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machxo2: Global placement and clock routing from nexus
Signed-off-by: gatecat <[email protected]>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,178 @@ | ||
| /* | ||
| * nextpnr -- Next Generation Place and Route | ||
| * | ||
| * Copyright (C) 2020-23 gatecat <[email protected]> | ||
| * | ||
| * | ||
| * 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 "log.h" | ||
| #include "nextpnr.h" | ||
| #include "util.h" | ||
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| #include <queue> | ||
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| NEXTPNR_NAMESPACE_BEGIN | ||
|
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| struct MachxoGlobalRouter | ||
| { | ||
| Context *ctx; | ||
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| MachxoGlobalRouter(Context *ctx) : ctx(ctx){}; | ||
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| // When routing globals; we allow global->local for some tricky cases but never local->local | ||
| bool global_pip_filter(PipId pip) const | ||
| { | ||
| WireId src = ctx->getPipSrcWire(pip); | ||
| const char *s = ctx->tile_info(src)->wire_data[src.index].name.get(); | ||
| if ((s[0] == 'H' || s[0] == 'V') && s[1] == '0') | ||
| return false; | ||
| return true; | ||
| } | ||
|
|
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| // Dedicated backwards BFS routing for global networks | ||
| template <typename Tfilt> | ||
| bool backwards_bfs_route(NetInfo *net, store_index<PortRef> user_idx, int iter_limit, bool strict, Tfilt pip_filter) | ||
| { | ||
| // Queue of wires to visit | ||
| std::queue<WireId> visit; | ||
| // Wire -> upstream pip | ||
| dict<WireId, PipId> backtrace; | ||
|
|
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| // Lookup source and destination wires | ||
| WireId src = ctx->getNetinfoSourceWire(net); | ||
| WireId dst = ctx->getNetinfoSinkWire(net, net->users.at(user_idx), 0); | ||
|
|
||
| if (src == WireId()) | ||
| log_error("Net '%s' has an invalid source port %s.%s\n", ctx->nameOf(net), ctx->nameOf(net->driver.cell), | ||
| ctx->nameOf(net->driver.port)); | ||
|
|
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| if (dst == WireId()) | ||
| log_error("Net '%s' has an invalid sink port %s.%s\n", ctx->nameOf(net), | ||
| ctx->nameOf(net->users.at(user_idx).cell), ctx->nameOf(net->users.at(user_idx).port)); | ||
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| if (ctx->getBoundWireNet(src) != net) | ||
| ctx->bindWire(src, net, STRENGTH_LOCKED); | ||
|
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| if (src == dst) { | ||
| // Nothing more to do | ||
| return true; | ||
| } | ||
|
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| visit.push(dst); | ||
| backtrace[dst] = PipId(); | ||
|
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| int iter = 0; | ||
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| while (!visit.empty() && (iter++ < iter_limit)) { | ||
| WireId cursor = visit.front(); | ||
| visit.pop(); | ||
| // Search uphill pips | ||
| for (PipId pip : ctx->getPipsUphill(cursor)) { | ||
| // Skip pip if unavailable, and not because it's already used for this net | ||
| if (!ctx->checkPipAvail(pip) && ctx->getBoundPipNet(pip) != net) | ||
| continue; | ||
| WireId prev = ctx->getPipSrcWire(pip); | ||
| // Ditto for the upstream wire | ||
| if (!ctx->checkWireAvail(prev) && ctx->getBoundWireNet(prev) != net) | ||
| continue; | ||
| // Skip already visited wires | ||
| if (backtrace.count(prev)) | ||
| continue; | ||
| // Apply our custom pip filter | ||
| if (!pip_filter(pip)) | ||
| continue; | ||
| // Add to the queue | ||
| visit.push(prev); | ||
| backtrace[prev] = pip; | ||
| // Check if we are done yet | ||
| if (prev == src) | ||
| goto done; | ||
| } | ||
| if (false) { | ||
| done: | ||
| break; | ||
| } | ||
| } | ||
|
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| if (backtrace.count(src)) { | ||
| WireId cursor = src; | ||
| std::vector<PipId> pips; | ||
| // Create a list of pips on the routed path | ||
| while (true) { | ||
| PipId pip = backtrace.at(cursor); | ||
| if (pip == PipId()) | ||
| break; | ||
| pips.push_back(pip); | ||
| cursor = ctx->getPipDstWire(pip); | ||
| } | ||
| // Reverse that list | ||
| std::reverse(pips.begin(), pips.end()); | ||
| // Bind pips until we hit already-bound routing | ||
| for (PipId pip : pips) { | ||
| WireId dst = ctx->getPipDstWire(pip); | ||
| if (ctx->getBoundWireNet(dst) == net) | ||
| break; | ||
| ctx->bindPip(pip, net, STRENGTH_LOCKED); | ||
| } | ||
| return true; | ||
| } else { | ||
| if (strict) | ||
| log_error("Failed to route net '%s' from %s to %s using dedicated routing.\n", ctx->nameOf(net), | ||
| ctx->nameOfWire(src), ctx->nameOfWire(dst)); | ||
| return false; | ||
| } | ||
| } | ||
|
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| bool is_relaxed_sink(const PortRef &sink) const | ||
| { | ||
| // Cases where global clocks are driving fabric | ||
| if ((sink.cell->type == id_TRELLIS_COMB && sink.port != id_WCK) || | ||
| (sink.cell->type == id_TRELLIS_FF && sink.port != id_CLK)) | ||
| return true; | ||
| return false; | ||
| } | ||
|
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| void route_clk_net(NetInfo *net) | ||
| { | ||
| for (auto usr : net->users.enumerate()) | ||
| backwards_bfs_route(net, usr.index, 1000000, true, | ||
| [&](PipId pip) { return (is_relaxed_sink(usr.value) || global_pip_filter(pip)); }); | ||
| log_info(" routed net '%s' using global resources\n", ctx->nameOf(net)); | ||
| } | ||
|
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| void operator()() | ||
| { | ||
| log_info("Routing globals...\n"); | ||
| for (auto &net : ctx->nets) { | ||
| NetInfo *ni = net.second.get(); | ||
| CellInfo *drv = ni->driver.cell; | ||
| if (drv == nullptr) | ||
| continue; | ||
| if (drv->type.in(id_DCCA, id_DCMA)) { | ||
| route_clk_net(ni); | ||
| continue; | ||
| } | ||
| } | ||
| } | ||
| }; | ||
|
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| void Arch::route_globals() | ||
| { | ||
| MachxoGlobalRouter glb_router(getCtx()); | ||
| glb_router(); | ||
| } | ||
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| NEXTPNR_NAMESPACE_END |
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