Change in design of GetBitString

    - It is no longer necessary to call GetBitString function of a
      register only when it is read atleast once.

RTC: 66086
Change-Id: Ia67903c03e4aea9cc5a128b05eecacdd9af59c89
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/3501
Tested-by: Jenkins Server
Reviewed-by: A. Patrick Williams III <iawillia@us.ibm.com>
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/3856

5 files changed, 81 insertions, 15 deletions

diff --git a/src/usr/diag/prdf/common/framework/register/prdfOperatorRegister.H b/src/usr/diag/prdf/common/framework/register/prdfOperatorRegister.H
index fff6a1642..8f866202b 100755
--- a/src/usr/diag/prdf/common/framework/register/prdfOperatorRegister.H
+++ b/src/usr/diag/prdf/common/framework/register/prdfOperatorRegister.H
@@ -401,7 +401,7 @@ class NullRegister : public SCAN_COMM_REGISTER_CLASS
         return *this;
     }
 
-    virtual uint32_t Read()  { return 0; }
+    virtual uint32_t Read() { return 0; }
     virtual uint32_t Write() { return 0; }
 
     const BIT_STRING_CLASS * GetBitString(
@@ -558,7 +558,7 @@ class ConstantRegister : public SCAN_COMM_REGISTER_CLASS
         return *this;
     }
 
-    virtual uint32_t Read()  { return SUCCESS; }
+    virtual uint32_t Read()   { return SUCCESS; }
     virtual uint32_t Write() { return SUCCESS; }
 
     const BIT_STRING_CLASS * GetBitString(
diff --git a/src/usr/diag/prdf/common/framework/register/prdfRegisterCache.C b/src/usr/diag/prdf/common/framework/register/prdfRegisterCache.C
index 228f34c0c..2c168e2e8 100644
--- a/src/usr/diag/prdf/common/framework/register/prdfRegisterCache.C
+++ b/src/usr/diag/prdf/common/framework/register/prdfRegisterCache.C
@@ -48,22 +48,20 @@ BIT_STRING_CLASS & RegDataCache::read(
                                 const SCAN_COMM_REGISTER_CLASS * i_pRegister,
                                 bool & o_readStat )
 {
-    BIT_STRING_CLASS * l_pBitString = NULL;
-    o_readStat = false;
     ScomRegisterAccess l_scomAccessKey ( *i_pRegister,i_pChip );
-    CacheDump::iterator itDump = iv_cachedRead.find( l_scomAccessKey );
-    if( iv_cachedRead.end() != itDump )
-    {
-        o_readStat = true;
-        l_pBitString = itDump->second ;
-    }
-    else
+    BIT_STRING_CLASS * l_pBitString = queryCache( l_scomAccessKey );
+    o_readStat = false;
+    if( NULL == l_pBitString )
     {
         // Creating new entry
         l_pBitString = new BitStringBuffer( i_pRegister->GetBitLength( ) );
         // Adding register in the cache
         iv_cachedRead[l_scomAccessKey] = l_pBitString;
     }
+    else
+    {
+        o_readStat = true;
+    }
     return *l_pBitString;
 }
 
@@ -101,4 +99,28 @@ void RegDataCache::flush( ExtensibleChip* i_pChip,
 
 //------------------------------------------------------------------------------
 
+BIT_STRING_CLASS * RegDataCache::queryCache(
+                            ExtensibleChip* i_pChip,
+                            const SCAN_COMM_REGISTER_CLASS * i_pRegister )const
+{
+    ScomRegisterAccess l_scomAccessKey ( *i_pRegister,i_pChip );
+    return queryCache( l_scomAccessKey );
+}
+
+//------------------------------------------------------------------------------
+
+BIT_STRING_CLASS * RegDataCache::queryCache(
+                        const ScomRegisterAccess & i_scomAccessKey ) const
+{
+    BIT_STRING_CLASS * l_pBitString = NULL;
+    CacheDump::const_iterator itDump = iv_cachedRead.find( i_scomAccessKey );
+    if( iv_cachedRead.end() != itDump )
+    {
+        l_pBitString = itDump->second ;
+    }
+
+    return l_pBitString;
+}
+
+//------------------------------------------------------------------------------
 }// end namespace  PRDF
diff --git a/src/usr/diag/prdf/common/framework/register/prdfRegisterCache.H b/src/usr/diag/prdf/common/framework/register/prdfRegisterCache.H
index b2eb2682c..411937af6 100644
--- a/src/usr/diag/prdf/common/framework/register/prdfRegisterCache.H
+++ b/src/usr/diag/prdf/common/framework/register/prdfRegisterCache.H
@@ -97,6 +97,22 @@ class RegDataCache
      */
     void flush( ExtensibleChip* i_pChip,
                 const SCAN_COMM_REGISTER_CLASS * i_pRegister );
+    /**
+     * @brief Queries if a specific entry exist in cache.
+     * @param i_pChip       The rulechip  associated with the register.
+     * @param i_pRegister   base part of register entry to be queried in cache.
+     * @return pointer to cache entry associated with a given register
+     */
+     BIT_STRING_CLASS * queryCache( ExtensibleChip* i_pChip,
+                            const SCAN_COMM_REGISTER_CLASS * i_pRegister )const;
+    /**
+     * @brief Queries if a specific entry exist in cache.
+     * @param i_scomAccessKey Reference to register to be queried.
+     * @return pointer to cache entry associated with a given register
+     */
+
+    BIT_STRING_CLASS * queryCache(
+                        const ScomRegisterAccess & i_scomAccessKey )const;
   private: // data
 
     typedef std::map<ScomRegisterAccess, BIT_STRING_CLASS *> CacheDump;
diff --git a/src/usr/diag/prdf/common/framework/register/prdfScomRegister.C b/src/usr/diag/prdf/common/framework/register/prdfScomRegister.C
index 2fdddf170..c2631ebfa 100755
--- a/src/usr/diag/prdf/common/framework/register/prdfScomRegister.C
+++ b/src/usr/diag/prdf/common/framework/register/prdfScomRegister.C
@@ -84,13 +84,41 @@ void ScomRegister::SetBitString( const BIT_STRING_CLASS *bs )
 
 const BIT_STRING_CLASS *ScomRegister::GetBitString( ATTENTION_TYPE i_type )const
 {
+    BIT_STRING_CLASS * l_pString = NULL;
     bool l_readStat = false;
-    return &( readCache( l_readStat ) );
+    //Expectation is, caller shall first call Read( ) and then GetBitString.
+    //This leaves an opportunity of mistake. One may call GetBitString without
+    //calling Read() first. As a result, a stray entry in cache gets created
+    //which  shall never be in sync with hardware.
+
+    //As a solution, first cache is queried.If the given entry exist, bitString
+    //pointer is returned else a new entry is created. This new entry is
+    //synchronized with hardware and then pointer to bit string is returned to
+    //caller.
+    RegDataCache & regDump = RegDataCache::getCachedRegisters();
+    l_pString = regDump.queryCache( getChip( ), this );
+
+    if( NULL == l_pString )
+    {
+        ForceRead( );
+        //if ForceRead fails, a dummy entry is returned that way analysis shall
+        //fail gracefully else we return a new entry which is in sync with
+        //hardware
+        l_pString = &( readCache( l_readStat ) );
+
+    }
+    return l_pString;
 }
 // ---------------------------------------------------------------------
 BIT_STRING_CLASS & ScomRegister::AccessBitString( )
 {
     bool l_readStat = false;
+    //Expectation is, caller shall first call Read( ) and then AccessBitString.
+    //This leaves an opportunity of mistake. One may call AccessBitString
+    //without calling Read() first. As a result, a stray entry in cache gets
+    //created which shall never be in sync with hardware. Calling Read( ) before
+    //readCache( ) inside function eliminates this scenario.
+    Read( );
     return ( readCache( l_readStat ) );
 
 }
@@ -113,7 +141,7 @@ uint32_t ScomRegister::Read( )
 }
 
 // ----------------------------------------------------------------------------
-uint32_t ScomRegister::ForceRead()
+uint32_t ScomRegister::ForceRead() const
 {
     int32_t rc = SUCCESS;
     bool l_readStat = false;
diff --git a/src/usr/diag/prdf/common/framework/register/prdfScomRegister.H b/src/usr/diag/prdf/common/framework/register/prdfScomRegister.H
index 41a611061..1717b27c8 100755
--- a/src/usr/diag/prdf/common/framework/register/prdfScomRegister.H
+++ b/src/usr/diag/prdf/common/framework/register/prdfScomRegister.H
@@ -102,13 +102,13 @@ public:
      * @brief     Directly reads from hardware register
      * @return    SUCCESS|FAIL
      */
-    virtual uint32_t ForceRead();
+    virtual uint32_t ForceRead() const ;
     /**
      * @brief     Returns contents of register.If entry does not exist in cache
      *            a  fresh entry is created and hardware is read.
      * @return    SUCCESS|FAIL
     */
-    virtual uint32_t Read( );
+    virtual uint32_t Read( ) ;
     /**
      * @brief     Writes cache contents to register.
      * @return    SUCCESS|FAIL