// Copyright (c) 2008-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

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

// which accompanies this distribution, and is available

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

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

//

#include <plat_priv.h>

#include "mm.h"

#include "mmu.h"

#include "mmanager.h"

#include "mobject.h"

#include "mmapping.h"

#include "mpager.h"

#include "mswap.h"

/**

Manages the swap via the data paging device.

*/

class DSwapManager

	{

public:

		{

		};

	TInt Create(DPagingDevice* aDevice);

	TInt ReserveSwap(DMemoryObject* aMemory, TUint aStartIndex, TUint aPageCount);

	TInt UnreserveSwap(DMemoryObject* aMemory, TUint aStartIndex, TUint aPageCount);

	TBool IsReserved(DMemoryObject* aMemory, TUint aStartIndex, TUint aPageCount);

	TInt ReadSwapPages(DMemoryObject* aMemory, TUint aIndex, TUint aCount, TLinAddr aLinAddr, DPageReadRequest* aRequest, TPhysAddr* aPhysAddrs);

	void GetSwapInfo(SVMSwapInfo& aInfoOut);

	TInt SetSwapThresholds(const SVMSwapThresholds& aThresholds);

 	TUint iSwapThesholdLow;

 	TUint iSwapThesholdGood;

	};

/**

Manager for demand paged memory objects which contain writeable data.

The contents of the memory are written to a backing store whenever its

pages are 'paged out'.

@see DSwapManager

*/

class DDataPagedMemoryManager : public DPagedMemoryManager

	{

private:

	// from DMemoryManager...

	virtual TInt Alloc(DMemoryObject* aMemory, TUint aIndex, TUint aCount);

	virtual void Free(DMemoryObject* aMemory, TUint aIndex, TUint aCount);

	virtual TInt Wipe(DMemoryObject* aMemory);

	// Methods inherited from DPagedMemoryManager

	virtual void Init3();

	virtual TInt InstallPagingDevice(DPagingDevice* aDevice);

	virtual TInt AcquirePageReadRequest(DPageReadRequest*& aRequest, DMemoryObject* aMemory, TUint aIndex, TUint aCount);

	virtual TInt ReadPages(DMemoryObject* aMemory, TUint aIndex, TUint aCount, TPhysAddr* aPages, DPageReadRequest* aRequest);

	virtual TBool IsAllocated(DMemoryObject* aMemory, TUint aIndex, TUint aCount);

public:

	void GetSwapInfo(SVMSwapInfo& aInfoOut);

	TInt SetSwapThresholds(const SVMSwapThresholds& aThresholds);

private:

	/**

	The paging device used for accessing the backing store.

	This is set by #InstallPagingDevice.

	*/

	DPagingDevice* iDevice;

	/**

	The instance of #DSwapManager being used by this manager.

	*/

	DSwapManager* iSwapManager;

public:

	/**

	The single instance of this manager class.

	*/

	static DDataPagedMemoryManager TheManager;

	};

DDataPagedMemoryManager DDataPagedMemoryManager::TheManager;

DPagedMemoryManager* TheDataPagedMemoryManager = &DDataPagedMemoryManager::TheManager;

/**

Create a swap manager.

@param	aDevice	The demand paging device for access to the swap.

*/

TInt DSwapManager::Create(DPagingDevice* aDevice)

	{

	__NK_ASSERT_DEBUG(iDevice == NULL);

	iDevice = aDevice;

	// Create the structures required to track the swap usage.

	TUint swapPages = (iDevice->iSwapSize << iDevice->iReadUnitShift) >> KPageShift;

	// Can't have more swap pages than we can map.

	__NK_ASSERT_DEBUG(swapPages<=DMemoryObject::KMaxPagingManagerData);

	__NK_ASSERT_DEBUG(swapPages<=(KMaxTUint>>ESwapIndexShift));

	if ((TheMmu.TotalPhysicalRamPages() << 2) < swapPages)

		{// The swap is limited to a maximum of 4 times the amount of RAM.

		return KErrTooBig;

		}

	iBitMap = TBitMapAllocator::New(swapPages, ETrue);

	if (iBitMap == NULL)

		{// Not enough RAM to keep track of the swap.

		return KErrNoMemory;

		}

	iAllocOffset = 0;

	return KErrNone;

	}

/**

Reserve some swap pages for the requested region of the memory object

@param aMemory		The memory object to reserve pages for.

@param aStartIndex	The page index in the memory object of the start of the region.

@param aPageCount	The number of pages to reserve.

@return KErrNone on success, KErrNoMemory if not enough swap space available.

@pre aMemory's lock is held.

@post aMemory's lock is held.

*/

TInt DSwapManager::ReserveSwap(DMemoryObject* aMemory, TUint aStartIndex, TUint aPageCount)

	{

	__NK_ASSERT_DEBUG(MemoryObjectLock::IsHeld(aMemory));

		{

		Kern::AsyncNotifyChanges(EChangesOutOfMemory);

		return KErrNoMemory;

		}

		{		

		// Grab MmuLock to stop manager data being accessed.

		MmuLock::Lock();

		MmuLock::Unlock();

		}

	return KErrNone;

	}

/**

Unreserve swap pages for the requested region of the memory object.

@param aMemory		The memory object to unreserve pages for.

@param aStartIndex	The page index in the memory object of the start of the region.

@param aPageCount	The number of pages to unreserve.

@return The number of pages freed.

@pre aMemory's lock is held.

@post aMemory's lock is held.

*/

TInt DSwapManager::UnreserveSwap(DMemoryObject* aMemory, TUint aStartIndex, TUint aPageCount)

	{

	__NK_ASSERT_DEBUG(MemoryObjectLock::IsHeld(aMemory));

	TUint freedPages = 0;

	const TUint indexEnd = aStartIndex + aPageCount;

	for (TUint index = aStartIndex; index < indexEnd; index++)

		{

		// Grab MmuLock to stop manager data being accessed.

		MmuLock::Lock();

		TUint swapData = aMemory->PagingManagerData(index);

			{

			freedPages++;

			}

		MmuLock::Unlock();

		}

	return freedPages;

	}

/**

Determine whether the specified pages in the memory object have swap reserved for them.

@param aMemory		The memory object that owns the pages.

@param aStartIndex	The first index of the pages to check.

@param aPageCount	The number of pages to check.

@return ETrue if swap is reserved for all the pages, EFalse otherwise.

*/

TBool DSwapManager::IsReserved(DMemoryObject* aMemory, TUint aStartIndex, TUint aPageCount)

	{// MmuLock required to protect manager data.

	__NK_ASSERT_DEBUG(MmuLock::IsHeld());

	__NK_ASSERT_DEBUG(aStartIndex < aMemory->iSizeInPages);

	__NK_ASSERT_DEBUG(aStartIndex + aPageCount <= aMemory->iSizeInPages);

	const TUint indexEnd = aStartIndex + aPageCount;

	for (TUint index = aStartIndex; index < indexEnd; index++)

		{

			{// This page is not allocated by swap manager.

			return EFalse;

			}

		}

	return ETrue;

	}

/**

Read from the swap the specified pages associated with the memory object.

@param aMemory 	The memory object to read the pages for

@param aIndex	The index of the first page within the memory object.

@param aCount	The number of pages to read.

@param aLinAddr	The address to copy the pages to.

@param aRequest	The request to use for the read.

@param aPhysAddrs	An array of the physical addresses for each page to read in.

*/

TInt DSwapManager::ReadSwapPages(DMemoryObject* aMemory, TUint aIndex, TUint aCount, TLinAddr aLinAddr, DPageReadRequest* aRequest, TPhysAddr* aPhysAddrs)

	{

	TInt r = KErrNone;

	const TUint readUnitShift = iDevice->iReadUnitShift;

	TUint readSize = KPageSize >> readUnitShift;

	const TUint indexEnd = aIndex + aCount;

	for (TUint index = aIndex; index < indexEnd; index++, aLinAddr += KPageSize, aPhysAddrs++)

		{

		START_PAGING_BENCHMARK;

		MmuLock::Lock();	// MmuLock required for atomic access to manager data.

		TUint swapData = aMemory->PagingManagerData(index);

			{// This page is not committed to the memory object

			MmuLock::Unlock();

			return KErrNotFound;			

			}

			{// This page has not been written to yet so don't read from swap 

			// just wipe it if required.

			MmuLock::Unlock();

			if (wipePages)

				{

				memset((TAny*)aLinAddr, wipeByte, KPageSize);

				}

			}

		else

			{

			// OK to release as if the object's data is decommitted the pager 

			// will check that data is still valid before mapping it.

			MmuLock::Unlock();

			START_PAGING_BENCHMARK;

			if (r != KErrNone)

				__KTRACE_OPT(KPANIC, Kern::Printf("DSwapManager::ReadSwapPages: error reading media at %08x + %x: %d", readStart << readUnitShift, readSize << readUnitShift, r));				

			__NK_ASSERT_DEBUG(r!=KErrNoMemory); // not allowed to allocate memory, therefore can't fail with KErrNoMemory

			END_PAGING_BENCHMARK(EPagingBmReadDataMedia);

			__NK_ASSERT_ALWAYS(r == KErrNone);

			}

		END_PAGING_BENCHMARK(EPagingBmReadDataPage);

		}

	return r;

	}

/**

Write the specified memory object's pages from the RAM into the swap.

@param	aMemory		The memory object who owns the pages.

@param	aIndex		The index within the memory object.

@param 	aCount		The number of pages to write out.

@param	aLinAddr	The location of the pages to write out.

*/

		{

			}