/**

  * $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 );

     }

 }