379 lines
8.9 KiB
C
379 lines
8.9 KiB
C
/*
|
|
Copyright (C) 1994-1995 Apogee Software, Ltd.
|
|
|
|
This program is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU General Public License
|
|
as published by the Free Software Foundation; either version 2
|
|
of the License, or (at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
|
|
|
|
See the GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, write to the Free Software
|
|
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
|
|
*/
|
|
/**********************************************************************
|
|
module: DMA.C
|
|
|
|
author: James R. Dose
|
|
date: February 4, 1994
|
|
|
|
Low level routines to for programming the DMA controller for 8 bit
|
|
and 16 bit transfers.
|
|
|
|
(c) Copyright 1994 James R. Dose. All Rights Reserved.
|
|
**********************************************************************/
|
|
|
|
#include <dos.h>
|
|
#include <conio.h>
|
|
#include <stdlib.h>
|
|
#include "dma.h"
|
|
|
|
#define DMA_MaxChannel 7
|
|
|
|
#define VALID ( 1 == 1 )
|
|
#define INVALID ( !VALID )
|
|
|
|
#define BYTE 0
|
|
#define WORD 1
|
|
|
|
typedef struct
|
|
{
|
|
int Valid;
|
|
int Width;
|
|
int Mask;
|
|
int Mode;
|
|
int Clear;
|
|
int Page;
|
|
int Address;
|
|
int Length;
|
|
} DMA_PORT;
|
|
|
|
static const DMA_PORT DMA_PortInfo[ DMA_MaxChannel + 1 ] =
|
|
{
|
|
{ VALID, BYTE, 0xA, 0xB, 0xC, 0x87, 0x0, 0x1 },
|
|
{ VALID, BYTE, 0xA, 0xB, 0xC, 0x83, 0x2, 0x3 },
|
|
{ INVALID, BYTE, 0xA, 0xB, 0xC, 0x81, 0x4, 0x5 },
|
|
{ VALID, BYTE, 0xA, 0xB, 0xC, 0x82, 0x6, 0x7 },
|
|
{ INVALID, WORD, 0xD4, 0xD6, 0xD8, 0x8F, 0xC0, 0xC2 },
|
|
{ VALID, WORD, 0xD4, 0xD6, 0xD8, 0x8B, 0xC4, 0xC6 },
|
|
{ VALID, WORD, 0xD4, 0xD6, 0xD8, 0x89, 0xC8, 0xCA },
|
|
{ VALID, WORD, 0xD4, 0xD6, 0xD8, 0x8A, 0xCC, 0xCE },
|
|
};
|
|
|
|
int DMA_ErrorCode = DMA_Ok;
|
|
|
|
#define DMA_SetErrorCode( status ) \
|
|
DMA_ErrorCode = ( status );
|
|
|
|
|
|
/*---------------------------------------------------------------------
|
|
Function: DMA_ErrorString
|
|
|
|
Returns a pointer to the error message associated with an error
|
|
number. A -1 returns a pointer the current error.
|
|
---------------------------------------------------------------------*/
|
|
|
|
char *DMA_ErrorString
|
|
(
|
|
int ErrorNumber
|
|
)
|
|
|
|
{
|
|
char *ErrorString;
|
|
|
|
switch( ErrorNumber )
|
|
{
|
|
case DMA_Error :
|
|
ErrorString = DMA_ErrorString( DMA_ErrorCode );
|
|
break;
|
|
|
|
case DMA_Ok :
|
|
ErrorString = "DMA channel ok.";
|
|
break;
|
|
|
|
case DMA_ChannelOutOfRange :
|
|
ErrorString = "DMA channel out of valid range.";
|
|
break;
|
|
|
|
case DMA_InvalidChannel :
|
|
ErrorString = "Unsupported DMA channel.";
|
|
break;
|
|
|
|
default :
|
|
ErrorString = "Unknown DMA error code.";
|
|
break;
|
|
}
|
|
|
|
return( ErrorString );
|
|
}
|
|
|
|
|
|
/*---------------------------------------------------------------------
|
|
Function: DMA_VerifyChannel
|
|
|
|
Verifies whether a DMA channel is available to transfer data.
|
|
---------------------------------------------------------------------*/
|
|
|
|
int DMA_VerifyChannel
|
|
(
|
|
int channel
|
|
)
|
|
|
|
{
|
|
int status;
|
|
int Error;
|
|
|
|
status = DMA_Ok;
|
|
Error = DMA_Ok;
|
|
|
|
if ( ( channel < 0 ) || ( DMA_MaxChannel < channel ) )
|
|
{
|
|
Error = DMA_ChannelOutOfRange;
|
|
status = DMA_Error;
|
|
}
|
|
else if ( DMA_PortInfo[ channel ].Valid == INVALID )
|
|
{
|
|
Error = DMA_InvalidChannel;
|
|
status = DMA_Error;
|
|
}
|
|
|
|
DMA_SetErrorCode( Error );
|
|
return( status );
|
|
}
|
|
|
|
|
|
/*---------------------------------------------------------------------
|
|
Function: DMA_SetupTransfer
|
|
|
|
Programs the specified DMA channel to transfer data.
|
|
---------------------------------------------------------------------*/
|
|
|
|
int DMA_SetupTransfer
|
|
(
|
|
int channel,
|
|
char *address,
|
|
int length,
|
|
int mode
|
|
)
|
|
|
|
{
|
|
DMA_PORT *Port;
|
|
int addr;
|
|
int ChannelSelect;
|
|
int Page;
|
|
int HiByte;
|
|
int LoByte;
|
|
int TransferLength;
|
|
int status;
|
|
|
|
status = DMA_VerifyChannel( channel );
|
|
|
|
if ( status == DMA_Ok )
|
|
{
|
|
Port = &DMA_PortInfo[ channel ];
|
|
ChannelSelect = channel & 0x3;
|
|
|
|
addr = ( int )address;
|
|
|
|
if ( Port->Width == WORD )
|
|
{
|
|
Page = ( addr >> 16 ) & 255;
|
|
HiByte = ( addr >> 9 ) & 255;
|
|
LoByte = ( addr >> 1 ) & 255;
|
|
|
|
// Convert the length in bytes to the length in words
|
|
TransferLength = ( length + 1 ) >> 1;
|
|
|
|
// The length is always one less the number of bytes or words
|
|
// that we're going to send
|
|
TransferLength--;
|
|
}
|
|
else
|
|
{
|
|
Page = ( addr >> 16 ) & 255;
|
|
HiByte = ( addr >> 8 ) & 255;
|
|
LoByte = addr & 255;
|
|
|
|
// The length is always one less the number of bytes or words
|
|
// that we're going to send
|
|
TransferLength = length - 1;
|
|
}
|
|
|
|
// Mask off DMA channel
|
|
outp( Port->Mask, 4 | ChannelSelect );
|
|
|
|
// Clear flip-flop to lower byte with any data
|
|
outp( Port->Clear, 0 );
|
|
|
|
// Set DMA mode
|
|
switch( mode )
|
|
{
|
|
case DMA_SingleShotRead :
|
|
outp( Port->Mode, 0x48 | ChannelSelect );
|
|
break;
|
|
|
|
case DMA_SingleShotWrite :
|
|
outp( Port->Mode, 0x44 | ChannelSelect );
|
|
break;
|
|
|
|
case DMA_AutoInitRead :
|
|
outp( Port->Mode, 0x58 | ChannelSelect );
|
|
break;
|
|
|
|
case DMA_AutoInitWrite :
|
|
outp( Port->Mode, 0x54 | ChannelSelect );
|
|
break;
|
|
}
|
|
|
|
// Send address
|
|
outp( Port->Address, LoByte );
|
|
outp( Port->Address, HiByte );
|
|
|
|
// Send page
|
|
outp( Port->Page, Page );
|
|
|
|
// Send length
|
|
outp( Port->Length, TransferLength );
|
|
outp( Port->Length, TransferLength >> 8 );
|
|
|
|
// enable DMA channel
|
|
outp( Port->Mask, ChannelSelect );
|
|
}
|
|
|
|
return( status );
|
|
}
|
|
|
|
|
|
/*---------------------------------------------------------------------
|
|
Function: DMA_EndTransfer
|
|
|
|
Ends use of the specified DMA channel.
|
|
---------------------------------------------------------------------*/
|
|
|
|
int DMA_EndTransfer
|
|
(
|
|
int channel
|
|
)
|
|
|
|
{
|
|
DMA_PORT *Port;
|
|
int ChannelSelect;
|
|
int status;
|
|
|
|
status = DMA_VerifyChannel( channel );
|
|
if ( status == DMA_Ok )
|
|
{
|
|
Port = &DMA_PortInfo[ channel ];
|
|
ChannelSelect = channel & 0x3;
|
|
|
|
// Mask off DMA channel
|
|
outp( Port->Mask, 4 | ChannelSelect );
|
|
|
|
// Clear flip-flop to lower byte with any data
|
|
outp( Port->Clear, 0 );
|
|
}
|
|
|
|
return( status );
|
|
}
|
|
|
|
|
|
/*---------------------------------------------------------------------
|
|
Function: DMA_GetCurrentPos
|
|
|
|
Returns the position of the specified DMA transfer.
|
|
---------------------------------------------------------------------*/
|
|
|
|
char *DMA_GetCurrentPos
|
|
(
|
|
int channel
|
|
)
|
|
|
|
{
|
|
DMA_PORT *Port;
|
|
unsigned long addr;
|
|
int status;
|
|
|
|
addr = NULL;
|
|
status = DMA_VerifyChannel( channel );
|
|
|
|
if ( status == DMA_Ok )
|
|
{
|
|
Port = &DMA_PortInfo[ channel ];
|
|
|
|
if ( Port->Width == WORD )
|
|
{
|
|
// Get address
|
|
addr = inp( Port->Address ) << 1;
|
|
addr |= inp( Port->Address ) << 9;
|
|
|
|
// Get page
|
|
addr |= inp( Port->Page ) << 16;
|
|
}
|
|
else
|
|
{
|
|
// Get address
|
|
addr = inp( Port->Address );
|
|
addr |= inp( Port->Address ) << 8;
|
|
|
|
// Get page
|
|
addr |= inp( Port->Page ) << 16;
|
|
}
|
|
}
|
|
|
|
return( ( char * )addr );
|
|
}
|
|
|
|
|
|
/*---------------------------------------------------------------------
|
|
Function: DMA_GetTransferCount
|
|
|
|
Returns how many bytes are left in the DMA's transfer.
|
|
---------------------------------------------------------------------*/
|
|
|
|
int DMA_GetTransferCount
|
|
(
|
|
int channel
|
|
)
|
|
|
|
{
|
|
DMA_PORT *Port;
|
|
int count;
|
|
int status;
|
|
|
|
status = DMA_Ok;
|
|
|
|
count = 0;
|
|
|
|
if ( ( channel < 0 ) || ( DMA_MaxChannel < channel ) )
|
|
{
|
|
status = DMA_ChannelOutOfRange;
|
|
}
|
|
else if ( DMA_PortInfo[ channel ].Valid == INVALID )
|
|
{
|
|
status = DMA_InvalidChannel;
|
|
}
|
|
|
|
if ( status == DMA_Ok )
|
|
{
|
|
Port = &DMA_PortInfo[ channel ];
|
|
|
|
outp( Port->Clear, 0 );
|
|
count = inp( Port->Length );
|
|
count += inp( Port->Length ) << 8;
|
|
|
|
if ( Port->Width == WORD )
|
|
{
|
|
count <<= 1;
|
|
}
|
|
}
|
|
|
|
DMA_SetErrorCode( status );
|
|
|
|
return( count );
|
|
}
|