/*

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Accenture Ltd

*

* Contributors:

*

* Description: This file is a part of sound driver for Syborg adaptation.

*

*/

#include "virtio.h"

namespace VirtIo 

{

#define MIN(x,y) (((x)<=(y))?(x):(y))

#define INVALID_PHYSADDR(x) ((x)==TPhysAddr(-1))

TInt LinearToSGL( TAny* aVirtual, TUint aSize, TAddrLen aSGL[], TUint& aSGLCount )

	{

	const TUint pageSize = Kern::RoundToPageSize(1);

	TUint8* virtAddr = reinterpret_cast<TUint8*>( aVirtual );

	TPhysAddr physAddr = Epoc::LinearToPhysical( TLinAddr(virtAddr) );

	if (INVALID_PHYSADDR(physAddr))

		{ return KErrArgument; }

	TUint sglLimit = aSGLCount;

	aSGLCount = 0;

	TUint left = aSize;

	while (left)

		{

		TPhysAddr startPhysAddr = physAddr;

		TUint8* startVirtAddr = virtAddr;

		while ( (left) 

			&& ( Epoc::LinearToPhysical( TLinAddr(virtAddr) ) == physAddr ) )

			{

			TUint size = MIN(left, pageSize);

			physAddr += size;

			virtAddr += size;

			left -= size;

			}

		if (INVALID_PHYSADDR(physAddr))

			{ return KErrArgument; }

		if ((aSGL) && (aSGLCount<sglLimit))

			{

			aSGL[aSGLCount].iAddr = (TUint32) startPhysAddr;

			aSGL[aSGLCount].iLen = virtAddr - startVirtAddr;

			}

		aSGLCount++;

		}

	return (aSGLCount<=sglLimit)?KErrNone:KErrNoMemory;

	}

} // namespace VirtIo