dma.h

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/*
 * COPYRIGHT:       GPL - See COPYING in the top level directory
 * PROJECT:         ReactOS Virtual DOS Machine
 * FILE:            subsystems/mvdm/ntvdm/hardware/dma.h
 * PURPOSE:         ISA DMA - Direct Memory Access Controller emulation -
 *                  i8237A compatible with 74LS612 Memory Mapper extension
 * PROGRAMMERS:     Hermes Belusca-Maito (hermes.belusca@sfr.fr)
 */
 
#ifndef _DMA_H_
#define _DMA_H_
 
/* DEFINES ********************************************************************/
 
#define DMA_CONTROLLERS         2
#define DMA_CONTROLLER_CHANNELS 4 // Each DMA controller has 4 channels
 
typedef struct _DMA_CHANNEL
{
    WORD BaseAddress;
    WORD BaseElemCnt;
    WORD CurrAddress;
    WORD CurrElemCnt;
    BYTE Mode;
} DMA_CHANNEL, *PDMA_CHANNEL;
 
typedef struct _DMA_CONTROLLER
{
    DMA_CHANNEL DmaChannel[DMA_CONTROLLER_CHANNELS];
 
    WORD TempAddress;
    WORD TempElemCnt;
 
    BYTE TempReg;
 
    BYTE Command;
    BYTE Request;
    BYTE Mask;
    BYTE Status;
 
    BOOLEAN FlipFlop; // 0: LSB ; 1: MSB
 
} DMA_CONTROLLER, *PDMA_CONTROLLER;
 
/* 74LS612 Memory Mapper extension */
typedef struct _DMA_PAGE_REGISTER
{
    BYTE Page;
} DMA_PAGE_REGISTER, *PDMA_PAGE_REGISTER;
 
// The 74LS612 contains 16 bytes, each of them being a page register.
// They are accessible via ports 0x80 through 0x8F.
 
/* FUNCTIONS ******************************************************************/
 
DWORD DmaRequest(IN WORD      iChannel,
                 IN OUT PVOID Buffer,
                 IN DWORD     length);
 
VOID DmaInitialize(VOID);
 
#endif /* _DMA_H_ */