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ecp5: Working on packer LUT pairing functionality

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Signed-off-by: David Shah <davey1576@gmail.com>
This commit is contained in:
David Shah 2018-07-17 15:25:10 +02:00
parent c2fe09ec83
commit c0567c0d30
1 changed files with 120 additions and 0 deletions
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120
ecp5/pack.cc
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@ -63,12 +63,127 @@ class Ecp5Packer
CellInfo *ff = net_only_drives(ctx, znet, is_ff, ctx->id("DI"), false); CellInfo *ff = net_only_drives(ctx, znet, is_ff, ctx->id("DI"), false);
if (ff != nullptr) { if (ff != nullptr) {
lutffPairs[ci->name] = ff->name; lutffPairs[ci->name] = ff->name;
fflutPairs[ff->name] = ci->name;
} }
} }
} }
} }
} }
// Return whether two FFs can be packed together in the same slice
bool can_pack_ffs(CellInfo *ff0, CellInfo *ff1)
{
if (str_or_default(ff0->params, ctx->id("GSR"), "DISABLED") !=
str_or_default(ff1->params, ctx->id("GSR"), "DISABLED"))
return false;
if (str_or_default(ff0->params, ctx->id("SRMODE"), "LSR_OVER_CE") !=
str_or_default(ff1->params, ctx->id("SRMODE"), "LSR_OVER_CE"))
return false;
if (str_or_default(ff0->params, ctx->id("CEMUX"), "1") != str_or_default(ff1->params, ctx->id("CEMUX"), "1"))
return false;
if (str_or_default(ff0->params, ctx->id("LSRMUX"), "LSR") !=
str_or_default(ff1->params, ctx->id("LSRMUX"), "LSR"))
return false;
if (str_or_default(ff0->params, ctx->id("CLKMUX"), "CLK") !=
str_or_default(ff1->params, ctx->id("CLKMUX"), "CLK"))
return false;
if (ff0->ports.at(ctx->id("CLK")).net != ff1->ports.at(ctx->id("CLK")).net)
return false;
if (ff0->ports.at(ctx->id("CE")).net != ff1->ports.at(ctx->id("CE")).net)
return false;
if (ff0->ports.at(ctx->id("LSR")).net != ff1->ports.at(ctx->id("LSR")).net)
return false;
return true;
}
// Return true if two LUTs can be paired considering FF compatibility
bool can_pack_lutff(IdString lut0, IdString lut1)
{
auto ff0 = lutffPairs.find(lut0), ff1 = lutffPairs.find(lut1);
if (ff0 != lutffPairs.end() && ff1 != lutffPairs.end()) {
return can_pack_ffs(ctx->cells.at(ff0->second).get(), ctx->cells.at(ff1->second).get());
} else {
return true;
}
}
// Find "closely connected" LUTs and pair them together
void pair_luts(std::unordered_map<IdString, IdString> &lutPairs)
{
std::unordered_set<IdString> procdLuts;
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (is_lut(ctx, ci) && procdLuts.find(cell.first) == procdLuts.end()) {
NetInfo *znet = ci->ports.at(ctx->id("Z")).net;
if (znet != nullptr) {
for (auto user : znet->users) {
if (is_lut(ctx, user.cell) && procdLuts.find(user.cell->name) == procdLuts.end()) {
if (can_pack_lutff(ci->name, user.cell->name)) {
procdLuts.insert(ci->name);
procdLuts.insert(user.cell->name);
lutPairs[ci->name] = user.cell->name;
goto paired;
}
}
}
if (false) {
paired:
continue;
}
}
if (lutffPairs.find(ci->name) != lutffPairs.end()) {
NetInfo *qnet = ctx->cells.at(lutffPairs[ci->name])->ports.at(ctx->id("Q")).net;
if (qnet != nullptr) {
for (auto user : qnet->users) {
if (is_lut(ctx, user.cell) && procdLuts.find(user.cell->name) == procdLuts.end()) {
if (can_pack_lutff(ci->name, user.cell->name)) {
procdLuts.insert(ci->name);
procdLuts.insert(user.cell->name);
lutPairs[ci->name] = user.cell->name;
goto paired_ff;
}
}
}
if (false) {
paired_ff:
continue;
}
}
}
for (char inp : "ABCD") {
NetInfo *innet = ci->ports.at(ctx->id(std::string("") + inp)).net;
if (innet != nullptr && innet->driver.cell != nullptr) {
CellInfo *drv = innet->driver.cell;
if (is_lut(ctx, drv) && innet->driver.port == ctx->id("Z")) {
if (procdLuts.find(drv->name) == procdLuts.end()) {
if (can_pack_lutff(ci->name, drv->name)) {
procdLuts.insert(ci->name);
procdLuts.insert(drv->name);
lutPairs[ci->name] = drv->name;
goto paired_inlut;
}
}
} else if (is_ff(ctx, drv) && innet->driver.port == ctx->id("Q")) {
auto fflut = fflutPairs.find(drv->name);
if (fflut != fflutPairs.end() && procdLuts.find(fflut->second) == procdLuts.end()) {
if (can_pack_lutff(ci->name, fflut->second)) {
procdLuts.insert(ci->name);
procdLuts.insert(fflut->second);
lutPairs[ci->name] = fflut->second;
goto paired_inlut;
}
}
}
}
}
if (false) {
paired_inlut:
continue;
}
}
}
}
// Simple "packer" to remove nextpnr IOBUFs, this assumes IOBUFs are manually instantiated // Simple "packer" to remove nextpnr IOBUFs, this assumes IOBUFs are manually instantiated
void pack_io() void pack_io()
{ {
@ -143,11 +258,15 @@ class Ecp5Packer
replace_port(ci, ctx->id("Z"), packed.get(), ctx->id("OFX0")); replace_port(ci, ctx->id("Z"), packed.get(), ctx->id("OFX0"));
ctx->nets.erase(f0->name); ctx->nets.erase(f0->name);
ctx->nets.erase(f1->name); ctx->nets.erase(f1->name);
sliceUsage[packed->name].lut0_used = true;
sliceUsage[packed->name].lut1_used = true;
sliceUsage[packed->name].mux5_used = true;
if (lutffPairs.find(ci->name) != lutffPairs.end()) { if (lutffPairs.find(ci->name) != lutffPairs.end()) {
CellInfo *ff = ctx->cells.at(lutffPairs[ci->name]).get(); CellInfo *ff = ctx->cells.at(lutffPairs[ci->name]).get();
ff_to_lc(ctx, ff, packed.get(), 0, true); ff_to_lc(ctx, ff, packed.get(), 0, true);
packed_cells.insert(ff->name); packed_cells.insert(ff->name);
sliceUsage[packed->name].ff0_used = true;
} }
new_cells.push_back(std::move(packed)); new_cells.push_back(std::move(packed));
@ -182,6 +301,7 @@ class Ecp5Packer
std::unordered_map<IdString, SliceUsage> sliceUsage; std::unordered_map<IdString, SliceUsage> sliceUsage;
std::unordered_map<IdString, IdString> lutffPairs; std::unordered_map<IdString, IdString> lutffPairs;
std::unordered_map<IdString, IdString> fflutPairs;
}; };
// Main pack function // Main pack function