/**

 * $Id: maple.c,v 1.5 2005-12-25 08:24:11 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.

 */

#include <assert.h>

#include "dream.h"

#include "modules.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 );

                        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)));

    }

}