/**

 * $Id: intc.c,v 1.6 2006-06-15 10:27:10 nkeynes Exp $

 *

 * SH4 onboard interrupt controller (INTC) implementation

 *

 * 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.

 */

#include <assert.h>

#include "sh4mmio.h"

#include "sh4core.h"

#include "intc.h"

struct intc_sources_t {

    char *name;

    uint32_t code;

} intc_sources[INT_NUM_SOURCES] = {

    { "IRQ0", 0x200 },  { "IRQ1", 0x220 },  { "IRQ2", 0x240 },

    { "IRQ3", 0x260 },  { "IRQ4", 0x280 },  { "IRQ5", 0x2A0 },

    { "IRQ6", 0x2C0 },  { "IRQ7", 0x2E0 },  { "IRQ8", 0x300 },

    { "IRQ9", 0x320 },  { "IRQ10",0x340 },  { "IRQ11",0x360 },

    { "IRQ12",0x380 },  { "IRQ13",0x3A0 },  { "IRQ14",0x3C0 },

    { "NMI", 0x1C0 },   { "H-UDI",0x600 },  { "GPIOI",0x620 },

    { "DMTE0",0x640 },  { "DMTE1",0x660 },  { "DMTE2",0x680 },

    { "DMTE3",0x6A0 },  { "DMTAE",0x6C0 },  { "TUNI0",0x400 },

    { "TUNI1",0x420 },  { "TUNI2",0x440 },  { "TICPI2",0x460 },

    { "RTC_ATI",0x480 },{ "RTC_PRI",0x4A0 },{ "RTC_CUI",0x4C0 },

    { "SCI_ERI",0x4E0 },{ "SCI_RXI",0x500 },{ "SCI_TXI",0x520 },

    { "SCI_TEI",0x540 },

    { "SCIF_ERI",0x700 },{ "SCIF_RXI",0x720, 0 },{ "SCIF_BRI",0x740 },

    { "SCIF_TXI",0x760 },

    { "WDT_ITI",0x560 },{ "RCMI",0x580 },   { "ROVI",0x5A0 } };

static int intc_default_priority[INT_NUM_SOURCES] = { 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 16 };

#define PRIORITY(which) intc_state.priority[which]

#define INTCODE(which) intc_sources[which].code

static struct intc_state {

    int num_pending;

    int pending[INT_NUM_SOURCES];

    int priority[INT_NUM_SOURCES];

} intc_state;

void mmio_region_INTC_write( uint32_t reg, uint32_t val )

{

    /* Well it saves having to use an intermediate table... */

    switch( reg ) {

        case ICR: /* care about this later */

            break;

        case IPRA:

            PRIORITY(INT_TMU_TUNI0) = (val>>12)&0x000F;

            PRIORITY(INT_TMU_TUNI1) = (val>>8)&0x000F;

            PRIORITY(INT_TMU_TUNI2) =

                PRIORITY(INT_TMU_TICPI2) = (val>>4)&0x000F;

            PRIORITY(INT_RTC_ATI) =

                PRIORITY(INT_RTC_PRI) =

                PRIORITY(INT_RTC_CUI) = val&0x000F;

            break;

        case IPRB:

            PRIORITY(INT_WDT_ITI) = (val>>12)&0x000F;

            PRIORITY(INT_REF_RCMI) =

                PRIORITY(INT_REF_ROVI) = (val>>8)&0x000F;

            PRIORITY(INT_SCI_ERI) =

                PRIORITY(INT_SCI_RXI) =

                PRIORITY(INT_SCI_TXI) =

                PRIORITY(INT_SCI_TEI) = (val>>4)&0x000F;

            /* Bits 0-3 reserved */

            break;

        case IPRC:

            PRIORITY(INT_GPIO) = (val>>12)&0x000F;

            PRIORITY(INT_DMA_DMTE0) =

                PRIORITY(INT_DMA_DMTE1) =

                PRIORITY(INT_DMA_DMTE2) =

                PRIORITY(INT_DMA_DMTE3) =

                PRIORITY(INT_DMA_DMAE) = (val>>8)&0x000F;

            PRIORITY(INT_SCIF_ERI) =

                PRIORITY(INT_SCIF_RXI) =

                PRIORITY(INT_SCIF_BRI) =

                PRIORITY(INT_SCIF_TXI) = (val>>4)&0x000F;

            PRIORITY(INT_HUDI) = val&0x000F;

            break;

    }

    MMIO_WRITE( INTC, reg, val );

}

int32_t mmio_region_INTC_read( uint32_t reg )

{

    return MMIO_READ( INTC, reg );

}

void INTC_reset()

{

    int i;

    intc_state.num_pending = 0;

    for( i=0; i<INT_NUM_SOURCES; i++ )

	intc_state.priority[i] = intc_default_priority[i];

    sh4r.int_pending = 0;

}

void INTC_save_state( FILE *f )

{

    fwrite( &intc_state, sizeof(intc_state), 1, f );

}

int INTC_load_state( FILE *f )

{

    if( fread(&intc_state, sizeof(intc_state), 1, f) != 1 )

	return -1;

    return 0;

}

/* We basically maintain a priority queue here, raise_interrupt adds an entry,

 * accept_interrupt takes it off. At the moment this is does as a simple

 * ordered array, on the basis that in practice there's unlikely to be more

 * than one at a time. There are lots of ways to optimize this if it turns out

 * to be necessary, but I'd doubt it will be...

 */

void intc_raise_interrupt( int which )

{

    int i, j, pri;

    pri = PRIORITY(which);

    if( pri == 0 ) return; /* masked off */

    for( i=0; i<intc_state.num_pending; i++ ) {

        if( intc_state.pending[i] == which ) return; /* Don't queue more than once */

        if( PRIORITY(intc_state.pending[i]) > pri ||

            (PRIORITY(intc_state.pending[i]) == pri &&

             intc_state.pending[i] < which))

            break;

    }

    /* i == insertion point */

    for( j=intc_state.num_pending; j > i; j-- )

        intc_state.pending[j] = intc_state.pending[j-1];

    intc_state.pending[i] = which;

    if( i == intc_state.num_pending && (sh4r.sr&SR_BL)==0 && SH4_INTMASK() < pri )

        sh4r.int_pending = 1;

    intc_state.num_pending++;

}

void intc_clear_interrupt( int which )

{

    int i;

    for( i=intc_state.num_pending-1; i>=0; i-- ) {

	if( intc_state.pending[i] == which ) {

	    /* Shift array contents down */

	    while( i < intc_state.num_pending-1 ) {

		intc_state.pending[i] = intc_state.pending[++i];

	    }

	    intc_state.num_pending--;

	    intc_mask_changed();

	    break;

	}

    }

}

uint32_t intc_accept_interrupt( void )

{

    assert(intc_state.num_pending > 0);

    return INTCODE(intc_state.pending[intc_state.num_pending-1]);

}

void intc_mask_changed( void )

{   

    if( intc_state.num_pending > 0 && (sh4r.sr&SR_BL)==0 &&

        SH4_INTMASK() < PRIORITY(intc_state.pending[intc_state.num_pending-1]) )

        sh4r.int_pending = 1;

    else sh4r.int_pending = 0;

}

char *intc_get_interrupt_name( int code )

{

    return intc_sources[code].name;

}