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Added support for syn_useioff for enabling tri-state control FF integration into IOLOGIC.

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Signed-off-by: Maciej Kurc <mkurc@antmicro.com>
This commit is contained in:
Maciej Kurc 2021-09-20 11:35:36 +02:00
parent 8ffd30cb2d
commit 80e2f8a791
1 changed files with 23 additions and 13 deletions
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28
nexus/pack.cc
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@ -2134,6 +2134,7 @@ struct NexusPacker
// IOLOGIC requires some special handling around itself and IOB. This
// function does that.
void handle_iologic() {
log_info("Packing IOLOGIC...\n");
// Map of flip-flop cells that drive IOLOGIC+IOB pairs
dict<IdString, std::vector<std::pair<IdString,IdString>>> tff_map;
@ -2231,10 +2232,17 @@ struct NexusPacker
log_info(" Reconnecting %s.TSDATA0 to %s\n", ctx->nameOf(iol), ctx->nameOf(iob_t));
}
// Check if the net wants to use the T flip-flop in
// IOLOGIC
bool syn_useioff = false;
if (iob_t->attrs.count(ctx->id("syn_useioff"))) {
syn_useioff = iob_t->attrs.at(ctx->id("syn_useioff")).as_bool();
}
// Check if the T input is driven by a flip-flop. Store
// in the map.
// in the map for later integration with IOLOGIC.
CellInfo* ff = get_ff_for_iob(iob, id_T, iol);
if (ff != nullptr) {
if (ff != nullptr && syn_useioff) {
tff_map[ff->name].push_back(std::make_pair(
iol->name, iob->name));
}
@ -2253,11 +2261,6 @@ struct NexusPacker
NetInfo* ff_q = get_net_or_empty(ff, id_Q);
NPNR_ASSERT(ff_q != nullptr);
log_info("FF '%s'\n", ctx->nameOf(ff));
for (auto& it : ff->params) {
log_info(" '%s'='%s'\n", it.first.c_str(ctx), it.second.as_string().c_str());
}
for (auto& ios : it.second) {
CellInfo* iol = ctx->cells.at(ios.first).get();
CellInfo* iob = ctx->cells.at(ios.second).get();
@ -2287,12 +2290,19 @@ struct NexusPacker
disconnect_port(ctx, ff, port.first);
}
// Remove the flip-flop
// Check if the flip-flop can be removed
bool can_remove = ff_q->users.empty();
// Remove the flip-flop and its output net
if (can_remove) {
if (ctx->debug) {
log_info(" Removing %s\n", ctx->nameOf(ff));
}
ctx->cells.erase(ff->name);
// Remove its output net
ctx->nets.erase(ff_q->name);
}
}
}
explicit NexusPacker(Context *ctx) : ctx(ctx) {}