diff options
| -rw-r--r-- | nexus/fasm.cc | 37 |
1 files changed, 34 insertions, 3 deletions
diff --git a/nexus/fasm.cc b/nexus/fasm.cc index db37458e..f39a30b0 100644 --- a/nexus/fasm.cc +++ b/nexus/fasm.cc @@ -227,9 +227,8 @@ struct NexusFasmWriter blank(); } // Find the CIBMUX output for a signal - WireId find_cibmux(const CellInfo *cell, IdString pin) + WireId find_cibmux(WireId cursor) { - WireId cursor = ctx->getBelPinWire(cell->bel, pin); if (cursor == WireId()) return WireId(); for (int i = 0; i < 10; i++) { @@ -270,7 +269,7 @@ struct NexusFasmWriter // Handle CIB muxes - these must be set such that floating pins really are floating to VCC and not connected // to another CIB signal if ((pin_style & PINBIT_CIBMUX) && port.second.net == nullptr) { - WireId cibmuxout = find_cibmux(cell, port.first); + WireId cibmuxout = find_cibmux(ctx->getBelPinWire(cell->bel, port.first)); if (cibmuxout != WireId()) { write_comment(stringf("CIBMUX for unused pin %s", ctx->nameOf(port.first))); bool found = false; @@ -287,6 +286,36 @@ struct NexusFasmWriter } } + // Handle route-through DCCs + void write_dcc_thru() + { + for (auto bel : ctx->getBels()) { + if (ctx->getBelType(bel) != id_DCC) + continue; + if (!ctx->checkBelAvail(bel)) + continue; + WireId dst = ctx->getBelPinWire(bel, id_CLKO); + if (ctx->getBoundWireNet(dst) == nullptr) + continue; + // Set up the CIBMUX so CE is guaranteed to be tied high + WireId ce = ctx->getBelPinWire(bel, id_CE); + WireId cibmuxout = find_cibmux(ce); + NPNR_ASSERT(cibmuxout != WireId()); + + write_comment(stringf("CE CIBMUX for DCC route-thru %s", ctx->nameOfBel(bel))); + bool found = false; + for (PipId pip : ctx->getPipsUphill(cibmuxout)) { + if (ctx->checkPipAvail(pip) && ctx->checkWireAvail(ctx->getPipSrcWire(pip))) { + write_pip(pip); + found = true; + break; + } + } + NPNR_ASSERT(found); + + } + } + // Write config for an OXIDE_COMB cell void write_comb(const CellInfo *cell) { @@ -846,6 +875,8 @@ struct NexusFasmWriter write_dphy(ci); blank(); } + // Handle DCC route-throughs + write_dcc_thru(); // Write config for unused bels write_unused(); // Write bank config |