From e5bfff6e9fbbbc743c504365ab41e4112aefb6d6 Mon Sep 17 00:00:00 2001 From: gatecat Date: Fri, 4 Feb 2022 20:49:32 +0000 Subject: viaduct: Allow constraining only cascades without fanout Signed-off-by: gatecat --- generic/viaduct_helpers.cc | 4 +++- generic/viaduct_helpers.h | 3 ++- 2 files changed, 5 insertions(+), 2 deletions(-) (limited to 'generic') diff --git a/generic/viaduct_helpers.cc b/generic/viaduct_helpers.cc index 36bdd6be..e9f7fa60 100644 --- a/generic/viaduct_helpers.cc +++ b/generic/viaduct_helpers.cc @@ -82,7 +82,7 @@ void ViaductHelpers::remove_nextpnr_iobs(const pool &top_ports) } int ViaductHelpers::constrain_cell_pairs(const pool &src_ports, const pool &sink_ports, - int delta_z) + int delta_z, bool allow_fanout) { int constrained = 0; for (auto &cell : ctx->cells) { @@ -96,6 +96,8 @@ int ViaductHelpers::constrain_cell_pairs(const pool &src_ports, co continue; if (!src_ports.count(CellTypePort(ci.type, port.first))) continue; + if (!allow_fanout && port.second.net->users.size() > 1) + continue; for (auto &usr : port.second.net->users) { if (!sink_ports.count(CellTypePort(usr))) continue; diff --git a/generic/viaduct_helpers.h b/generic/viaduct_helpers.h index 8cba8411..cac22304 100644 --- a/generic/viaduct_helpers.h +++ b/generic/viaduct_helpers.h @@ -70,7 +70,8 @@ struct ViaductHelpers // expects a set of top-level port types void remove_nextpnr_iobs(const pool &top_ports); // Constrain cells with certain port connection patterns together with a fixed z-offset - int constrain_cell_pairs(const pool &src_ports, const pool &sink_ports, int delta_z); + int constrain_cell_pairs(const pool &src_ports, const pool &sink_ports, int delta_z, + bool allow_fanout = true); // Replace constants with given driving cells void replace_constants(CellTypePort vcc_driver, CellTypePort gnd_driver, const dict &vcc_params = {}, -- cgit v1.2.3