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// ----------------------------------------------------------------------------
// Copyright (c) 1992 Olivetti
//
// File: eisaintr.c
//
// Description: EISA code interrupt related routines
// ----------------------------------------------------------------------------
//
#include "fwp.h"
#include "oli2msft.h"
#include "arceisa.h"
#include "inc.h"
#include "string.h"
#include "debug.h"
extern EISA_BUS_INFO EisaBusInfo[];
// ----------------------------------------------------------------------------
// Declare Function Prototypes
// ----------------------------------------------------------------------------
VOID
EisaBeginCriticalSection
(
IN VOID
);
VOID
EisaEndCriticalSection
(
IN VOID
);
ARC_STATUS
EisaProcessEndOfInterrupt
(
IN ULONG BusNumber,
IN USHORT Irq
);
BOOLEAN_ULONG
EisaTestEisaInterrupt
(
IN ULONG BusNumber,
IN USHORT Irq
);
// ----------------------------------------------------------------------------
// General Function Prototypes
// ----------------------------------------------------------------------------
ULONG
StatusReg
(
IN ULONG,
IN ULONG
);
// ----------------------------------------------------------------------------
// General : Begin/End Critical Setction functions
// ----------------------------------------------------------------------------
ULONG NestedCounter = 0 ; // nested conter;
ULONG StatusRegBuff = 0 ; // used to store the old ints status
// bits 31-16 Reserved (0)
// bits 15- 8 Specific interrupt mask
// bits 7- 1 Reserved (0)
// bit 0 General Interrupt mask
// ----------------------------------------------------------------------------
// PROCEDURE: EisaBeginCriticalSection:
//
// DESCRIPTION: This function disables all the hardware interrupts
// except for the EISA NMI interrupt. The old interrupt
// status is saved for "EisaEndCriticalSection" routine.
//
// ARGUMENTS: none
//
// RETURN: none
//
// ASSUMPTIONS:
//
// CALLS:
//
// GLOBALS:
//
// NOTES:
// ----------------------------------------------------------------------------
//
VOID
EisaBeginCriticalSection
(
IN VOID
)
{
// Disable interrupts (except for the EISA NMI) and save the old interrupt
// status only if no previous calls to this routine were made.
// The first argument is "&" and the second is "|" with the status
// register.
if ( !NestedCounter++ )
{
StatusRegBuff = StatusReg(~STATUS_INT_MASK, STATUS_EISA_NMI+STATUS_IE);
}
// all done
return;
}
// ----------------------------------------------------------------------------
// PROCEDURE: EisaEndCriticalSection:
//
// DESCRIPTION: This function restores the hardware interrupt status
// at the CPU level as it was before calling the
// "EisaBeginCriticalSection" function.
//
// ARGUMENTS: none
//
// RETURN: none
//
// ASSUMPTIONS:
//
// CALLS:
//
// GLOBALS:
//
// NOTES:
// ----------------------------------------------------------------------------
//
VOID
EisaEndCriticalSection
(
IN VOID
)
{
// Restore the interrupts status only if NestedCounter equals zero.
// The first argument is "&" and the second is "|" with the status
// register.
if ( !--NestedCounter )
{
StatusReg(~STATUS_INT_MASK, StatusRegBuff & STATUS_INT_MASK);
}
// all done
return;
}
// ----------------------------------------------------------------------------
// PROCEDURE: EisaProcessEndOfInterrupt:
//
// DESCRIPTION: Because the EISA interrupts are masked at PIC
// (8259A) level, this routine function doesn't need
// to do anything.
// It doesn't matter if the interrupt channel is level
// or edge triggered, when the interrupt sources goes
// away, the corrisponding bit within the interrupt
// request register (IRR) is cleared.
//
// ARGUMENTS: BusNumber EISA bus number
// Irq IRQ to process
//
// RETURN: ESUCCESS All done
//
// ASSUMPTIONS: none
//
// CALLS: none
//
// GLOBALS: none
//
// NOTES: none
// ----------------------------------------------------------------------------
//
ARC_STATUS
EisaProcessEndOfInterrupt
(
IN ULONG BusNumber,
IN USHORT Irq
)
{
// Return all done.
return ESUCCESS;
}
// ----------------------------------------------------------------------------
// PROCEDURE: EisaTestEisaInterrupt:
//
// DESCRIPTION: This function checks if there is an interrupt pending
// on the specified IRQ.
//
// ARGUMENTS: BusNumber EISA bus number
// Irq IRQ to process
//
// RETURN: TRUE Interrupt is pending
// FALSE Interrupt is not pending
//
// ASSUMPTIONS: none
//
// CALLS: none
//
// GLOBALS: none
//
// NOTES: none
// ----------------------------------------------------------------------------
//
BOOLEAN_ULONG
EisaTestEisaInterrupt
(
IN ULONG BusNumber,
IN USHORT Irq
)
{
// define local variables
BOOLEAN_ULONG IntPending = FALSE; // assume no interrupt is pending
PUCHAR PicPort; // PIC virtual address
UCHAR PicMask; // to check the requested IRQ
// check the IRQ only if the input parameters are valid
// if ( EisaCheckBusNumber( BusNumber ) == ESUCCESS && Irq <= IRQ15 )
if ( Irq <= IRQ15 )
{
// load the virtual address of the specified EISA I/O bus and
// build the mask for checking the specified IRQ.
PicPort = EisaBusInfo[ BusNumber ].IoBusInfo->VirAddr;
if ( Irq < IRQ8 )
{
PicPort += PIC1; // the IRQ is on the 1st PIC
PicMask = 1 << Irq; // set the mask
}
else
{
PicPort += PIC2; // the IRQ is on the 2nd PIC
PicMask = 1 << (Irq - IRQ8); // set the mask
}
// to check the spcified IRQ we need to send first an OCW3 command
// to the PIC to request the interrupt request register (IRR).
WRITE_REGISTER_UCHAR( PicPort, OCW3_IRR );
EISA_IO_DELAY;
if ( READ_REGISTER_UCHAR(PicPort) & PicMask )
{
IntPending = TRUE; // interrupt is pending
}
}
// return the specified IRQ status
return IntPending;
}
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