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kernel/ff: Refactor FfData to enable FFs with async load.

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- *_en is split into *_ce (clock enable) and *_aload (async load aka
  latch gate enable), so both can be present at once
- has_d is removed
- has_gclk is added (to have a clear marker for $ff)
- d_is_const and val_d leftovers are removed
- async2sync, clk2fflogic, opt_dff are updated to operate correctly on
  FFs with async load
This commit is contained in:
Marcelina Kościelnicka 2021-10-01 23:50:48 +02:00
parent ec2b5548fe
commit 63b9df8693
10 changed files with 565 additions and 325 deletions
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61
passes/sat/async2sync.cc
View file

@ -41,8 +41,6 @@ struct Async2syncPass : public Pass {
log("reset value in the next cycle regardless of the data-in value at the time of\n");
log("the clock edge.\n");
log("\n");
log("Currently only $adff, $dffsr, and $dlatch cells are supported by this pass.\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
@ -74,14 +72,11 @@ struct Async2syncPass : public Pass {
FfData ff(&initvals, cell);
// Skip for $_FF_ and $ff cells.
if (ff.has_d && !ff.has_clk && !ff.has_en)
if (ff.has_gclk)
continue;
if (ff.has_clk)
{
if (!ff.has_sr && !ff.has_arst)
continue;
if (ff.has_sr) {
ff.unmap_ce_srst(module);
@ -128,6 +123,39 @@ struct Async2syncPass : public Pass {
ff.sig_d = new_d;
ff.sig_q = new_q;
ff.has_sr = false;
} else if (ff.has_aload) {
ff.unmap_ce_srst(module);
log("Replacing %s.%s (%s): ALOAD=%s, AD=%s, D=%s, Q=%s\n",
log_id(module), log_id(cell), log_id(cell->type),
log_signal(ff.sig_aload), log_signal(ff.sig_ad), log_signal(ff.sig_d), log_signal(ff.sig_q));
initvals.remove_init(ff.sig_q);
Wire *new_d = module->addWire(NEW_ID, ff.width);
Wire *new_q = module->addWire(NEW_ID, ff.width);
if (ff.pol_aload) {
if (!ff.is_fine) {
module->addMux(NEW_ID, new_q, ff.sig_ad, ff.sig_aload, ff.sig_q);
module->addMux(NEW_ID, ff.sig_d, ff.sig_ad, ff.sig_aload, new_d);
} else {
module->addMuxGate(NEW_ID, new_q, ff.sig_ad, ff.sig_aload, ff.sig_q);
module->addMuxGate(NEW_ID, ff.sig_d, ff.sig_ad, ff.sig_aload, new_d);
}
} else {
if (!ff.is_fine) {
module->addMux(NEW_ID, ff.sig_ad, new_q, ff.sig_aload, ff.sig_q);
module->addMux(NEW_ID, ff.sig_ad, ff.sig_d, ff.sig_aload, new_d);
} else {
module->addMuxGate(NEW_ID, ff.sig_ad, new_q, ff.sig_aload, ff.sig_q);
module->addMuxGate(NEW_ID, ff.sig_ad, ff.sig_d, ff.sig_aload, new_d);
}
}
ff.sig_d = new_d;
ff.sig_q = new_q;
ff.has_aload = false;
} else if (ff.has_arst) {
ff.unmap_srst(module);
@ -154,9 +182,12 @@ struct Async2syncPass : public Pass {
ff.sig_q = new_q;
ff.has_arst = false;
ff.has_srst = true;
ff.ce_over_srst = false;
ff.val_srst = ff.val_arst;
ff.sig_srst = ff.sig_arst;
ff.pol_srst = ff.pol_arst;
} else {
continue;
}
}
else
@ -164,25 +195,25 @@ struct Async2syncPass : public Pass {
// Latch.
log("Replacing %s.%s (%s): EN=%s, D=%s, Q=%s\n",
log_id(module), log_id(cell), log_id(cell->type),
log_signal(ff.sig_en), log_signal(ff.sig_d), log_signal(ff.sig_q));
log_signal(ff.sig_aload), log_signal(ff.sig_ad), log_signal(ff.sig_q));
initvals.remove_init(ff.sig_q);
Wire *new_q = module->addWire(NEW_ID, ff.width);
Wire *new_d;
if (ff.has_d) {
if (ff.has_aload) {
new_d = module->addWire(NEW_ID, ff.width);
if (ff.pol_en) {
if (ff.pol_aload) {
if (!ff.is_fine)
module->addMux(NEW_ID, new_q, ff.sig_d, ff.sig_en, new_d);
module->addMux(NEW_ID, new_q, ff.sig_ad, ff.sig_aload, new_d);
else
module->addMuxGate(NEW_ID, new_q, ff.sig_d, ff.sig_en, new_d);
module->addMuxGate(NEW_ID, new_q, ff.sig_ad, ff.sig_aload, new_d);
} else {
if (!ff.is_fine)
module->addMux(NEW_ID, ff.sig_d, new_q, ff.sig_en, new_d);
module->addMux(NEW_ID, ff.sig_ad, new_q, ff.sig_aload, new_d);
else
module->addMuxGate(NEW_ID, ff.sig_d, new_q, ff.sig_en, new_d);
module->addMuxGate(NEW_ID, ff.sig_ad, new_q, ff.sig_aload, new_d);
}
} else {
new_d = new_q;
@ -231,10 +262,10 @@ struct Async2syncPass : public Pass {
ff.sig_d = new_d;
ff.sig_q = new_q;
ff.has_en = false;
ff.has_aload = false;
ff.has_arst = false;
ff.has_sr = false;
ff.has_d = true;
ff.has_gclk = true;
}
IdString name = cell->name;

34
passes/sat/clk2fflogic.cc
View file

@ -148,7 +148,7 @@ struct Clk2fflogicPass : public Pass {
if (RTLIL::builtin_ff_cell_types().count(cell->type)) {
FfData ff(&initvals, cell);
if (ff.has_d && !ff.has_clk && !ff.has_en) {
if (ff.has_gclk) {
// Already a $ff or $_FF_ cell.
continue;
}
@ -202,25 +202,27 @@ struct Clk2fflogicPass : public Pass {
qval = module->Mux(NEW_ID, past_q, past_d, clock_edge);
else
qval = module->MuxGate(NEW_ID, past_q, past_d, clock_edge);
} else if (ff.has_d) {
} else {
if (ff.has_aload) {
log("Replacing %s.%s (%s): EN=%s, D=%s, Q=%s\n",
log_id(module), log_id(cell), log_id(cell->type),
log_signal(ff.sig_aload), log_signal(ff.sig_ad), log_signal(ff.sig_q));
} else {
// $sr.
log("Replacing %s.%s (%s): SET=%s, CLR=%s, Q=%s\n",
log_id(module), log_id(cell), log_id(cell->type),
log_signal(ff.sig_set), log_signal(ff.sig_clr), log_signal(ff.sig_q));
}
qval = past_q;
}
log("Replacing %s.%s (%s): EN=%s, D=%s, Q=%s\n",
log_id(module), log_id(cell), log_id(cell->type),
log_signal(ff.sig_en), log_signal(ff.sig_d), log_signal(ff.sig_q));
SigSpec sig_en = wrap_async_control(module, ff.sig_en, ff.pol_en);
if (ff.has_aload) {
SigSpec sig_aload = wrap_async_control(module, ff.sig_aload, ff.pol_aload);
if (!ff.is_fine)
qval = module->Mux(NEW_ID, past_q, ff.sig_d, sig_en);
qval = module->Mux(NEW_ID, qval, ff.sig_ad, sig_aload);
else
qval = module->MuxGate(NEW_ID, past_q, ff.sig_d, sig_en);
} else {
log("Replacing %s.%s (%s): SET=%s, CLR=%s, Q=%s\n",
log_id(module), log_id(cell), log_id(cell->type),
log_signal(ff.sig_set), log_signal(ff.sig_clr), log_signal(ff.sig_q));
qval = past_q;
qval = module->MuxGate(NEW_ID, qval, ff.sig_ad, sig_aload);
}
if (ff.has_sr) {