kicad/pcbnew/drc/drc_test_provider_diff_pair_coupling.cpp

/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2004-2020 KiCad Developers.
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#include <common.h>
#include <class_board.h>
#include <class_drawsegment.h>
#include <class_pad.h>
#include <class_track.h>

#include <drc/drc_engine.h>
#include <drc/drc_item.h>
#include <drc/drc_rule.h>
#include <drc/drc_test_provider.h>
#include <drc/drc_length_report.h>

#include <connectivity/connectivity_data.h>
#include <connectivity/from_to_cache.h>

#include <pcb_expr_evaluator.h>

/*
    Differential pair gap/coupling test.
    Errors generated:
    - DRCE_DIFF_PAIR_GAP_OUT_OF_RANGE
    - DRCE_DIFF_PAIR_UNCOUPLED_LENGTH_TOO_LONG
    - DRCE_TOO_MANY_VIAS
    Todo: 
    - arc support.
    - improve recognition of coupled segments (now anything that's parallel is considered coupled, causing
      DRC errors on meanders)
*/

namespace test {

class DRC_TEST_PROVIDER_DIFF_PAIR_COUPLING : public DRC_TEST_PROVIDER
{
public:
    DRC_TEST_PROVIDER_DIFF_PAIR_COUPLING ()
    {
    }

    virtual ~DRC_TEST_PROVIDER_DIFF_PAIR_COUPLING() 
    {
    }

    virtual bool Run() override;

    virtual const wxString GetName() const override 
    {
        return "diff_pair_coupling";
    };

    virtual const wxString GetDescription() const override
    {
        return "Tests differential pair coupling";
    }

    virtual int GetNumPhases() const override
    {
        return 1;
    }

    virtual std::set<DRC_CONSTRAINT_TYPE_T> GetConstraintTypes() const override;

private:

    BOARD* m_board;
};

};


// fixme: move two functions below to pcbcommon?
static int matchDpSuffix( const wxString& aNetName, wxString& aComplementNet,
                                             wxString& aBaseDpName )
{
    int rv = 0;

    if( aNetName.EndsWith( "+" ) )
    {
        aComplementNet = "-";
        rv = 1;
    }
    else if( aNetName.EndsWith( "P" ) )
    {
        aComplementNet = "N";
        rv = 1;
    }
    else if( aNetName.EndsWith( "-" ) )
    {
        aComplementNet = "+";
        rv = -1;
    }
    else if( aNetName.EndsWith( "N" ) )
    {
        aComplementNet = "P";
        rv = -1;
    }
    // Match P followed by 2 digits
    else if( aNetName.Right( 2 ).IsNumber() && aNetName.Right( 3 ).Left( 1 ) == "P" )
    {
        aComplementNet = "N" + aNetName.Right( 2 );
        rv = 1;
    }
    // Match P followed by 1 digit
    else if( aNetName.Right( 1 ).IsNumber() && aNetName.Right( 2 ).Left( 1 ) == "P" )
    {
        aComplementNet = "N" + aNetName.Right( 1 );
        rv = 1;
    }
    // Match N followed by 2 digits
    else if( aNetName.Right( 2 ).IsNumber() && aNetName.Right( 3 ).Left( 1 ) == "N" )
    {
        aComplementNet = "P" + aNetName.Right( 2 );
        rv = -1;
    }
    // Match N followed by 1 digit
    else if( aNetName.Right( 1 ).IsNumber() && aNetName.Right( 2 ).Left( 1 ) == "N" )
    {
        aComplementNet = "P" + aNetName.Right( 1 );
        rv = -1;
    }
    if( rv != 0 )
    {
        aBaseDpName = aNetName.Left( aNetName.Length() - aComplementNet.Length() );
        aComplementNet = aBaseDpName + aComplementNet;
    }

    return rv;
}


static int isNetADiffPair( BOARD* aBoard, int aNet, int& aNetP, int& aNetN )
{
    wxString refName = aBoard->FindNet( aNet )->GetNetname();
    wxString dummy, coupledNetName;

    if( int polarity = matchDpSuffix( refName, coupledNetName, dummy ) )
    {
        NETINFO_ITEM* net = aBoard->FindNet( coupledNetName );

        if( !net )
            return false;

        if( polarity > 0 )
        {
            aNetP = aNet;
            aNetN = net->GetNet();
        }
        else
        {
            aNetP = net->GetNet();
            aNetN = aNet;
        }

        return true;
    }

    return false;
}

static bool commonParallelProjection( SEG p, SEG n, SEG &pClip, SEG& nClip )
{
    SEG n_proj_p( p.LineProject( n.A ), p.LineProject( n.B ) );

    int64_t t_a = 0;
    int64_t t_b = p.TCoef( p.B );

    int64_t tproj_a = p.TCoef( n_proj_p.A );
    int64_t tproj_b = p.TCoef( n_proj_p.B );

    if( t_b < t_a )
        std::swap( t_b, t_a );

    if( tproj_b < tproj_a )
        std::swap( tproj_b, tproj_a );

    if( t_b <= tproj_a )
        return false;

    if( t_a >= tproj_b )
        return false;

    int64_t t[4] = { 0, p.TCoef( p.B ), p.TCoef( n_proj_p.A ), p.TCoef( n_proj_p.B ) };
    std::vector<int64_t> tv( t, t + 4 );
    std::sort( tv.begin(), tv.end() ); // fixme: awful and disgusting way of finding 2 midpoints

    int64_t pLenSq = p.SquaredLength();

    VECTOR2I dp = p.B - p.A;
    pClip.A.x = p.A.x + rescale( (int64_t)dp.x, tv[1], pLenSq );
    pClip.A.y = p.A.y + rescale( (int64_t)dp.y, tv[1], pLenSq );

    pClip.B.x = p.A.x + rescale( (int64_t)dp.x, tv[2], pLenSq );
    pClip.B.y = p.A.y + rescale( (int64_t)dp.y, tv[2], pLenSq );

    nClip.A = n.LineProject( pClip.A );
    nClip.B = n.LineProject( pClip.B );

    return true;
}


struct DIFF_PAIR_KEY
    {
        bool operator<( const DIFF_PAIR_KEY& b ) const
        {
            if( netP < b.netP )
                return true;
            else if( netP > b.netP )
                return false;
            else // netP == b.netP
            {
                if( netN < b.netN )
                    return true;
                else if( netN > b.netN )
                    return false;
                else
                {
                    if( parentRule < b.parentRule )
                        return true;
                    else
                    {
                        return false;
                    }
                }
            }
        }

        int       netP, netN;
        DRC_RULE* parentRule;
    };

    struct DIFF_PAIR_COUPLED_SEGMENTS
    {
        SEG coupledN, coupledP;
        TRACK* parentN, *parentP;
        int computedGap;
        bool couplingOK;
    };

    struct DIFF_PAIR_ITEMS
    {
        std::set<BOARD_CONNECTED_ITEM*> itemsP, itemsN;
        std::vector<DIFF_PAIR_COUPLED_SEGMENTS> coupled;
        int totalCoupled;
        int totalLengthN;
        int totalLengthP;
    };

static void extractDiffPairCoupledItems( DIFF_PAIR_ITEMS& aDp )
{

    for( BOARD_CONNECTED_ITEM* itemP : aDp.itemsP )
    {
        auto sp = dyn_cast<TRACK*>( itemP );

        if(!sp)
            continue;

        for ( BOARD_CONNECTED_ITEM* itemN : aDp.itemsN )
        {
            auto sn = dyn_cast<TRACK*> ( itemN );

            if(!sn)
                continue;

            if( ( sn->GetLayerSet() & sp->GetLayerSet() ).none() )
                continue;

            SEG ssp ( sp->GetStart(), sp->GetEnd() );
            SEG ssn ( sn->GetStart(), sn->GetEnd() );

            if( ssp.ApproxParallel(ssn) )
            {
                DIFF_PAIR_COUPLED_SEGMENTS cpair;
                bool coupled = commonParallelProjection( ssp, ssn, cpair.coupledP, cpair.coupledN );

                if( coupled )
                {
                    cpair.parentP = sp;
                    cpair.parentN = sn;

                    aDp.coupled.push_back( cpair );
                }
            }
        }
    }
}


bool test::DRC_TEST_PROVIDER_DIFF_PAIR_COUPLING::Run()
{
    m_board = m_drcEngine->GetBoard();

    

    std::map<DIFF_PAIR_KEY, DIFF_PAIR_ITEMS> dpRuleMatches;

    auto evaluateDpConstraints =
            [&]( BOARD_ITEM *item ) -> bool
            {
                DIFF_PAIR_KEY key;
                auto citem = static_cast<BOARD_CONNECTED_ITEM*>( item );
                int refNet = citem->GetNetCode();

                if( !isNetADiffPair( m_board, refNet, key.netP, key.netN ) ) // not our business
                    return true;

                const DRC_CONSTRAINT_TYPE_T constraintsToCheck[] = {
                    DRC_CONSTRAINT_TYPE_DIFF_PAIR_GAP,
                    DRC_CONSTRAINT_TYPE_DIFF_PAIR_MAX_UNCOUPLED
                };

                for( int i = 0; i < 2; i++ )
                {
                    auto constraint = m_drcEngine->EvalRulesForItems( constraintsToCheck[i], item, nullptr, item->GetLayer() );

                    if( constraint.IsNull() )
                        continue;

                    key.parentRule = constraint.GetParentRule();

                    if( refNet == key.netN )
                        dpRuleMatches[key].itemsN.insert( citem );
                    else
                        dpRuleMatches[key].itemsP.insert( citem );
                }

                return true;
            };

    m_board->GetConnectivity()->GetFromToCache()->Rebuild( m_board );

    forEachGeometryItem( { PCB_TRACE_T, PCB_VIA_T, PCB_ARC_T },
                    LSET::AllCuMask(), evaluateDpConstraints );


    reportAux( wxString::Format( _("DPs evaluated:") ) );

    for( auto& it : dpRuleMatches )
    {
        NETINFO_ITEM *niP = m_board->GetNetInfo().GetNetItem( it.first.netP );
        NETINFO_ITEM *niN = m_board->GetNetInfo().GetNetItem( it.first.netN );

        assert( niP );
        assert( niN );

        wxString nameP = niP->GetNetname();
        wxString nameN = niN->GetNetname();

        reportAux( wxString::Format( "Rule '%s', DP: (+) %s - (-) %s", it.first.parentRule->m_Name, nameP, nameN ) );

        extractDiffPairCoupledItems( it.second );

        it.second.totalCoupled = 0;
        it.second.totalLengthN = 0;
        it.second.totalLengthP = 0;

        drc_dbg(10, "       coupled prims : %d\n", (int) it.second.coupled.size() );

        OPT<DRC_CONSTRAINT> gapConstraint = it.first.parentRule->FindConstraint( DRC_CONSTRAINT_TYPE_DIFF_PAIR_GAP );
        OPT<DRC_CONSTRAINT> maxUncoupledConstraint = it.first.parentRule->FindConstraint( DRC_CONSTRAINT_TYPE_DIFF_PAIR_MAX_UNCOUPLED );

        for( auto& item : it.second.itemsN )
        {
            // fixme: include vias
            if( auto track = dyn_cast<TRACK*>( item ) )
                it.second.totalLengthN += track->GetLength();
        }

        for( auto& item : it.second.itemsP )
        {
            // fixme: include vias
            if( auto track = dyn_cast<TRACK*>( item ) )
                it.second.totalLengthP += track->GetLength();
        }

        for( auto& cpair : it.second.coupled )
        {
            int length = cpair.coupledN.Length();
            int gap = cpair.coupledN.Distance( cpair.coupledP );

            gap -= cpair.parentN->GetWidth() / 2;
            gap -= cpair.parentP->GetWidth() / 2;

            cpair.computedGap = gap;

            drc_dbg(10, "               len %d gap %d l %d\n", length, gap, cpair.parentP->GetLayer() );

            if( gapConstraint )
            {
                auto val = gapConstraint->GetValue();
                bool insideRange = true;
                if ( val.HasMin() && gap < val.Min() )
                    insideRange = false;
                if ( val.HasMax() && gap > val.Max() )
                    insideRange = false;


//                if(val.HasMin() && val.HasMax() )
  //                  drc_dbg(10, "Vmin %d vmax %d\n", val.Min(), val.Max() );

                cpair.couplingOK = insideRange;

                if( insideRange )
                    it.second.totalCoupled += length;
            }
        }

        int totalLen = std::max( it.second.totalLengthN, it.second.totalLengthP );
            reportAux( wxString::Format( "   - coupled length: %s, total length: %s",

            MessageTextFromValue( userUnits(), it.second.totalCoupled, false),
            MessageTextFromValue( userUnits(), totalLen, false ) ) );

        int totalUncoupled = totalLen - it.second.totalCoupled;

        bool uncoupledViolation = false;

        if( maxUncoupledConstraint )
        {
            auto val = maxUncoupledConstraint->GetValue();

            if ( val.HasMax() && totalUncoupled > val.Max() )
            {
                std::shared_ptr<DRC_ITEM> drcItem = DRC_ITEM::Create( DRCE_DIFF_PAIR_UNCOUPLED_LENGTH_TOO_LONG );
                wxString                  msg =
                    drcItem->GetErrorText() + " (" + maxUncoupledConstraint->GetParentRule()->m_Name + " ";

                msg += wxString::Format( _( "maximum uncoupled length: %s; actual: %s)" ),
                        MessageTextFromValue( userUnits(), val.Max(), true ),
                        MessageTextFromValue( userUnits(), totalUncoupled, true ) );

                drcItem->SetErrorMessage( msg );

                for( auto offendingTrack : it.second.itemsP )
                    drcItem->AddItem( offendingTrack );
                for( auto offendingTrack : it.second.itemsN )
                    drcItem->AddItem( offendingTrack );

                uncoupledViolation = true;

                drcItem->SetViolatingRule( maxUncoupledConstraint->GetParentRule() );

                reportViolation( drcItem, (*it.second.itemsP.begin())->GetPosition() );
            }
        }

        if ( gapConstraint && (uncoupledViolation || !maxUncoupledConstraint ) )
        {
            for( auto& cpair : it.second.coupled )
            {
                if( !cpair.couplingOK )
                {
                    auto val = gapConstraint->GetValue();

                    std::shared_ptr<DRC_ITEM> drcItem = DRC_ITEM::Create( DRCE_DIFF_PAIR_GAP_OUT_OF_RANGE );
                    wxString                  msg =
                    drcItem->GetErrorText() + " (" + maxUncoupledConstraint->GetParentRule()->m_Name + " ";

                    if( val.HasMin() )
                        msg += wxString::Format( _( "minimum gap: %s; " ),
                        MessageTextFromValue( userUnits(), val.Min(), true ) );

                    if( val.HasMax() )
                        msg += wxString::Format( _( "maximum gap: %s; " ),
                        MessageTextFromValue( userUnits(), val.Max(), true ) );


                    msg += wxString::Format( _( "actual: %s)" ),
                        MessageTextFromValue( userUnits(), cpair.computedGap, true ) );

                    drcItem->SetErrorMessage( msg );

                    drcItem->AddItem( cpair.parentP );
                    drcItem->AddItem( cpair.parentN );

                    drcItem->SetViolatingRule( gapConstraint->GetParentRule() );

                    reportViolation( drcItem, cpair.parentP->GetPosition() );
                }
            }
        }
    }

    reportRuleStatistics();

    return true;
}


std::set<DRC_CONSTRAINT_TYPE_T> test::DRC_TEST_PROVIDER_DIFF_PAIR_COUPLING::GetConstraintTypes() const
{
    return { DRC_CONSTRAINT_TYPE_DIFF_PAIR_GAP, DRC_CONSTRAINT_TYPE_DIFF_PAIR_MAX_UNCOUPLED };
}


namespace detail
{
    static DRC_REGISTER_TEST_PROVIDER<test::DRC_TEST_PROVIDER_DIFF_PAIR_COUPLING> dummy;
}