/**

  * $Id: maple.c,v 1.7 2006-03-20 12:00:15 nkeynes Exp $

  *

  * Implements the core Maple bus, including DMA transfers to and from the bus.

  *

  * 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 maple_module

 #include <assert.h>

 #include "dream.h"

 #include "mem.h"

 #include "asic.h"

 #include "maple.h"

 void maple_init( void );

 struct dreamcast_module maple_module = { "Maple", maple_init, NULL, NULL, NULL,

 					 NULL, NULL, NULL };

 void maple_init( void )

 {

 }

 /**

  * Input data looks like this:

  *    0: transfer control word

  *      0: length of data in words (not including 3 word header)

  *      1: low bit = lightgun mode

  *      2: low 2 bits = port # (0..3)

  *      3: 0x80 = last packet, 0x00 = normal packet

  *    4: output buffer address

  *    8: Command word

  *      8: command code

  *      9: destination address

  *     10: source address

  *     11: length of data in words (not including 3 word header)

  *   12: command-specific data

  */

 /**

  * array is [port][subperipheral], so [0][0] is main peripheral on port A,

  * [1][2] is the second subperipheral on port B and so on.

  */

 maple_device_t maple_devices[4][6];

 int maple_periph_mask[4];

 #define GETBYTE(n) ((uint32_t)(buf[n]))

 #define GETWORD(n) (*((uint32_t *)(buf+(n))))

 #define PUTBYTE(n,x) (buf[n] = (char)x)

 #define PUTWORD(n,x) (*((uint32_t *)(return_buf+(n))) = (x))

 void maple_handle_buffer( uint32_t address ) {

     unsigned char *buf = (unsigned char *)mem_get_region(address);

     if( buf == NULL ) {

         ERROR( "Invalid or unmapped buffer passed to maple (0x%08X)", address );

     } else {

         unsigned int last = 0;

         int i = 0, count;

         for( count=0; !last; count++ ) {

             unsigned int port, length, gun, periph, periph_id, out_length;

             unsigned int cmd, recv_addr, send_addr;

             uint32_t return_addr;

             unsigned char *return_buf;

             last = GETBYTE(3) & 0x80; /* indicates last packet */

             port = GETBYTE(2) & 0x03;

             gun = GETBYTE(1) & 0x01;

             length = GETBYTE(0) & 0xFF;

             return_addr = GETWORD(4);

             if( return_addr == 0 ) {

                 /* ERROR */

             }

             return_buf = mem_get_region(return_addr);

             cmd = GETBYTE(8);

             recv_addr = GETBYTE(9);

             send_addr = GETBYTE(10);

             /* Sanity checks */

             if( GETBYTE(11) != length ||

                 send_addr != (port<<6) ||

                 recv_addr >> 6 != port ||

                 return_buf == NULL ) {

                 /* ERROR */

             }

             periph = 0;

             periph_id = recv_addr & 0x3F;

             if( periph_id != 0x20 ) {

                 for( i=0;i<5;i++ ) {

                     if( periph_id == (1<<i) ) {

                         periph = i+1;

                         break;

                     }

                 }

                 if( periph == 0 ) { /* Bad setting */

                     /* ERROR */

                 }

             }

             INFO( "Maple packet %d: Cmd %d on port %d device %d", count, cmd, port, periph );

             maple_device_t dev = maple_devices[port][periph];

             if( dev == NULL ) {

                 /* no device attached */

                 *((uint32_t *)return_buf) = -1;

             } else {

                 int status, func, block;

                 out_length = 0;

                 switch( cmd ) {

                     case MAPLE_CMD_INFO:

                         status = MAPLE_RESP_INFO;

                         memcpy( return_buf+4, dev->ident, 112 );

                         out_length = 0x1C;

                         break;

                     case MAPLE_CMD_EXT_INFO:

                         status = MAPLE_RESP_EXT_INFO;

                         memcpy( return_buf+4, dev->ident, 192 );

                         out_length = 0x30;

                         break;

                     case MAPLE_CMD_RESET:

                         if( dev->reset == NULL )

                             status = MAPLE_RESP_ACK;

                         else status = dev->reset(dev);

                         break;

                     case MAPLE_CMD_SHUTDOWN:

                         if( dev->shutdown == NULL )

                             status = MAPLE_RESP_ACK;

                         else status = dev->shutdown(dev);

                         break;

                     case MAPLE_CMD_GET_COND:

                         func = GETWORD(12);

                         if( dev->get_condition == NULL )

                             status = MAPLE_ERR_CMD_UNKNOWN;

                         else status = dev->get_condition(dev, func,

                                                          return_buf+8,

                                                          &out_length );

 			out_length++;

                         if( status == 0 ) {

                             status = MAPLE_RESP_DATA;

                             PUTWORD(4,func);

                         }

                         break;

                     case MAPLE_CMD_SET_COND:

                         func = GETWORD(12);

                         if( dev->set_condition == NULL )

                             status = MAPLE_ERR_CMD_UNKNOWN;

                         else status = dev->set_condition(dev, func,

                                                          buf+16,

                                                          length);

                         if( status == 0 )

                             status = MAPLE_RESP_ACK;

                         break;

                     case MAPLE_CMD_READ_BLOCK:

                         func = GETWORD(12);

                         block = GETWORD(16);

                         if( dev->read_block == NULL )

                             status = MAPLE_ERR_CMD_UNKNOWN;

                         else status = dev->read_block(dev, func, block,

                                                       return_buf+12,

                                                       &out_length );

                         if( status == 0 ) {

                             status = MAPLE_RESP_DATA;

                             PUTWORD(4,func);

                             PUTWORD(8,block);

                         }

                         break;

                     case MAPLE_CMD_WRITE_BLOCK:

                         func = GETWORD(12);

                         block = GETWORD(16);

                         if( dev->write_block == NULL )

                             status = MAPLE_ERR_CMD_UNKNOWN;

                         else {

                             status = dev->write_block(dev, func, block, 

                                                       buf+20, length);

                             if( status == 0 )

                                 status = MAPLE_RESP_ACK;

                         }

                         break;

                     default:

                         status = MAPLE_ERR_CMD_UNKNOWN;

                 }

                 return_buf[0] = status;

                 return_buf[1] = send_addr;

                 return_buf[2] = recv_addr;

                 if( periph == 0 )

                     return_buf[2] |= maple_periph_mask[port];

                 return_buf[3] = out_length;

             }

             buf += 12 + (length<<2);

         }

         asic_event( EVENT_MAPLE_DMA );

     }

 }

 void maple_attach_device( maple_device_t dev, unsigned int port,

                           unsigned int periph ) {

     assert( port < 4 );

     assert( periph < 6 );

     if( maple_devices[port][periph] != NULL ) {

         /* Detach existing peripheral first */

         maple_detach_device( port, periph );

     }

     maple_devices[port][periph] = dev;

     if( periph != 0 )

         maple_periph_mask[port] |= (1<<(periph-1));

     else maple_periph_mask[port] |= 0x20;

     if( dev->attach != NULL ) {

         dev->attach( dev );

     }

 }

 void maple_detach_device( unsigned int port, unsigned int periph ) {

     assert( port < 4 );

     assert( periph < 6 );

     maple_device_t dev = maple_devices[port][periph];

     if( dev == NULL ) /* already detached */

         return;

     maple_devices[port][periph] = NULL;

     if( dev->detach != NULL ) {

         dev->detach(dev);

     }

     if( periph == 0 ) {

         /* If we detach the main peripheral, we also have to detach all the

          * subperipherals, or the system could get quite confused

          */

         int i;

         maple_periph_mask[port] = 0;

         for( i=1; i<6; i++ ) {

             maple_detach_device(port,i);

         }

     } else {

         maple_periph_mask[port] &= (~(1<<(periph-1)));

     }

 }