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Pdn secondary ground #9521

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e4a4dab
pdn: add secondary_ground support and fix secondary power net ordering
Bbn08 Feb 22, 2026
9d447f5
pdn: add run() spanning buildGrids+writeToDb, disable tests pending d…
Bbn08 Feb 23, 2026
d399058
pdn: refactor duplicated secondary net logic into helpers
Bbn08 Feb 23, 2026
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7 changes: 5 additions & 2 deletions src/pdn/include/pdn/PdnGen.hh
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Original file line number Diff line number Diff line change
Expand Up @@ -72,15 +72,18 @@ class PdnGen
void setCoreDomain(odb::dbNet* power,
odb::dbNet* switched_power,
odb::dbNet* ground,
const std::vector<odb::dbNet*>& secondary);
const std::vector<odb::dbNet*>& secondary_power,
const std::vector<odb::dbNet*>& secondary_ground);
void makeRegionVoltageDomain(const std::string& name,
odb::dbNet* power,
odb::dbNet* switched_power,
odb::dbNet* ground,
const std::vector<odb::dbNet*>& secondary_nets,
const std::vector<odb::dbNet*>& secondary_power,
const std::vector<odb::dbNet*>& secondary_ground,
odb::dbRegion* region);

// Grids
void run(bool trim, bool add_pins, const std::string& report_file);
void buildGrids(bool trim);
std::vector<Grid*> findGrid(const std::string& name) const;
void makeCoreGrid(VoltageDomain* domain,
Expand Down
30 changes: 24 additions & 6 deletions src/pdn/src/PdnGen.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@
#include "straps.h"
#include "techlayer.h"
#include "utl/Logger.h"
#include "utl/timer.h"
#include "via.h"
#include "via_repair.h"

Expand Down Expand Up @@ -58,6 +59,14 @@ void PdnGen::resetShapes()
updateRenderer();
}

void PdnGen::run(bool trim, bool add_pins, const std::string& report_file)
{
utl::Timer timer;
buildGrids(trim);
writeToDb(add_pins, report_file);
logger_->info(utl::PDN, 500, "Runtime: {:.2f}s", timer.elapsed());
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@gadfort gadfort Feb 23, 2026

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I like this function, but I think we need to resolve the formatting question before adding the timer code here.

}

void PdnGen::buildGrids(bool trim)
{
debugPrint(logger_, utl::PDN, "Make", 1, "Build - begin");
Expand Down Expand Up @@ -254,7 +263,7 @@ VoltageDomain* PdnGen::getCoreDomain() const
void PdnGen::ensureCoreDomain()
{
if (core_domain_ == nullptr) {
setCoreDomain(nullptr, nullptr, nullptr, {});
setCoreDomain(nullptr, nullptr, nullptr, {}, {});
}
}

Expand Down Expand Up @@ -291,14 +300,15 @@ VoltageDomain* PdnGen::findDomain(const std::string& name)
void PdnGen::setCoreDomain(odb::dbNet* power,
odb::dbNet* switched_power,
odb::dbNet* ground,
const std::vector<odb::dbNet*>& secondary)
const std::vector<odb::dbNet*>& secondary_power,
const std::vector<odb::dbNet*>& secondary_ground)
{
auto* block = db_->getChip()->getBlock();
if (core_domain_ != nullptr) {
logger_->warn(utl::PDN, 183, "Replacing existing core voltage domain.");
}
core_domain_ = std::make_unique<VoltageDomain>(
this, block, power, ground, secondary, logger_);
this, block, power, ground, secondary_power, secondary_ground, logger_);

if (importUPF(core_domain_.get())) {
if (switched_power) {
Expand All @@ -315,7 +325,8 @@ void PdnGen::makeRegionVoltageDomain(
odb::dbNet* power,
odb::dbNet* switched_power,
odb::dbNet* ground,
const std::vector<odb::dbNet*>& secondary_nets,
const std::vector<odb::dbNet*>& secondary_power,
const std::vector<odb::dbNet*>& secondary_ground,
odb::dbRegion* region)
{
if (region == nullptr) {
Expand All @@ -331,8 +342,15 @@ void PdnGen::makeRegionVoltageDomain(
}
}
auto* block = db_->getChip()->getBlock();
auto domain = std::make_unique<VoltageDomain>(
this, name, block, power, ground, secondary_nets, region, logger_);
auto domain = std::make_unique<VoltageDomain>(this,
name,
block,
power,
ground,
secondary_power,
secondary_ground,
region,
logger_);

if (importUPF(domain.get())) {
if (switched_power) {
Expand Down
27 changes: 23 additions & 4 deletions src/pdn/src/PdnGen.i
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Original file line number Diff line number Diff line change
Expand Up @@ -44,16 +44,29 @@ using utl::PDN;

namespace pdn {

void set_core_domain(odb::dbNet* power, odb::dbNet* switched_power, odb::dbNet* ground, const std::vector<odb::dbNet*>& secondary_nets)
void set_core_domain(odb::dbNet* power,
odb::dbNet* switched_power,
odb::dbNet* ground,
const std::vector<odb::dbNet*>& secondary_power,
const std::vector<odb::dbNet*>& secondary_ground)
{
PdnGen* pdngen = ord::getPdnGen();
pdngen->setCoreDomain(power, switched_power, ground, secondary_nets);
pdngen->setCoreDomain(
power, switched_power, ground, secondary_power, secondary_ground);
}

void make_region_domain(const char* name, odb::dbNet* power, odb::dbNet* switched_power, odb::dbNet* ground, const std::vector<odb::dbNet*>& secondary_nets, odb::dbRegion* region)
void make_region_domain(const char* name,
odb::dbNet* power,
odb::dbNet* switched_power,
odb::dbNet* ground,
const std::vector<odb::dbNet*>& secondary_power,
const std::vector<odb::dbNet*>& secondary_ground,
odb::dbRegion* region)
{
PdnGen* pdngen = ord::getPdnGen();
pdngen->makeRegionVoltageDomain(name, power, switched_power, ground, secondary_nets, region);
pdngen->makeRegionVoltageDomain(
name, power, switched_power, ground, secondary_power, secondary_ground,
region);
}

void reset()
Expand All @@ -68,6 +81,12 @@ void reset_shapes()
pdngen->resetShapes();
}

void run_pdngen(bool trim, bool add_pins, const char* report_file)
{
PdnGen* pdngen = ord::getPdnGen();
pdngen->run(trim, add_pins, report_file);
}

void build_grids(bool trim = true)
{
PdnGen* pdngen = ord::getPdnGen();
Expand Down
53 changes: 39 additions & 14 deletions src/pdn/src/domain.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,19 +18,37 @@

namespace pdn {

namespace {
void reportSecondaryNets(utl::Logger* logger,
const char* label,
const std::vector<odb::dbNet*>& nets)
{
if (nets.empty()) {
return;
}
std::string names;
for (auto* net : nets) {
names += net->getName() + " ";
}
logger->report(" Secondary {} nets: {}", label, names);
}
} // namespace
Comment on lines +22 to +35
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@gadfort gadfort Feb 23, 2026

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I think you can just make a loop in the reporting function to avoid needing to add this function.


VoltageDomain::VoltageDomain(PdnGen* pdngen,
odb::dbBlock* block,
odb::dbNet* power,
odb::dbNet* ground,
const std::vector<odb::dbNet*>& secondary_nets,
const std::vector<odb::dbNet*>& secondary_power,
const std::vector<odb::dbNet*>& secondary_ground,
utl::Logger* logger)
: name_("Core"),
pdngen_(pdngen),
block_(block),
power_(power),
switched_power_(nullptr),
ground_(ground),
secondary_(secondary_nets),
secondary_power_(secondary_power),
secondary_ground_(secondary_ground),
region_(nullptr),
logger_(logger)
{
Expand All @@ -42,7 +60,8 @@ VoltageDomain::VoltageDomain(PdnGen* pdngen,
odb::dbBlock* block,
odb::dbNet* power,
odb::dbNet* ground,
const std::vector<odb::dbNet*>& secondary_nets,
const std::vector<odb::dbNet*>& secondary_power,
const std::vector<odb::dbNet*>& secondary_ground,
odb::dbRegion* region,
utl::Logger* logger)
: name_(name),
Expand All @@ -51,7 +70,8 @@ VoltageDomain::VoltageDomain(PdnGen* pdngen,
power_(power),
switched_power_(nullptr),
ground_(ground),
secondary_(secondary_nets),
secondary_power_(secondary_power),
secondary_ground_(secondary_ground),
region_(region),
logger_(logger)
{
Expand All @@ -75,21 +95,31 @@ std::vector<odb::dbNet*> VoltageDomain::getNets(bool start_with_power) const
std::vector<odb::dbNet*> nets;

if (start_with_power) {
// Order: primary power, switched power, secondary power nets,
// secondary ground nets, primary ground.
// This groups all supply rails together before the ground rails,
// fixing the ordering issue for multi-rail designs (e.g., VDDA, VDD, VSS).
nets.push_back(power_);
if (switched_power_ != nullptr) {
nets.push_back(switched_power_);
}
nets.insert(nets.end(), secondary_power_.begin(), secondary_power_.end());
nets.insert(
nets.end(), secondary_ground_.begin(), secondary_ground_.end());
nets.push_back(ground_);
} else {
// Reverse order: primary ground, secondary ground nets,
// secondary power nets, switched power, primary power.
nets.push_back(ground_);
nets.push_back(power_);
nets.insert(
nets.end(), secondary_ground_.begin(), secondary_ground_.end());
nets.insert(nets.end(), secondary_power_.begin(), secondary_power_.end());
if (switched_power_ != nullptr) {
nets.push_back(switched_power_);
}
nets.push_back(power_);
}

nets.insert(nets.end(), secondary_.begin(), secondary_.end());
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@gadfort gadfort Feb 23, 2026

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I think it will be okay, but I'm a little worried about reordering of the nets for folks who are currently expecting the current order.


return nets;
}

Expand Down Expand Up @@ -210,13 +240,8 @@ void VoltageDomain::report() const
logger_->report(" Switched power net: {}", switched_power_->getName());
}

if (!secondary_.empty()) {
std::string nets;
for (auto* net : secondary_) {
nets += net->getName() + " ";
}
logger_->report(" Secondary nets: {}", nets);
}
reportSecondaryNets(logger_, "power", secondary_power_);
reportSecondaryNets(logger_, "ground", secondary_ground_);

for (const auto& grid : grids_) {
grid->report();
Expand Down
20 changes: 17 additions & 3 deletions src/pdn/src/domain.h
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Expand Up @@ -33,15 +33,17 @@ class VoltageDomain
odb::dbBlock* block,
odb::dbNet* power,
odb::dbNet* ground,
const std::vector<odb::dbNet*>& secondary_nets,
const std::vector<odb::dbNet*>& secondary_power,
const std::vector<odb::dbNet*>& secondary_ground,
odb::dbRegion* region,
utl::Logger* logger);

VoltageDomain(PdnGen* pdngen,
odb::dbBlock* block,
odb::dbNet* power,
odb::dbNet* ground,
const std::vector<odb::dbNet*>& secondary_nets,
const std::vector<odb::dbNet*>& secondary_power,
const std::vector<odb::dbNet*>& secondary_ground,
utl::Logger* logger); // Core

const std::string& getName() const { return name_; }
Expand All @@ -54,6 +56,14 @@ class VoltageDomain
odb::dbNet* getGround() const { return ground_; }
odb::dbNet* getAlwaysOnPower() const { return power_; }
odb::dbNet* getSwitchedPower() const { return switched_power_; }
const std::vector<odb::dbNet*>& getSecondaryPower() const
{
return secondary_power_;
}
const std::vector<odb::dbNet*>& getSecondaryGround() const
{
return secondary_ground_;
}

void setSwitchedPower(odb::dbNet* switched_power)
{
Expand All @@ -62,6 +72,9 @@ class VoltageDomain
bool hasSwitchedPower() const { return switched_power_ != nullptr; }

// returns the order in which the nets should be arranged in the grid shapes
// ordering: [power, switched_power?, ...secondary_power,
// ...secondary_ground, ground] when start_with_power is true,
// and the reverse when false.
std::vector<odb::dbNet*> getNets(bool start_with_power = true) const;

bool hasRegion() const { return region_ != nullptr; }
Expand Down Expand Up @@ -90,7 +103,8 @@ class VoltageDomain
odb::dbNet* power_;
odb::dbNet* switched_power_;
odb::dbNet* ground_;
std::vector<odb::dbNet*> secondary_;
std::vector<odb::dbNet*> secondary_power_;
std::vector<odb::dbNet*> secondary_ground_;

odb::dbRegion* region_;

Expand Down
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