--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/baseport/syborg/soundsc/virtio_queue.h	Thu Mar 04 00:55:21 2010 +0000
@@ -0,0 +1,139 @@
+/*
+* This component and the accompanying materials are made available
+* under the terms of the License "Eclipse Public License v1.0"
+* which accompanies this distribution, and is available
+* at the URL "http://www.eclipse.org/legal/epl-v10.html".
+*
+* Initial Contributors:
+* Accenture Ltd
+*
+* Contributors:
+*
+* Description: This file is a part of sound driver for Syborg adaptation.
+*
+*/
+
+#ifndef VIRTIO_QUEUE_H
+#define VIRTIO_QUEUE_H
+
+#include "virtio.h"
+#include <e32def.h>
+
+namespace VirtIo
+{
+
+/// @brief implements VirtIo Queue.
+/// 
+///
+/// @note functions are not enclosed with any synchronisation primitives.
+/// However, implementation is believed to split operations in 3 groups with the following concurrency constraints:
+/// <li> A GetBuf, DetachBuf
+/// <li> B AddBuf
+/// <li> C Processing, Completed, Sync
+/// Group C can be executed concurrently with any other functions.
+/// Group A can be executed concurrently with a group B function.
+/// Group A or B function cannot be executed concurrently with function from the same group.
+///
+/// Memory barries would have to be introduced for SMP.
+///
+class DQueue : public DBase, public MQueue
+	{
+	typedef TUint16 TIdx;
+
+	struct TTransactionInfo
+		{
+		Token iToken;
+		TUint iTotalLen;
+		};
+	
+	static const TUint KFreeDescriptorMarker = 0xFFFF;
+	
+public:
+
+	/// @brief Creates a VirtIo Queue with a MIo object, Queue Id,
+	/// and descriptor count/ring lenght.
+	DQueue( MIo& aVirtIo, TUint aId, TUint aCount );
+	
+	/// Allocates resources
+	TInt Construct();
+		
+	virtual ~DQueue();
+	
+public: // implementation of MQueue
+	
+	virtual TInt AddBuf( const TAddrLen aScatterList[], TUint32 aOutNum, TUint32 aInNum, Token aToken);
+	
+	virtual TInt DetachBuf( Token aToken );
+	
+	virtual Token GetBuf( TUint& aLen );
+	
+	virtual void Sync();
+	
+	virtual TUint Id() 
+		{ return iId; }
+	
+	virtual TBool Restart()
+		{ return ETrue;	}
+	
+	virtual TInt Processing();
+			
+	virtual TInt Completed();	
+	
+public:	// Debug functions 
+	void DumpUsedPending();
+	
+	void DumpUsed(TUint usedSlot);
+	void DumpAvailPending();
+	
+	void DumpAvail(TUint availSlot);
+	void DumpDescs(TUint descId );
+	
+	virtual void DumpAll();
+		
+private:
+	void Wipe();
+
+	TUint Slot( TUint i )
+		{ return i & (iCount - 1); }
+				
+	void FreeDescs( TUint firstDescIdx );
+	
+	TUint8* AllocMem( TUint aSize );
+	
+	TInt AllocQueue();
+	
+	void PreInitQueue();
+	
+	void PostInitQueue();
+	
+private:
+	MIo& iVirtIo;
+	const TUint iId;
+	const TUint iCount;
+	volatile TUint iNextUsedToRead;
+	TUint iFirstEverToRead;
+	volatile TUint iNextAvailToSync;
+	TUint iFirstEverToSync;
+
+	TUint iDescSize;
+	TUint iAvailSize;
+	TUint iTokenSize;
+	TUint iUsedSize;
+	
+	TRingDesc* iDesc;
+	TRingAvail* iAvail;
+	volatile TRingUsed* iUsed;
+	TTransactionInfo* iToken;
+	
+	// managed
+	TUint8* iMem;
+	TPhysAddr iPhysAddr;
+	TBool iPhysMemReallyAllocated;
+	DPlatChunkHw* iChunk;
+	
+	};
+
+
+} // namespace VirtIo
+
+#endif