diff -r 000000000000 -r a41df078684a kernel/eka/drivers/usbc/usbdma.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/kernel/eka/drivers/usbc/usbdma.cpp	Mon Oct 19 15:55:17 2009 +0100
@@ -0,0 +1,974 @@
+// Copyright (c) 2000-2009 Nokia Corporation and/or its subsidiary(-ies).
+// All rights reserved.
+// 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:
+// Nokia Corporation - initial contribution.
+//
+// Contributors:
+//
+// Description:
+// e32\drivers\usbc\usbdma.cpp
+// LDD for USB Device driver stack:
+// Management of DMA-capable data buffers.
+// 
+//
+
+/**
+ @file usbdma.cpp
+ @internalTechnology
+*/
+
+#include <drivers/usbc.h>
+
+
+#if defined(_DEBUG)
+static const char KUsbPanicLdd[] = "USB LDD";
+#endif
+
+
+TDmaBuf::TDmaBuf(TUsbcEndpointInfo* aEndpointInfo, TInt aBandwidthPriority)
+	: iBufBasePtr(NULL),
+	  iCurrentDrainingBuffer(NULL),
+	  iCurrentPacket(0),
+	  iCurrentPacketIndexArray(NULL),
+	  iCurrentPacketSizeArray(NULL)
+	{
+	iMaxPacketSize = aEndpointInfo->iSize;
+	iEndpointType = aEndpointInfo->iType;
+
+	switch (aEndpointInfo->iType)
+		{
+	case KUsbEpTypeControl:
+		iBufSz = KUsbcDmaBufSzControl;
+		iNumberofBuffers = KUsbcDmaBufNumControl;
+		break;
+	case KUsbEpTypeIsochronous:
+		iBufSz = KUsbcDmaBufSzIsochronous;
+		iNumberofBuffers = KUsbcDmaBufNumIsochronous;
+		break;
+	case KUsbEpTypeBulk:
+		{
+		if (aEndpointInfo->iDir == KUsbEpDirOut)
+			{
+			const TInt priorityOUT = aBandwidthPriority & 0x0f;
+			iBufSz = KUsbcDmaBufSizesBulkOUT[priorityOUT];
+			}
+		else
+			{
+			const TInt priorityIN = (aBandwidthPriority >> 4) & 0x0f;
+			iBufSz = KUsbcDmaBufSizesBulkIN[priorityIN];
+			}
+		iNumberofBuffers = KUsbcDmaBufNumBulk;
+		}
+		break;
+	case KUsbEpTypeInterrupt:
+		iBufSz = KUsbcDmaBufSzInterrupt;
+		iNumberofBuffers = KUsbcDmaBufNumInterrupt;
+		break;
+	default:
+		iBufSz = 0;
+		iNumberofBuffers = 0;
+		}
+
+	if (aEndpointInfo->iDir == KUsbEpDirIn)
+		{
+		iNumberofBuffers = 1;								// IN endpoints only have 1 buffer
+		}
+
+	for (TInt i = 0; i < KUsbcDmaBufNumMax; i++)
+		{
+		// Buffer logical addresses (pointers)
+		iBuffers[i] = NULL;
+		// Buffer physical addresses
+		iBufferPhys[i] = 0;
+		// Packet indexes base array
+		iPacketIndex[i] = NULL;
+		// Packet sizes base array
+		iPacketSize[i] = NULL;
+		}
+	}
+
+
+TInt TDmaBuf::Construct(TUsbcEndpointInfo* aEndpointInfo)
+	{
+	if (aEndpointInfo->iDir != KUsbEpDirIn)
+		{
+		// IN endpoints don't need a packet array
+
+		// At most 2 packets (clump of max packet size packets) + possible zlp
+		TUsbcPacketArray* bufPtr = iPacketInfoStorage;
+		// this divides up the packet indexing & packet size array over the number of buffers
+		__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::Construct() array base=0x%08x", bufPtr));
+		for (TInt i = 0; i < iNumberofBuffers; i++)
+			{
+			iPacketIndex[i] = bufPtr;
+			bufPtr += KUsbcDmaBufMaxPkts;
+			iPacketSize[i] = bufPtr;
+			bufPtr += KUsbcDmaBufMaxPkts;
+			__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::Construct() packetIndex[%d]=0x%08x packetSize[%d]=0x%08x",
+											i, iPacketIndex[i], i, iPacketSize[i]));
+			}
+		}
+	else
+		{
+		__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::Construct() IN endpoint"));
+		}
+	Flush();
+	return KErrNone;
+	}
+
+
+TDmaBuf::~TDmaBuf()
+	{
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::~TDmaBuf()"));
+	}
+
+
+TUint8* TDmaBuf::SetBufferBase(TUint8* aBase)
+	{
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::SetBufferBase base=0x%08x size=0x%08x", aBase, iBufSz));
+	TUint8* bufPtr = aBase;
+	iBufBasePtr = aBase;
+	for (TInt i = 0; i < iNumberofBuffers; i++)
+		{
+		iDrainable[i] = iCanBeFreed[i] = EFalse;
+		iBuffers[i] = bufPtr;
+		iBufferPhys[i] = Epoc::LinearToPhysical((TLinAddr)bufPtr);
+		bufPtr += iBufSz;
+		__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::SetBufferBase() iBuffers[%d]=0x%08x", i, iBuffers[i]));
+		}
+	return bufPtr;
+	}
+
+
+TInt TDmaBuf::BufferTotalSize() const
+	{
+	return iBufSz * iNumberofBuffers;
+	}
+
+
+TUint8* TDmaBuf::BufferBase() const
+	{
+	return iBufBasePtr;
+	}
+
+
+void TDmaBuf::SetMaxPacketSize(TInt aSize)
+	{
+	iMaxPacketSize = aSize;
+	}
+
+
+void TDmaBuf::Flush()
+	{
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::Flush %x", this));
+	iRxActive = EFalse;
+	iTxActive = EFalse;
+	iExtractOffset = 0;
+	iTotalRxBytesAvail = 0;
+	iTotalRxPacketsAvail = 0;
+	iCurrentDrainingBufferIndex = KUsbcInvalidBufferIndex;
+	iCurrentFillingBufferIndex = 0;
+	iDrainQueueIndex = KUsbcInvalidDrainQueueIndex;
+	for (TInt i = 0; i < KUsbcDmaBufNumMax; i++)
+		{
+		iDrainable[i] = EFalse;
+		iCanBeFreed[i] = EFalse;
+		iNumberofBytesRx[i] = 0;
+		iNumberofPacketsRx[i] = 0;
+		iError[i] = KErrGeneral;
+		iDrainQueue[i] = KUsbcInvalidBufferIndex;
+#if defined(USBC_LDD_BUFFER_TRACE)
+		iFillingOrderArray[i] = 0;
+		iNumberofBytesRxRemain[i] = 0;
+		iNumberofPacketsRxRemain[i] = 0;
+#endif
+		}
+	// Drain queue is 1 oversized
+	iDrainQueue[KUsbcDmaBufNumMax] = KUsbcInvalidBufferIndex;
+
+#if defined(USBC_LDD_BUFFER_TRACE)
+	iFillingOrder = 0;
+	iDrainingOrder = 0;
+#endif
+	}
+
+
+void TDmaBuf::RxSetActive()
+	{
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxSetActive %x", this));
+	iRxActive = ETrue;
+	}
+
+
+void TDmaBuf::RxSetInActive()
+	{
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxSetInActive %x", this));
+	iRxActive = EFalse;
+	}
+
+
+TBool TDmaBuf::RxIsActive()
+	{
+	return iRxActive;
+	}
+
+
+void TDmaBuf::TxSetActive()
+	{
+	iTxActive = ETrue;
+	}
+
+
+void TDmaBuf::TxSetInActive()
+	{
+	iTxActive = EFalse;
+	}
+
+
+TBool TDmaBuf::TxIsActive()
+	{
+	return iTxActive;
+	}
+
+
+/**************************** Rx DMA Buffer Access *************************/
+
+void TDmaBuf::ModifyTotalRxBytesAvail(TInt aVal)
+	{
+	iTotalRxBytesAvail += aVal;
+	}
+
+
+void TDmaBuf::ModifyTotalRxPacketsAvail(TInt aVal)
+	{
+	iTotalRxPacketsAvail += aVal;
+	}
+
+
+TBool TDmaBuf::AdvancePacket()
+	{
+	ModifyTotalRxPacketsAvail(-1);
+	TBool r = ETrue;
+	__ASSERT_DEBUG((iCurrentDrainingBufferIndex >= 0),
+					   Kern::Fault(KUsbPanicLdd, __LINE__));
+	if (++iCurrentPacket >= iNumberofPacketsRx[iCurrentDrainingBufferIndex])
+		{
+		r = NextDrainableBuffer();
+		}
+	iExtractOffset = 0;
+	__ASSERT_DEBUG((iCurrentDrainingBufferIndex == KUsbcInvalidBufferIndex) ||
+				   (iCurrentPacket < KUsbcDmaBufMaxPkts),
+				   Kern::Fault(KUsbPanicLdd, __LINE__));
+	return r;
+	}
+
+
+TInt TDmaBuf::PeekNextPacketSize()
+	{
+	TUint pkt = iCurrentPacket;
+	TInt index = iCurrentDrainingBufferIndex;
+	TInt size = -1;
+	if (pkt >= iNumberofPacketsRx[index])
+		{
+		index = PeekNextDrainableBuffer();
+		pkt = 0;
+		}
+
+	if ((index != KUsbcInvalidBufferIndex) && iNumberofPacketsRx[index])
+		{
+		const TUsbcPacketArray* sizeArray = iPacketSize[index];
+		size = (TInt)sizeArray[pkt];
+		}
+
+	__ASSERT_DEBUG((iCurrentDrainingBufferIndex == KUsbcInvalidBufferIndex) ||
+				   (iCurrentPacket < KUsbcDmaBufMaxPkts),
+				   Kern::Fault(KUsbPanicLdd, __LINE__));
+	return size;
+	}
+
+
+inline TInt TDmaBuf::GetCurrentError()
+	{
+	// USB bus errors are v.rare. To avoid having an error code attached to every packet since
+	// almost every errorcode will be KErrNone, we have a single error code per buffer
+	// If the error code is != KErrNone then it refers to the LAST packet in the buffer
+	TInt errorCode = KErrNone;
+	//Check the index, it's not equal to negative (-1) value defined in 
+	//KUsbcInvalidBufferIndex.
+	__ASSERT_DEBUG((iCurrentDrainingBufferIndex >= 0),
+					   Kern::Fault(KUsbPanicLdd, __LINE__));
+	
+	if (iError[iCurrentDrainingBufferIndex] != KErrNone)
+		{
+		// See if we are at the last packet
+		if ((iCurrentPacket + 1) == iNumberofPacketsRx[iCurrentDrainingBufferIndex])
+			{
+			errorCode = iError[iCurrentDrainingBufferIndex];
+			}
+		}
+	return errorCode;
+	}
+
+
+// used to decide whether a client read can complete straight away
+TBool TDmaBuf::IsReaderEmpty()
+	{
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::IsReaderEmpty iTotalRxPacketsAvail=%d",
+									iTotalRxPacketsAvail));
+	return (iTotalRxPacketsAvail == 0);
+	}
+
+
+void TDmaBuf::ReadXferComplete(TInt aNoBytesRecv, TInt aNoPacketsRecv, TInt aErrorCode)
+	{
+	// Adjust pending packet
+	if ((aNoBytesRecv == 0) && (aErrorCode != KErrNone))
+		{
+		// Make the buffer available for reuse
+		iDrainable[iCurrentFillingBufferIndex] = EFalse;
+		return;
+		}
+
+	ModifyTotalRxBytesAvail(aNoBytesRecv);
+	ModifyTotalRxPacketsAvail(aNoPacketsRecv);
+	iNumberofBytesRx[iCurrentFillingBufferIndex] = aNoBytesRecv;
+	iNumberofPacketsRx[iCurrentFillingBufferIndex] = aNoPacketsRecv;
+
+#if defined(USBC_LDD_BUFFER_TRACE)
+	iNumberofBytesRxRemain[iCurrentFillingBufferIndex] = aNoBytesRecv;
+	iNumberofPacketsRxRemain[iCurrentFillingBufferIndex] = aNoPacketsRecv;
+#endif
+
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::ReadXferComplete 2 # of bytes=%d # of packets=%d",
+									iTotalRxBytesAvail, iTotalRxPacketsAvail));
+	iDrainable[iCurrentFillingBufferIndex] = ETrue;
+	iError[iCurrentFillingBufferIndex] = aErrorCode;
+	AddToDrainQueue(iCurrentFillingBufferIndex);
+	if (iCurrentDrainingBufferIndex == KUsbcInvalidBufferIndex)
+		{
+		NextDrainableBuffer();
+		}
+	}
+
+
+TInt TDmaBuf::RxGetNextXfer(TUint8*& aBufferAddr, TUsbcPacketArray*& aIndexArray,
+							TUsbcPacketArray*& aSizeArray, TInt& aLength, TPhysAddr& aBufferPhys)
+	{
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxGetNextXfer 1"));
+	if (RxIsActive())
+		{
+		__KTRACE_OPT(KUSB, Kern::Printf(" ---> RxIsActive, returning"));
+		return KErrInUse;
+		}
+
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxGetNextXfer Current buffer=%d",
+									iCurrentFillingBufferIndex));
+	if (iDrainable[iCurrentFillingBufferIndex])
+		{
+		// If the controller refused the last read request, then the current buffer will still be marked
+		// as !Drainable, because the controller never completed the read to the ldd. and therefore the buffer
+		// can be reused.
+		if (!NextFillableBuffer())
+			{
+			return KErrNoMemory;
+			}
+		}
+
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxGetNextXfer New buffer=%d",
+									iCurrentFillingBufferIndex));
+	aBufferAddr = iBuffers[iCurrentFillingBufferIndex];
+	aBufferPhys = iBufferPhys[iCurrentFillingBufferIndex];
+	aIndexArray = iPacketIndex[iCurrentFillingBufferIndex];
+	aSizeArray = iPacketSize[iCurrentFillingBufferIndex];
+	aLength = iBufSz;
+
+#if defined(USBC_LDD_BUFFER_TRACE)
+	iFillingOrderArray[iCurrentFillingBufferIndex] = ++iFillingOrder;
+#endif
+
+	return KErrNone;
+	}
+
+
+TInt TDmaBuf::RxCopyPacketToClient(DThread* aThread, TClientBuffer *aTcb, TInt aLength)
+	{
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxCopyPacketToClient 1"));
+
+#if defined(USBC_LDD_BUFFER_TRACE)
+	const TInt numPkts = NoRxPackets();
+	const TInt numPktsAlt = NoRxPacketsAlt();
+	const TInt numBytes = RxBytesAvailable();
+	const TInt numBytesAlt = NoRxBytesAlt();
+
+	if (numPkts != numPktsAlt)
+		{
+		Kern::Printf(
+			"TDmaBuf::RxCopyPacketToClient: Error: #pkts mismatch global=%d actual=%d",
+			numPkts, numPktsAlt);
+		}
+	if (numBytes != numBytesAlt)
+		{
+		Kern::Printf(
+			"TDmaBuf::RxCopyPacketToClient: Error: #bytes mismatch global=%d actual=%d",
+			numBytes, numBytesAlt);
+		}
+	if ((numPkts == 0) && (numBytes !=0))
+		{
+		Kern::Printf(
+			"TDmaBuf::RxCopyPacketToClient: Error: global bytes & pkts mismatch pkts=%d bytes=%d",
+			numPkts, numBytes);
+		}
+	if ((numPktsAlt == 0) && (numBytesAlt !=0))
+		{
+		Kern::Printf(
+			"TDmaBuf::RxCopyPacketToClient: Error: actual bytes & pkts mismatch pkts=%d bytes=%d",
+			numPktsAlt, numBytesAlt);
+		}
+#endif
+
+	if (!NoRxPackets())
+		return KErrNotFound;
+
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxCopyPacketToClient 2"));
+	// the next condition should be true because we have some packets available
+	// coverity[var_tested_neg]
+	if (iCurrentDrainingBufferIndex == KUsbcInvalidBufferIndex)
+		{
+		// Marked as Coverity "Intentional" as the member variable
+		// iCurrentDrainingBufferIndex is attentionaly negative, from previous 
+		// initialization to KUsbcInvalidBufferIndex (which equals -1).
+		if (!NextDrainableBuffer())
+			return KErrNotFound;
+		}
+
+	__ASSERT_DEBUG((iCurrentDrainingBufferIndex >= 0 ),
+						   Kern::Fault(KUsbPanicLdd, __LINE__));
+	
+	if (!iDrainable[iCurrentDrainingBufferIndex])
+		return KErrNotFound;
+
+	// Calculate copy-from address & adjust for the fact that
+	// some data may have already been read from the packet
+	TUint8* logicalSrc = iCurrentDrainingBuffer + iCurrentPacketIndexArray[iCurrentPacket] + iExtractOffset;
+	TInt packetSz = iCurrentPacketSizeArray[iCurrentPacket];
+	TInt thisPacketSz = packetSz - iExtractOffset;
+	TInt errorCode;
+	// try and sort out what a "packet" might mean.
+	// in a multi-packet dma environment, we might see super-packets
+	// i.e. we might just see one packet, maybe 4K or so long, made of lots of small packets
+	// Since we don't know where the packet boundaries will be, we have to assume that
+	// any 'packet' larger than the max packet size of the ep is, in fact, a conglomeration
+	// of smaller packets. However, for the purposes of the packet count, this is still regarded
+	// as a single packet and the packet count only decremented when it is consumed.
+	// As before, if the user fails to read an entire packet out then the next packet is moved onto anyway
+	// To be safe the user must always supply a buffer of at least max packet size bytes.
+	if (thisPacketSz > iMaxPacketSize)
+		{
+		// Multiple packets left in buffer
+		// calculate number of bytes to end of packet
+		if (iEndpointType == KUsbEpTypeBulk)
+			{
+			thisPacketSz = iMaxPacketSize - (iExtractOffset & (iMaxPacketSize - 1));
+			}
+		else
+			{
+			thisPacketSz = iMaxPacketSize - (iExtractOffset % iMaxPacketSize);
+			}
+		errorCode = KErrNone;
+		}
+	else
+		{
+		errorCode = GetCurrentError();						// single packet left
+		}
+
+	iExtractOffset += thisPacketSz;			// iExtractOffset is now at the end of the real or notional packet
+
+	ModifyTotalRxBytesAvail(-thisPacketSz);
+#if defined(USBC_LDD_BUFFER_TRACE)
+	iNumberofBytesRxRemain[iCurrentDrainingBufferIndex] -= thisPacketSz;
+#endif
+	// this can only be untrue if the "packet" is a conglomeration of smaller packets:
+	if (iExtractOffset == packetSz)
+		{
+		// packet consumed, advance to next packet in buffer
+#if defined(USBC_LDD_BUFFER_TRACE)
+		iNumberofPacketsRxRemain[iCurrentDrainingBufferIndex] -= 1;
+#endif
+		AdvancePacket();
+		}
+
+	TPtrC8 des(logicalSrc, thisPacketSz);
+	TInt r=Kern::ThreadBufWrite(aThread, aTcb, des, 0, 0, aThread);
+	if (r == KErrNone)
+		{
+		r = errorCode;
+		}
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxCopyPacketToClient 3"));
+
+	FreeDrainedBuffers();
+
+	// Use this error code to complete client read request:
+	return r;
+	}
+
+
+TInt TDmaBuf::RxCopyDataToClient(DThread* aThread, TClientBuffer *aTcb, TInt aLength, TUint32& aDestOffset,
+								 TBool aRUS, TBool& aCompleteNow)
+	{
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxCopyDataToClient 1"));
+	aCompleteNow = ETrue;
+
+#if defined(USBC_LDD_BUFFER_TRACE)
+	const TInt numPkts = NoRxPackets();
+	const TInt numPktsAlt = NoRxPacketsAlt();
+	const TInt numBytes = RxBytesAvailable();
+	const TInt numBytesAlt = NoRxBytesAlt();
+
+	if (numPkts != numPktsAlt)
+		{
+		Kern::Printf(
+			"TDmaBuf::RxCopyDataToClient: Error: #pkts mismatch global=%d actual=%d",
+			numPkts, numPktsAlt);
+		}
+	if (numBytes != numBytesAlt)
+		{
+		Kern::Printf(
+			"TDmaBuf::RxCopyDataToClient: Error: #bytes mismatch global=%d actual=%d",
+			numBytes, numBytesAlt);
+		}
+	if ((numPkts == 0) && (numBytes != 0))
+		{
+		Kern::Printf(
+			"TDmaBuf::RxCopyDataToClient: Error: global bytes & pkts mismatch pkts=%d bytes=%d",
+			numPkts, numBytes);
+		}
+	if ((numPktsAlt == 0) && (numBytesAlt != 0))
+		{
+		Kern::Printf(
+			"TDmaBuf::RxCopyDataToClient: Error: actual bytes & pkts mismatch pkts=%d bytes=%d",
+			numPktsAlt, numBytesAlt);
+		}
+#endif
+
+	if (!NoRxPackets())
+		{
+		return KErrNotFound;
+		}
+
+	// coverity[var_tested_neg]
+	if (iCurrentDrainingBufferIndex == KUsbcInvalidBufferIndex)
+		{
+		// Marked as Coverity "Inentional" as the member variable
+		// iCurrentDrainingBufferIndex is attentionaly negative, from previous 
+		// initialization to KUsbcInvalidBufferIndex (which equals -1).
+
+		if (!NextDrainableBuffer())
+			{
+#if defined(USBC_LDD_BUFFER_TRACE)
+			Kern::Printf("TDmaBuf::RxCopyDataToClient: Error:  No buffer draining=%d, packets=%d",
+						 iCurrentDrainingBufferIndex, iTotalRxPacketsAvail);
+#endif
+			return KErrNotFound;
+			}
+		}
+#if defined(USBC_LDD_BUFFER_TRACE)
+
+	__ASSERT_DEBUG((iCurrentDrainingBufferIndex >= 0 ),
+							   Kern::Fault(KUsbPanicLdd, __LINE__));
+		
+	if (iDrainingOrder != iFillingOrderArray[iCurrentDrainingBufferIndex])
+		{
+		Kern::Printf("!!! Out of Order Draining TDmaBuf::RxCopyDataToClient 10 draining=%d",
+					 iCurrentDrainingBufferIndex);
+		}
+#endif
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxCopyDataToClient 2"));
+
+	TUint8* blockStartAddr = iCurrentDrainingBuffer + iCurrentPacketIndexArray[iCurrentPacket] + iExtractOffset;
+	TUint8* lastEndAddr = blockStartAddr;					// going to track the contiguity of the memory
+	TUint8* thisStartAddr = blockStartAddr;
+	TInt toDo = Min(aLength - (TInt)aDestOffset, iTotalRxBytesAvail);
+#if defined(USBC_LDD_BUFFER_TRACE)
+	TInt bufnum = iCurrentDrainingBufferIndex;
+#endif
+	TInt errorCode = KErrNone;
+	TBool isShortPacket = EFalse;
+	const TInt maxPacketSizeMask = iMaxPacketSize - 1;
+	do
+		{
+#if defined(USBC_LDD_BUFFER_TRACE)
+		if (bufnum != iCurrentDrainingBufferIndex)
+			{
+			bufnum = iCurrentDrainingBufferIndex;
+			if (iDrainingOrder != iFillingOrderArray[iCurrentDrainingBufferIndex])
+				{
+				Kern::Printf("!!! Out of Order Draining TDmaBuf::RxCopyDataToClient 20 draining=%d",
+							 iCurrentDrainingBufferIndex);
+				}
+			}
+#endif
+		if (errorCode == KErrNone)
+			{
+			errorCode = GetCurrentError();
+			}
+		thisStartAddr = iCurrentDrainingBuffer + iCurrentPacketIndexArray[iCurrentPacket] + iExtractOffset;
+		const TInt thisPacketSize = iCurrentPacketSizeArray[iCurrentPacket];
+		const TInt size = thisPacketSize - iExtractOffset;
+		if (aRUS)
+			{
+			if (iEndpointType == KUsbEpTypeBulk)
+				{
+				isShortPacket = (size < iMaxPacketSize) || (size & maxPacketSizeMask);
+				}
+			else
+				{
+				// this 'if' block is arranged to avoid a division on packet sizes <= iMaxPacketSize
+				isShortPacket = (size < iMaxPacketSize) ||
+					((size > iMaxPacketSize) && (size % iMaxPacketSize));
+				}
+			}
+		TInt copySize = Min(size, toDo);
+		iExtractOffset += copySize;
+		toDo -= copySize;
+		if (thisStartAddr != lastEndAddr)
+			{
+			TInt bytesToCopy = lastEndAddr - blockStartAddr;
+			TInt r=CopyToUser(aThread, blockStartAddr, bytesToCopy, aTcb, aDestOffset);
+			if(r != KErrNone)
+				Kern::ThreadKill(aThread, EExitPanic, r, KUsbLDDKillCat);
+			blockStartAddr = thisStartAddr;
+			}
+
+		ModifyTotalRxBytesAvail(-copySize);
+#if defined(USBC_LDD_BUFFER_TRACE)
+		iNumberofBytesRxRemain[iCurrentDrainingBufferIndex] -= copySize;
+#endif
+		lastEndAddr = thisStartAddr + copySize;
+		if (iExtractOffset == thisPacketSize)
+			{
+			// More data to copy, so need to access new packet
+#if defined(USBC_LDD_BUFFER_TRACE)
+			iNumberofPacketsRxRemain[iCurrentDrainingBufferIndex] -= 1;
+#endif
+			if (!AdvancePacket())
+				{
+				break;										// no more packets left
+				}
+			}
+		} while (toDo > 0 && !isShortPacket);
+
+	if (thisStartAddr != lastEndAddr)
+		{
+		TInt bytesToCopy = lastEndAddr - blockStartAddr;
+		TInt r=CopyToUser(aThread, blockStartAddr, bytesToCopy, aTcb, aDestOffset);
+		if(r != KErrNone)
+			Kern::ThreadKill(aThread, EExitPanic, r, KUsbLDDKillCat);
+		}
+
+	// If we have transferred the requested amount of data it is still possible that
+	// the next packet is a zlp which needs to be bumped over
+
+	if (aRUS && (toDo == 0) && (iExtractOffset == 0) && (!isShortPacket) && (!IsReaderEmpty()) &&
+		(PeekNextPacketSize() == 0))
+		{
+		// swallow a zlp
+		isShortPacket = ETrue;
+#if defined(USBC_LDD_BUFFER_TRACE)
+		iNumberofPacketsRxRemain[iCurrentDrainingBufferIndex] -= 1;
+#endif
+		AdvancePacket();
+		}
+	aCompleteNow = isShortPacket || (((TInt)aDestOffset) == aLength) || (errorCode != KErrNone);
+
+	FreeDrainedBuffers();
+
+	// Use this error code to complete client read request
+	return errorCode;
+	}
+
+
+inline TInt TDmaBuf::CopyToUser(DThread* aThread, const TUint8* aSourceAddr,
+								TInt aLength, TClientBuffer *aTcb, TUint32& aDestOffset)
+	{
+	TPtrC8 des(aSourceAddr, aLength);
+	TInt errorCode = Kern::ThreadBufWrite(aThread, aTcb, des, aDestOffset, KChunkShiftBy0, aThread);
+	if (errorCode == KErrNone)
+		{
+		aDestOffset += aLength;
+		}
+	return errorCode;
+	}
+
+
+inline TInt TDmaBuf::NoRxPackets() const
+	{
+	return iTotalRxPacketsAvail;
+	}
+
+
+inline void TDmaBuf::IncrementBufferIndex(TInt& aIndex)
+	{
+	if (++aIndex == iNumberofBuffers)
+		aIndex = 0;
+	}
+
+
+TBool TDmaBuf::NextDrainableBuffer()
+	{
+	TBool r = EFalse;
+	if (iCurrentDrainingBufferIndex != KUsbcInvalidBufferIndex)
+		{
+		iCanBeFreed[iCurrentDrainingBufferIndex] = ETrue;
+		iNumberofPacketsRx[iCurrentDrainingBufferIndex] = 0; // Current buffer is empty
+		iNumberofBytesRx[iCurrentDrainingBufferIndex] = 0;	// Current buffer is empty
+
+#if defined(USBC_LDD_BUFFER_TRACE)
+		TUint& bytesRemain = iNumberofBytesRxRemain[iCurrentDrainingBufferIndex];
+		TUint& pktsRemain = iNumberofPacketsRxRemain[iCurrentDrainingBufferIndex];
+		if ((bytesRemain != 0) || (pktsRemain != 0))
+			{
+			Kern::Printf(
+				"TDmaBuf::NextDrainableBuffer: Error: data discarded buffer=%d pkts=%d bytes=%d",
+				iCurrentDrainingBufferIndex, pktsRemain, bytesRemain);
+			bytesRemain = 0;
+			pktsRemain = 0;
+			}
+#endif
+
+		iCurrentDrainingBufferIndex = KUsbcInvalidBufferIndex;
+		iCurrentPacket = KUsbcInvalidPacketIndex;
+		}
+
+	if (iDrainQueueIndex != KUsbcInvalidDrainQueueIndex)
+		{
+		r = ETrue;
+		const TInt index = iDrainQueue[0];
+		iDrainQueueIndex--;
+		for (TInt i = 0; i < iNumberofBuffers; i++)
+			{
+			iDrainQueue[i] = iDrainQueue[i+1];
+			}
+
+#if defined(USBC_LDD_BUFFER_TRACE)
+		if (index != KUsbcInvalidBufferIndex)
+			iDrainingOrder++;
+#endif
+
+		iCurrentDrainingBufferIndex = index;
+		iCurrentDrainingBuffer = iBuffers[index];
+		iCurrentPacketIndexArray = iPacketIndex[index];
+		iCurrentPacketSizeArray = iPacketSize[index];
+		iCurrentPacket = 0;
+		}
+	return r;
+	}
+
+
+TInt TDmaBuf::PeekNextDrainableBuffer()
+	{
+	TInt r = KUsbcInvalidBufferIndex;
+	if (iDrainQueueIndex != KUsbcInvalidDrainQueueIndex)
+		{
+		r = iDrainQueue[0];
+		}
+	return r;
+	}
+
+
+TBool TDmaBuf::NextFillableBuffer()
+	{
+	TBool r = EFalse;
+	TInt index = iCurrentFillingBufferIndex;
+	IncrementBufferIndex(index);
+	// the sequence will restart at 0 if a buffer can't be found this time
+	iCurrentFillingBufferIndex = 0;
+	for (TInt i = 0; i < iNumberofBuffers; i++)
+		{
+		if (!iDrainable[index])
+			{
+			iCurrentFillingBufferIndex = index;
+			r = ETrue;
+			break;
+			}
+		IncrementBufferIndex(index);
+		}
+	return r;
+	}
+
+
+void TDmaBuf::FreeDrainedBuffers()
+	{
+	for (TInt i = 0; i < iNumberofBuffers; i++)
+		{
+		if (iDrainable[i] && iCanBeFreed[i])
+			{
+			iDrainable[i] = iCanBeFreed[i] = EFalse;
+			}
+		}
+	}
+
+
+TBool TDmaBuf::ShortPacketExists()
+	{
+	// Actually, a short packet or residue data
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::ShortPacketExists 1"));
+	TInt index = iCurrentDrainingBufferIndex;
+	TUsbcPacketArray* pktSizeArray = iCurrentPacketSizeArray;
+
+	if (iMaxPacketSize > 0)
+		{
+		// No buffers available for draining
+		if ((iCurrentDrainingBufferIndex == KUsbcInvalidBufferIndex) ||
+			(iCurrentPacket == KUsbcInvalidPacketIndex))
+			return EFalse;
+
+		// Zlp waiting at tail
+		if ((iTotalRxBytesAvail == 0) && (NoRxPackets() == 1))
+			return ETrue;
+
+		if (iEndpointType == KUsbEpTypeBulk)
+			{
+			const TInt mask = iMaxPacketSize - 1;
+			if (iTotalRxBytesAvail & mask)
+				return ETrue;
+
+			// residue==0; this can be because
+			// zlps exist, or short packets combine to n * max_packet_size
+			// This means spadework
+			const TInt s = iCurrentPacketSizeArray[iCurrentPacket] - iExtractOffset;
+			if ((s == 0) || (s & mask))
+				{
+				return ETrue;
+				}
+
+			for (TInt i = 0; i < iNumberofBuffers; i++)
+				{
+				if (index == KUsbcInvalidBufferIndex)
+					break;
+				if (iDrainable[index])
+					{
+					const TInt packetCount = iNumberofPacketsRx[index];
+					const TInt lastPacketSize=pktSizeArray[packetCount - 1];
+					if ((lastPacketSize < iMaxPacketSize) || (lastPacketSize & mask))
+						{
+						return ETrue;
+						}
+					}
+				index = iDrainQueue[i];
+				pktSizeArray = iPacketSize[index];
+				}
+			}
+		else
+			{
+			if (iTotalRxBytesAvail % iMaxPacketSize)
+				return ETrue;
+
+			// residue==0; this can be because
+			// zlps exist, or short packets combine to n * max_packet_size
+			// This means spadework
+			const TInt s = iCurrentPacketSizeArray[iCurrentPacket] - iExtractOffset;
+			if ((s == 0) || (s % iMaxPacketSize))
+				{
+				return ETrue;
+				}
+
+			for (TInt i = 0; i < iNumberofBuffers; i++)
+				{
+				if (index == KUsbcInvalidBufferIndex)
+					break;
+				if (iDrainable[index])
+					{
+					const TInt packetCount = iNumberofPacketsRx[index];
+					const TInt lastPacketSize = pktSizeArray[packetCount - 1];
+					if ((lastPacketSize < iMaxPacketSize) || (lastPacketSize % iMaxPacketSize))
+						{
+						return ETrue;
+						}
+					}
+				index = iDrainQueue[i];
+				pktSizeArray = iPacketSize[index];
+				}
+			}
+		}
+
+	return EFalse;
+	}
+
+
+void TDmaBuf::AddToDrainQueue(TInt aBufferIndex)
+	{
+	if (iDrainQueue[iDrainQueueIndex + 1] != KUsbcInvalidBufferIndex)
+		{
+#if defined(USBC_LDD_BUFFER_TRACE)
+		Kern::Printf("TDmaBuf::AddToDrainQueue: Error: invalid iDrainQueue[x]");
+#endif
+		}
+	iDrainQueue[++iDrainQueueIndex] = aBufferIndex;
+	}
+
+
+#if defined(USBC_LDD_BUFFER_TRACE)
+TInt TDmaBuf::NoRxPacketsAlt() const
+	{
+	TInt pktCount = 0;
+	for(TInt i = 0; i < iNumberofBuffers; i++)
+		{
+		if (iDrainable[i])
+			{
+			pktCount += iNumberofPacketsRxRemain[i];
+			}
+		}
+	return pktCount;
+	}
+
+
+TInt TDmaBuf::NoRxBytesAlt() const
+	{
+	TInt byteCount = 0;
+	for(TInt i = 0; i < iNumberofBuffers; i++)
+		{
+		if (iDrainable[i])
+			{
+			byteCount += iNumberofBytesRxRemain[i];
+			}
+		}
+	return byteCount;
+	}
+#endif
+
+
+// We only store 1 transaction, no other buffering is done
+TInt TDmaBuf::TxStoreData(DThread* aThread, TClientBuffer *aTcb, TInt aTxLength, TUint32 aBufferOffset)
+	{
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::TxStoreData 1"));
+	if (!IsReaderEmpty())
+		return KErrInUse;
+
+	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::TxStoreData 2"));
+	TUint8* logicalDest = iBufBasePtr;
+	TInt xferSz = Min(aTxLength, BufferTotalSize());
+	TPtr8 des(logicalDest, xferSz, xferSz);
+	TInt r = Kern::ThreadBufRead(aThread, aTcb, des, aBufferOffset,KChunkShiftBy0);
+	if(r != KErrNone)
+		Kern::ThreadKill(aThread, EExitPanic, r, KUsbLDDKillCat);
+	return r;
+	}
+
+
+TInt TDmaBuf::TxGetNextXfer(TUint8*& aBufferAddr, TInt& aTxLength, TPhysAddr& aBufferPhys)
+	{
+	if (iTxActive)
+		return KErrInUse;
+
+	aBufferAddr = iBuffers[0];								// only 1 tx buffer
+	aBufferPhys = iBufferPhys[0];
+	aTxLength = BufferTotalSize();
+
+	return KErrNone;
+	}
+