/*
 * Copyright 2010, Ingo Weinhold, ingo_weinhold@gmx.de.
 * Distributed under the terms of the MIT License.
 */
#ifndef IO_CACHE_H
#define IO_CACHE_H


#include <lock.h>
#include <vm/vm_page.h>

#include "dma_resources.h"
#include "IOScheduler.h"


struct VMCache;
struct vm_page;


class IOCache : public IOScheduler {
public:
								IOCache(DMAResource* resource,
									size_t cacheLineSize);
	virtual						~IOCache();

	virtual	status_t			Init(const char* name);

	virtual	void				SetDeviceCapacity(off_t deviceCapacity);
	virtual void				MediaChanged();

	virtual	status_t			ScheduleRequest(IORequest* request);

	virtual	void				AbortRequest(IORequest* request,
									status_t status = B_CANCELED);
	virtual	void				OperationCompleted(IOOperation* operation,
									status_t status,
									generic_size_t transferredBytes);

	virtual	void				Dump() const;

private:
			struct Operation;

private:
			status_t			_DoRequest(IORequest* request,
									generic_size_t& _bytesTransferred);
			status_t			_TransferRequestLine(IORequest* request,
									off_t lineOffset, size_t lineSize,
									off_t requestOffset, size_t requestLength);
			status_t			_TransferRequestLineUncached(IORequest* request,
									off_t lineOffset, off_t requestOffset,
									size_t requestLength);
			status_t			_DoOperation(Operation& operation);

			status_t			_TransferPages(size_t firstPage,
									size_t pageCount, bool isWrite, bool isVIP);
			void				_DiscardPages(size_t firstPage,
									size_t pageCount);
			void				_CachePages(size_t firstPage, size_t pageCount);

			status_t			_CopyPages(IORequest* request,
									size_t pagesRelativeOffset,
									off_t requestOffset, size_t requestLength,
									bool toRequest);

			status_t			_MapPages(size_t firstPage, size_t endPage);
			void				_UnmapPages(size_t firstPage, size_t endPage);

private:
			mutex				fSerializationLock;
			off_t				fDeviceCapacity;
			size_t				fLineSize;
			uint32				fLineSizeShift;
			size_t				fPagesPerLine;
			area_id				fArea;
			void*				fAreaBase;
			vm_page_reservation	fMappingReservation;
			VMCache*			fCache;
			vm_page**			fPages;
			generic_io_vec*		fVecs;
};


#endif	// IO_CACHE_H