/**

 * $Id: ide.c,v 1.7 2005-12-27 12:41:33 nkeynes Exp $

 *

 * IDE interface 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.

 */

#define MODULE ide_module

#include <stdlib.h>

#include "dream.h"

#include "gdrom/ide.h"

#define MAX_WRITE_BUF 4096;

void ide_init( void );

void ide_init( void );

struct dreamcast_module ide_module = { "IDE", ide_init, ide_reset, NULL, NULL,

				       NULL, NULL, NULL };

struct ide_registers idereg;

static char command_buffer[12];

/* "\0\0\0\0\xb4\x19\0\0\x08SE      REV 6.42990316" */

char gdrom_ident[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0xb4, 0x19, 0x00,

                       0x00, 0x08, 0x53, 0x45, 0x20, 0x20, 0x20, 0x20,

                       0x20, 0x20, 0x52, 0x65, 0x76, 0x20, 0x36, 0x2e,

                       0x34, 0x32, 0x39, 0x39, 0x30, 0x33, 0x31, 0x36 };

void set_write_buffer( char *buf, int len )

{

    idereg.status |= IDE_ST_DATA;

    idereg.data = buf;

    idereg.datalen = len;

    idereg.writeptr = (uint16_t *)buf;

    idereg.readptr = NULL;

}

void set_read_buffer( char *buf, int len )

{

    idereg.status |= IDE_ST_DATA;

    idereg.data = buf;

    idereg.datalen = len;

    idereg.readptr = (uint16_t *)buf;

    idereg.writeptr = NULL;

    idereg.lba1 = len&0xFF;

    idereg.lba2 = len>>8;

}

void ide_clear_interrupt( void )

{

    /* TODO */

}

void ide_init( void )

{

}

void ide_reset( void )

{

    ide_clear_interrupt();

    idereg.error = 0x01;

    idereg.count = 0x01;

    idereg.lba0 = 0x21;

    idereg.lba1 = 0x14;

    idereg.lba2 = 0xeb;

    idereg.feature = 0; /* Indeterminate really */

    idereg.status = 0x00;

    idereg.device = 0x00;

    idereg.disc = IDE_DISC_GDROM | IDE_DISC_READY;

}

uint16_t ide_read_data_pio( void ) {

    if( idereg.readptr == NULL )

        return 0xFFFF;

    uint16_t rv = *idereg.readptr++;

    idereg.datalen-=2;

    if( idereg.datalen <=0 ) {

        idereg.readptr = NULL;

        idereg.status &= ~IDE_ST_DATA;

    }

    return rv;

}

void ide_write_data_pio( uint16_t val ) {

    if( idereg.writeptr == NULL )

        return;

    *idereg.writeptr++ = val;

    idereg.datalen-=2;

    if( idereg.datalen <= 0 ) {

        idereg.writeptr = NULL;

        idereg.status &= ~IDE_ST_DATA;

        ide_write_buffer( idereg.data );

    }

}

void ide_write_control( uint8_t val ) {

    /* TODO: In theory we can cause a soft-reset here, but the DC doesn't

     * appear to support it.

     */

}

void ide_write_command( uint8_t val ) {

    idereg.command = val;

    switch( val ) {

    case IDE_CMD_RESET_DEVICE:

	ide_reset();

	break;

    case IDE_CMD_PACKET:

	set_write_buffer(command_buffer,12);

	break;

    case IDE_CMD_SET_FEATURE:

	switch( idereg.feature ) {

	case IDE_FEAT_SET_TRANSFER_MODE:

	    switch( idereg.count & 0xF8 ) {

	    case IDE_XFER_PIO:

		INFO( "Set PIO default mode: %d", idereg.count&0x07 );

		break;

	    case IDE_XFER_PIO_FLOW:

		INFO( "Set PIO Flow-control mode: %d", idereg.count&0x07 );

		break;

	    case IDE_XFER_MULTI_DMA:

		INFO( "Set Multiword DMA mode: %d", idereg.count&0x07 );

		break;

	    case IDE_XFER_ULTRA_DMA:

		INFO( "Set Ultra DMA mode: %d", idereg.count&0x07 );

		break;

	    default:

		INFO( "Setting unknown transfer mode: %02X", idereg.count );

		break;

	    }

	    break;

	default:

	    WARN( "IDE: unimplemented feature: %02X", idereg.feature );

	}

	break;

    default:

	WARN( "IDE: Unimplemented command: %02X", val );

    }

    idereg.status |= IDE_ST_READY | IDE_ST_SERV;

}

void ide_write_buffer( char *data ) {

    uint16_t length;

    switch( idereg.command ) {

        case IDE_CMD_PACKET:

            /* Okay we have the packet in the command buffer */

            WARN( "ATAPI: Received Packet command: %02X", data[0] );

            switch( command_buffer[0] ) {

                case PKT_CMD_IDENTIFY:

                    /* NB: Bios sets data[4] = 0x08, no idea what this is for;

                     * different values here appear to have no effect.

                     */

                    length = *((uint16_t*)(data+2));

                    if( length > sizeof(gdrom_ident) )

                        length = sizeof(gdrom_ident);

                    set_read_buffer(gdrom_ident, length);

                    break;

            }

            break;

    }

}