--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/kernel/eka/drivers/dma/dma2_pil.cpp	Mon Jan 18 21:31:10 2010 +0200
@@ -0,0 +1,2311 @@
+// Copyright (c) 2002-2009 Nokia Corporation and/or its subsidiary(-ies).
+// All rights reserved.
+// This component and the accompanying materials are made available
+// under the terms of "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/dma2_pil.cpp
+// DMA Platform Independent Layer (PIL)
+//
+//
+
+#include <drivers/dma.h>
+#include <drivers/dma_hai.h>
+
+#include <kernel/kern_priv.h>
+
+
+// Symbian Min() & Max() are broken, so we have to define them ourselves
+inline TUint Min(TUint aLeft, TUint aRight)
+	{return(aLeft < aRight ? aLeft : aRight);}
+inline TUint Max(TUint aLeft, TUint aRight)
+	{return(aLeft > aRight ? aLeft : aRight);}
+
+
+// Uncomment the following #define only when freezing the DMA2 export library.
+//#define __FREEZE_DMA2_LIB
+#ifdef __FREEZE_DMA2_LIB
+TInt DmaChannelMgr::StaticExtension(TInt, TAny*) {return 0;}
+TDmaChannel* DmaChannelMgr::Open(TUint32, TBool, TUint) {return 0;}
+void DmaChannelMgr::Close(TDmaChannel*) {}
+EXPORT_C const TDmaTestInfo& DmaTestInfo() {static TDmaTestInfo a; return a;}
+EXPORT_C const TDmaV2TestInfo& DmaTestInfoV2() {static TDmaV2TestInfo a; return a;}
+#endif	// #ifdef __FREEZE_DMA2_LIB
+
+
+static const char KDmaPanicCat[] = "DMA " __FILE__;
+
+//////////////////////////////////////////////////////////////////////
+// DmaChannelMgr
+//
+// Wait, Signal, and Initialise are defined here in the PIL.
+// Open, Close and Extension must be defined in the PSL.
+
+NFastMutex DmaChannelMgr::Lock;
+
+
+void DmaChannelMgr::Wait()
+	{
+	NKern::FMWait(&Lock);
+	}
+
+
+void DmaChannelMgr::Signal()
+	{
+	NKern::FMSignal(&Lock);
+	}
+
+
+TInt DmaChannelMgr::Initialise()
+	{
+	return KErrNone;
+	}
+
+
+class TDmaCancelInfo : public SDblQueLink
+	{
+public:
+	TDmaCancelInfo();
+	void Signal();
+public:
+	NFastSemaphore iSem;
+	};
+
+
+TDmaCancelInfo::TDmaCancelInfo()
+	: iSem(0)
+	{
+	iNext = this;
+	iPrev = this;
+	}
+
+
+void TDmaCancelInfo::Signal()
+	{
+	TDmaCancelInfo* p = this;
+	FOREVER
+		{
+		TDmaCancelInfo* next = (TDmaCancelInfo*)p->iNext;
+		if (p!=next)
+			p->Deque();
+		NKern::FSSignal(&p->iSem);	// Don't dereference p after this
+		if (p==next)
+			break;
+		p = next;
+		}
+	}
+
+
+//////////////////////////////////////////////////////////////////////////////
+
+#ifdef __DMASIM__
+#ifdef __WINS__
+typedef TLinAddr TPhysAddr;
+#endif
+static inline TPhysAddr LinToPhys(TLinAddr aLin) {return aLin;}
+#else
+static inline TPhysAddr LinToPhys(TLinAddr aLin) {return Epoc::LinearToPhysical(aLin);}
+#endif
+
+//
+// Return minimum of aMaxSize and size of largest physically contiguous block
+// starting at aLinAddr.
+//
+static TInt MaxPhysSize(TLinAddr aLinAddr, const TInt aMaxSize)
+	{
+	const TPhysAddr physBase = LinToPhys(aLinAddr);
+	TLinAddr lin = aLinAddr;
+	TInt size = 0;
+	for (;;)
+		{
+		// Round up the linear address to the next MMU page boundary
+		const TLinAddr linBoundary = Kern::RoundToPageSize(lin + 1);
+		size += linBoundary - lin;
+		if (size >= aMaxSize)
+			return aMaxSize;
+		if ((physBase + size) != LinToPhys(linBoundary))
+			return size;
+		lin = linBoundary;
+		}
+	}
+
+
+//////////////////////////////////////////////////////////////////////////////
+// TDmac
+
+TDmac::TDmac(const SCreateInfo& aInfo)
+	: iMaxDesCount(aInfo.iDesCount),
+	  iAvailDesCount(aInfo.iDesCount),
+	  iHdrPool(NULL),
+#ifndef __WINS__
+	  iHwDesChunk(NULL),
+#endif
+	  iDesPool(NULL),
+	  iDesSize(aInfo.iDesSize),
+	  iCapsHwDes(aInfo.iCapsHwDes),
+	  iFreeHdr(NULL)
+	{
+	__DMA_ASSERTD(iMaxDesCount > 0);
+	__DMA_ASSERTD(iDesSize > 0);
+	}
+
+
+//
+// Second-phase c'tor
+//
+TInt TDmac::Create(const SCreateInfo& aInfo)
+	{
+	iHdrPool = new SDmaDesHdr[iMaxDesCount];
+	if (iHdrPool == NULL)
+		{
+		return KErrNoMemory;
+		}
+
+	TInt r = AllocDesPool(aInfo.iDesChunkAttribs);
+	if (r != KErrNone)
+		{
+		return KErrNoMemory;
+		}
+
+	// Link all descriptor headers together on the free list
+	iFreeHdr = iHdrPool;
+	for (TInt i = 0; i < iMaxDesCount - 1; i++)
+		iHdrPool[i].iNext = iHdrPool + i + 1;
+	iHdrPool[iMaxDesCount-1].iNext = NULL;
+
+	__DMA_INVARIANT();
+	return KErrNone;
+	}
+
+
+TDmac::~TDmac()
+	{
+	__DMA_INVARIANT();
+
+	FreeDesPool();
+	delete[] iHdrPool;
+	}
+
+
+void TDmac::Transfer(const TDmaChannel& /*aChannel*/, const SDmaDesHdr& /*aHdr*/)
+	{
+	// TDmac needs to override this function if it has reported the channel
+	// type for which the PIL calls it.
+	__DMA_CANT_HAPPEN();
+	}
+
+
+void TDmac::Transfer(const TDmaChannel& /*aChannel*/, const SDmaDesHdr& /*aSrcHdr*/,
+					 const SDmaDesHdr& /*aDstHdr*/)
+	{
+	// TDmac needs to override this function if it has reported the channel
+	// type for which the PIL calls it.
+	__DMA_CANT_HAPPEN();
+	}
+
+
+TInt TDmac::PauseTransfer(const TDmaChannel& /*aChannel*/)
+	{
+	// TDmac needs to override this function if it has reported support for
+	// channel pausing/resuming.
+	return KErrNotSupported;
+	}
+
+
+TInt TDmac::ResumeTransfer(const TDmaChannel& /*aChannel*/)
+	{
+	// TDmac needs to override this function if it has reported support for
+	// channel pausing/resuming.
+	return KErrNotSupported;
+	}
+
+
+TInt TDmac::AllocDesPool(TUint aAttribs)
+	{
+	// Calling thread must be in CS
+	__ASSERT_CRITICAL;
+	TInt r;
+	if (iCapsHwDes)
+		{
+		const TInt size = iMaxDesCount * iDesSize;
+#ifdef __WINS__
+		(void)aAttribs;
+		iDesPool = new TUint8[size];
+		r = iDesPool ? KErrNone : KErrNoMemory;
+#else
+		// Chunk not mapped as supervisor r/w user none? incorrect mask passed by PSL
+		__DMA_ASSERTD((aAttribs & EMapAttrAccessMask) == EMapAttrSupRw);
+		TPhysAddr phys;
+		r = Epoc::AllocPhysicalRam(size, phys);
+		if (r == KErrNone)
+			{
+			r = DPlatChunkHw::New(iHwDesChunk, phys, size, aAttribs);
+			if (r == KErrNone)
+				{
+				iDesPool = (TAny*)iHwDesChunk->LinearAddress();
+				__KTRACE_OPT(KDMA, Kern::Printf("descriptor hw chunk created lin=0x%08X phys=0x%08X, size=0x%X",
+												iHwDesChunk->iLinAddr, iHwDesChunk->iPhysAddr, size));
+				}
+			else
+				Epoc::FreePhysicalRam(phys, size);
+			}
+#endif
+		}
+	else
+		{
+		iDesPool = new TDmaTransferArgs[iMaxDesCount];
+		r = iDesPool ? KErrNone : KErrNoMemory;
+		}
+	return r;
+	}
+
+
+void TDmac::FreeDesPool()
+	{
+	// Calling thread must be in CS
+	__ASSERT_CRITICAL;
+	if (iCapsHwDes)
+		{
+#ifdef __WINS__
+		delete[] iDesPool;
+#else
+		if (iHwDesChunk)
+			{
+			const TPhysAddr phys = iHwDesChunk->PhysicalAddress();
+			const TInt size = iHwDesChunk->iSize;
+			iHwDesChunk->Close(NULL);
+			Epoc::FreePhysicalRam(phys, size);
+			}
+#endif
+		}
+	else
+		{
+		Kern::Free(iDesPool);
+		}
+	}
+
+
+//
+// Prealloc the given number of descriptors.
+//
+TInt TDmac::ReserveSetOfDes(TInt aCount)
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("TDmac::ReserveSetOfDes count=%d", aCount));
+	__DMA_ASSERTD(aCount > 0);
+	TInt r = KErrTooBig;
+	Wait();
+	if (iAvailDesCount - aCount >= 0)
+		{
+		iAvailDesCount -= aCount;
+		r = KErrNone;
+		}
+	Signal();
+	__DMA_INVARIANT();
+	return r;
+	}
+
+
+//
+// Return the given number of preallocated descriptors to the free pool.
+//
+void TDmac::ReleaseSetOfDes(TInt aCount)
+	{
+	__DMA_ASSERTD(aCount >= 0);
+	Wait();
+	iAvailDesCount += aCount;
+	Signal();
+	__DMA_INVARIANT();
+	}
+
+
+//
+// Queue DFC and update word used to communicate with channel DFC.
+//
+// Called in interrupt context by PSL.
+//
+void TDmac::HandleIsr(TDmaChannel& aChannel, TUint aEventMask, TBool aIsComplete)
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("TDmac::HandleIsr"));
+
+	// Function needs to be called by PSL in ISR context
+	__DMA_ASSERTD(NKern::CurrentContext() == NKern::EInterrupt);
+
+	// First the ISR callback stuff
+
+	// Is this a transfer completion notification?
+	if (aEventMask & EDmaCallbackRequestCompletion)
+		{
+		// If so, has the client requested an ISR callback?
+		if (__e32_atomic_load_acq32(&aChannel.iIsrCbRequest))
+			{
+			__KTRACE_OPT(KDMA, Kern::Printf("ISR callback"));
+
+			// Since iIsrCbRequest was set no threads will be
+			// modifying the request queue.
+			const DDmaRequest* const req = _LOFF(aChannel.iReqQ.First(), DDmaRequest, iLink);
+
+			// We expect the request to have requested
+			// ISR callback
+			__NK_ASSERT_DEBUG(req->iIsrCb);
+
+			TDmaCallback const cb = req->iDmaCb;
+			TAny* const arg = req->iDmaCbArg;
+			// Execute the client callback
+			(*cb)(EDmaCallbackRequestCompletion,
+				  (aIsComplete ? EDmaResultOK : EDmaResultError),
+				  arg,
+				  NULL);
+			// Now let's see if the callback rescheduled the transfer request
+			// (see TDmaChannel::IsrRedoRequest()).
+			const TBool redo = aChannel.iRedoRequest;
+			aChannel.iRedoRequest = EFalse;
+			const TBool stop = __e32_atomic_load_acq32(&aChannel.iIsrDfc) &
+				(TUint32)TDmaChannel::KCancelFlagMask;
+			// There won't be another ISR callback if this callback didn't
+			// reschedule the request, or the client cancelled all requests, or
+			// this callback rescheduled the request with a DFC callback.
+			if (!redo || stop || !req->iIsrCb)
+				{
+				__e32_atomic_store_rel32(&aChannel.iIsrCbRequest, EFalse);
+				}
+			if (redo && !stop)
+				{
+				// We won't queue the channel DFC in this case and just return.
+				__KTRACE_OPT(KDMA, Kern::Printf("CB rescheduled xfer -> no DFC"));
+				return;
+				}
+			// Not redoing or being cancelled means we've been calling the
+			// request's ISR callback for the last time. We're going to
+			// complete the request via the DFC in the usual way.
+			}
+		}
+
+	// Now queue a DFC if necessary. The possible scenarios are:
+	// a) DFC not queued (orig == 0)              -> update iIsrDfc + queue DFC
+	// b) DFC queued, not running yet (orig != 0) -> just update iIsrDfc
+	// c) DFC running / iIsrDfc not reset yet (orig != 0) -> just update iIsrDfc
+	// d) DFC running / iIsrDfc already reset (orig == 0) -> update iIsrDfc + requeue DFC
+
+	// Set error flag if necessary.
+	const TUint32 inc = aIsComplete ? 1u : TUint32(TDmaChannel::KErrorFlagMask) | 1u;
+
+	// Add 'inc' (interrupt count increment + poss. error flag) to 'iIsrDfc' if
+	// cancel flag is not set, do nothing otherwise. Assign original value of
+	// 'iIsrDfc' to 'orig' in any case.
+	const TUint32 orig = __e32_atomic_tau_ord32(&aChannel.iIsrDfc,
+												TUint32(TDmaChannel::KCancelFlagMask),
+												0,
+												inc);
+
+	// As transfer should be suspended when an error occurs, we
+	// should never get there with the error flag already set.
+	__DMA_ASSERTD((orig & inc & (TUint32)TDmaChannel::KErrorFlagMask) == 0);
+
+	if (orig == 0)
+		{
+		aChannel.iDfc.Add();
+		}
+	}
+
+
+TInt TDmac::InitDes(const SDmaDesHdr& aHdr, const TDmaTransferArgs& aTransferArgs)
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("TDmac::InitDes"));
+	TInt r;
+	if (iCapsHwDes)
+		{
+		__KTRACE_OPT(KDMA, Kern::Printf("iCaps.iHwDescriptors"));
+		r = InitHwDes(aHdr, aTransferArgs);
+		}
+	else
+		{
+		TDmaTransferArgs& args = HdrToDes(aHdr);
+		args = aTransferArgs;
+		r = KErrNone;
+		}
+	return r;
+	}
+
+
+TInt TDmac::InitHwDes(const SDmaDesHdr& /*aHdr*/, const TDmaTransferArgs& /*aTransferArgs*/)
+	{
+	// concrete controller must override if SDmacCaps::iHwDescriptors set
+	__DMA_CANT_HAPPEN();
+	return KErrGeneral;
+	}
+
+
+TInt TDmac::InitSrcHwDes(const SDmaDesHdr& /*aHdr*/, const TDmaTransferArgs& /*aTransferArgs*/)
+	{
+	// concrete controller must override if SDmacCaps::iAsymHwDescriptors set
+	__DMA_CANT_HAPPEN();
+	return KErrGeneral;
+	}
+
+
+TInt TDmac::InitDstHwDes(const SDmaDesHdr& /*aHdr*/, const TDmaTransferArgs& /*aTransferArgs*/)
+	{
+	// concrete controller must override if SDmacCaps::iAsymHwDescriptors set
+	__DMA_CANT_HAPPEN();
+	return KErrGeneral;
+	}
+
+
+TInt TDmac::UpdateDes(const SDmaDesHdr& aHdr, TUint32 aSrcAddr, TUint32 aDstAddr,
+					  TUint aTransferCount, TUint32 aPslRequestInfo)
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("TDmac::UpdateDes"));
+	TInt r;
+	if (iCapsHwDes)
+		{
+		__KTRACE_OPT(KDMA, Kern::Printf("iCaps.iHwDescriptors"));
+		r = UpdateHwDes(aHdr, aSrcAddr, aDstAddr, aTransferCount, aPslRequestInfo);
+		}
+	else
+		{
+		TDmaTransferArgs& args = HdrToDes(aHdr);
+		if (aSrcAddr != KPhysAddrInvalid)
+			args.iSrcConfig.iAddr = aSrcAddr;
+		if (aDstAddr != KPhysAddrInvalid)
+			args.iDstConfig.iAddr = aDstAddr;
+		if (aTransferCount)
+			args.iTransferCount = aTransferCount;
+		if (aPslRequestInfo)
+			args.iPslRequestInfo = aPslRequestInfo;
+		r = KErrNone;
+		}
+	return r;
+	}
+
+
+TInt TDmac::UpdateHwDes(const SDmaDesHdr& /*aHdr*/, TUint32 /*aSrcAddr*/, TUint32 /*aDstAddr*/,
+						TUint /*aTransferCount*/, TUint32 /*aPslRequestInfo*/)
+	{
+	// concrete controller must override if SDmacCaps::iHwDescriptors set
+	__DMA_CANT_HAPPEN();
+	return KErrGeneral;
+	}
+
+
+TInt TDmac::UpdateSrcHwDes(const SDmaDesHdr& /*aHdr*/, TUint32 /*aSrcAddr*/,
+						   TUint /*aTransferCount*/, TUint32 /*aPslRequestInfo*/)
+	{
+	// concrete controller must override if SDmacCaps::iAsymHwDescriptors set
+	__DMA_CANT_HAPPEN();
+	return KErrGeneral;
+	}
+
+
+TInt TDmac::UpdateDstHwDes(const SDmaDesHdr& /*aHdr*/, TUint32 /*aDstAddr*/,
+						   TUint /*aTransferCount*/, TUint32 /*aPslRequestInfo*/)
+	{
+	// concrete controller must override if SDmacCaps::iAsymHwDescriptors set
+	__DMA_CANT_HAPPEN();
+	return KErrGeneral;
+	}
+
+
+void TDmac::ChainHwDes(const SDmaDesHdr& /*aHdr*/, const SDmaDesHdr& /*aNextHdr*/)
+	{
+	// concrete controller must override if SDmacCaps::iHwDescriptors set
+	__DMA_CANT_HAPPEN();
+	}
+
+
+void TDmac::AppendHwDes(const TDmaChannel& /*aChannel*/, const SDmaDesHdr& /*aLastHdr*/,
+						const SDmaDesHdr& /*aNewHdr*/)
+	{
+ 	// concrete controller must override if SDmacCaps::iHwDescriptors set
+	__DMA_CANT_HAPPEN();
+	}
+
+
+void TDmac::AppendHwDes(const TDmaChannel& /*aChannel*/,
+						const SDmaDesHdr& /*aSrcLastHdr*/, const SDmaDesHdr& /*aSrcNewHdr*/,
+						const SDmaDesHdr& /*aDstLastHdr*/, const SDmaDesHdr& /*aDstNewHdr*/)
+	{
+	// concrete controller must override if SDmacCaps::iAsymHwDescriptors set
+	__DMA_CANT_HAPPEN();
+	}
+
+
+void TDmac::UnlinkHwDes(const TDmaChannel& /*aChannel*/, SDmaDesHdr& /*aHdr*/)
+	{
+ 	// concrete controller must override if SDmacCaps::iHwDescriptors set
+	__DMA_CANT_HAPPEN();
+	}
+
+
+void TDmac::ClearHwDes(const SDmaDesHdr& /*aHdr*/)
+	{
+	// default implementation - NOP; concrete controller may override
+	return;
+	}
+
+
+TInt TDmac::LinkChannels(TDmaChannel& /*a1stChannel*/, TDmaChannel& /*a2ndChannel*/)
+	{
+	// default implementation - NOP; concrete controller may override
+	return KErrNotSupported;
+	}
+
+
+TInt TDmac::UnlinkChannel(TDmaChannel& /*aChannel*/)
+	{
+	// default implementation - NOP; concrete controller may override
+	return KErrNotSupported;
+	}
+
+
+TInt TDmac::FailNext(const TDmaChannel& /*aChannel*/)
+	{
+	// default implementation - NOP; concrete controller may override
+	return KErrNotSupported;
+	}
+
+
+TInt TDmac::MissNextInterrupts(const TDmaChannel& /*aChannel*/, TInt /*aInterruptCount*/)
+	{
+	// default implementation - NOP; concrete controller may override
+	return KErrNotSupported;
+	}
+
+
+TInt TDmac::Extension(TDmaChannel& /*aChannel*/, TInt /*aCmd*/, TAny* /*aArg*/)
+	{
+	// default implementation - NOP; concrete controller may override
+	return KErrNotSupported;
+	}
+
+
+TUint32 TDmac::HwDesNumDstElementsTransferred(const SDmaDesHdr& /*aHdr*/)
+	{
+ 	// Concrete controller must override if SDmacCaps::iHwDescriptors set.
+	__DMA_CANT_HAPPEN();
+	return 0;
+	}
+
+
+TUint32 TDmac::HwDesNumSrcElementsTransferred(const SDmaDesHdr& /*aHdr*/)
+	{
+ 	// Concrete controller must override if SDmacCaps::iHwDescriptors set.
+	__DMA_CANT_HAPPEN();
+	return 0;
+	}
+
+
+#ifdef _DEBUG
+
+void TDmac::Invariant()
+	{
+	Wait();
+	__DMA_ASSERTD(0 <= iAvailDesCount && iAvailDesCount <= iMaxDesCount);
+	__DMA_ASSERTD(! iFreeHdr || IsValidHdr(iFreeHdr));
+	for (TInt i = 0; i < iMaxDesCount; i++)
+		__DMA_ASSERTD(iHdrPool[i].iNext == NULL || IsValidHdr(iHdrPool[i].iNext));
+	Signal();
+	}
+
+
+TBool TDmac::IsValidHdr(const SDmaDesHdr* aHdr)
+	{
+	return (iHdrPool <= aHdr) && (aHdr < iHdrPool + iMaxDesCount);
+	}
+
+#endif
+
+
+
+
+//
+// Internal compat version, used by legacy Fragment()
+//
+TDmaTransferConfig::TDmaTransferConfig(TUint32 aAddr, TUint aFlags, TBool aAddrInc)
+	: iAddr(aAddr),
+	  iAddrMode(aAddrInc ? KDmaAddrModePostIncrement : KDmaAddrModeConstant),
+	  iElementSize(0),
+	  iElementsPerFrame(0),
+	  iElementsPerPacket(0),
+	  iFramesPerTransfer(0),
+	  iElementSkip(0),
+	  iFrameSkip(0),
+	  iBurstSize(KDmaBurstSizeAny),
+	  iFlags(aFlags),
+	  iSyncFlags(KDmaSyncAuto),
+	  iPslTargetInfo(0),
+	  iRepeatCount(0),
+	  iDelta(~0u),
+	  iReserved(0)
+	{
+	}
+
+
+
+//
+// Internal compat version, used by legacy Fragment()
+//
+TDmaTransferArgs::TDmaTransferArgs(TUint32 aSrc, TUint32 aDest, TInt aCount,
+								   TUint aFlags, TUint32 aPslInfo)
+	: iSrcConfig(aSrc, RequestFlags2SrcConfigFlags(aFlags), (aFlags & KDmaIncSrc)),
+	  iDstConfig(aDest, RequestFlags2DstConfigFlags(aFlags), (aFlags & KDmaIncDest)),
+	  iTransferCount(aCount),
+	  iGraphicsOps(KDmaGraphicsOpNone),
+	  iColour(0),
+	  iFlags(0),
+	  iChannelPriority(KDmaPriorityNone),
+	  iPslRequestInfo(aPslInfo),
+	  iDelta(~0u),
+	  iReserved1(0),
+	  iChannelCookie(0),
+	  iReserved2(0)
+	{
+	}
+
+
+//
+// As DDmaRequest is derived from DBase, the initializations with zero aren't
+// strictly necessary here, but this way it's nicer.
+//
+EXPORT_C DDmaRequest::DDmaRequest(TDmaChannel& aChannel, TCallback aCb,
+								  TAny* aCbArg, TInt aMaxTransferSize)
+	: iChannel(aChannel),
+	  iCb(aCb),
+	  iCbArg(aCbArg),
+	  iDmaCb(NULL),
+	  iDmaCbArg(NULL),
+	  iIsrCb(EFalse),
+	  iDesCount(0),
+	  iFirstHdr(NULL),
+	  iLastHdr(NULL),
+	  iSrcDesCount(0),
+	  iSrcFirstHdr(NULL),
+	  iSrcLastHdr(NULL),
+	  iDstDesCount(0),
+	  iDstFirstHdr(NULL),
+	  iDstLastHdr(NULL),
+	  iQueued(EFalse),
+	  iMaxTransferSize(aMaxTransferSize),
+	  iTotalNumSrcElementsTransferred(0),
+	  iTotalNumDstElementsTransferred(0)
+	{
+	iChannel.iReqCount++;
+	__DMA_ASSERTD(0 <= aMaxTransferSize);
+	__DMA_INVARIANT();
+	}
+
+
+//
+// As DDmaRequest is derived from DBase, the initializations with zero aren't
+// strictly necessary here, but this way it's nicer.
+//
+EXPORT_C DDmaRequest::DDmaRequest(TDmaChannel& aChannel, TDmaCallback aDmaCb,
+								  TAny* aCbArg, TUint aMaxTransferSize)
+	: iChannel(aChannel),
+	  iCb(NULL),
+	  iCbArg(NULL),
+	  iDmaCb(aDmaCb),
+	  iDmaCbArg(aCbArg),
+	  iIsrCb(EFalse),
+	  iDesCount(0),
+	  iFirstHdr(NULL),
+	  iLastHdr(NULL),
+	  iSrcDesCount(0),
+	  iSrcFirstHdr(NULL),
+	  iSrcLastHdr(NULL),
+	  iDstDesCount(0),
+	  iDstFirstHdr(NULL),
+	  iDstLastHdr(NULL),
+	  iQueued(EFalse),
+	  iMaxTransferSize(aMaxTransferSize),
+	  iTotalNumSrcElementsTransferred(0),
+	  iTotalNumDstElementsTransferred(0)
+	{
+	__e32_atomic_add_ord32(&iChannel.iReqCount, 1);
+	__DMA_INVARIANT();
+	}
+
+
+EXPORT_C DDmaRequest::~DDmaRequest()
+	{
+	__DMA_ASSERTD(!iQueued);
+	__DMA_INVARIANT();
+	FreeDesList();
+	__e32_atomic_add_ord32(&iChannel.iReqCount, TUint32(-1));
+	}
+
+
+EXPORT_C TInt DDmaRequest::Fragment(TUint32 aSrc, TUint32 aDest, TInt aCount,
+									TUint aFlags, TUint32 aPslInfo)
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("DDmaRequest::Fragment thread %O "
+									"src=0x%08X dest=0x%08X count=%d flags=0x%X psl=0x%08X",
+									&Kern::CurrentThread(), aSrc, aDest, aCount, aFlags, aPslInfo));
+	__DMA_ASSERTD(aCount > 0);
+
+	TDmaTransferArgs args(aSrc, aDest, aCount, aFlags, aPslInfo);
+
+	return Frag(args);
+	}
+
+
+EXPORT_C TInt DDmaRequest::Fragment(const TDmaTransferArgs& aTransferArgs)
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("DDmaRequest::Fragment thread %O", &Kern::CurrentThread()));
+
+	// Writable temporary working copy of the transfer arguments.
+	// We need this because we may have to modify some fields before passing it
+	// to the PSL (for example iChannelCookie, iTransferCount,
+	// iDstConfig::iAddr, and iSrcConfig::iAddr).
+	TDmaTransferArgs args(aTransferArgs);
+
+	return Frag(args);
+	}
+
+
+TUint DDmaRequest::GetTransferCount(const TDmaTransferArgs& aTransferArgs)
+	{
+	const TDmaTransferConfig& src = aTransferArgs.iSrcConfig;
+	const TDmaTransferConfig& dst = aTransferArgs.iDstConfig;
+
+	TUint count = aTransferArgs.iTransferCount;
+	if (count == 0)
+		{
+		__KTRACE_OPT(KDMA, Kern::Printf("iTransferCount == 0"));
+		count = src.iElementSize * src.iElementsPerFrame *
+			src.iFramesPerTransfer;
+		const TUint dst_cnt = dst.iElementSize * dst.iElementsPerFrame *
+			dst.iFramesPerTransfer;
+		if (count != dst_cnt)
+			{
+			__KTRACE_OPT(KPANIC, Kern::Printf("Error: (count != dst_cnt)"));
+			return 0;
+			}
+		}
+	else
+		{
+		__KTRACE_OPT(KDMA, Kern::Printf("iTransferCount == %d", count));
+		// Client shouldn't specify contradictory or incomplete things
+		if (src.iElementSize != 0)
+			{
+			if ((count % src.iElementSize) != 0)
+				{
+				__KTRACE_OPT(KPANIC,
+							 Kern::Printf("Error: ((count %% src.iElementSize) != 0)"));
+				return 0;
+				}
+			if (src.iElementsPerFrame != 0)
+				{
+				if ((src.iElementSize * src.iElementsPerFrame * src.iFramesPerTransfer) != count)
+					{
+					__KTRACE_OPT(KPANIC,
+								 Kern::Printf("Error: ((src.iElementSize * "
+											  "src.iElementsPerFrame * "
+											  "src.iFramesPerTransfer) != count)"));
+					return 0;
+					}
+				}
+			}
+		else
+			{
+			if (src.iElementsPerFrame != 0)
+				{
+				__KTRACE_OPT(KPANIC,
+							 Kern::Printf("Error: (src.iElementsPerFrame != 0)"));
+				return 0;
+				}
+			if (src.iFramesPerTransfer != 0)
+				{
+				__KTRACE_OPT(KPANIC,
+							 Kern::Printf("Error: (src.iFramesPerTransfer != 0)"));
+				return 0;
+				}
+			if (src.iElementsPerPacket != 0)
+				{
+				__KTRACE_OPT(KPANIC,
+							 Kern::Printf("Error: (src.iElementsPerPacket != 0)"));
+				return 0;
+				}
+			}
+		if (dst.iElementSize != 0)
+			{
+			if ((count % dst.iElementSize) != 0)
+				{
+				__KTRACE_OPT(KPANIC,
+							 Kern::Printf("Error: ((count %% dst.iElementSize) != 0)"));
+				return 0;
+				}
+			if (dst.iElementsPerFrame != 0)
+				{
+				if ((dst.iElementSize * dst.iElementsPerFrame * dst.iFramesPerTransfer) != count)
+					{
+					__KTRACE_OPT(KPANIC,
+								 Kern::Printf("Error: ((dst.iElementSize * "
+											  "dst.iElementsPerFrame * "
+											  "dst.iFramesPerTransfer) != count)"));
+					return 0;
+					}
+				}
+			}
+		else
+			{
+			if (dst.iElementsPerFrame != 0)
+				{
+				__KTRACE_OPT(KPANIC,
+							 Kern::Printf("Error: (dst.iElementsPerFrame != 0)"));
+				return 0;
+				}
+			if (dst.iFramesPerTransfer != 0)
+				{
+				__KTRACE_OPT(KPANIC,
+							 Kern::Printf("Error: (dst.iFramesPerTransfer != 0)"));
+				return 0;
+				}
+			if (dst.iElementsPerPacket != 0)
+				{
+				__KTRACE_OPT(KPANIC,
+							 Kern::Printf("Error: (dst.iElementsPerPacket != 0)"));
+				return 0;
+				}
+			}
+		}
+	return count;
+	}
+
+
+TInt DDmaRequest::Frag(TDmaTransferArgs& aTransferArgs)
+	{
+	__DMA_ASSERTD(!iQueued);
+
+	// Transfer count checks
+	const TUint count = GetTransferCount(aTransferArgs);
+	if (count == 0)
+		{
+		return KErrArgument;
+		}
+
+	const TDmaTransferConfig& src = aTransferArgs.iSrcConfig;
+	const TDmaTransferConfig& dst = aTransferArgs.iDstConfig;
+
+	// Ask the PSL what the maximum length possible for this transfer is
+	TUint max_xfer_len = iChannel.MaxTransferLength(src.iFlags, dst.iFlags,
+													aTransferArgs.iPslRequestInfo);
+	if (iMaxTransferSize)
+		{
+		// User has set a size cap
+		__KTRACE_OPT(KDMA, Kern::Printf("iMaxTransferSize != 0"));
+		__DMA_ASSERTA((iMaxTransferSize <= max_xfer_len) || (max_xfer_len == 0));
+		max_xfer_len = iMaxTransferSize;
+		}
+	else
+		{
+		// User doesn't care about max size
+		if (max_xfer_len == 0)
+			{
+			// No maximum imposed by controller
+			max_xfer_len = count;
+			}
+		}
+
+	// ISR callback requested?
+	const TBool isr_cb = (aTransferArgs.iFlags & KDmaRequestCallbackFromIsr);
+	if (isr_cb)
+		{
+		// Requesting an ISR callback w/o supplying one?
+		if (!iDmaCb)
+			{
+			return KErrArgument;
+			}
+		}
+
+	// Set the channel cookie for the PSL
+	aTransferArgs.iChannelCookie = iChannel.PslId();
+
+	// Now the actual fragmentation
+	TInt r;
+	if (iChannel.iDmacCaps->iAsymHwDescriptors)
+		{
+		r = FragAsym(aTransferArgs, count, max_xfer_len);
+		}
+	else
+		{
+		r = FragSym(aTransferArgs, count, max_xfer_len);
+		}
+
+	if (r == KErrNone)
+		{
+		iIsrCb = isr_cb;
+		}
+
+	__DMA_INVARIANT();
+	return r;
+	};
+
+
+TInt DDmaRequest::FragSym(TDmaTransferArgs& aTransferArgs, TUint aCount,
+						  TUint aMaxTransferLen)
+	{
+	TDmaTransferConfig& src = aTransferArgs.iSrcConfig;
+	TDmaTransferConfig& dst = aTransferArgs.iDstConfig;
+
+	const TBool mem_src = (src.iFlags & KDmaMemAddr);
+	const TBool mem_dst = (dst.iFlags & KDmaMemAddr);
+
+	const TUint align_mask_src = iChannel.AddressAlignMask(src.iFlags,
+														   src.iElementSize,
+														   aTransferArgs.iPslRequestInfo);
+	const TUint align_mask_dst = iChannel.AddressAlignMask(dst.iFlags,
+														   dst.iElementSize,
+														   aTransferArgs.iPslRequestInfo);
+	// Memory buffers must satisfy alignment constraint
+	__DMA_ASSERTD(!mem_src || ((src.iAddr & align_mask_src) == 0));
+	__DMA_ASSERTD(!mem_dst || ((dst.iAddr & align_mask_dst) == 0));
+
+	const TUint max_aligned_len = (aMaxTransferLen &
+								   ~(Max(align_mask_src, align_mask_dst)));
+	// Client and PSL sane?
+	__DMA_ASSERTD(max_aligned_len > 0);
+
+	FreeDesList();			   // revert any previous fragmentation attempt
+	TInt r;
+	do
+		{
+		// Allocate fragment
+		r = ExpandDesList(/*1*/);
+		if (r != KErrNone)
+			{
+			FreeDesList();
+			break;
+			}
+		// Compute fragment size
+		TUint c = Min(aMaxTransferLen, aCount);
+		if (mem_src && !(src.iFlags & KDmaPhysAddr))
+			{
+			__KTRACE_OPT(KDMA, Kern::Printf("mem_src && !(src.iFlags & KDmaPhysAddr)"));
+			// @@@ Should also take into account (src.iFlags & KDmaMemIsContiguous)!
+			c = MaxPhysSize(src.iAddr, c);
+			}
+		if (mem_dst && !(dst.iFlags & KDmaPhysAddr))
+			{
+			__KTRACE_OPT(KDMA, Kern::Printf("mem_dst && !(dst.iFlags & KDmaPhysAddr)"));
+			// @@@ Should also take into account (dst.iFlags & KDmaMemIsContiguous)!
+			c = MaxPhysSize(dst.iAddr, c);
+			}
+		if ((mem_src || mem_dst) && (c < aCount) && (c > max_aligned_len))
+			{
+			// This is not the last fragment of a transfer to/from memory.
+			// We must round down the fragment size so the next one is
+			// correctly aligned.
+			__KTRACE_OPT(KDMA, Kern::Printf("(mem_src || mem_dst) && (c < aCount) && (c > max_aligned_len)"));
+			c = max_aligned_len;
+			}
+
+		// TODO: Make sure an element or frame on neither src or dst side
+		// (which can be of different sizes) never straddles a DMA subtransfer.
+		// (This would be a fragmentation error by the PIL.)
+
+		// Set transfer count for the PSL
+		aTransferArgs.iTransferCount = c;
+		__KTRACE_OPT(KDMA, Kern::Printf("this fragm.: %d (0x%x) total remain.: %d (0x%x)",
+										c, c, aCount, aCount));
+		// Initialise fragment
+		r = iChannel.iController->InitDes(*iLastHdr, aTransferArgs);
+		if (r != KErrNone)
+			{
+			FreeDesList();
+			break;
+			}
+		// Update for next iteration
+		aCount -= c;
+		if (mem_src)
+			src.iAddr += c;
+		if (mem_dst)
+			dst.iAddr += c;
+		}
+	while (aCount > 0);
+
+	return r;
+	}
+
+
+TInt DDmaRequest::FragAsym(TDmaTransferArgs& aTransferArgs, TUint aCount,
+						   TUint aMaxTransferLen)
+	{
+	TInt r = FragAsymSrc(aTransferArgs, aCount, aMaxTransferLen);
+	if (r != KErrNone)
+		{
+		FreeSrcDesList();
+		return r;
+		}
+	r = FragAsymDst(aTransferArgs, aCount, aMaxTransferLen);
+	if (r != KErrNone)
+		{
+		FreeSrcDesList();
+		FreeDstDesList();
+		}
+	return r;
+	}
+
+
+TInt DDmaRequest::FragAsymSrc(TDmaTransferArgs& aTransferArgs, TUint aCount,
+							  TUint aMaxTransferLen)
+	{
+	TDmaTransferConfig& src = aTransferArgs.iSrcConfig;
+
+	const TBool mem_src = (src.iFlags & KDmaMemAddr);
+
+	const TUint align_mask = iChannel.AddressAlignMask(src.iFlags,
+													   src.iElementSize,
+													   aTransferArgs.iPslRequestInfo);
+	// Memory buffers must satisfy alignment constraint
+	__DMA_ASSERTD(!mem_src || ((src.iAddr & align_mask) == 0));
+
+	const TUint max_aligned_len = (aMaxTransferLen & ~align_mask);
+	__DMA_ASSERTD(max_aligned_len > 0);				  // bug in PSL if not true
+
+	FreeSrcDesList();
+	TInt r;
+	do
+		{
+		// Allocate fragment
+		r = ExpandSrcDesList(/*1*/);
+		if (r != KErrNone)
+			{
+			break;
+			}
+		// Compute fragment size
+		TUint c = Min(aMaxTransferLen, aCount);
+		if (mem_src && !(src.iFlags & KDmaPhysAddr))
+			{
+			__KTRACE_OPT(KDMA, Kern::Printf("mem_src && !(src.iFlags & KDmaPhysAddr)"));
+			c = MaxPhysSize(src.iAddr, c);
+			}
+		if (mem_src && (c < aCount) && (c > max_aligned_len))
+			{
+			// This is not the last fragment of a transfer from memory.
+			// We must round down the fragment size so the next one is
+			// correctly aligned.
+			__KTRACE_OPT(KDMA, Kern::Printf("mem_src && (c < aCount) && (c > max_aligned_len)"));
+			c = max_aligned_len;
+			}
+		// Set transfer count for the PSL
+		aTransferArgs.iTransferCount = c;
+		__KTRACE_OPT(KDMA, Kern::Printf("this fragm.: %d (0x%x) total remain.: %d (0x%x)",
+										c, c, aCount, aCount));
+		// Initialise fragment
+		r = iChannel.iController->InitSrcHwDes(*iSrcLastHdr, aTransferArgs);
+		if (r != KErrNone)
+			{
+			break;
+			}
+		// Update for next iteration
+		aCount -= c;
+		if (mem_src)
+			src.iAddr += c;
+		}
+	while (aCount > 0);
+
+	return r;
+	}
+
+
+TInt DDmaRequest::FragAsymDst(TDmaTransferArgs& aTransferArgs, TUint aCount,
+							  TUint aMaxTransferLen)
+	{
+	TDmaTransferConfig& dst = aTransferArgs.iDstConfig;
+
+	const TBool mem_dst = (dst.iFlags & KDmaMemAddr);
+
+	const TUint align_mask = iChannel.AddressAlignMask(dst.iFlags,
+													   dst.iElementSize,
+													   aTransferArgs.iPslRequestInfo);
+	// Memory buffers must satisfy alignment constraint
+	__DMA_ASSERTD(!mem_dst || ((dst.iAddr & align_mask) == 0));
+
+	const TUint max_aligned_len = (aMaxTransferLen & ~align_mask);
+	__DMA_ASSERTD(max_aligned_len > 0);				  // bug in PSL if not true
+
+	FreeDstDesList();
+	TInt r;
+	do
+		{
+		// Allocate fragment
+		r = ExpandDstDesList(/*1*/);
+		if (r != KErrNone)
+			{
+			break;
+			}
+		// Compute fragment size
+		TUint c = Min(aMaxTransferLen, aCount);
+		if (mem_dst && !(dst.iFlags & KDmaPhysAddr))
+			{
+			__KTRACE_OPT(KDMA, Kern::Printf("mem_dst && !(dst.iFlags & KDmaPhysAddr)"));
+			c = MaxPhysSize(dst.iAddr, c);
+			}
+		if (mem_dst && (c < aCount) && (c > max_aligned_len))
+			{
+			// This is not the last fragment of a transfer to memory.
+			// We must round down the fragment size so the next one is
+			// correctly aligned.
+			__KTRACE_OPT(KDMA, Kern::Printf("mem_dst && (c < aCount) && (c > max_aligned_len)"));
+			c = max_aligned_len;
+			}
+		// Set transfer count for the PSL
+		aTransferArgs.iTransferCount = c;
+		__KTRACE_OPT(KDMA, Kern::Printf("this fragm.: %d (0x%x) total remain.: %d (0x%x)",
+										c, c, aCount, aCount));
+		// Initialise fragment
+		r = iChannel.iController->InitDstHwDes(*iDstLastHdr, aTransferArgs);
+		if (r != KErrNone)
+			{
+			break;
+			}
+		// Update for next iteration
+		aCount -= c;
+		if (mem_dst)
+			dst.iAddr += c;
+		}
+	while (aCount > 0);
+
+	return r;
+	}
+
+
+EXPORT_C TInt DDmaRequest::Queue()
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("DDmaRequest::Queue thread %O", &Kern::CurrentThread()));
+	__DMA_ASSERTD(iDesCount > 0);	// Not configured? Call Fragment() first!
+	__DMA_ASSERTD(!iQueued);
+
+	// Append request to queue and link new descriptor list to existing one.
+	iChannel.Wait();
+
+	TInt r = KErrGeneral;
+	const TBool ch_isr_cb = __e32_atomic_load_acq32(&iChannel.iIsrCbRequest);
+	if (ch_isr_cb)
+		{
+		// Client mustn't try to queue any new request while one with an ISR
+		// callback is already queued on this channel. This is to make sure
+		// that the channel's Transfer() function is not called by both the ISR
+		// and the client thread at the same time.
+		__KTRACE_OPT(KPANIC, Kern::Printf("An ISR cb request exists - not queueing"));
+		}
+	else if (iIsrCb && !iChannel.IsQueueEmpty())
+		{
+		// Client mustn't try to queue an ISR callback request whilst any
+		// others are still queued on this channel. This is to make sure that
+		// the ISR callback doesn't get executed together with the DFC(s) of
+		// any previous request(s).
+		__KTRACE_OPT(KPANIC, Kern::Printf("Request queue not empty - not queueing"));
+		}
+	else if (iChannel.iIsrDfc & (TUint32)TDmaChannel::KCancelFlagMask)
+		{
+		__KTRACE_OPT(KPANIC, Kern::Printf("Channel requests cancelled - not queueing"));
+		}
+	else
+		{
+		iQueued = ETrue;
+		iChannel.iReqQ.Add(&iLink);
+		// iChannel.iNullPtr points to iChannel.iCurHdr for an empty queue
+		*iChannel.iNullPtr = iFirstHdr;
+		iChannel.iNullPtr = &(iLastHdr->iNext);
+		if (iIsrCb)
+			{
+			// Since we've made sure that there is no other request in the
+			// queue before this, the only thing of relevance is the channel
+			// DFC which might yet have to complete for the previous request,
+			// and this function might indeed have been called from there via
+			// the client callback. This should be all right though as once
+			// we've set the following flag no further Queue()'s will be
+			// possible.
+			__e32_atomic_store_rel32(&iChannel.iIsrCbRequest, ETrue);
+			}
+		iChannel.DoQueue(const_cast<const DDmaRequest&>(*this));
+		r = KErrNone;
+		}
+	iChannel.Signal();
+
+	__DMA_INVARIANT();
+	return r;
+	}
+
+
+EXPORT_C TInt DDmaRequest::ExpandDesList(TInt aCount)
+	{
+	return ExpandDesList(aCount, iDesCount, iFirstHdr, iLastHdr);
+	}
+
+
+EXPORT_C TInt DDmaRequest::ExpandSrcDesList(TInt aCount)
+	{
+	return ExpandDesList(aCount, iSrcDesCount, iSrcFirstHdr, iSrcLastHdr);
+	}
+
+
+EXPORT_C TInt DDmaRequest::ExpandDstDesList(TInt aCount)
+	{
+	return ExpandDesList(aCount, iDstDesCount, iDstFirstHdr, iDstLastHdr);
+	}
+
+
+TInt DDmaRequest::ExpandDesList(TInt aCount, TInt& aDesCount,
+								SDmaDesHdr*& aFirstHdr,
+								SDmaDesHdr*& aLastHdr)
+	{
+	__DMA_ASSERTD(!iQueued);
+	__DMA_ASSERTD(aCount > 0);
+
+	if (aCount > iChannel.iAvailDesCount)
+		{
+		return KErrTooBig;
+		}
+
+	iChannel.iAvailDesCount -= aCount;
+	aDesCount += aCount;
+
+	TDmac& c = *(iChannel.iController);
+	c.Wait();
+
+	if (aFirstHdr == NULL)
+		{
+		// Handle an empty list specially to simplify the following loop
+		aFirstHdr = aLastHdr = c.iFreeHdr;
+		c.iFreeHdr = c.iFreeHdr->iNext;
+		--aCount;
+		}
+	else
+		{
+		aLastHdr->iNext = c.iFreeHdr;
+		}
+
+	// Remove as many descriptors and headers from the free pool as necessary
+	// and ensure hardware descriptors are chained together.
+	while (aCount-- > 0)
+		{
+		__DMA_ASSERTD(c.iFreeHdr != NULL);
+		if (c.iCapsHwDes)
+			{
+			c.ChainHwDes(*aLastHdr, *(c.iFreeHdr));
+			}
+		aLastHdr = c.iFreeHdr;
+		c.iFreeHdr = c.iFreeHdr->iNext;
+		}
+
+	c.Signal();
+
+	aLastHdr->iNext = NULL;
+
+	__DMA_INVARIANT();
+	return KErrNone;
+	}
+
+
+EXPORT_C void DDmaRequest::FreeDesList()
+	{
+	FreeDesList(iDesCount, iFirstHdr, iLastHdr);
+	}
+
+
+EXPORT_C void DDmaRequest::FreeSrcDesList()
+	{
+	FreeDesList(iSrcDesCount, iSrcFirstHdr, iSrcLastHdr);
+	}
+
+
+EXPORT_C void DDmaRequest::FreeDstDesList()
+	{
+	FreeDesList(iDstDesCount, iDstFirstHdr, iDstLastHdr);
+	}
+
+
+void DDmaRequest::FreeDesList(TInt& aDesCount, SDmaDesHdr*& aFirstHdr, SDmaDesHdr*& aLastHdr)
+	{
+	__DMA_ASSERTD(!iQueued);
+
+	if (aDesCount > 0)
+		{
+		iChannel.iAvailDesCount += aDesCount;
+		TDmac& c = *(iChannel.iController);
+		const SDmaDesHdr* hdr = aFirstHdr;
+		while (hdr)
+			{
+			c.ClearHwDes(*hdr);
+			hdr = hdr->iNext;
+			};
+		c.Wait();
+		aLastHdr->iNext = c.iFreeHdr;
+		c.iFreeHdr = aFirstHdr;
+		c.Signal();
+		aFirstHdr = aLastHdr = NULL;
+		aDesCount = 0;
+		}
+	}
+
+
+EXPORT_C void DDmaRequest::EnableSrcElementCounting(TBool /*aResetElementCount*/)
+	{
+	// Not yet implemented.
+	return;
+	}
+
+
+EXPORT_C void DDmaRequest::EnableDstElementCounting(TBool /*aResetElementCount*/)
+	{
+	// Not yet implemented.
+	return;
+	}
+
+
+EXPORT_C void DDmaRequest::DisableSrcElementCounting()
+	{
+	// Not yet implemented.
+	return;
+	}
+
+
+EXPORT_C void DDmaRequest::DisableDstElementCounting()
+	{
+	// Not yet implemented.
+	return;
+	}
+
+
+EXPORT_C TUint32 DDmaRequest::TotalNumSrcElementsTransferred()
+	{
+	// Not yet implemented.
+
+	// So far largely bogus code (just to touch some symbols)...
+	iTotalNumSrcElementsTransferred = 0;
+	TDmac& c = *(iChannel.iController);
+	if (c.iCapsHwDes)
+		{
+		for (const SDmaDesHdr* pH = iFirstHdr; pH != NULL; pH = pH->iNext)
+			{
+			iTotalNumSrcElementsTransferred += c.HwDesNumDstElementsTransferred(*pH);
+			}
+		}
+	else
+		{
+		// Do something different for pseudo descriptors...
+		}
+	return iTotalNumSrcElementsTransferred;
+	}
+
+
+EXPORT_C TUint32 DDmaRequest::TotalNumDstElementsTransferred()
+	{
+	// Not yet implemented.
+	return iTotalNumDstElementsTransferred;
+	}
+
+
+EXPORT_C TInt DDmaRequest::FragmentCount()
+	{
+	return FragmentCount(iFirstHdr);
+	}
+
+
+EXPORT_C TInt DDmaRequest::SrcFragmentCount()
+	{
+	return FragmentCount(iSrcFirstHdr);
+	}
+
+
+EXPORT_C TInt DDmaRequest::DstFragmentCount()
+	{
+	return FragmentCount(iDstFirstHdr);
+	}
+
+
+TInt DDmaRequest::FragmentCount(const SDmaDesHdr* aHdr)
+	{
+	TInt count = 0;
+	for (const SDmaDesHdr* pH = aHdr; pH != NULL; pH = pH->iNext)
+		{
+		count++;
+		}
+	return count;
+	}
+
+
+//
+// Called when request is removed from request queue in channel
+//
+inline void DDmaRequest::OnDeque()
+	{
+	iQueued = EFalse;
+	iLastHdr->iNext = NULL;
+	iChannel.DoUnlink(*iLastHdr);
+	}
+
+
+#ifdef _DEBUG
+void DDmaRequest::Invariant()
+	{
+	iChannel.Wait();
+	__DMA_ASSERTD(LOGICAL_XOR(iCb, iDmaCb));
+	if (iChannel.iDmacCaps->iAsymHwDescriptors)
+		{
+		__DMA_ASSERTD((0 <= iSrcDesCount) && (iSrcDesCount <= iChannel.iMaxDesCount) &&
+					  (0 <= iDstDesCount) && (iDstDesCount <= iChannel.iMaxDesCount));
+		if (iSrcDesCount == 0)
+			{
+			__DMA_ASSERTD(iDstDesCount == 0);
+			__DMA_ASSERTD(!iQueued);
+			__DMA_ASSERTD(!iSrcFirstHdr && !iSrcLastHdr &&
+						  !iDstFirstHdr && !iDstLastHdr);
+			}
+		else
+			{
+			__DMA_ASSERTD(iChannel.iController->IsValidHdr(iSrcFirstHdr));
+			__DMA_ASSERTD(iChannel.iController->IsValidHdr(iSrcLastHdr));
+			__DMA_ASSERTD(iChannel.iController->IsValidHdr(iDstFirstHdr));
+			__DMA_ASSERTD(iChannel.iController->IsValidHdr(iDstLastHdr));
+			}
+		}
+	else
+		{
+		__DMA_ASSERTD((0 <= iDesCount) && (iDesCount <= iChannel.iMaxDesCount));
+		if (iDesCount == 0)
+			{
+			__DMA_ASSERTD(!iQueued);
+			__DMA_ASSERTD(!iFirstHdr && !iLastHdr);
+			}
+		else
+			{
+			__DMA_ASSERTD(iChannel.iController->IsValidHdr(iFirstHdr));
+			__DMA_ASSERTD(iChannel.iController->IsValidHdr(iLastHdr));
+			}
+		}
+	iChannel.Signal();
+	}
+#endif
+
+
+//////////////////////////////////////////////////////////////////////////////
+// TDmaChannel
+
+_LIT(KDmaChannelMutex, "DMA-Channel");
+
+TDmaChannel::TDmaChannel()
+	: iController(NULL),
+	  iDmacCaps(NULL),
+	  iPslId(0),
+	  iDynChannel(EFalse),
+	  iPriority(KDmaPriorityNone),
+	  iCurHdr(NULL),
+	  iNullPtr(&iCurHdr),
+	  iDfc(Dfc, NULL, 0),
+	  iMaxDesCount(0),
+	  iAvailDesCount(0),
+	  iIsrDfc(0),
+	  iReqQ(),
+	  iReqCount(0),
+	  iCancelInfo(NULL),
+	  iRedoRequest(EFalse),
+	  iIsrCbRequest(EFalse)
+	{
+	const TInt r = Kern::MutexCreate(iMutex, KDmaChannelMutex, KMutexOrdDmaChannel);
+	__DMA_ASSERTA(r == KErrNone);
+
+#ifndef __WINS__
+	// On the emulator this code is called from within the codeseg mutex.
+	// The invariant tries to hold the dma channel mutex, but this is not allowed
+	__DMA_INVARIANT();
+#endif
+	}
+
+
+TDmaChannel::~TDmaChannel()
+	{
+	Kern::SafeClose((DObject*&)iMutex, NULL);
+	}
+
+
+//
+// static member function
+//
+EXPORT_C TInt TDmaChannel::Open(const SCreateInfo& aInfo, TDmaChannel*& aChannel)
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("TDmaChannel::Open thread %O", &Kern::CurrentThread()));
+
+	__DMA_ASSERTD(aInfo.iDesCount >= 1);
+	__DMA_ASSERTD(aInfo.iPriority <= KDmaPriority8);
+	__DMA_ASSERTD(aInfo.iDfcQ != NULL);
+	__DMA_ASSERTD(aInfo.iDfcPriority < KNumDfcPriorities);
+
+	aChannel = NULL;
+
+	DmaChannelMgr::Wait();
+	TDmaChannel* pC = DmaChannelMgr::Open(aInfo.iCookie, aInfo.iDynChannel, aInfo.iPriority);
+	DmaChannelMgr::Signal();
+	if (!pC)
+		{
+		return KErrInUse;
+		}
+	__DMA_ASSERTD(pC->iController != NULL);
+	__DMA_ASSERTD(pC->iDmacCaps != NULL);
+	__DMA_ASSERTD(pC->iController->iCapsHwDes == pC->DmacCaps().iHwDescriptors);
+	// PSL needs to set iDynChannel if and only if dynamic channel was requested
+	__DMA_ASSERTD(!LOGICAL_XOR(aInfo.iDynChannel, pC->iDynChannel));
+
+	const TInt r = pC->iController->ReserveSetOfDes(aInfo.iDesCount);
+	if (r != KErrNone)
+		{
+		pC->Close();
+		return r;
+		}
+	pC->iAvailDesCount = pC->iMaxDesCount = aInfo.iDesCount;
+
+	new (&pC->iDfc) TDfc(&Dfc, pC, aInfo.iDfcQ, aInfo.iDfcPriority);
+
+	aChannel = pC;
+
+#ifdef _DEBUG
+	pC->Invariant();
+#endif
+	__KTRACE_OPT(KDMA, Kern::Printf("opened channel %d", pC->iPslId));
+	return KErrNone;
+	}
+
+
+EXPORT_C void TDmaChannel::Close()
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("TDmaChannel::Close %d iReqCount=%d", iPslId, iReqCount));
+	__DMA_ASSERTD(IsQueueEmpty());
+	__DMA_ASSERTD(iReqCount == 0);
+
+	// Descriptor leak? -> bug in request code
+	__DMA_ASSERTD(iAvailDesCount == iMaxDesCount);
+
+	__DMA_ASSERTD(!iRedoRequest);
+	__DMA_ASSERTD(!iIsrCbRequest);
+
+	iController->ReleaseSetOfDes(iMaxDesCount);
+	iAvailDesCount = iMaxDesCount = 0;
+
+	DmaChannelMgr::Wait();
+	DmaChannelMgr::Close(this);
+	// The following assignment will be removed once IsOpened() has been
+	// removed. That's because 'this' shouldn't be touched any more once
+	// Close() has returned from the PSL.
+	iController = NULL;
+	DmaChannelMgr::Signal();
+	}
+
+
+EXPORT_C TInt TDmaChannel::LinkToChannel(TDmaChannel* aChannel)
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("TDmaChannel::LinkToChannel thread %O",
+									&Kern::CurrentThread()));
+	if (aChannel)
+		{
+		return iController->LinkChannels(*this, *aChannel);
+		}
+	else
+		{
+		return iController->UnlinkChannel(*this);
+		}
+	}
+
+
+EXPORT_C TInt TDmaChannel::Pause()
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("TDmaChannel::Pause thread %O",
+									&Kern::CurrentThread()));
+	return iController->PauseTransfer(*this);
+	}
+
+
+EXPORT_C TInt TDmaChannel::Resume()
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("TDmaChannel::Resume thread %O",
+									&Kern::CurrentThread()));
+	return iController->ResumeTransfer(*this);
+	}
+
+
+EXPORT_C void TDmaChannel::CancelAll()
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("TDmaChannel::CancelAll thread %O channel - %d",
+									&Kern::CurrentThread(), iPslId));
+	NThread* const nt = NKern::CurrentThread();
+	TBool wait = EFalse;
+	TDmaCancelInfo cancelinfo;
+	TDmaCancelInfo* waiters = NULL;
+
+	NKern::ThreadEnterCS();
+	Wait();
+
+	NThreadBase* const dfc_nt = iDfc.Thread();
+	// Shouldn't be NULL (i.e. an IDFC)
+	__DMA_ASSERTD(dfc_nt);
+
+	__e32_atomic_store_ord32(&iIsrDfc, (TUint32)KCancelFlagMask);
+	// ISRs after this point will not post a DFC, however a DFC may already be
+	// queued or running or both.
+	if (!IsQueueEmpty())
+		{
+		// There is a transfer in progress. It may complete before the DMAC
+		// has stopped, but the resulting ISR will not post a DFC.
+		// ISR should not happen after this function returns.
+		iController->StopTransfer(*this);
+
+		ResetStateMachine();
+
+		// Clean-up the request queue.
+		SDblQueLink* pL;
+		while ((pL = iReqQ.GetFirst()) != NULL)
+			{
+			DDmaRequest* pR = _LOFF(pL, DDmaRequest, iLink);
+			pR->OnDeque();
+			}
+		}
+	if (dfc_nt == nt)
+		{
+		// DFC runs in this thread, so just cancel it and we're finished
+		iDfc.Cancel();
+
+		// If other calls to CancelAll() are waiting for the DFC, release them here
+		waiters = iCancelInfo;
+		iCancelInfo = NULL;
+
+		// Reset the ISR count
+		__e32_atomic_store_rel32(&iIsrDfc, 0);
+		}
+	else
+		{
+		// DFC runs in another thread. Make sure it's queued and then wait for it to run.
+		if (iCancelInfo)
+			{
+			// Insert cancelinfo into the list so that it precedes iCancelInfo
+			cancelinfo.InsertBefore(iCancelInfo);
+			}
+		else
+			{
+			iCancelInfo = &cancelinfo;
+			}
+		wait = ETrue;
+		iDfc.Enque();
+		}
+
+	Signal();
+
+	if (waiters)
+		{
+		waiters->Signal();
+		}
+	else if (wait)
+		{
+		NKern::FSWait(&cancelinfo.iSem);
+		}
+
+ 	NKern::ThreadLeaveCS();
+	__DMA_INVARIANT();
+	}
+
+
+EXPORT_C TInt TDmaChannel::IsrRedoRequest(TUint32 aSrcAddr, TUint32 aDstAddr,
+										  TUint aTransferCount,
+										  TUint32 aPslRequestInfo,
+										  TBool aIsrCb)
+	{
+	__KTRACE_OPT(KDMA,
+				 Kern::Printf("TDmaChannel::IsrRedoRequest src=0x%08x, "
+							  "dst=0x%08x, count=%d, pslInfo=0x%08x, isrCb=%d",
+							  aSrcAddr, aDstAddr, aTransferCount, aPslRequestInfo,
+							  aIsrCb));
+	// Function needs to be called in ISR context.
+	__DMA_ASSERTD(NKern::CurrentContext() == NKern::EInterrupt);
+
+	__DMA_ASSERTD(!iReqQ.IsEmpty());
+	__DMA_ASSERTD(iIsrCbRequest);
+
+#ifdef _DEBUG
+	if ((aSrcAddr != KPhysAddrInvalid) && (aSrcAddr == aDstAddr))
+		{
+		__KTRACE_OPT(KPANIC,
+					 Kern::Printf("Error: Updating src & dst to same address: 0x%08x",
+								  aSrcAddr));
+		return KErrArgument;
+		}
+#endif
+
+	// We assume here that the just completed request is the first one in the
+	// queue, i.e. that even if there is more than one request in the queue,
+	// their respective last and first (hw) descriptors are *not* linked.
+	// (Although that's what apparently happens in TDmaSgChannel::DoQueue() /
+	// TDmac::AppendHwDes() @@@).
+	DDmaRequest* const pCurReq = _LOFF(iReqQ.First(), DDmaRequest, iLink);
+	TInt r;
+
+	if (iDmacCaps->iAsymHwDescriptors)
+		{
+		// We don't allow multiple-descriptor chains to be updated here
+		__DMA_ASSERTD((pCurReq->iSrcDesCount == 1) && (pCurReq->iDstDesCount == 1));
+		// Adjust parameters if necessary (asymmetrical s/g variety)
+		const SDmaDesHdr* const pSrcFirstHdr = pCurReq->iSrcFirstHdr;
+		if ((aSrcAddr != KPhysAddrInvalid) || aTransferCount || aPslRequestInfo)
+			{
+			r = iController->UpdateSrcHwDes(*pSrcFirstHdr, aSrcAddr,
+											aTransferCount, aPslRequestInfo);
+			if (r != KErrNone)
+				{
+				__KTRACE_OPT(KPANIC, Kern::Printf("Src descriptor updating failed in PSL"));
+				return r;
+				}
+			}
+		const SDmaDesHdr* const pDstFirstHdr = pCurReq->iDstFirstHdr;
+		if ((aDstAddr != KPhysAddrInvalid) || aTransferCount || aPslRequestInfo)
+			{
+			r = iController->UpdateDstHwDes(*pDstFirstHdr, aSrcAddr,
+											aTransferCount, aPslRequestInfo);
+			if (r != KErrNone)
+				{
+				__KTRACE_OPT(KPANIC, Kern::Printf("Dst descriptor updating failed in PSL"));
+				return r;
+				}
+			}
+		// Reschedule the request
+		iController->Transfer(*this, *pSrcFirstHdr, *pDstFirstHdr);
+		}
+	else
+		{
+		// We don't allow multiple-descriptor chains to be updated here
+		__DMA_ASSERTD(pCurReq->iDesCount == 1);
+		// Adjust parameters if necessary (symmetrical s/g and non-s/g variety)
+		const SDmaDesHdr* const pFirstHdr = pCurReq->iFirstHdr;
+		if ((aSrcAddr != KPhysAddrInvalid) || (aDstAddr != KPhysAddrInvalid) ||
+			aTransferCount || aPslRequestInfo)
+			{
+			r = iController->UpdateDes(*pFirstHdr, aSrcAddr, aDstAddr,
+									   aTransferCount, aPslRequestInfo);
+			if (r != KErrNone)
+				{
+				__KTRACE_OPT(KPANIC, Kern::Printf("Descriptor updating failed"));
+				return r;
+				}
+			}
+		// Reschedule the request
+		iController->Transfer(*this, *pFirstHdr);
+		}
+
+	if (!aIsrCb)
+		{
+		// Not another ISR callback please
+		pCurReq->iIsrCb = aIsrCb;
+		}
+	iRedoRequest = ETrue;
+
+	return KErrNone;
+	}
+
+
+EXPORT_C TInt TDmaChannel::FailNext(TInt /*aFragmentCount*/)
+	{
+	return iController->FailNext(*this);
+	}
+
+
+EXPORT_C TInt TDmaChannel::MissNextInterrupts(TInt aInterruptCount)
+	{
+	return iController->MissNextInterrupts(*this, aInterruptCount);
+	}
+
+
+EXPORT_C TInt TDmaChannel::Extension(TInt aCmd, TAny* aArg)
+	{
+	return iController->Extension(*this, aCmd, aArg);
+	}
+
+
+//
+// static member function
+//
+EXPORT_C TInt TDmaChannel::StaticExtension(TInt aCmd, TAny* aArg)
+	{
+	return DmaChannelMgr::StaticExtension(aCmd, aArg);
+	}
+
+
+EXPORT_C TUint TDmaChannel::MaxTransferLength(TUint aSrcFlags, TUint aDstFlags,
+											  TUint32 aPslInfo)
+	{
+	return iController->MaxTransferLength(*this, aSrcFlags, aDstFlags, aPslInfo);
+	}
+
+
+EXPORT_C TUint TDmaChannel::AddressAlignMask(TUint aTargetFlags, TUint aElementSize,
+											 TUint32 aPslInfo)
+	{
+	return iController->AddressAlignMask(*this, aTargetFlags, aElementSize, aPslInfo);
+	}
+
+
+EXPORT_C const SDmacCaps& TDmaChannel::DmacCaps()
+	{
+	return *iDmacCaps;
+	}
+
+
+//
+// DFC callback function (static member).
+//
+void TDmaChannel::Dfc(TAny* aArg)
+	{
+	static_cast<TDmaChannel*>(aArg)->DoDfc();
+	}
+
+
+//
+// This is quite a long function, but what can you do...
+//
+void TDmaChannel::DoDfc()
+	{
+	__KTRACE_OPT(KDMA, Kern::Printf("TDmaChannel::DoDfc thread %O channel - %d",
+									&Kern::CurrentThread(), iPslId));
+	Wait();
+
+	// Atomically fetch and reset the number of DFCs queued by the ISR and the
+	// error flag. Leave the cancel flag alone for now.
+	const TUint32 w = __e32_atomic_and_ord32(&iIsrDfc, (TUint32)KCancelFlagMask);
+	TUint32 count = w & KDfcCountMask;
+	const TBool error = w & (TUint32)KErrorFlagMask;
+	TBool stop = w & (TUint32)KCancelFlagMask;
+	__DMA_ASSERTD((count > 0) || stop);
+
+	__DMA_ASSERTD(!iRedoRequest); // We shouldn't be here if this is true
+
+	while (count && !stop)
+		{
+		--count;
+
+		__DMA_ASSERTD(!iReqQ.IsEmpty());
+
+		// If an error occurred it must have been reported on the last
+		// interrupt since transfers are suspended after an error.
+		DDmaRequest::TResult const res = (count == 0 && error) ?
+			DDmaRequest::EError : DDmaRequest::EOk;
+		DDmaRequest* pCompletedReq = NULL;
+		DDmaRequest* const pCurReq = _LOFF(iReqQ.First(), DDmaRequest, iLink);
+
+		if (res == DDmaRequest::EOk)
+			{
+			// Update state machine, current fragment, completed fragment and
+			// tell the DMAC to transfer the next fragment if necessary.
+			SDmaDesHdr* pCompletedHdr = NULL;
+			DoDfc(const_cast<const DDmaRequest&>(*pCurReq), pCompletedHdr);
+
+			// If just completed last fragment from current request, switch to
+			// next request (if any).
+			if (pCompletedHdr == pCurReq->iLastHdr)
+				{
+				pCompletedReq = pCurReq;
+				pCurReq->iLink.Deque();
+				if (iReqQ.IsEmpty())
+					iNullPtr = &iCurHdr;
+				pCompletedReq->OnDeque();
+				}
+			}
+		else
+			{
+			pCompletedReq = pCurReq;
+			}
+
+		if (pCompletedReq && !pCompletedReq->iIsrCb)
+			{
+			// Don't execute ISR callbacks here (they have already been called)
+			DDmaRequest::TCallback const cb = pCompletedReq->iCb;
+			if (cb)
+				{
+				// Old style callback
+				TAny* const arg = pCompletedReq->iCbArg;
+				Signal();
+				__KTRACE_OPT(KDMA, Kern::Printf("Client CB res=%d", res));
+				(*cb)(res, arg);
+				Wait();
+				}
+			else
+				{
+				// New style callback
+				TDmaCallback const ncb = pCompletedReq->iDmaCb;
+				if (ncb)
+					{
+					TAny* const arg = pCompletedReq->iDmaCbArg;
+					TDmaResult const result = (res == DDmaRequest::EOk) ?
+						EDmaResultOK : EDmaResultError;
+					Signal();
+					__KTRACE_OPT(KDMA, Kern::Printf("Client CB result=%d", result));
+					(*ncb)(EDmaCallbackRequestCompletion, result, arg, NULL);
+					Wait();
+					}
+				}
+			}
+		else
+			{
+			// Allow another thread in, in case they are trying to cancel
+			Flash();
+			}
+		stop = __e32_atomic_load_acq32(&iIsrDfc) & (TUint32)KCancelFlagMask;
+		}
+
+	// Some interrupts may be missed (double-buffer and scatter-gather
+	// controllers only) if two or more transfers complete while interrupts are
+	// disabled in the CPU. If this happens, the framework will go out of sync
+	// and leave some orphaned requests in the queue.
+	//
+	// To ensure correctness we handle this case here by checking that the request
+	// queue is empty when all transfers have completed and, if not, cleaning up
+	// and notifying the client of the completion of the orphaned requests.
+	//
+	// Note that if some interrupts are missed and the controller raises an
+	// error while transferring a subsequent fragment, the error will be reported
+	// on a fragment which was successfully completed.  There is no easy solution
+	// to this problem, but this is okay as the only possible action following a
+	// failure is to flush the whole queue.
+	if (stop)
+		{
+		// If another thread set the cancel flag, it should have
+		// cleaned up the request queue
+		__DMA_ASSERTD(IsQueueEmpty());
+
+		TDmaCancelInfo* const waiters = iCancelInfo;
+		iCancelInfo = NULL;
+
+		// make sure DFC doesn't run again until a new request completes
+		iDfc.Cancel();
+
+		// reset the ISR count - new requests can now be processed
+		__e32_atomic_store_rel32(&iIsrDfc, 0);
+
+		Signal();
+
+		// release threads doing CancelAll()
+		waiters->Signal();
+		}
+	else if (!error && !iReqQ.IsEmpty() && iController->IsIdle(*this))
+		{
+#ifdef __SMP__
+		// On an SMP system we must call stop transfer, it will block until
+		// any ISRs have completed so that the system does not spuriously
+		// attempt to recover from a missed interrupt.
+		//
+		// On an SMP system it is possible for the code here to execute
+		// concurrently with the DMA ISR. It is therefore possible that at this
+		// point the previous transfer has already completed (so that IsIdle
+		// reports true), but that the ISR has not yet queued a DFC. Therefore
+		// we must wait for the ISR to complete.
+		//
+		// StopTransfer should have no other side effect, given that the
+		// channel is already idle.
+		iController->StopTransfer(*this); // should block till ISR completion
+#endif
+
+		const TBool cleanup = !iDfc.Queued();
+		if(cleanup)
+			{
+			__KTRACE_OPT(KDMA, Kern::Printf("Missed interrupt(s) - draining request queue"));
+			ResetStateMachine();
+
+			// Move orphaned requests to temporary queue so channel queue can
+			// accept new requests.
+			SDblQue q;
+			q.MoveFrom(&iReqQ);
+
+			SDblQueLink* pL;
+			while ((pL = q.GetFirst()) != NULL)
+				{
+				DDmaRequest* const pR = _LOFF(pL, DDmaRequest, iLink);
+				__KTRACE_OPT(KDMA, Kern::Printf("Removing request from queue and notifying client"));
+				pR->OnDeque();
+				// Old style callback
+				DDmaRequest::TCallback const cb = pR->iCb;
+				if (cb)
+					{
+					TAny* const arg = pR->iCbArg;
+					Signal();
+					(*cb)(DDmaRequest::EOk, arg);
+					Wait();
+					}
+				else
+					{
+					// New style callback
+					TDmaCallback const ncb = pR->iDmaCb;
+					if (ncb)
+						{
+						TAny* const arg = pR->iDmaCbArg;
+						Signal();
+						(*ncb)(EDmaCallbackRequestCompletion, EDmaResultOK, arg, NULL);
+						Wait();
+						}
+					}
+				}
+			}
+		Signal();
+		}
+	else
+		Signal();
+
+	__DMA_INVARIANT();
+	}
+
+
+//
+// Reset state machine only, request queue is unchanged */
+//
+void TDmaChannel::ResetStateMachine()
+	{
+	DoCancelAll();
+	iCurHdr = NULL;
+	iNullPtr = &iCurHdr;
+	}
+
+
+void TDmaChannel::DoQueue(const DDmaRequest& /*aReq*/)
+	{
+	// Must be overridden
+	__DMA_CANT_HAPPEN();
+	}
+
+
+//
+// Unlink the last item of a LLI chain from the next chain.
+// Default implementation does nothing. This is overridden by scatter-gather
+// channels.
+//
+void TDmaChannel::DoUnlink(SDmaDesHdr& /*aHdr*/)
+	{
+	}
+
+
+void TDmaChannel::DoDfc(const DDmaRequest& /*aCurReq*/, SDmaDesHdr*& /*aCompletedHdr*/)
+	{
+	// To make sure this version of the function isn't called for channels for
+	// which it isn't appropriate (and which therefore don't override it) we
+	// put this check in here.
+	__DMA_CANT_HAPPEN();
+	}
+
+
+void TDmaChannel::DoDfc(const DDmaRequest& /*aCurReq*/, SDmaDesHdr*& /*aSrcCompletedHdr*/,
+						SDmaDesHdr*& /*aDstCompletedHdr*/)
+	{
+	// To make sure this version of the function isn't called for channels for
+	// which it isn't appropriate (and which therefore don't override it) we
+	// put this check in here.
+	__DMA_CANT_HAPPEN();
+	}
+
+
+#ifdef _DEBUG
+void TDmaChannel::Invariant()
+	{
+	Wait();
+
+	__DMA_ASSERTD(iReqCount >= 0);
+
+	__DMA_ASSERTD(iCurHdr == NULL || iController->IsValidHdr(iCurHdr));
+
+	// should always point to NULL pointer ending fragment queue
+	__DMA_ASSERTD(*iNullPtr == NULL);
+
+	__DMA_ASSERTD((0 <= iAvailDesCount) && (iAvailDesCount <= iMaxDesCount));
+
+	__DMA_ASSERTD(LOGICAL_XOR(iCurHdr, IsQueueEmpty()));
+	if (iCurHdr == NULL)
+		{
+		__DMA_ASSERTD(iNullPtr == &iCurHdr);
+		}
+
+	Signal();
+	}
+#endif
+
+
+//////////////////////////////////////////////////////////////////////////////
+// TDmaSbChannel
+
+void TDmaSbChannel::DoQueue(const DDmaRequest& /*aReq*/)
+	{
+	if (iState != ETransferring)
+		{
+		iController->Transfer(*this, *iCurHdr);
+		iState = ETransferring;
+		}
+	}
+
+
+void TDmaSbChannel::DoCancelAll()
+	{
+	__DMA_ASSERTD(iState == ETransferring);
+	iState = EIdle;
+	}
+
+
+void TDmaSbChannel::DoDfc(const DDmaRequest& /*aCurReq*/, SDmaDesHdr*& aCompletedHdr)
+	{
+	__DMA_ASSERTD(iState == ETransferring);
+	aCompletedHdr = iCurHdr;
+	iCurHdr = iCurHdr->iNext;
+	if (iCurHdr != NULL)
+		{
+		iController->Transfer(*this, *iCurHdr);
+		}
+	else
+		{
+		iState = EIdle;
+		}
+	}
+
+
+//////////////////////////////////////////////////////////////////////////////
+// TDmaDbChannel
+
+void TDmaDbChannel::DoQueue(const DDmaRequest& aReq)
+	{
+	switch (iState)
+		{
+	case EIdle:
+		iController->Transfer(*this, *iCurHdr);
+		if (iCurHdr->iNext)
+			{
+			iController->Transfer(*this, *(iCurHdr->iNext));
+			iState = ETransferring;
+			}
+		else
+			iState = ETransferringLast;
+		break;
+	case ETransferring:
+		// nothing to do
+		break;
+	case ETransferringLast:
+		iController->Transfer(*this, *(aReq.iFirstHdr));
+		iState = ETransferring;
+		break;
+	default:
+		__DMA_CANT_HAPPEN();
+		}
+	}
+
+
+void TDmaDbChannel::DoCancelAll()
+	{
+	iState = EIdle;
+	}
+
+
+void TDmaDbChannel::DoDfc(const DDmaRequest& /*aCurReq*/, SDmaDesHdr*& aCompletedHdr)
+	{
+	aCompletedHdr = iCurHdr;
+	iCurHdr = iCurHdr->iNext;
+	switch (iState)
+		{
+	case ETransferringLast:
+		iState = EIdle;
+		break;
+	case ETransferring:
+		if (iCurHdr->iNext == NULL)
+			iState = ETransferringLast;
+		else
+			iController->Transfer(*this, *(iCurHdr->iNext));
+		break;
+	default:
+		__DMA_CANT_HAPPEN();
+		}
+	}
+
+
+//////////////////////////////////////////////////////////////////////////////
+// TDmaSgChannel
+
+void TDmaSgChannel::DoQueue(const DDmaRequest& aReq)
+	{
+	if (iState == ETransferring)
+		{
+		__DMA_ASSERTD(!aReq.iLink.Alone());
+		DDmaRequest* pReqPrev = _LOFF(aReq.iLink.iPrev, DDmaRequest, iLink);
+		iController->AppendHwDes(*this, *(pReqPrev->iLastHdr), *(aReq.iFirstHdr));
+		}
+	else
+		{
+		iController->Transfer(*this, *(aReq.iFirstHdr));
+		iState = ETransferring;
+		}
+	}
+
+
+void TDmaSgChannel::DoCancelAll()
+	{
+	__DMA_ASSERTD(iState == ETransferring);
+	iState = EIdle;
+	}
+
+
+void TDmaSgChannel::DoUnlink(SDmaDesHdr& aHdr)
+	{
+	iController->UnlinkHwDes(*this, aHdr);
+	}
+
+
+void TDmaSgChannel::DoDfc(const DDmaRequest& aCurReq, SDmaDesHdr*& aCompletedHdr)
+	{
+	__DMA_ASSERTD(iState == ETransferring);
+	aCompletedHdr = aCurReq.iLastHdr;
+	iCurHdr = aCompletedHdr->iNext;
+	iState = (iCurHdr != NULL) ? ETransferring : EIdle;
+	}
+
+
+//////////////////////////////////////////////////////////////////////////////
+// TDmaAsymSgChannel
+
+void TDmaAsymSgChannel::DoQueue(const DDmaRequest& aReq)
+	{
+	if (iState == ETransferring)
+		{
+		__DMA_ASSERTD(!aReq.iLink.Alone());
+		DDmaRequest* pReqPrev = _LOFF(aReq.iLink.iPrev, DDmaRequest, iLink);
+		iController->AppendHwDes(*this,
+								 *(pReqPrev->iSrcLastHdr), *(aReq.iSrcFirstHdr),
+								 *(pReqPrev->iDstLastHdr), *(aReq.iDstFirstHdr));
+		}
+	else
+		{
+		iController->Transfer(*this, *(aReq.iSrcFirstHdr), *(aReq.iDstFirstHdr));
+		iState = ETransferring;
+		}
+	}
+
+
+void TDmaAsymSgChannel::DoCancelAll()
+	{
+	__DMA_ASSERTD(iState == ETransferring);
+	iState = EIdle;
+	}
+
+
+void TDmaAsymSgChannel::DoUnlink(SDmaDesHdr& aHdr)
+	{
+	iController->UnlinkHwDes(*this, aHdr);
+	}
+
+
+void TDmaAsymSgChannel::DoDfc(const DDmaRequest& aCurReq, SDmaDesHdr*& aSrcCompletedHdr,
+							  SDmaDesHdr*& aDstCompletedHdr)
+	{
+	__DMA_ASSERTD(iState == ETransferring);
+	aSrcCompletedHdr = aCurReq.iSrcLastHdr;
+	iSrcCurHdr = aSrcCompletedHdr->iNext;
+	aDstCompletedHdr = aCurReq.iDstLastHdr;
+	iDstCurHdr = aDstCompletedHdr->iNext;
+	// Must be either both NULL or none of them.
+	__DMA_ASSERTD(!LOGICAL_XOR(iSrcCurHdr, iDstCurHdr));
+	iState = (iSrcCurHdr != NULL) ? ETransferring : EIdle;
+	}
+