os/kernelhwsrv/kernel/eka/drivers/usbc/usbdma.cpp
changeset 0 bde4ae8d615e
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/os/kernelhwsrv/kernel/eka/drivers/usbc/usbdma.cpp	Fri Jun 15 03:10:57 2012 +0200
     1.3 @@ -0,0 +1,983 @@
     1.4 +// Copyright (c) 2000-2009 Nokia Corporation and/or its subsidiary(-ies).
     1.5 +// All rights reserved.
     1.6 +// This component and the accompanying materials are made available
     1.7 +// under the terms of the License "Eclipse Public License v1.0"
     1.8 +// which accompanies this distribution, and is available
     1.9 +// at the URL "http://www.eclipse.org/legal/epl-v10.html".
    1.10 +//
    1.11 +// Initial Contributors:
    1.12 +// Nokia Corporation - initial contribution.
    1.13 +//
    1.14 +// Contributors:
    1.15 +//
    1.16 +// Description:
    1.17 +// e32\drivers\usbc\usbdma.cpp
    1.18 +// LDD for USB Device driver stack:
    1.19 +// Management of DMA-capable data buffers.
    1.20 +// 
    1.21 +//
    1.22 +
    1.23 +/**
    1.24 + @file usbdma.cpp
    1.25 + @internalTechnology
    1.26 +*/
    1.27 +
    1.28 +#include <drivers/usbc.h>
    1.29 +
    1.30 +
    1.31 +#if defined(_DEBUG)
    1.32 +static const char KUsbPanicLdd[] = "USB LDD";
    1.33 +#endif
    1.34 +
    1.35 +
    1.36 +TDmaBuf::TDmaBuf(TUsbcEndpointInfo* aEndpointInfo, TInt aBandwidthPriority)
    1.37 +	: iBufBasePtr(NULL),
    1.38 +	  iCurrentDrainingBuffer(NULL),
    1.39 +	  iCurrentPacket(0),
    1.40 +	  iCurrentPacketIndexArray(NULL),
    1.41 +	  iCurrentPacketSizeArray(NULL)
    1.42 +	{
    1.43 +	iMaxPacketSize = aEndpointInfo->iSize;
    1.44 +	iEndpointType = aEndpointInfo->iType;
    1.45 +
    1.46 +	switch (aEndpointInfo->iType)
    1.47 +		{
    1.48 +	case KUsbEpTypeControl:
    1.49 +		iBufSz = KUsbcDmaBufSzControl;
    1.50 +		iNumberofBuffers = KUsbcDmaBufNumControl;
    1.51 +		break;
    1.52 +	case KUsbEpTypeIsochronous:
    1.53 +		iBufSz = KUsbcDmaBufSzIsochronous;
    1.54 +		iNumberofBuffers = KUsbcDmaBufNumIsochronous;
    1.55 +		break;
    1.56 +	case KUsbEpTypeBulk:
    1.57 +		{
    1.58 +		if (aEndpointInfo->iDir == KUsbEpDirOut)
    1.59 +			{
    1.60 +			const TInt priorityOUT = aBandwidthPriority & 0x0f;
    1.61 +			iBufSz = KUsbcDmaBufSizesBulkOUT[priorityOUT];
    1.62 +			}
    1.63 +		else
    1.64 +			{
    1.65 +			const TInt priorityIN = (aBandwidthPriority >> 4) & 0x0f;
    1.66 +			iBufSz = KUsbcDmaBufSizesBulkIN[priorityIN];
    1.67 +			}
    1.68 +		iNumberofBuffers = KUsbcDmaBufNumBulk;
    1.69 +		}
    1.70 +		break;
    1.71 +	case KUsbEpTypeInterrupt:
    1.72 +		iBufSz = KUsbcDmaBufSzInterrupt;
    1.73 +		iNumberofBuffers = KUsbcDmaBufNumInterrupt;
    1.74 +		break;
    1.75 +	default:
    1.76 +		iBufSz = 0;
    1.77 +		iNumberofBuffers = 0;
    1.78 +		}
    1.79 +
    1.80 +	if (aEndpointInfo->iDir == KUsbEpDirIn)
    1.81 +		{
    1.82 +		iNumberofBuffers = 1;								// IN endpoints only have 1 buffer
    1.83 +		}
    1.84 +
    1.85 +	for (TInt i = 0; i < KUsbcDmaBufNumMax; i++)
    1.86 +		{
    1.87 +		// Buffer logical addresses (pointers)
    1.88 +		iBuffers[i] = NULL;
    1.89 +		// Buffer physical addresses
    1.90 +		iBufferPhys[i] = 0;
    1.91 +		// Packet indexes base array
    1.92 +		iPacketIndex[i] = NULL;
    1.93 +		// Packet sizes base array
    1.94 +		iPacketSize[i] = NULL;
    1.95 +		}
    1.96 +	}
    1.97 +
    1.98 +
    1.99 +TInt TDmaBuf::Construct(TUsbcEndpointInfo* aEndpointInfo)
   1.100 +	{
   1.101 +	if (aEndpointInfo->iDir != KUsbEpDirIn)
   1.102 +		{
   1.103 +		// IN endpoints don't need a packet array
   1.104 +
   1.105 +		// At most 2 packets (clump of max packet size packets) + possible zlp
   1.106 +		TUsbcPacketArray* bufPtr = iPacketInfoStorage;
   1.107 +		// this divides up the packet indexing & packet size array over the number of buffers
   1.108 +		__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::Construct() array base=0x%08x", bufPtr));
   1.109 +		for (TInt i = 0; i < iNumberofBuffers; i++)
   1.110 +			{
   1.111 +			iPacketIndex[i] = bufPtr;
   1.112 +			bufPtr += KUsbcDmaBufMaxPkts;
   1.113 +			iPacketSize[i] = bufPtr;
   1.114 +			bufPtr += KUsbcDmaBufMaxPkts;
   1.115 +			__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::Construct() packetIndex[%d]=0x%08x packetSize[%d]=0x%08x",
   1.116 +											i, iPacketIndex[i], i, iPacketSize[i]));
   1.117 +			}
   1.118 +		}
   1.119 +	else
   1.120 +		{
   1.121 +		__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::Construct() IN endpoint"));
   1.122 +		}
   1.123 +	Flush();
   1.124 +	return KErrNone;
   1.125 +	}
   1.126 +
   1.127 +
   1.128 +TDmaBuf::~TDmaBuf()
   1.129 +	{
   1.130 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::~TDmaBuf()"));
   1.131 +	}
   1.132 +
   1.133 +TInt TDmaBuf::BufferTotalSize() const
   1.134 +	{
   1.135 +	return iBufSz * iNumberofBuffers;
   1.136 +	}
   1.137 +
   1.138 +TInt TDmaBuf::BufferSize() const
   1.139 +    {
   1.140 +    return iBufSz;
   1.141 +    }
   1.142 +
   1.143 +TInt TDmaBuf::SetBufferAddr(TInt aBufInd, TUint8* aBufAddr)
   1.144 +    {
   1.145 +    __ASSERT_DEBUG((aBufInd < iNumberofBuffers),
   1.146 +                       Kern::Fault(KUsbPanicLdd, __LINE__));
   1.147 +    iDrainable[aBufInd] = iCanBeFreed[aBufInd] = EFalse;
   1.148 +    iBuffers[aBufInd] = aBufAddr;
   1.149 +    iBufferPhys[aBufInd] = Epoc::LinearToPhysical((TLinAddr)aBufAddr);
   1.150 +    __KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::SetBufferAddr() iBuffers[%d]=0x%08x", aBufInd, iBuffers[aBufInd]));
   1.151 +    return KErrNone;
   1.152 +    }
   1.153 +
   1.154 +TInt TDmaBuf::BufferNumber() const
   1.155 +    {
   1.156 +    return iNumberofBuffers;
   1.157 +    }
   1.158 +
   1.159 +void TDmaBuf::SetMaxPacketSize(TInt aSize)
   1.160 +	{
   1.161 +	iMaxPacketSize = aSize;
   1.162 +	}
   1.163 +
   1.164 +
   1.165 +void TDmaBuf::Flush()
   1.166 +	{
   1.167 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::Flush %x", this));
   1.168 +	iRxActive = EFalse;
   1.169 +	iTxActive = EFalse;
   1.170 +	iExtractOffset = 0;
   1.171 +	iTotalRxBytesAvail = 0;
   1.172 +	iTotalRxPacketsAvail = 0;
   1.173 +	iCurrentDrainingBufferIndex = KUsbcInvalidBufferIndex;
   1.174 +	iCurrentFillingBufferIndex = 0;
   1.175 +	iDrainQueueIndex = KUsbcInvalidDrainQueueIndex;
   1.176 +	for (TInt i = 0; i < KUsbcDmaBufNumMax; i++)
   1.177 +		{
   1.178 +		iDrainable[i] = EFalse;
   1.179 +		iCanBeFreed[i] = EFalse;
   1.180 +		iNumberofBytesRx[i] = 0;
   1.181 +		iNumberofPacketsRx[i] = 0;
   1.182 +		iError[i] = KErrGeneral;
   1.183 +		iDrainQueue[i] = KUsbcInvalidBufferIndex;
   1.184 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.185 +		iFillingOrderArray[i] = 0;
   1.186 +		iNumberofBytesRxRemain[i] = 0;
   1.187 +		iNumberofPacketsRxRemain[i] = 0;
   1.188 +#endif
   1.189 +		}
   1.190 +	// Drain queue is 1 oversized
   1.191 +	iDrainQueue[KUsbcDmaBufNumMax] = KUsbcInvalidBufferIndex;
   1.192 +
   1.193 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.194 +	iFillingOrder = 0;
   1.195 +	iDrainingOrder = 0;
   1.196 +#endif
   1.197 +	}
   1.198 +
   1.199 +
   1.200 +void TDmaBuf::RxSetActive()
   1.201 +	{
   1.202 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxSetActive %x", this));
   1.203 +	iRxActive = ETrue;
   1.204 +	}
   1.205 +
   1.206 +
   1.207 +void TDmaBuf::RxSetInActive()
   1.208 +	{
   1.209 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxSetInActive %x", this));
   1.210 +	iRxActive = EFalse;
   1.211 +	}
   1.212 +
   1.213 +
   1.214 +TBool TDmaBuf::RxIsActive()
   1.215 +	{
   1.216 +	return iRxActive;
   1.217 +	}
   1.218 +
   1.219 +
   1.220 +void TDmaBuf::TxSetActive()
   1.221 +	{
   1.222 +	iTxActive = ETrue;
   1.223 +	}
   1.224 +
   1.225 +
   1.226 +void TDmaBuf::TxSetInActive()
   1.227 +	{
   1.228 +	iTxActive = EFalse;
   1.229 +	}
   1.230 +
   1.231 +
   1.232 +TBool TDmaBuf::TxIsActive()
   1.233 +	{
   1.234 +	return iTxActive;
   1.235 +	}
   1.236 +
   1.237 +
   1.238 +/**************************** Rx DMA Buffer Access *************************/
   1.239 +
   1.240 +void TDmaBuf::ModifyTotalRxBytesAvail(TInt aVal)
   1.241 +	{
   1.242 +	iTotalRxBytesAvail += aVal;
   1.243 +	}
   1.244 +
   1.245 +
   1.246 +void TDmaBuf::ModifyTotalRxPacketsAvail(TInt aVal)
   1.247 +	{
   1.248 +	iTotalRxPacketsAvail += aVal;
   1.249 +	}
   1.250 +
   1.251 +
   1.252 +TBool TDmaBuf::AdvancePacket()
   1.253 +	{
   1.254 +	ModifyTotalRxPacketsAvail(-1);
   1.255 +	TBool r = ETrue;
   1.256 +	__ASSERT_DEBUG((iCurrentDrainingBufferIndex >= 0),
   1.257 +					   Kern::Fault(KUsbPanicLdd, __LINE__));
   1.258 +	if (++iCurrentPacket >= iNumberofPacketsRx[iCurrentDrainingBufferIndex])
   1.259 +		{
   1.260 +		r = NextDrainableBuffer();
   1.261 +		}
   1.262 +	iExtractOffset = 0;
   1.263 +	__ASSERT_DEBUG((iCurrentDrainingBufferIndex == KUsbcInvalidBufferIndex) ||
   1.264 +				   (iCurrentPacket < KUsbcDmaBufMaxPkts),
   1.265 +				   Kern::Fault(KUsbPanicLdd, __LINE__));
   1.266 +	return r;
   1.267 +	}
   1.268 +
   1.269 +
   1.270 +TInt TDmaBuf::PeekNextPacketSize()
   1.271 +	{
   1.272 +	TUint pkt = iCurrentPacket;
   1.273 +	TInt index = iCurrentDrainingBufferIndex;
   1.274 +	TInt size = -1;
   1.275 +	if (pkt >= iNumberofPacketsRx[index])
   1.276 +		{
   1.277 +		index = PeekNextDrainableBuffer();
   1.278 +		pkt = 0;
   1.279 +		}
   1.280 +
   1.281 +	if ((index != KUsbcInvalidBufferIndex) && iNumberofPacketsRx[index])
   1.282 +		{
   1.283 +		const TUsbcPacketArray* sizeArray = iPacketSize[index];
   1.284 +		size = (TInt)sizeArray[pkt];
   1.285 +		}
   1.286 +
   1.287 +	__ASSERT_DEBUG((iCurrentDrainingBufferIndex == KUsbcInvalidBufferIndex) ||
   1.288 +				   (iCurrentPacket < KUsbcDmaBufMaxPkts),
   1.289 +				   Kern::Fault(KUsbPanicLdd, __LINE__));
   1.290 +	return size;
   1.291 +	}
   1.292 +
   1.293 +
   1.294 +inline TInt TDmaBuf::GetCurrentError()
   1.295 +	{
   1.296 +	// USB bus errors are v.rare. To avoid having an error code attached to every packet since
   1.297 +	// almost every errorcode will be KErrNone, we have a single error code per buffer
   1.298 +	// If the error code is != KErrNone then it refers to the LAST packet in the buffer
   1.299 +	TInt errorCode = KErrNone;
   1.300 +	//Check the index, it's not equal to negative (-1) value defined in 
   1.301 +	//KUsbcInvalidBufferIndex.
   1.302 +	__ASSERT_DEBUG((iCurrentDrainingBufferIndex >= 0),
   1.303 +					   Kern::Fault(KUsbPanicLdd, __LINE__));
   1.304 +	
   1.305 +	if (iError[iCurrentDrainingBufferIndex] != KErrNone)
   1.306 +		{
   1.307 +		// See if we are at the last packet
   1.308 +		if ((iCurrentPacket + 1) == iNumberofPacketsRx[iCurrentDrainingBufferIndex])
   1.309 +			{
   1.310 +			errorCode = iError[iCurrentDrainingBufferIndex];
   1.311 +			}
   1.312 +		}
   1.313 +	return errorCode;
   1.314 +	}
   1.315 +
   1.316 +
   1.317 +// used to decide whether a client read can complete straight away
   1.318 +TBool TDmaBuf::IsReaderEmpty()
   1.319 +	{
   1.320 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::IsReaderEmpty iTotalRxPacketsAvail=%d",
   1.321 +									iTotalRxPacketsAvail));
   1.322 +	return (iTotalRxPacketsAvail == 0);
   1.323 +	}
   1.324 +
   1.325 +
   1.326 +void TDmaBuf::ReadXferComplete(TInt aNoBytesRecv, TInt aNoPacketsRecv, TInt aErrorCode)
   1.327 +	{
   1.328 +	// Adjust pending packet
   1.329 +	if ((aNoBytesRecv == 0) && (aErrorCode != KErrNone))
   1.330 +		{
   1.331 +		// Make the buffer available for reuse
   1.332 +		iDrainable[iCurrentFillingBufferIndex] = EFalse;
   1.333 +		return;
   1.334 +		}
   1.335 +
   1.336 +	ModifyTotalRxBytesAvail(aNoBytesRecv);
   1.337 +	ModifyTotalRxPacketsAvail(aNoPacketsRecv);
   1.338 +	iNumberofBytesRx[iCurrentFillingBufferIndex] = aNoBytesRecv;
   1.339 +	iNumberofPacketsRx[iCurrentFillingBufferIndex] = aNoPacketsRecv;
   1.340 +
   1.341 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.342 +	iNumberofBytesRxRemain[iCurrentFillingBufferIndex] = aNoBytesRecv;
   1.343 +	iNumberofPacketsRxRemain[iCurrentFillingBufferIndex] = aNoPacketsRecv;
   1.344 +#endif
   1.345 +
   1.346 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::ReadXferComplete 2 # of bytes=%d # of packets=%d",
   1.347 +									iTotalRxBytesAvail, iTotalRxPacketsAvail));
   1.348 +	iDrainable[iCurrentFillingBufferIndex] = ETrue;
   1.349 +	iError[iCurrentFillingBufferIndex] = aErrorCode;
   1.350 +	AddToDrainQueue(iCurrentFillingBufferIndex);
   1.351 +	if (iCurrentDrainingBufferIndex == KUsbcInvalidBufferIndex)
   1.352 +		{
   1.353 +		NextDrainableBuffer();
   1.354 +		}
   1.355 +	}
   1.356 +
   1.357 +
   1.358 +TInt TDmaBuf::RxGetNextXfer(TUint8*& aBufferAddr, TUsbcPacketArray*& aIndexArray,
   1.359 +							TUsbcPacketArray*& aSizeArray, TInt& aLength, TPhysAddr& aBufferPhys)
   1.360 +	{
   1.361 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxGetNextXfer 1"));
   1.362 +	if (RxIsActive())
   1.363 +		{
   1.364 +		__KTRACE_OPT(KUSB, Kern::Printf(" ---> RxIsActive, returning"));
   1.365 +		return KErrInUse;
   1.366 +		}
   1.367 +
   1.368 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxGetNextXfer Current buffer=%d",
   1.369 +									iCurrentFillingBufferIndex));
   1.370 +	if (iDrainable[iCurrentFillingBufferIndex])
   1.371 +		{
   1.372 +		// If the controller refused the last read request, then the current buffer will still be marked
   1.373 +		// as !Drainable, because the controller never completed the read to the ldd. and therefore the buffer
   1.374 +		// can be reused.
   1.375 +		if (!NextFillableBuffer())
   1.376 +			{
   1.377 +			return KErrNoMemory;
   1.378 +			}
   1.379 +		}
   1.380 +
   1.381 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxGetNextXfer New buffer=%d",
   1.382 +									iCurrentFillingBufferIndex));
   1.383 +	aBufferAddr = iBuffers[iCurrentFillingBufferIndex];
   1.384 +	aBufferPhys = iBufferPhys[iCurrentFillingBufferIndex];
   1.385 +	aIndexArray = iPacketIndex[iCurrentFillingBufferIndex];
   1.386 +	aSizeArray = iPacketSize[iCurrentFillingBufferIndex];
   1.387 +	aLength = iBufSz;
   1.388 +
   1.389 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.390 +	iFillingOrderArray[iCurrentFillingBufferIndex] = ++iFillingOrder;
   1.391 +#endif
   1.392 +
   1.393 +	return KErrNone;
   1.394 +	}
   1.395 +
   1.396 +
   1.397 +TInt TDmaBuf::RxCopyPacketToClient(DThread* aThread, TClientBuffer *aTcb, TInt aLength)
   1.398 +	{
   1.399 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxCopyPacketToClient 1"));
   1.400 +
   1.401 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.402 +	const TInt numPkts = NoRxPackets();
   1.403 +	const TInt numPktsAlt = NoRxPacketsAlt();
   1.404 +	const TInt numBytes = RxBytesAvailable();
   1.405 +	const TInt numBytesAlt = NoRxBytesAlt();
   1.406 +
   1.407 +	if (numPkts != numPktsAlt)
   1.408 +		{
   1.409 +		Kern::Printf(
   1.410 +			"TDmaBuf::RxCopyPacketToClient: Error: #pkts mismatch global=%d actual=%d",
   1.411 +			numPkts, numPktsAlt);
   1.412 +		}
   1.413 +	if (numBytes != numBytesAlt)
   1.414 +		{
   1.415 +		Kern::Printf(
   1.416 +			"TDmaBuf::RxCopyPacketToClient: Error: #bytes mismatch global=%d actual=%d",
   1.417 +			numBytes, numBytesAlt);
   1.418 +		}
   1.419 +	if ((numPkts == 0) && (numBytes !=0))
   1.420 +		{
   1.421 +		Kern::Printf(
   1.422 +			"TDmaBuf::RxCopyPacketToClient: Error: global bytes & pkts mismatch pkts=%d bytes=%d",
   1.423 +			numPkts, numBytes);
   1.424 +		}
   1.425 +	if ((numPktsAlt == 0) && (numBytesAlt !=0))
   1.426 +		{
   1.427 +		Kern::Printf(
   1.428 +			"TDmaBuf::RxCopyPacketToClient: Error: actual bytes & pkts mismatch pkts=%d bytes=%d",
   1.429 +			numPktsAlt, numBytesAlt);
   1.430 +		}
   1.431 +#endif
   1.432 +
   1.433 +	if (!NoRxPackets())
   1.434 +		return KErrNotFound;
   1.435 +
   1.436 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxCopyPacketToClient 2"));
   1.437 +	// the next condition should be true because we have some packets available
   1.438 +	// coverity[var_tested_neg]
   1.439 +	if (iCurrentDrainingBufferIndex == KUsbcInvalidBufferIndex)
   1.440 +		{
   1.441 +		// Marked as Coverity "Intentional" as the member variable
   1.442 +		// iCurrentDrainingBufferIndex is attentionaly negative, from previous 
   1.443 +		// initialization to KUsbcInvalidBufferIndex (which equals -1).
   1.444 +		if (!NextDrainableBuffer())
   1.445 +			return KErrNotFound;
   1.446 +		}
   1.447 +
   1.448 +	__ASSERT_DEBUG((iCurrentDrainingBufferIndex >= 0 ),
   1.449 +						   Kern::Fault(KUsbPanicLdd, __LINE__));
   1.450 +	
   1.451 +	if (!iDrainable[iCurrentDrainingBufferIndex])
   1.452 +		return KErrNotFound;
   1.453 +
   1.454 +	// Calculate copy-from address & adjust for the fact that
   1.455 +	// some data may have already been read from the packet
   1.456 +	TUint8* logicalSrc = iCurrentDrainingBuffer + iCurrentPacketIndexArray[iCurrentPacket] + iExtractOffset;
   1.457 +	TInt packetSz = iCurrentPacketSizeArray[iCurrentPacket];
   1.458 +	TInt thisPacketSz = packetSz - iExtractOffset;
   1.459 +	TInt errorCode;
   1.460 +	// try and sort out what a "packet" might mean.
   1.461 +	// in a multi-packet dma environment, we might see super-packets
   1.462 +	// i.e. we might just see one packet, maybe 4K or so long, made of lots of small packets
   1.463 +	// Since we don't know where the packet boundaries will be, we have to assume that
   1.464 +	// any 'packet' larger than the max packet size of the ep is, in fact, a conglomeration
   1.465 +	// of smaller packets. However, for the purposes of the packet count, this is still regarded
   1.466 +	// as a single packet and the packet count only decremented when it is consumed.
   1.467 +	// As before, if the user fails to read an entire packet out then the next packet is moved onto anyway
   1.468 +	// To be safe the user must always supply a buffer of at least max packet size bytes.
   1.469 +	if (thisPacketSz > iMaxPacketSize)
   1.470 +		{
   1.471 +		// Multiple packets left in buffer
   1.472 +		// calculate number of bytes to end of packet
   1.473 +		if (iEndpointType == KUsbEpTypeBulk)
   1.474 +			{
   1.475 +			thisPacketSz = iMaxPacketSize - (iExtractOffset & (iMaxPacketSize - 1));
   1.476 +			}
   1.477 +		else
   1.478 +			{
   1.479 +			thisPacketSz = iMaxPacketSize - (iExtractOffset % iMaxPacketSize);
   1.480 +			}
   1.481 +		errorCode = KErrNone;
   1.482 +		}
   1.483 +	else
   1.484 +		{
   1.485 +		errorCode = GetCurrentError();						// single packet left
   1.486 +		}
   1.487 +
   1.488 +	iExtractOffset += thisPacketSz;			// iExtractOffset is now at the end of the real or notional packet
   1.489 +
   1.490 +	ModifyTotalRxBytesAvail(-thisPacketSz);
   1.491 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.492 +	iNumberofBytesRxRemain[iCurrentDrainingBufferIndex] -= thisPacketSz;
   1.493 +#endif
   1.494 +	// this can only be untrue if the "packet" is a conglomeration of smaller packets:
   1.495 +	if (iExtractOffset == packetSz)
   1.496 +		{
   1.497 +		// packet consumed, advance to next packet in buffer
   1.498 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.499 +		iNumberofPacketsRxRemain[iCurrentDrainingBufferIndex] -= 1;
   1.500 +#endif
   1.501 +		AdvancePacket();
   1.502 +		}
   1.503 +
   1.504 +	TPtrC8 des(logicalSrc, thisPacketSz);
   1.505 +	TInt r=Kern::ThreadBufWrite(aThread, aTcb, des, 0, 0, aThread);
   1.506 +	if (r == KErrNone)
   1.507 +		{
   1.508 +		r = errorCode;
   1.509 +		}
   1.510 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxCopyPacketToClient 3"));
   1.511 +
   1.512 +	FreeDrainedBuffers();
   1.513 +
   1.514 +	// Use this error code to complete client read request:
   1.515 +	return r;
   1.516 +	}
   1.517 +
   1.518 +
   1.519 +TInt TDmaBuf::RxCopyDataToClient(DThread* aThread, TClientBuffer *aTcb, TInt aLength, TUint32& aDestOffset,
   1.520 +								 TBool aRUS, TBool& aCompleteNow)
   1.521 +	{
   1.522 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxCopyDataToClient 1"));
   1.523 +	aCompleteNow = ETrue;
   1.524 +
   1.525 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.526 +	const TInt numPkts = NoRxPackets();
   1.527 +	const TInt numPktsAlt = NoRxPacketsAlt();
   1.528 +	const TInt numBytes = RxBytesAvailable();
   1.529 +	const TInt numBytesAlt = NoRxBytesAlt();
   1.530 +
   1.531 +	if (numPkts != numPktsAlt)
   1.532 +		{
   1.533 +		Kern::Printf(
   1.534 +			"TDmaBuf::RxCopyDataToClient: Error: #pkts mismatch global=%d actual=%d",
   1.535 +			numPkts, numPktsAlt);
   1.536 +		}
   1.537 +	if (numBytes != numBytesAlt)
   1.538 +		{
   1.539 +		Kern::Printf(
   1.540 +			"TDmaBuf::RxCopyDataToClient: Error: #bytes mismatch global=%d actual=%d",
   1.541 +			numBytes, numBytesAlt);
   1.542 +		}
   1.543 +	if ((numPkts == 0) && (numBytes != 0))
   1.544 +		{
   1.545 +		Kern::Printf(
   1.546 +			"TDmaBuf::RxCopyDataToClient: Error: global bytes & pkts mismatch pkts=%d bytes=%d",
   1.547 +			numPkts, numBytes);
   1.548 +		}
   1.549 +	if ((numPktsAlt == 0) && (numBytesAlt != 0))
   1.550 +		{
   1.551 +		Kern::Printf(
   1.552 +			"TDmaBuf::RxCopyDataToClient: Error: actual bytes & pkts mismatch pkts=%d bytes=%d",
   1.553 +			numPktsAlt, numBytesAlt);
   1.554 +		}
   1.555 +#endif
   1.556 +
   1.557 +	if (!NoRxPackets())
   1.558 +		{
   1.559 +		return KErrNotFound;
   1.560 +		}
   1.561 +
   1.562 +	// coverity[var_tested_neg]
   1.563 +	if (iCurrentDrainingBufferIndex == KUsbcInvalidBufferIndex)
   1.564 +		{
   1.565 +		// Marked as Coverity "Inentional" as the member variable
   1.566 +		// iCurrentDrainingBufferIndex is attentionaly negative, from previous 
   1.567 +		// initialization to KUsbcInvalidBufferIndex (which equals -1).
   1.568 +
   1.569 +		if (!NextDrainableBuffer())
   1.570 +			{
   1.571 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.572 +			Kern::Printf("TDmaBuf::RxCopyDataToClient: Error:  No buffer draining=%d, packets=%d",
   1.573 +						 iCurrentDrainingBufferIndex, iTotalRxPacketsAvail);
   1.574 +#endif
   1.575 +			return KErrNotFound;
   1.576 +			}
   1.577 +		}
   1.578 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.579 +
   1.580 +	__ASSERT_DEBUG((iCurrentDrainingBufferIndex >= 0 ),
   1.581 +							   Kern::Fault(KUsbPanicLdd, __LINE__));
   1.582 +		
   1.583 +	if (iDrainingOrder != iFillingOrderArray[iCurrentDrainingBufferIndex])
   1.584 +		{
   1.585 +		Kern::Printf("!!! Out of Order Draining TDmaBuf::RxCopyDataToClient 10 draining=%d",
   1.586 +					 iCurrentDrainingBufferIndex);
   1.587 +		}
   1.588 +#endif
   1.589 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::RxCopyDataToClient 2"));
   1.590 +
   1.591 +	TUint8* blockStartAddr = iCurrentDrainingBuffer + iCurrentPacketIndexArray[iCurrentPacket] + iExtractOffset;
   1.592 +	TUint8* lastEndAddr = blockStartAddr;					// going to track the contiguity of the memory
   1.593 +	TUint8* thisStartAddr = blockStartAddr;
   1.594 +	TInt toDo = Min(aLength - (TInt)aDestOffset, iTotalRxBytesAvail);
   1.595 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.596 +	TInt bufnum = iCurrentDrainingBufferIndex;
   1.597 +#endif
   1.598 +	TInt errorCode = KErrNone;
   1.599 +	TBool isShortPacket = EFalse;
   1.600 +	const TInt maxPacketSizeMask = iMaxPacketSize - 1;
   1.601 +	do
   1.602 +		{
   1.603 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.604 +		if (bufnum != iCurrentDrainingBufferIndex)
   1.605 +			{
   1.606 +			bufnum = iCurrentDrainingBufferIndex;
   1.607 +			if (iDrainingOrder != iFillingOrderArray[iCurrentDrainingBufferIndex])
   1.608 +				{
   1.609 +				Kern::Printf("!!! Out of Order Draining TDmaBuf::RxCopyDataToClient 20 draining=%d",
   1.610 +							 iCurrentDrainingBufferIndex);
   1.611 +				}
   1.612 +			}
   1.613 +#endif
   1.614 +		if (errorCode == KErrNone)
   1.615 +			{
   1.616 +			errorCode = GetCurrentError();
   1.617 +			}
   1.618 +		thisStartAddr = iCurrentDrainingBuffer + iCurrentPacketIndexArray[iCurrentPacket] + iExtractOffset;
   1.619 +		const TInt thisPacketSize = iCurrentPacketSizeArray[iCurrentPacket];
   1.620 +		const TInt size = thisPacketSize - iExtractOffset;
   1.621 +		if (aRUS)
   1.622 +			{
   1.623 +			if (iEndpointType == KUsbEpTypeBulk)
   1.624 +				{
   1.625 +				isShortPacket = (size < iMaxPacketSize) || (size & maxPacketSizeMask);
   1.626 +				}
   1.627 +			else
   1.628 +				{
   1.629 +				// this 'if' block is arranged to avoid a division on packet sizes <= iMaxPacketSize
   1.630 +				isShortPacket = (size < iMaxPacketSize) ||
   1.631 +					((size > iMaxPacketSize) && (size % iMaxPacketSize));
   1.632 +				}
   1.633 +			}
   1.634 +		TInt copySize = Min(size, toDo);
   1.635 +		iExtractOffset += copySize;
   1.636 +		toDo -= copySize;
   1.637 +		if (thisStartAddr != lastEndAddr)
   1.638 +			{
   1.639 +			TInt bytesToCopy = lastEndAddr - blockStartAddr;
   1.640 +			TInt r=CopyToUser(aThread, blockStartAddr, bytesToCopy, aTcb, aDestOffset);
   1.641 +			if(r != KErrNone)
   1.642 +				Kern::ThreadKill(aThread, EExitPanic, r, KUsbLDDKillCat);
   1.643 +			blockStartAddr = thisStartAddr;
   1.644 +			}
   1.645 +
   1.646 +		ModifyTotalRxBytesAvail(-copySize);
   1.647 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.648 +		iNumberofBytesRxRemain[iCurrentDrainingBufferIndex] -= copySize;
   1.649 +#endif
   1.650 +		lastEndAddr = thisStartAddr + copySize;
   1.651 +		if (iExtractOffset == thisPacketSize)
   1.652 +			{
   1.653 +			// More data to copy, so need to access new packet
   1.654 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.655 +			iNumberofPacketsRxRemain[iCurrentDrainingBufferIndex] -= 1;
   1.656 +#endif
   1.657 +			if (!AdvancePacket())
   1.658 +				{
   1.659 +				break;										// no more packets left
   1.660 +				}
   1.661 +			}
   1.662 +		} while (toDo > 0 && !isShortPacket);
   1.663 +
   1.664 +	if (thisStartAddr != lastEndAddr)
   1.665 +		{
   1.666 +		TInt bytesToCopy = lastEndAddr - blockStartAddr;
   1.667 +		TInt r=CopyToUser(aThread, blockStartAddr, bytesToCopy, aTcb, aDestOffset);
   1.668 +		if(r != KErrNone)
   1.669 +			Kern::ThreadKill(aThread, EExitPanic, r, KUsbLDDKillCat);
   1.670 +		}
   1.671 +
   1.672 +	// If we have transferred the requested amount of data it is still possible that
   1.673 +	// the next packet is a zlp which needs to be bumped over
   1.674 +
   1.675 +	if (aRUS && (toDo == 0) && (iExtractOffset == 0) && (!isShortPacket) && (!IsReaderEmpty()) &&
   1.676 +		(PeekNextPacketSize() == 0))
   1.677 +		{
   1.678 +		// swallow a zlp
   1.679 +		isShortPacket = ETrue;
   1.680 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.681 +		iNumberofPacketsRxRemain[iCurrentDrainingBufferIndex] -= 1;
   1.682 +#endif
   1.683 +		AdvancePacket();
   1.684 +		}
   1.685 +	aCompleteNow = isShortPacket || (((TInt)aDestOffset) == aLength) || (errorCode != KErrNone);
   1.686 +
   1.687 +	FreeDrainedBuffers();
   1.688 +
   1.689 +	// Use this error code to complete client read request
   1.690 +	return errorCode;
   1.691 +	}
   1.692 +
   1.693 +
   1.694 +inline TInt TDmaBuf::CopyToUser(DThread* aThread, const TUint8* aSourceAddr,
   1.695 +								TInt aLength, TClientBuffer *aTcb, TUint32& aDestOffset)
   1.696 +	{
   1.697 +	TPtrC8 des(aSourceAddr, aLength);
   1.698 +	TInt errorCode = Kern::ThreadBufWrite(aThread, aTcb, des, aDestOffset, KChunkShiftBy0, aThread);
   1.699 +	if (errorCode == KErrNone)
   1.700 +		{
   1.701 +		aDestOffset += aLength;
   1.702 +		}
   1.703 +	return errorCode;
   1.704 +	}
   1.705 +
   1.706 +
   1.707 +inline TInt TDmaBuf::NoRxPackets() const
   1.708 +	{
   1.709 +	return iTotalRxPacketsAvail;
   1.710 +	}
   1.711 +
   1.712 +
   1.713 +inline void TDmaBuf::IncrementBufferIndex(TInt& aIndex)
   1.714 +	{
   1.715 +	if (++aIndex == iNumberofBuffers)
   1.716 +		aIndex = 0;
   1.717 +	}
   1.718 +
   1.719 +
   1.720 +TBool TDmaBuf::NextDrainableBuffer()
   1.721 +	{
   1.722 +	TBool r = EFalse;
   1.723 +	if (iCurrentDrainingBufferIndex != KUsbcInvalidBufferIndex)
   1.724 +		{
   1.725 +		iCanBeFreed[iCurrentDrainingBufferIndex] = ETrue;
   1.726 +		iNumberofPacketsRx[iCurrentDrainingBufferIndex] = 0; // Current buffer is empty
   1.727 +		iNumberofBytesRx[iCurrentDrainingBufferIndex] = 0;	// Current buffer is empty
   1.728 +
   1.729 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.730 +		TUint& bytesRemain = iNumberofBytesRxRemain[iCurrentDrainingBufferIndex];
   1.731 +		TUint& pktsRemain = iNumberofPacketsRxRemain[iCurrentDrainingBufferIndex];
   1.732 +		if ((bytesRemain != 0) || (pktsRemain != 0))
   1.733 +			{
   1.734 +			Kern::Printf(
   1.735 +				"TDmaBuf::NextDrainableBuffer: Error: data discarded buffer=%d pkts=%d bytes=%d",
   1.736 +				iCurrentDrainingBufferIndex, pktsRemain, bytesRemain);
   1.737 +			bytesRemain = 0;
   1.738 +			pktsRemain = 0;
   1.739 +			}
   1.740 +#endif
   1.741 +
   1.742 +		iCurrentDrainingBufferIndex = KUsbcInvalidBufferIndex;
   1.743 +		iCurrentPacket = KUsbcInvalidPacketIndex;
   1.744 +		}
   1.745 +
   1.746 +	if (iDrainQueueIndex != KUsbcInvalidDrainQueueIndex)
   1.747 +		{
   1.748 +		r = ETrue;
   1.749 +		const TInt index = iDrainQueue[0];
   1.750 +		iDrainQueueIndex--;
   1.751 +		for (TInt i = 0; i < iNumberofBuffers; i++)
   1.752 +			{
   1.753 +			iDrainQueue[i] = iDrainQueue[i+1];
   1.754 +			}
   1.755 +
   1.756 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.757 +		if (index != KUsbcInvalidBufferIndex)
   1.758 +			iDrainingOrder++;
   1.759 +#endif
   1.760 +
   1.761 +		iCurrentDrainingBufferIndex = index;
   1.762 +		iCurrentDrainingBuffer = iBuffers[index];
   1.763 +		iCurrentPacketIndexArray = iPacketIndex[index];
   1.764 +		iCurrentPacketSizeArray = iPacketSize[index];
   1.765 +		iCurrentPacket = 0;
   1.766 +		}
   1.767 +	return r;
   1.768 +	}
   1.769 +
   1.770 +
   1.771 +TInt TDmaBuf::PeekNextDrainableBuffer()
   1.772 +	{
   1.773 +	TInt r = KUsbcInvalidBufferIndex;
   1.774 +	if (iDrainQueueIndex != KUsbcInvalidDrainQueueIndex)
   1.775 +		{
   1.776 +		r = iDrainQueue[0];
   1.777 +		}
   1.778 +	return r;
   1.779 +	}
   1.780 +
   1.781 +
   1.782 +TBool TDmaBuf::NextFillableBuffer()
   1.783 +	{
   1.784 +	TBool r = EFalse;
   1.785 +	TInt index = iCurrentFillingBufferIndex;
   1.786 +	IncrementBufferIndex(index);
   1.787 +	// the sequence will restart at 0 if a buffer can't be found this time
   1.788 +	iCurrentFillingBufferIndex = 0;
   1.789 +	for (TInt i = 0; i < iNumberofBuffers; i++)
   1.790 +		{
   1.791 +		if (!iDrainable[index])
   1.792 +			{
   1.793 +			iCurrentFillingBufferIndex = index;
   1.794 +			r = ETrue;
   1.795 +			break;
   1.796 +			}
   1.797 +		IncrementBufferIndex(index);
   1.798 +		}
   1.799 +	return r;
   1.800 +	}
   1.801 +
   1.802 +
   1.803 +void TDmaBuf::FreeDrainedBuffers()
   1.804 +	{
   1.805 +	for (TInt i = 0; i < iNumberofBuffers; i++)
   1.806 +		{
   1.807 +		if (iDrainable[i] && iCanBeFreed[i])
   1.808 +			{
   1.809 +			iDrainable[i] = iCanBeFreed[i] = EFalse;
   1.810 +			}
   1.811 +		}
   1.812 +	}
   1.813 +
   1.814 +
   1.815 +TBool TDmaBuf::ShortPacketExists()
   1.816 +	{
   1.817 +	// Actually, a short packet or residue data
   1.818 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::ShortPacketExists 1"));
   1.819 +	TInt index = iCurrentDrainingBufferIndex;
   1.820 +	TUsbcPacketArray* pktSizeArray = iCurrentPacketSizeArray;
   1.821 +
   1.822 +	if (iMaxPacketSize > 0)
   1.823 +		{
   1.824 +		// No buffers available for draining
   1.825 +		if ((iCurrentDrainingBufferIndex == KUsbcInvalidBufferIndex) ||
   1.826 +			(iCurrentPacket == KUsbcInvalidPacketIndex))
   1.827 +			return EFalse;
   1.828 +
   1.829 +		// Zlp waiting at tail
   1.830 +		if ((iTotalRxBytesAvail == 0) && (NoRxPackets() == 1))
   1.831 +			return ETrue;
   1.832 +
   1.833 +		if (iEndpointType == KUsbEpTypeBulk)
   1.834 +			{
   1.835 +			const TInt mask = iMaxPacketSize - 1;
   1.836 +			if (iTotalRxBytesAvail & mask)
   1.837 +				return ETrue;
   1.838 +
   1.839 +			// residue==0; this can be because
   1.840 +			// zlps exist, or short packets combine to n * max_packet_size
   1.841 +			// This means spadework
   1.842 +			const TInt s = iCurrentPacketSizeArray[iCurrentPacket] - iExtractOffset;
   1.843 +			if ((s == 0) || (s & mask))
   1.844 +				{
   1.845 +				return ETrue;
   1.846 +				}
   1.847 +
   1.848 +			for (TInt i = 0; i < iNumberofBuffers; i++)
   1.849 +				{
   1.850 +				if (index == KUsbcInvalidBufferIndex)
   1.851 +					break;
   1.852 +				if (iDrainable[index])
   1.853 +					{
   1.854 +					const TInt packetCount = iNumberofPacketsRx[index];
   1.855 +					const TInt lastPacketSize=pktSizeArray[packetCount - 1];
   1.856 +					if ((lastPacketSize < iMaxPacketSize) || (lastPacketSize & mask))
   1.857 +						{
   1.858 +						return ETrue;
   1.859 +						}
   1.860 +					}
   1.861 +				index = iDrainQueue[i];
   1.862 +				pktSizeArray = iPacketSize[index];
   1.863 +				}
   1.864 +			}
   1.865 +		else
   1.866 +			{
   1.867 +			if (iTotalRxBytesAvail % iMaxPacketSize)
   1.868 +				return ETrue;
   1.869 +
   1.870 +			// residue==0; this can be because
   1.871 +			// zlps exist, or short packets combine to n * max_packet_size
   1.872 +			// This means spadework
   1.873 +			const TInt s = iCurrentPacketSizeArray[iCurrentPacket] - iExtractOffset;
   1.874 +			if ((s == 0) || (s % iMaxPacketSize))
   1.875 +				{
   1.876 +				return ETrue;
   1.877 +				}
   1.878 +
   1.879 +			for (TInt i = 0; i < iNumberofBuffers; i++)
   1.880 +				{
   1.881 +				if (index == KUsbcInvalidBufferIndex)
   1.882 +					break;
   1.883 +				if (iDrainable[index])
   1.884 +					{
   1.885 +					const TInt packetCount = iNumberofPacketsRx[index];
   1.886 +					const TInt lastPacketSize = pktSizeArray[packetCount - 1];
   1.887 +					if ((lastPacketSize < iMaxPacketSize) || (lastPacketSize % iMaxPacketSize))
   1.888 +						{
   1.889 +						return ETrue;
   1.890 +						}
   1.891 +					}
   1.892 +				index = iDrainQueue[i];
   1.893 +				pktSizeArray = iPacketSize[index];
   1.894 +				}
   1.895 +			}
   1.896 +		}
   1.897 +
   1.898 +	return EFalse;
   1.899 +	}
   1.900 +
   1.901 +
   1.902 +void TDmaBuf::AddToDrainQueue(TInt aBufferIndex)
   1.903 +	{
   1.904 +	if (iDrainQueue[iDrainQueueIndex + 1] != KUsbcInvalidBufferIndex)
   1.905 +		{
   1.906 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.907 +		Kern::Printf("TDmaBuf::AddToDrainQueue: Error: invalid iDrainQueue[x]");
   1.908 +#endif
   1.909 +		}
   1.910 +	iDrainQueue[++iDrainQueueIndex] = aBufferIndex;
   1.911 +	}
   1.912 +
   1.913 +
   1.914 +#if defined(USBC_LDD_BUFFER_TRACE)
   1.915 +TInt TDmaBuf::NoRxPacketsAlt() const
   1.916 +	{
   1.917 +	TInt pktCount = 0;
   1.918 +	for(TInt i = 0; i < iNumberofBuffers; i++)
   1.919 +		{
   1.920 +		if (iDrainable[i])
   1.921 +			{
   1.922 +			pktCount += iNumberofPacketsRxRemain[i];
   1.923 +			}
   1.924 +		}
   1.925 +	return pktCount;
   1.926 +	}
   1.927 +
   1.928 +
   1.929 +TInt TDmaBuf::NoRxBytesAlt() const
   1.930 +	{
   1.931 +	TInt byteCount = 0;
   1.932 +	for(TInt i = 0; i < iNumberofBuffers; i++)
   1.933 +		{
   1.934 +		if (iDrainable[i])
   1.935 +			{
   1.936 +			byteCount += iNumberofBytesRxRemain[i];
   1.937 +			}
   1.938 +		}
   1.939 +	return byteCount;
   1.940 +	}
   1.941 +#endif
   1.942 +
   1.943 +
   1.944 +// We only store 1 transaction, no other buffering is done
   1.945 +TInt TDmaBuf::TxStoreData(DThread* aThread, TClientBuffer *aTcb, TInt aTxLength, TUint32 aBufferOffset)
   1.946 +	{
   1.947 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::TxStoreData 1"));
   1.948 +	if (!IsReaderEmpty())
   1.949 +		return KErrInUse;
   1.950 +
   1.951 +	__KTRACE_OPT(KUSB, Kern::Printf("TDmaBuf::TxStoreData 2"));
   1.952 +	
   1.953 +	TInt remainTxLength = aTxLength;
   1.954 +	TUint32 bufferOffset = aBufferOffset;
   1.955 +	// Store each buffer separately
   1.956 +	for( TInt i=0;(i<iNumberofBuffers)&&(remainTxLength>0);i++)
   1.957 +	    {
   1.958 +	    TUint8* logicalDest = iBuffers[i];
   1.959 +	    TInt xferSz = Min(remainTxLength, iBufSz);
   1.960 +	    TPtr8 des(logicalDest, xferSz, xferSz);
   1.961 +	    TInt r = Kern::ThreadBufRead(aThread, aTcb, des, bufferOffset, KChunkShiftBy0);
   1.962 +	    if(r != KErrNone)
   1.963 +	        {
   1.964 +	        Kern::ThreadKill(aThread, EExitPanic, r, KUsbLDDKillCat);
   1.965 +	        return r;
   1.966 +	        }
   1.967 +	    remainTxLength -= iBufSz;
   1.968 +	    bufferOffset += iBufSz;
   1.969 +	    }
   1.970 +
   1.971 +	return KErrNone;
   1.972 +	}
   1.973 +
   1.974 +
   1.975 +TInt TDmaBuf::TxGetNextXfer(TUint8*& aBufferAddr, TInt& aTxLength, TPhysAddr& aBufferPhys)
   1.976 +	{
   1.977 +	if (iTxActive)
   1.978 +		return KErrInUse;
   1.979 +
   1.980 +	aBufferAddr = iBuffers[0];								// only 1 tx buffer
   1.981 +	aBufferPhys = iBufferPhys[0];
   1.982 +	aTxLength = BufferTotalSize();
   1.983 +
   1.984 +	return KErrNone;
   1.985 +	}
   1.986 +