay = fmaxf(maxDelay, visited[dst_wire].delay);
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if (verbose)
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log(" Route (from destination to source):\n");
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WireId cursor = dst_wire;
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while (1) {
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if (verbose)
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log(" %8.2f %s\n", visited[cursor].delay,
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chip.getWireName(cursor).c_str());
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if (src_wires.count(cursor))
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break;
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IdString conflicting_net = chip.getWireNet(cursor, true);
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if (conflicting_net != IdString()) {
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assert(ripup);
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assert(conflicting_net != net_name);
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ripup_net(design, conflicting_net);
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rippedNets.insert(conflicting_net);
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}
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conflicting_net = chip.getPipNet(visited[cursor].pip, true);
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if (conflicting_net != IdString()) {
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assert(ripup);
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assert(conflicting_net != net_name);
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ripup_net(design, conflicting_net);
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rippedNets.insert(conflicting_net);
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}
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net_info->wires[cursor] = visited[cursor].pip;
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chip.bindWire(cursor, net_name);
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chip.bindPip(visited[cursor].pip, net_name);
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src_wires[cursor] = chip.getPipDelay(visited[cursor].pip);
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cursor = chip.getPipSrcWire(visited[cursor].pip);
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}
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}
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routedOkay = true;
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}
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};
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} // namespace
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NEXTPNR_NAMESPACE_BEGIN
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void route_design(Design *design, bool verbose)
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{
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auto &chip = design->chip;
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float maxDelay = 0.0;
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float ripup_pip_penalty = 5.0;
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float ripup_wire_penalty = 5.0;
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log_info("Routing..\n");
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std::unordered_set<IdString> netsQueue;
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for (auto &net_it : design->nets) {
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auto net_name = net_it.first;
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auto net_info = net_it.second;
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if (net_info->driver.cell == nullptr)
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continue;
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if (!net_info->wires.empty())
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continue;
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netsQueue.insert(net_name);
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}
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if (netsQueue.empty()) {
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log_info("found no unrouted nets. no routing necessary.\n");
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return;
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}
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log_info("found %d unrouted nets. starting routing procedure.\n",
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int(netsQueue.size()));
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float estimatedTotalDelay = 0.0;
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int estimatedTotalDelayCnt = 0;
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for (auto net_name : netsQueue) {
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auto net_info = design->nets.at(net_name);
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auto src_bel = net_info->driver.cell->bel;
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if (src_bel == BelId())
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continue;
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IdString driver_port = net_info->driver.port;
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auto driver_port_it = net_info->driver.cell->pins.find(driver_port);
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if (driver_port_it != net_info->driver.cell->pins.end())
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driver_port = driver_port_it->second;
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auto src_wire = chip.getWireBelPin(src_bel, portPinFromId(driver_port));
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if (src_wire == WireId())
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continue;
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for (auto &user_it : net_info->users) {
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auto dst_bel = user_it.cell->bel;
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if (dst_bel == BelId())
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continue;
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IdString user_port = user_it.port;
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auto user_port_it = user_it.cell->pins.find(user_port);
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if (user_port_it != user_it.cell->pins.end())
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user_port = user_port_it->second;
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auto dst_wire =
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chip.getWireBelPin(dst_bel, portPinFromId(user_port));
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if (dst_wire == WireId())
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continue;
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estimatedTotalDelay += chip.estimateDelay(src_wire, dst_wire);
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estimatedTotalDelayCnt++;
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}
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}
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log_info("estimated total wire delay: %.2f (avg %.2f)\n",
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estimatedTotalDelay, estimatedTotalDelay / estimatedTotalDelayCnt);
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while (!netsQueue.empty()) {
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int visitCnt = 0, revisitCnt = 0, netCnt = 0;
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std::unordered_set<IdString> ripupQueue;
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for (auto net_name : netsQueue) {
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Router router(design, net_name, verbose, false);
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netCnt++;
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visitCnt += router.visitCnt;
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revisitCnt += router.revisitCnt;
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if (router.routedOkay) {
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maxDelay = fmaxf(maxDelay, router.maxDelay);
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} else {
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ripupQueue.insert(net_name);
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}
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if (netCnt % 100 == 0)
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log_info(" processed %d nets. (%d routed, %d failed)\n",
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netCnt, netCnt - int(ripupQueue.size()),
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int(ripupQueue.size()));
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}
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netsQueue.clear();
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if (netCnt % 100 != 0)
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log_info(" processed %d nets. (%d routed, %d failed)\n", netCnt,
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netCnt - int(ripupQueue.size()), int(ripupQueue.size()));
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log_info("routing pass visited %d PIPs (%.2f%% revisits).\n", visitCnt,
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(100.0 * revisitCnt) / visitCnt);
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if (!ripupQueue.empty()) {
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log_info("failed to route %d nets. re-routing in ripup mode.\n",
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int(ripupQueue.size()));
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visitCnt = 0;
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revisitCnt = 0;
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netCnt = 0;
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int ripCnt = 0;
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for (auto net_name : ripupQueue) {
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Router router(design, net_name, verbose, true,
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ripup_pip_penalty, ripup_wire_penalty);
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netCnt++;
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visitCnt += router.visitCnt;
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revisitCnt += router.revisitCnt;
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if (!router.routedOkay)
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log_error("Net %s is impossible to route.\n",
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net_name.c_str());
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maxDelay = fmaxf(maxDelay, router.maxDelay);
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for (auto it : router.rippedNets)
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netsQueue.insert(it);
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ripCnt += router.rippedNets.size();
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if (netCnt % 100 == 0)
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log_info(" routed %d nets, ripped %d nets.\n", netCnt,
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ripCnt);
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}
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if (netCnt % 100 != 0)
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log_info(" routed %d nets, ripped %d nets.\n", netCnt, ripCnt);
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log_info("routing pass visited %d PIPs (%.2f%% revisits).\n",
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visitCnt, (100.0 * revisitCnt) / visitCnt);
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log_info("ripped up %d previously routed nets. continue routing.\n",
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int(netsQueue.size()));
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ripup_pip_penalty *= 1.5;
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ripup_wire_penalty *= 1.5;
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}
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}
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log_info("routing complete. longest path delay: %.2f\n", maxDelay);
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}
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NEXTPNR_NAMESPACE_END
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