/*

  * 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;

     }

 }