/**

 * $Id$

 * 

 * "Fake" BIOS functions, for operation without the actual BIOS.

 *

 * Copyright (c) 2005-2010 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 "dream.h"

#include "mem.h"

#include "syscall.h"

#include "asic.h"

#include "dreamcast.h"

#include "bootstrap.h"

#include "sh4/sh4.h"

#include "drivers/cdrom/cdrom.h"

#include "drivers/cdrom/isofs.h"

#include "gdrom/gdrom.h"

gboolean bios_boot_gdrom_disc( void );

/* Definitions from KOS */

#define COMMAND_QUEUE_LENGTH 16

#define GD_CMD_PIOREAD     16  /* readcd */

#define GD_CMD_DMAREAD     17  /* readcd */

#define GD_CMD_GETTOC      18

#define GD_CMD_GETTOC2     19  /* toc2 */

#define GD_CMD_PLAY        20  /* playcd */

#define GD_CMD_PLAY2       21  /* playcd */

#define GD_CMD_PAUSE       22  /* No params */

#define GD_CMD_RELEASE     23  /* No params */

#define GD_CMD_INIT        24  /* No params */

#define GD_CMD_SEEK        27

#define GD_CMD_READ        28

#define GD_CMD_STOP        33  /* No params */

#define GD_CMD_GETSCD      34

#define GD_CMD_GETSES      35

#define GD_CMD_STATUS_NONE   0

#define GD_CMD_STATUS_ACTIVE 1

#define GD_CMD_STATUS_DONE   2

#define GD_CMD_STATUS_ABORT  3

#define GD_CMD_STATUS_ERROR  4

#define GD_ERROR_OK          0

#define GD_ERROR_NO_DISC     2

#define GD_ERROR_DISC_CHANGE 6

#define GD_ERROR_SYSTEM      1

struct gdrom_toc2_params {

    uint32_t session;

    sh4addr_t buffer;

};

struct gdrom_readcd_params {

    cdrom_lba_t lba;

    cdrom_count_t count;

    sh4addr_t buffer;

    uint32_t unknown;

};

struct gdrom_playcd_params {

    cdrom_lba_t start;

    cdrom_lba_t end;

    uint32_t repeat;

};

typedef union gdrom_cmd_params {

    struct gdrom_toc2_params toc2;

    struct gdrom_readcd_params readcd;

    struct gdrom_playcd_params playcd;

} *gdrom_cmd_params_t;

typedef struct gdrom_queue_entry {

    int status;

    uint32_t cmd_code;

    union gdrom_cmd_params params;

    uint32_t result[4];

} *gdrom_queue_entry_t;

static struct gdrom_queue_entry gdrom_cmd_queue[COMMAND_QUEUE_LENGTH];

static struct bios_gdrom_status {

    uint32_t status;

    uint32_t disk_type;

} bios_gdrom_status;

void bios_gdrom_init( void )

{

    memset( &gdrom_cmd_queue, 0, sizeof(gdrom_cmd_queue) );

}

void bios_gdrom_run_command( gdrom_queue_entry_t cmd )

{

    DEBUG( "BIOS GD command %d", cmd->cmd_code );

    cdrom_error_t status = CDROM_ERROR_OK;

    sh4ptr_t ptr;

    switch( cmd->cmd_code ) {

    case GD_CMD_INIT:

        /* *shrug* */

        cmd->status = GD_CMD_STATUS_DONE;

        break;

    case GD_CMD_GETTOC2:

        ptr = mem_get_region( cmd->params.toc2.buffer );

        status = gdrom_read_toc( ptr );

        if( status == CDROM_ERROR_OK ) {

            /* Convert data to little-endian */

            struct gdrom_toc *toc = (struct gdrom_toc *)ptr;

            for( unsigned i=0; i<99; i++ ) {

                toc->track[i] = ntohl(toc->track[i]);

            }

            toc->first = ntohl(toc->first);

            toc->last = ntohl(toc->last);

            toc->leadout = ntohl(toc->leadout);

        }

        break;

    case GD_CMD_PIOREAD:

    case GD_CMD_DMAREAD:

        ptr = mem_get_region( cmd->params.readcd.buffer );

        status = gdrom_read_cd( cmd->params.readcd.lba,

                cmd->params.readcd.count, 0x28, ptr, NULL );

        break;

    default:

        WARN( "Unknown BIOS GD command %d\n", cmd->cmd_code );

        cmd->status = GD_CMD_STATUS_ERROR;

        cmd->result[0] = GD_ERROR_SYSTEM;

        return;

    }

    switch( status ) {

    case CDROM_ERROR_OK:

        cmd->status = GD_CMD_STATUS_DONE;

        cmd->result[0] = GD_ERROR_OK;

        break;

    case CDROM_ERROR_NODISC:

        cmd->status = GD_CMD_STATUS_ERROR;

        cmd->result[0] = GD_ERROR_NO_DISC;

        break;

    default:

        cmd->status = GD_CMD_STATUS_ERROR;

        cmd->result[0] = GD_ERROR_SYSTEM;

    }

}

uint32_t bios_gdrom_enqueue( uint32_t cmd, sh4addr_t data )

{

    int i;

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

        if( gdrom_cmd_queue[i].status != GD_CMD_STATUS_ACTIVE ) {

            gdrom_cmd_queue[i].status = GD_CMD_STATUS_ACTIVE;

            gdrom_cmd_queue[i].cmd_code = cmd;

            switch( cmd ) {

            case GD_CMD_PIOREAD:

            case GD_CMD_DMAREAD:

                mem_copy_from_sh4( (unsigned char *)&gdrom_cmd_queue[i].params.readcd, data, sizeof(struct gdrom_readcd_params) );

                break;

            case GD_CMD_GETTOC2:

                mem_copy_from_sh4( (unsigned char *)&gdrom_cmd_queue[i].params.toc2, data, sizeof(struct gdrom_toc2_params) );

                break;

            case GD_CMD_PLAY:

            case GD_CMD_PLAY2:

                mem_copy_from_sh4( (unsigned char *)&gdrom_cmd_queue[i].params.playcd, data, sizeof(struct gdrom_playcd_params) );

                break;

            }

            return i;

        }

    }

    return -1;

}

void bios_gdrom_run_queue( void ) 

{

    int i;

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

        if( gdrom_cmd_queue[i].status == GD_CMD_STATUS_ACTIVE ) {

            bios_gdrom_run_command( &gdrom_cmd_queue[i] );

        }

    }

}

gdrom_queue_entry_t bios_gdrom_get_command( uint32_t id )

{

    if( id >= COMMAND_QUEUE_LENGTH ||

            gdrom_cmd_queue[id].status == GD_CMD_STATUS_NONE )

        return NULL;

    return &gdrom_cmd_queue[id];

}

/**

 * Address of the system information block (in the flash rom). Also repeats

 * at FLASH_SYSINFO_SEGMENT+0xA0

 */

#define FLASH_SYSINFO_SEGMENT 0x0021a000

#define FLASH_CONFIG_SEGMENT  0x0021c000

#define FLASH_CONFIG_LENGTH   0x00004000

#define FLASH_PARTITION_MAGIC "KATANA_FLASH____"

/**

 * Locate the active config block. FIXME: This isn't completely correct, but it works

 * under at least some circumstances. 

 */

static sh4ptr_t bios_find_flash_config( sh4addr_t segment, uint32_t length )

{

    sh4ptr_t start = mem_get_region(segment);

    sh4ptr_t p = start + 0x80;

    sh4ptr_t end = p + length;

    sh4ptr_t result = NULL;

    if( memcmp( start, FLASH_PARTITION_MAGIC, 16 ) != 0 )

        return NULL; /* Missing magic */

    while( p < end ) {

        if( p[0] == 0x05 && p[1] == 0 ) {

            result = p;

        }

        p += 0x40;

    }

    return result;

}

/**

 * Syscall information courtesy of Marcus Comstedt

 */

static void bios_sysinfo_vector( uint32_t syscallid )

{

    sh4ptr_t flash_segment, flash_config;

    sh4ptr_t dest;

    DEBUG( "BIOS SYSINFO: r4 = %08X, r5 = %08X, r6 = %08x, r7= %08X", sh4r.r[4], sh4r.r[5], sh4r.r[6], sh4r.r[7] );

    switch( sh4r.r[7] ) {

    case 0: /* SYSINFO_INIT */

        /* Initialize the region 8c000068 .. 8c00007f from the flash rom

         *   uint64_t system_id;

         *   char [5] system_props;

         *   char [3] zero_pad (?)

         *   char [8] settings;

         **/

        flash_segment = mem_get_region(FLASH_SYSINFO_SEGMENT);

        flash_config = bios_find_flash_config(FLASH_CONFIG_SEGMENT,FLASH_CONFIG_LENGTH);

        dest = mem_get_region( 0x8c000068 );

        memset( dest, 0, 24 );

        memcpy( dest, flash_segment + 0x56, 8 );

        memcpy( dest + 8, flash_segment, 5 );

        if( flash_config != NULL ) {

            memcpy( dest+16, flash_config+2, 8 );

        }

        break;

    case 2: /* SYSINFO_ICON */

        /* Not supported yet */

        break;

    case 3: /* SYSINFO_ID */

        sh4r.r[0] = 0x8c000068;

        break;

    }

}

static void bios_flashrom_vector( uint32_t syscallid )

{

    DEBUG( "BIOS FLASHROM: r4 = %08X, r5 = %08X, r6 = %08x, r7= %08X", sh4r.r[4], sh4r.r[5], sh4r.r[6], sh4r.r[7] );

    switch( sh4r.r[7] ) {

    case 0: /* FLASHROM_INFO */

        break;

    case 1: /* FLASHROM_READ */

        break;

    case 2: /* FLASHROM_WRITE */

        break;

    case 3: /* FLASHROM_DELETE */

        break;

    }

}

static void bios_romfont_vector( uint32_t syscallid )

{

    DEBUG( "BIOS ROMFONT: r4 = %08X, r5 = %08X, r6 = %08x, r7= %08X", sh4r.r[4], sh4r.r[5], sh4r.r[6], sh4r.r[7] );

    /* Not implemented */

}

static void bios_gdrom_vector( uint32_t syscallid )

{

    gdrom_queue_entry_t cmd;

    DEBUG( "BIOS GDROM: r4 = %08X, r5 = %08X, r6 = %08x, r7= %08X", sh4r.r[4], sh4r.r[5], sh4r.r[6], sh4r.r[7] );

    switch( sh4r.r[6] ) {

    case 0: /* GD-Rom */

        switch( sh4r.r[7] ) {

        case 0: /* Send command */

            sh4r.r[0] = bios_gdrom_enqueue( sh4r.r[4], sh4r.r[5] );

            break;

        case 1:  /* Check command */

            cmd = bios_gdrom_get_command( sh4r.r[4] );

            if( cmd == NULL ) {

                sh4r.r[0] = GD_CMD_STATUS_NONE;

            } else {

                sh4r.r[0] = cmd->status;

                if( cmd->status == GD_CMD_STATUS_ERROR &&

                        sh4r.r[5] != 0 ) {

                    mem_copy_to_sh4( sh4r.r[5], (sh4ptr_t)&cmd->result, sizeof(cmd->result) );

                }

            }

            break;

        case 2: /* Mainloop */

            bios_gdrom_run_queue();

            break;

        case 3: /* Init */

            bios_gdrom_init();

            break;

        case 4: /* Drive status */

            if( sh4r.r[4] != 0 ) {

                mem_copy_to_sh4( sh4r.r[4], (sh4ptr_t)&bios_gdrom_status,

                        sizeof(bios_gdrom_status) );

            }

            sh4r.r[0] = 0;

            break;

        case 8: /* Abort command */

            cmd = bios_gdrom_get_command( sh4r.r[4] );

            if( cmd == NULL || cmd->status != GD_CMD_STATUS_ACTIVE ) {

                sh4r.r[0] = -1;

            } else {

                cmd->status = GD_CMD_STATUS_ABORT;

                sh4r.r[0] = 0;

            }

            break;

        case 9: /* Reset */

            break;

        case 10: /* Set mode */

            sh4r.r[0] = 0;

            break;

        }

        break;

        case -1: /* Misc */

        break;

        default: /* ??? */

            break;

    }

}

static void bios_menu_vector( uint32_t syscallid )

{

    DEBUG( "BIOS MENU: r4 = %08X, r5 = %08X, r6 = %08x, r7= %08X", sh4r.r[4], sh4r.r[5], sh4r.r[6], sh4r.r[7] );

    switch( sh4r.r[4] ) {

    case 0:

        WARN( "Entering main program" );

        break;

    case 1:

        WARN( "Program aborted to DC menu");

        dreamcast_stop();

        break;

    }

}

void bios_boot( uint32_t syscallid )

{

    /* Initialize hardware */

    /* Boot disc if present */

    if( !bios_boot_gdrom_disc() ) {

        dreamcast_stop();

    }

}

void bios_install( void ) 

{

    bios_gdrom_init();

    syscall_add_hook_vector( 0xB0, 0x8C0000B0, bios_sysinfo_vector );

    syscall_add_hook_vector( 0xB4, 0x8C0000B4, bios_romfont_vector );

    syscall_add_hook_vector( 0xB8, 0x8C0000B8, bios_flashrom_vector );

    syscall_add_hook_vector( 0xBC, 0x8C0000BC, bios_gdrom_vector );

    syscall_add_hook_vector( 0xE0, 0x8C0000E0, bios_menu_vector );

}

#define MIN_ISO_SECTORS 32

static gboolean bios_load_ipl( cdrom_disc_t disc, cdrom_track_t track, const char *program_name,

                               unsigned char *buffer, gboolean unscramble )

{

    gboolean rv = TRUE;

    IsoImageFilesystem *iso = iso_filesystem_new_from_track( disc, track, NULL );

    if( iso == NULL ) {

        ERROR( "Disc is not bootable (invalid ISO9660 filesystem)" );

        return FALSE;

    }

    IsoFileSource *file = NULL;

    int status = iso->get_by_path(iso, program_name, &file );

    if( status != 1 ) {

        ERROR( "Disc is not bootable (initial program '%s' not found)", program_name );

        iso_filesystem_unref(iso);

        return FALSE;

    }

    struct stat st;

    if( iso_file_source_stat(file, &st) == 1 ) {

        if( st.st_size > (0x8D000000 - BINARY_LOAD_ADDR) ) {

            ERROR( "Disc is not bootable (Initial program is too large to fit into memory)" );

            rv = FALSE;

        } else if( iso_file_source_open(file) == 1 ) {

            size_t len;

            if( unscramble ) {

                unsigned char *tmp = g_malloc(st.st_size);

                len = iso_file_source_read(file, tmp, st.st_size);

                bootprogram_unscramble(buffer, tmp, st.st_size);

                g_free(tmp);

            } else {

                len = iso_file_source_read(file, buffer, st.st_size);

            }

            if( len != st.st_size ) {

                ERROR( "Disc is not bootable (Unable to read initial program '%s')", program_name );

                rv = FALSE;

            }

            iso_file_source_close(file);

        }

    } else {

        ERROR( "Disc is not bootable (Unable to get size of initial program '%s')", program_name );

        rv = FALSE;

    }

    iso_file_source_unref(file);

    iso_filesystem_unref(iso);

    return rv;

}

gboolean bios_boot_gdrom_disc( void )

{

    cdrom_disc_t disc = gdrom_get_current_disc();

    int status = gdrom_get_drive_status();

    if( status == CDROM_DISC_NONE ) {

        ERROR( "No disc in drive" );

        return FALSE;

    }

    /* Find the bootable data track (if present) */

    cdrom_track_t track = gdrom_disc_get_boot_track(disc);

    if( track == NULL ) {

        ERROR( "Disc is not bootable" );

        return FALSE;

    }

    uint32_t sectors = cdrom_disc_get_track_size(disc,track);

    if( sectors < MIN_ISO_SECTORS ) {

        ERROR( "Disc is not bootable" );

        return FALSE;

    }

    /* Load the initial bootstrap into DC ram at 8c008000 */

    size_t length = BOOTSTRAP_SIZE;

    unsigned char *bootstrap = mem_get_region(BOOTSTRAP_LOAD_ADDR);

    if( cdrom_disc_read_sectors( disc, track->lba, BOOTSTRAP_SIZE/2048,

            CDROM_READ_DATA|CDROM_READ_MODE2_FORM1, bootstrap, &length ) !=

            CDROM_ERROR_OK ) {

        ERROR( "Disc is not bootable" );

        return FALSE;

    }

    /* Check the magic just to be sure */

    dc_bootstrap_head_t metadata = (dc_bootstrap_head_t)bootstrap;

    if( memcmp( metadata->magic, BOOTSTRAP_MAGIC, BOOTSTRAP_MAGIC_SIZE ) != 0 ) {

        ERROR( "Disc is not bootable (missing dreamcast bootstrap)" );

        return FALSE;

    }

    /* Get the initial program from the bootstrap (usually 1ST_READ.BIN) */

    char program_name[18] = "/";

    memcpy(program_name+1, metadata->boot_file, 16);

    program_name[17] = '\0';

    for( int i=16; i >= 0 && program_name[i] == ' '; i-- ) {

        program_name[i] = '\0';

    }

    /* Bootstrap is good. Now find the program in the actual filesystem... */

    unsigned char *program = mem_get_region(BINARY_LOAD_ADDR);

    gboolean isGDROM = (disc->disc_type == CDROM_DISC_GDROM );

    if( !bios_load_ipl( disc, track, program_name, program, !isGDROM ) )

        return FALSE;

    asic_enable_ide_interface(isGDROM);

    dreamcast_program_loaded( "", BOOTSTRAP_ENTRY_ADDR );

    return TRUE;

}