/*

 * ide.c    31 Mar 2004  - IDE Interface implementation

 *

 * Copyright (c) 2004 Nathan Keynes. Distribution and modification permitted

 * under the terms of the GNU General Public License version 2 or later. 

 */

#include <stdlib.h>

#include "ide.h"

#define MAX_WRITE_BUF 4096;

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_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;

        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;

    }

}