/**

 * $Id: asic.c,v 1.9 2005-12-26 10:48:55 nkeynes Exp $

 *

 * Support for the miscellaneous ASIC functions (Primarily event multiplexing,

 * and DMA). 

 *

 * Copyright (c) 2005 Nathan Keynes.

 *

 * 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.

 */

#define MODULE asic_module

#include <assert.h>

#include "dream.h"

#include "mem.h"

#include "sh4/intc.h"

#include "dreamcast.h"

#include "maple/maple.h"

#include "gdrom/ide.h"

#include "asic.h"

#define MMIO_IMPL

#include "asic.h"

/*

 * Open questions:

 *   1) Does changing the mask after event occurance result in the

 *      interrupt being delivered immediately?

 * TODO: Logic diagram of ASIC event/interrupt logic.

 *

 * ... don't even get me started on the "EXTDMA" page, about which, apparently,

 * practically nothing is publicly known...

 */

struct dreamcast_module asic_module = { "ASIC", asic_init, NULL, NULL, NULL,

					NULL, NULL, NULL };

void asic_check_cleared_events( void );

void asic_init( void )

{

    register_io_region( &mmio_region_ASIC );

    register_io_region( &mmio_region_EXTDMA );

    mmio_region_ASIC.trace_flag = 0; /* Because this is called so often */

    asic_event( EVENT_GDROM_CMD );

}

void mmio_region_ASIC_write( uint32_t reg, uint32_t val )

{

    switch( reg ) {

        case PIRQ0:

        case PIRQ1:

        case PIRQ2:

            /* Clear any interrupts */

            MMIO_WRITE( ASIC, reg, MMIO_READ(ASIC, reg)&~val );

	    asic_check_cleared_events();

            break;

        case MAPLE_STATE:

            MMIO_WRITE( ASIC, reg, val );

            if( val & 1 ) {

                uint32_t maple_addr = MMIO_READ( ASIC, MAPLE_DMA) &0x1FFFFFE0;

		WARN( "Maple request initiated at %08X, halting", maple_addr );

                maple_handle_buffer( maple_addr );

                MMIO_WRITE( ASIC, reg, 0 );

//                dreamcast_stop();

            }

            break;

        default:

            MMIO_WRITE( ASIC, reg, val );

            WARN( "Write to ASIC (%03X <= %08X) [%s: %s]",

                  reg, val, MMIO_REGID(ASIC,reg), MMIO_REGDESC(ASIC,reg) );

    }

}

int32_t mmio_region_ASIC_read( uint32_t reg )

{

    int32_t val;

    switch( reg ) {

        /*

        case 0x89C:

            sh4_stop();

            return 0x000000B;

        */     

        case PIRQ0:

        case PIRQ1:

        case PIRQ2:

            val = MMIO_READ(ASIC, reg);

//            WARN( "Read from ASIC (%03X => %08X) [%s: %s]",

//                  reg, val, MMIO_REGID(ASIC,reg), MMIO_REGDESC(ASIC,reg) );

            return val;            

        case G2STATUS:

            return 0; /* find out later if there's any cases we actually need to care about */

        default:

            val = MMIO_READ(ASIC, reg);

            WARN( "Read from ASIC (%03X => %08X) [%s: %s]",

                  reg, val, MMIO_REGID(ASIC,reg), MMIO_REGDESC(ASIC,reg) );

            return val;

    }

}

void asic_event( int event )

{

    int offset = ((event&0x60)>>3);

    int result = (MMIO_READ(ASIC, PIRQ0 + offset))  |=  (1<<(event&0x1F));

    if( result & MMIO_READ(ASIC, IRQA0 + offset) )

        intc_raise_interrupt( INT_IRQ13 );

    if( result & MMIO_READ(ASIC, IRQB0 + offset) )

        intc_raise_interrupt( INT_IRQ11 );

    if( result & MMIO_READ(ASIC, IRQC0 + offset) )

        intc_raise_interrupt( INT_IRQ9 );

}

void asic_check_cleared_events( )

{

    int i, setA = 0, setB = 0, setC = 0;

    uint32_t bits;

    for( i=0; i<3; i++ ) {

	bits = MMIO_READ( ASIC, PIRQ0 + i );

	setA |= (bits & MMIO_READ(ASIC, IRQA0 + i ));

	setB |= (bits & MMIO_READ(ASIC, IRQB0 + i ));

	setC |= (bits & MMIO_READ(ASIC, IRQC0 + i ));

    }

    if( setA == 0 )

	intc_clear_interrupt( INT_IRQ13 );

    if( setB == 0 )

	intc_clear_interrupt( INT_IRQ11 );

    if( setC == 0 )

	intc_clear_interrupt( INT_IRQ9 );

}

MMIO_REGION_WRITE_FN( EXTDMA, reg, val )

{

    switch( reg ) {

        case IDEALTSTATUS: /* Device control */

            ide_write_control( val );

            break;

        case IDEDATA:

            ide_write_data_pio( val );

            break;

        case IDEFEAT:

            if( ide_can_write_regs() )

                idereg.feature = (uint8_t)val;

            break;

        case IDECOUNT:

            if( ide_can_write_regs() )

                idereg.count = (uint8_t)val;

            break;

        case IDELBA0:

            if( ide_can_write_regs() )

                idereg.lba0 = (uint8_t)val;

            break;

        case IDELBA1:

            if( ide_can_write_regs() )

                idereg.lba1 = (uint8_t)val;

            break;

        case IDELBA2:

            if( ide_can_write_regs() )

                idereg.lba2 = (uint8_t)val;

            break;

        case IDEDEV:

            if( ide_can_write_regs() )

                idereg.device = (uint8_t)val;

            break;

        case IDECMD:

            if( ide_can_write_regs() ) {

                ide_clear_interrupt();

                ide_write_command( (uint8_t)val );

            }

            break;

        default:

            MMIO_WRITE( EXTDMA, reg, val );

    }

}

MMIO_REGION_READ_FN( EXTDMA, reg )

{

    switch( reg ) {

        case IDEALTSTATUS: return idereg.status;

        case IDEDATA: return ide_read_data_pio( );

        case IDEFEAT: return idereg.error;

        case IDECOUNT:return idereg.count;

        case IDELBA0: return idereg.disc;

        case IDELBA1: return idereg.lba1;

        case IDELBA2: return idereg.lba2;

        case IDEDEV: return idereg.device;

        case IDECMD:

            ide_clear_interrupt();

            return idereg.status;

        default:

            return MMIO_READ( EXTDMA, reg );

    }

}