86Box/src/scsi/scsi_disk.c

/*
 * 86Box    A hypervisor and IBM PC system emulator that specializes in
 *          running old operating systems and software designed for IBM
 *          PC systems and compatibles from 1981 through fairly recent
 *          system designs based on the PCI bus.
 *
 *          Emulation of SCSI fixed disks.
 *
 *
 *
 * Authors: Miran Grca, <mgrca8@gmail.com>
 *
 *          Copyright 2017-2018 Miran Grca.
 */
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <wchar.h>
#define HAVE_STDARG_H
#include <86box/86box.h>
#include <86box/timer.h>
#include <86box/device.h>
#include <86box/nvr.h>
#include <86box/hdd.h>
#include <86box/hdc.h>
#include <86box/scsi.h>
#include <86box/scsi_device.h>
#include <86box/hdc_ide.h>
#include <86box/plat.h>
#include <86box/ui.h>
#include <86box/scsi_disk.h>
#include <86box/version.h>

#define scsi_disk_sense_error dev->sense[0]
#define scsi_disk_sense_key   dev->sense[2]
#define scsi_disk_asc         dev->sense[12]
#define scsi_disk_ascq        dev->sense[13]

/* Table of all SCSI commands and their flags, needed for the new disc change / not ready handler. */
const uint8_t scsi_disk_command_flags[0x100] = {
    IMPLEMENTED | CHECK_READY | NONDATA,          /* 0x00 */
    IMPLEMENTED | ALLOW_UA | NONDATA | SCSI_ONLY, /* 0x01 */
    0,
    IMPLEMENTED | ALLOW_UA,                                     /* 0x03 */
    IMPLEMENTED | CHECK_READY | ALLOW_UA | NONDATA | SCSI_ONLY, /* 0x04 */
    0, 0, 0,
    IMPLEMENTED | CHECK_READY, /* 0x08 */
    0,
    IMPLEMENTED | CHECK_READY,           /* 0x0A */
    IMPLEMENTED | CHECK_READY | NONDATA, /* 0x0B */
    0, 0, 0, 0, 0, 0,
    IMPLEMENTED | ALLOW_UA,                          /* 0x12 */
    IMPLEMENTED | CHECK_READY | NONDATA | SCSI_ONLY, /* 0x13 */
    0,
    IMPLEMENTED,             /* 0x15 */
    IMPLEMENTED | SCSI_ONLY, /* 0x16 */
    IMPLEMENTED | SCSI_ONLY, /* 0x17 */
    0, 0,
    IMPLEMENTED, /* 0x1A */
    0, 0,
    IMPLEMENTED,               /* 0x1D */
    IMPLEMENTED | CHECK_READY, /* 0x1E */
    0, 0, 0, 0, 0, 0,
    IMPLEMENTED | CHECK_READY, /* 0x25 */
    0, 0,
    IMPLEMENTED | CHECK_READY, /* 0x28 */
    0,
    IMPLEMENTED | CHECK_READY,           /* 0x2A */
    IMPLEMENTED | CHECK_READY | NONDATA, /* 0x2B */
    0, 0,
    IMPLEMENTED | CHECK_READY,                       /* 0x2E */
    IMPLEMENTED | CHECK_READY | NONDATA | SCSI_ONLY, /* 0x2F */
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0,
    IMPLEMENTED | CHECK_READY, /* 0x41 */
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0,
    IMPLEMENTED, /* 0x55 */
    0, 0, 0, 0,
    IMPLEMENTED, /* 0x5A */
    0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    IMPLEMENTED | CHECK_READY, /* 0xA8 */
    0,
    IMPLEMENTED | CHECK_READY, /* 0xAA */
    0, 0, 0,
    IMPLEMENTED | CHECK_READY,                       /* 0xAE */
    IMPLEMENTED | CHECK_READY | NONDATA | SCSI_ONLY, /* 0xAF */
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    IMPLEMENTED, /* 0xBD */
    0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

uint64_t scsi_disk_mode_sense_page_flags = (GPMODEP_FORMAT_DEVICE_PAGE | GPMODEP_RIGID_DISK_PAGE | GPMODEP_UNK_VENDOR_PAGE | GPMODEP_ALL_PAGES);

/* This should be done in a better way but for time being, it's been done this way so it's not as huge and more readable. */
static const mode_sense_pages_t scsi_disk_mode_sense_pages_default = {
    {[GPMODE_FORMAT_DEVICE_PAGE] = { GPMODE_FORMAT_DEVICE_PAGE, 0x16, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
     [GPMODE_RIGID_DISK_PAGE]    = { GPMODE_RIGID_DISK_PAGE, 0x16, 0, 0x10, 0, 64, 0, 0, 0, 0, 0, 0, 0, 200, 0xff, 0xff, 0xff, 0, 0, 0, 0x15, 0x18, 0, 0 },
     [GPMODE_UNK_VENDOR_PAGE]    = { 0xB0, 0x16, '8', '6', 'B', 'o', 'x', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ' }}
};

static const mode_sense_pages_t scsi_disk_mode_sense_pages_changeable = {
    {[GPMODE_FORMAT_DEVICE_PAGE] = { GPMODE_FORMAT_DEVICE_PAGE, 0x16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
     [GPMODE_RIGID_DISK_PAGE]    = { GPMODE_RIGID_DISK_PAGE, 0x16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
     [GPMODE_UNK_VENDOR_PAGE]    = { 0xB0, 0x16, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }}
};

#ifdef ENABLE_SCSI_DISK_LOG
int scsi_disk_do_log = ENABLE_SCSI_DISK_LOG;

static void
scsi_disk_log(const char *fmt, ...)
{
    va_list ap;

    if (scsi_disk_do_log) {
        va_start(ap, fmt);
        pclog_ex(fmt, ap);
        va_end(ap);
    }
}
#else
#    define scsi_disk_log(fmt, ...)
#endif

void
scsi_disk_mode_sense_load(scsi_disk_t *dev)
{
    FILE *f;
    char  file_name[512];

    memset(&dev->ms_pages_saved, 0, sizeof(mode_sense_pages_t));
    memcpy(&dev->ms_pages_saved, &scsi_disk_mode_sense_pages_default, sizeof(mode_sense_pages_t));

    memset(file_name, 0, 512);
    sprintf(file_name, "scsi_disk_%02i_mode_sense.bin", dev->id);
    f = plat_fopen(nvr_path(file_name), "rb");
    if (f) {
        if (fread(dev->ms_pages_saved.pages[0x30], 1, 0x18, f) != 0x18)
            fatal("scsi_disk_mode_sense_load(): Error reading data\n");
        fclose(f);
    }
}

void
scsi_disk_mode_sense_save(scsi_disk_t *dev)
{
    FILE *f;
    char  file_name[512];

    memset(file_name, 0, 512);
    sprintf(file_name, "scsi_disk_%02i_mode_sense.bin", dev->id);
    f = plat_fopen(nvr_path(file_name), "wb");
    if (f) {
        fwrite(dev->ms_pages_saved.pages[0x30], 1, 0x18, f);
        fclose(f);
    }
}

/*SCSI Mode Sense 6/10*/
uint8_t
scsi_disk_mode_sense_read(scsi_disk_t *dev, uint8_t page_control, uint8_t page, uint8_t pos)
{
    if (page_control == 1)
        return scsi_disk_mode_sense_pages_changeable.pages[page][pos];

    if (page == GPMODE_RIGID_DISK_PAGE)
        switch (page_control) {
            /* Rigid disk geometry page. */
            case 0:
            case 2:
            case 3:
                switch (pos) {
                    default:
                    case 0:
                    case 1:
                        return scsi_disk_mode_sense_pages_default.pages[page][pos];
                    case 2:
                    case 6:
                    case 9:
                        return (dev->drv->tracks >> 16) & 0xff;
                    case 3:
                    case 7:
                    case 10:
                        return (dev->drv->tracks >> 8) & 0xff;
                    case 4:
                    case 8:
                    case 11:
                        return dev->drv->tracks & 0xff;
                    case 5:
                        return dev->drv->hpc & 0xff;
                }

            default:
                break;
        }
    else if (page == GPMODE_FORMAT_DEVICE_PAGE)
        switch (page_control) {
            /* Format device page. */
            case 0:
            case 2:
            case 3:
                switch (pos) {
                    default:
                    case 0:
                    case 1:
                        return scsi_disk_mode_sense_pages_default.pages[page][pos];
                    /* Actual sectors + the 1 "alternate sector" we report. */
                    case 10:
                        return ((dev->drv->spt + 1) >> 8) & 0xff;
                    case 11:
                        return (dev->drv->spt + 1) & 0xff;
                }

            default:
                break;
        }
    else
        switch (page_control) {
            case 0:
            case 3:
                return dev->ms_pages_saved.pages[page][pos];
            case 2:
                return scsi_disk_mode_sense_pages_default.pages[page][pos];

            default:
                break;
        }

    return 0;
}

uint32_t
scsi_disk_mode_sense(scsi_disk_t *dev, uint8_t *buf, uint32_t pos, uint8_t page, uint8_t block_descriptor_len)
{
    uint8_t msplen;
    uint8_t page_control = (page >> 6) & 3;
    int     size = 0;

    page &= 0x3f;

    size = hdd_image_get_last_sector(dev->id);

    if (block_descriptor_len) {
        buf[pos++] = 1;                   /* Density code. */
        buf[pos++] = (size >> 16) & 0xff; /* Number of blocks (0 = all). */
        buf[pos++] = (size >> 8) & 0xff;
        buf[pos++] = size & 0xff;
        buf[pos++] = 0; /* Reserved. */
        buf[pos++] = 0; /* Block length (0x200 = 512 bytes). */
        buf[pos++] = 2;
        buf[pos++] = 0;
    }

    for (uint8_t i = 0; i < 0x40; i++) {
        if ((page == GPMODE_ALL_PAGES) || (page == i)) {
            if (scsi_disk_mode_sense_page_flags & (1LL << (uint64_t) page)) {
                buf[pos++] = scsi_disk_mode_sense_read(dev, page_control, i, 0);
                msplen     = scsi_disk_mode_sense_read(dev, page_control, i, 1);
                buf[pos++] = msplen;
                scsi_disk_log("SCSI HDD %i: MODE SENSE: Page [%02X] length %i\n", dev->id, i, msplen);
                for (uint8_t j = 0; j < msplen; j++)
                    buf[pos++] = scsi_disk_mode_sense_read(dev, page_control, i, 2 + j);
            }
        }
    }

    return pos;
}

static void
scsi_disk_command_common(scsi_disk_t *dev)
{
    dev->status = BUSY_STAT;
    dev->phase  = 1;
    if (dev->packet_status == PHASE_COMPLETE)
        dev->callback = 0.0;
    else
        dev->callback = -1.0; /* Speed depends on SCSI controller */
}

static void
scsi_disk_command_complete(scsi_disk_t *dev)
{
    ui_sb_update_icon(SB_HDD | dev->drv->bus, 0);
    dev->packet_status = PHASE_COMPLETE;
    scsi_disk_command_common(dev);
}

static void
scsi_disk_command_read_dma(scsi_disk_t *dev)
{
    dev->packet_status = PHASE_DATA_IN_DMA;
    scsi_disk_command_common(dev);
}

static void
scsi_disk_command_write_dma(scsi_disk_t *dev)
{
    dev->packet_status = PHASE_DATA_OUT_DMA;
    scsi_disk_command_common(dev);
}

static void
scsi_disk_data_command_finish(scsi_disk_t *dev, int len, UNUSED(int block_len), int alloc_len, int direction)
{
    scsi_disk_log("SCSI HD %i: Finishing command (%02X): %i, %i, %i, %i, %i\n", dev->id,
                  dev->current_cdb[0], len, block_len, alloc_len, direction, dev->request_length);
    if (alloc_len >= 0) {
        if (alloc_len < len)
            len = alloc_len;
    }
    if (len == 0)
        scsi_disk_command_complete(dev);
    else {
        if (direction == 0)
            scsi_disk_command_read_dma(dev);
        else
            scsi_disk_command_write_dma(dev);
    }
}

static void
scsi_disk_sense_clear(scsi_disk_t *dev, UNUSED(int command))
{
    scsi_disk_sense_key = scsi_disk_asc = scsi_disk_ascq = 0;
}

static void
scsi_disk_set_phase(scsi_disk_t *dev, uint8_t phase)
{
    uint8_t scsi_bus = (dev->drv->scsi_id >> 4) & 0x0f;
    uint8_t scsi_id  = dev->drv->scsi_id & 0x0f;

    if (dev->drv->bus != HDD_BUS_SCSI)
        return;

    scsi_devices[scsi_bus][scsi_id].phase = phase;
}

static void
scsi_disk_cmd_error(scsi_disk_t *dev)
{
    scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
    dev->error         = ((scsi_disk_sense_key & 0xf) << 4) | ABRT_ERR;
    dev->status        = READY_STAT | ERR_STAT;
    dev->phase         = 3;
    dev->packet_status = PHASE_ERROR;
    dev->callback      = 50.0 * SCSI_TIME;
    ui_sb_update_icon(SB_HDD | dev->drv->bus, 0);
    scsi_disk_log("SCSI HD %i: ERROR: %02X/%02X/%02X\n", dev->id, scsi_disk_sense_key, scsi_disk_asc, scsi_disk_ascq);
}

static void
scsi_disk_invalid_lun(scsi_disk_t *dev)
{
    scsi_disk_sense_key = SENSE_ILLEGAL_REQUEST;
    scsi_disk_asc       = ASC_INV_LUN;
    scsi_disk_ascq      = 0;
    scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
    scsi_disk_cmd_error(dev);
}

static void
scsi_disk_illegal_opcode(scsi_disk_t *dev)
{
    scsi_disk_sense_key = SENSE_ILLEGAL_REQUEST;
    scsi_disk_asc       = ASC_ILLEGAL_OPCODE;
    scsi_disk_ascq      = 0;
    scsi_disk_cmd_error(dev);
}

static void
scsi_disk_lba_out_of_range(scsi_disk_t *dev)
{
    scsi_disk_sense_key = SENSE_ILLEGAL_REQUEST;
    scsi_disk_asc       = ASC_LBA_OUT_OF_RANGE;
    scsi_disk_ascq      = 0;
    scsi_disk_cmd_error(dev);
}

static void
scsi_disk_invalid_field(scsi_disk_t *dev)
{
    scsi_disk_sense_key = SENSE_ILLEGAL_REQUEST;
    scsi_disk_asc       = ASC_INV_FIELD_IN_CMD_PACKET;
    scsi_disk_ascq      = 0;
    scsi_disk_cmd_error(dev);
    dev->status = 0x53;
}

static void
scsi_disk_invalid_field_pl(scsi_disk_t *dev)
{
    scsi_disk_sense_key = SENSE_ILLEGAL_REQUEST;
    scsi_disk_asc       = ASC_INV_FIELD_IN_PARAMETER_LIST;
    scsi_disk_ascq      = 0;
    scsi_disk_cmd_error(dev);
    dev->status = 0x53;
}

static void
scsi_disk_data_phase_error(scsi_disk_t *dev)
{
    scsi_disk_sense_key = SENSE_ILLEGAL_REQUEST;
    scsi_disk_asc       = ASC_DATA_PHASE_ERROR;
    scsi_disk_ascq      = 0;
    scsi_disk_cmd_error(dev);
}

static int
scsi_disk_pre_execution_check(scsi_disk_t *dev, uint8_t *cdb)
{
    if ((cdb[0] != GPCMD_REQUEST_SENSE) && (dev->cur_lun == SCSI_LUN_USE_CDB) && (cdb[1] & 0xe0)) {
        scsi_disk_log("SCSI HD %i: Attempting to execute a unknown command targeted at SCSI LUN %i\n",
                      dev->id, ((dev->request_length >> 5) & 7));
        scsi_disk_invalid_lun(dev);
        return 0;
    }

    if (!(scsi_disk_command_flags[cdb[0]] & IMPLEMENTED)) {
        scsi_disk_log("SCSI HD %i: Attempting to execute unknown command %02X\n", dev->id, cdb[0]);
        scsi_disk_illegal_opcode(dev);
        return 0;
    }

    /* Unless the command is REQUEST SENSE, clear the sense. This will *NOT*
       the UNIT ATTENTION condition if it's set. */
    if (cdb[0] != GPCMD_REQUEST_SENSE)
        scsi_disk_sense_clear(dev, cdb[0]);

    scsi_disk_log("SCSI HD %i: Continuing with command\n", dev->id);

    return 1;
}

static void
scsi_disk_seek(scsi_disk_t *dev, uint32_t pos)
{
    /* scsi_disk_log("SCSI HD %i: Seek %08X\n", dev->id, pos); */
    hdd_image_seek(dev->id, pos);
}

static void
scsi_disk_rezero(scsi_disk_t *dev)
{
    if (dev->id == 0xff)
        return;

    dev->sector_pos = dev->sector_len = 0;
    scsi_disk_seek(dev, 0);
}

static void
scsi_disk_reset(scsi_common_t *sc)
{
    scsi_disk_t *dev = (scsi_disk_t *) sc;

    scsi_disk_rezero(dev);
    dev->status        = 0;
    dev->callback      = 0.0;
    dev->packet_status = PHASE_NONE;
    dev->cur_lun       = SCSI_LUN_USE_CDB;
}

void
scsi_disk_request_sense(scsi_disk_t *dev, uint8_t *buffer, uint8_t alloc_length, int desc)
{
    /*Will return 18 bytes of 0*/
    if (alloc_length != 0) {
        memset(buffer, 0, alloc_length);
        if (!desc)
            memcpy(buffer, dev->sense, alloc_length);
        else {
            buffer[1] = scsi_disk_sense_key;
            buffer[2] = scsi_disk_asc;
            buffer[3] = scsi_disk_ascq;
        }
    } else
        return;

    buffer[0] = 0x70;

    scsi_disk_log("SCSI HD %i: Reporting sense: %02X %02X %02X\n", dev->id, buffer[2], buffer[12], buffer[13]);

    /* Clear the sense stuff as per the spec. */
    scsi_disk_sense_clear(dev, GPCMD_REQUEST_SENSE);
}

static void
scsi_disk_request_sense_for_scsi(scsi_common_t *sc, uint8_t *buffer, uint8_t alloc_length)
{
    scsi_disk_t *dev = (scsi_disk_t *) sc;

    scsi_disk_request_sense(dev, buffer, alloc_length, 0);
}

static void
scsi_disk_set_buf_len(UNUSED(scsi_disk_t *dev), int32_t *BufLen, int32_t *src_len)
{
    if (*BufLen == -1)
        *BufLen = *src_len;
    else {
        *BufLen  = MIN(*src_len, *BufLen);
        *src_len = *BufLen;
    }
    scsi_disk_log("SCSI HD %i: Actual transfer length: %i\n", dev->id, *BufLen);
}

static void
scsi_disk_buf_alloc(scsi_disk_t *dev, uint32_t len)
{
    scsi_disk_log("SCSI HD %i: Allocated buffer length: %i\n", dev->id, len);
    if (!dev->temp_buffer)
        dev->temp_buffer = (uint8_t *) malloc(len);
}

static void
scsi_disk_buf_free(scsi_disk_t *dev)
{
    if (dev->temp_buffer) {
        scsi_disk_log("SCSI HD %i: Freeing buffer...\n", dev->id);
        free(dev->temp_buffer);
        dev->temp_buffer = NULL;
    }
}

static void
scsi_disk_command(scsi_common_t *sc, uint8_t *cdb)
{
    scsi_disk_t *dev = (scsi_disk_t *) sc;
    int32_t     *BufLen;
    int32_t      len;
    int32_t      max_len;
    int32_t      alloc_length;
    int          pos = 0;
    int          idx = 0;
    unsigned     size_idx;
    unsigned     preamble_len;
    uint32_t     last_sector            = 0;
    char         device_identify[9]     = { '8', '6', 'B', '_', 'H', 'D', '0', '0', 0 };
    char         device_identify_ex[15] = { '8', '6', 'B', '_', 'H', 'D', '0', '0', ' ', 'v', '1', '.', '0', '0', 0 };
    int          block_desc             = 0;
    uint8_t      scsi_bus               = (dev->drv->scsi_id >> 4) & 0x0f;
    uint8_t      scsi_id                = dev->drv->scsi_id & 0x0f;

    BufLen = &scsi_devices[scsi_bus][scsi_id].buffer_length;

    last_sector = hdd_image_get_last_sector(dev->id);

    dev->status &= ~ERR_STAT;
    dev->packet_len = 0;

    device_identify[6] = (dev->id / 10) + 0x30;
    device_identify[7] = (dev->id % 10) + 0x30;

    device_identify_ex[6]  = (dev->id / 10) + 0x30;
    device_identify_ex[7]  = (dev->id % 10) + 0x30;
    device_identify_ex[10] = EMU_VERSION_EX[0];
    device_identify_ex[12] = EMU_VERSION_EX[2];
    device_identify_ex[13] = EMU_VERSION_EX[3];

    memcpy(dev->current_cdb, cdb, 12);

    if (cdb[0] != 0) {
        scsi_disk_log("SCSI HD %i: Command 0x%02X, Sense Key %02X, Asc %02X, Ascq %02X\n",
                      dev->id, cdb[0], scsi_disk_sense_key, scsi_disk_asc, scsi_disk_ascq);
        scsi_disk_log("SCSI HD %i: Request length: %04X\n", dev->id, dev->request_length);

        scsi_disk_log("SCSI HD %i: CDB: %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X %02X\n", dev->id,
                      cdb[0], cdb[1], cdb[2], cdb[3], cdb[4], cdb[5], cdb[6], cdb[7],
                      cdb[8], cdb[9], cdb[10], cdb[11]);
    }

    dev->sector_len = 0;

    scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);

    /* This handles the Not Ready/Unit Attention check if it has to be handled at this point. */
    if (scsi_disk_pre_execution_check(dev, cdb) == 0)
        return;

    switch (cdb[0]) {
        case GPCMD_SEND_DIAGNOSTIC:
            if (!(cdb[1] & (1 << 2))) {
                scsi_disk_invalid_field(dev);
                return;
            }
#ifdef FALLTHROUGH_ANNOTATION
            [[fallthrough]];
#endif
        case GPCMD_SCSI_RESERVE:
        case GPCMD_SCSI_RELEASE:
        case GPCMD_TEST_UNIT_READY:
        case GPCMD_FORMAT_UNIT:
            scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
            scsi_disk_command_complete(dev);
            break;

        case GPCMD_REZERO_UNIT:
            dev->sector_pos = dev->sector_len = 0;
            scsi_disk_seek(dev, 0);
            scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
            break;

        case GPCMD_REQUEST_SENSE:
            /* If there's a unit attention condition and there's a buffered not ready, a standalone REQUEST SENSE
               should forget about the not ready, and report unit attention straight away. */
            len = cdb[4];

            if (!len) {
                scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
                dev->packet_status = PHASE_COMPLETE;
                dev->callback      = 20.0 * SCSI_TIME;
                break;
            }

            scsi_disk_buf_alloc(dev, 256);
            scsi_disk_set_buf_len(dev, BufLen, &len);

            if (*BufLen < cdb[4])
                cdb[4] = *BufLen;

            len = (cdb[1] & 1) ? 8 : 18;

            scsi_disk_request_sense(dev, dev->temp_buffer, *BufLen, cdb[1] & 1);
            scsi_disk_set_phase(dev, SCSI_PHASE_DATA_IN);
            scsi_disk_data_command_finish(dev, len, len, cdb[4], 0);
            break;

        case GPCMD_MECHANISM_STATUS:
            scsi_disk_set_phase(dev, SCSI_PHASE_DATA_IN);
            len = (cdb[8] << 8) | cdb[9];

            scsi_disk_buf_alloc(dev, 8);
            scsi_disk_set_buf_len(dev, BufLen, &len);

            memset(dev->temp_buffer, 0, 8);
            dev->temp_buffer[5] = 1;

            scsi_disk_data_command_finish(dev, 8, 8, len, 0);
            break;

        case GPCMD_READ_6:
        case GPCMD_READ_10:
        case GPCMD_READ_12:
            switch (cdb[0]) {
                case GPCMD_READ_6:
                    dev->sector_len = cdb[4];
                    if (dev->sector_len == 0)
                        dev->sector_len = 256; /* For READ (6) and WRITE (6), a length of 0 indicates a transfer of 256 sector. */
                    dev->sector_pos = ((((uint32_t) cdb[1]) & 0x1f) << 16) | (((uint32_t) cdb[2]) << 8) | ((uint32_t) cdb[3]);
                    break;
                case GPCMD_READ_10:
                    dev->sector_len = (cdb[7] << 8) | cdb[8];
                    dev->sector_pos = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
                    break;
                case GPCMD_READ_12:
                    dev->sector_len = (((uint32_t) cdb[6]) << 24) | (((uint32_t) cdb[7]) << 16) | (((uint32_t) cdb[8]) << 8) | ((uint32_t) cdb[9]);
                    dev->sector_pos = (((uint32_t) cdb[2]) << 24) | (((uint32_t) cdb[3]) << 16) | (((uint32_t) cdb[4]) << 8) | ((uint32_t) cdb[5]);
                    break;

                default:
                    break;
            }

            if ((dev->sector_pos > last_sector) /* || ((dev->sector_pos + dev->sector_len - 1) > last_sector)*/) {
                scsi_disk_lba_out_of_range(dev);
                return;
            }

            if ((!dev->sector_len) || (*BufLen == 0)) {
                scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
                scsi_disk_log("SCSI HD %i: All done - callback set\n", dev);
                dev->packet_status = PHASE_COMPLETE;
                dev->callback      = 20.0 * SCSI_TIME;
                break;
            }

            max_len               = dev->sector_len;
            dev->requested_blocks = max_len;

            alloc_length = dev->packet_len = max_len << 9;
            scsi_disk_buf_alloc(dev, dev->packet_len);
            scsi_disk_set_buf_len(dev, BufLen, &alloc_length);
            scsi_disk_set_phase(dev, SCSI_PHASE_DATA_IN);

            if ((dev->requested_blocks > 0) && (*BufLen > 0)) {
                if (dev->packet_len > (uint32_t) *BufLen)
                    hdd_image_read(dev->id, dev->sector_pos, *BufLen >> 9, dev->temp_buffer);
                else
                    hdd_image_read(dev->id, dev->sector_pos, dev->requested_blocks, dev->temp_buffer);
            }

            if (dev->requested_blocks > 1)
                scsi_disk_data_command_finish(dev, alloc_length, alloc_length / dev->requested_blocks, alloc_length, 0);
            else
                scsi_disk_data_command_finish(dev, alloc_length, alloc_length, alloc_length, 0);

            if (dev->packet_status != PHASE_COMPLETE)
                ui_sb_update_icon(SB_HDD | dev->drv->bus, 1);
            else
                ui_sb_update_icon(SB_HDD | dev->drv->bus, 0);
            return;

        case GPCMD_VERIFY_6:
        case GPCMD_VERIFY_10:
        case GPCMD_VERIFY_12:
            if (!(cdb[1] & 2)) {
                scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
                scsi_disk_command_complete(dev);
                break;
            }
        case GPCMD_WRITE_6:
        case GPCMD_WRITE_10:
        case GPCMD_WRITE_AND_VERIFY_10:
        case GPCMD_WRITE_12:
        case GPCMD_WRITE_AND_VERIFY_12:
            switch (cdb[0]) {
                case GPCMD_VERIFY_6:
                case GPCMD_WRITE_6:
                    dev->sector_len = cdb[4];
                    if (dev->sector_len == 0)
                        dev->sector_len = 256; /* For READ (6) and WRITE (6), a length of 0 indicates a transfer of 256 sector. */
                    dev->sector_pos = ((((uint32_t) cdb[1]) & 0x1f) << 16) | (((uint32_t) cdb[2]) << 8) | ((uint32_t) cdb[3]);
                    scsi_disk_log("SCSI HD %i: Length: %i, LBA: %i\n", dev->id, dev->sector_len, dev->sector_pos);
                    break;
                case GPCMD_VERIFY_10:
                case GPCMD_WRITE_10:
                case GPCMD_WRITE_AND_VERIFY_10:
                    dev->sector_len = (cdb[7] << 8) | cdb[8];
                    dev->sector_pos = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
                    scsi_disk_log("SCSI HD %i: Length: %i, LBA: %i\n", dev->id, dev->sector_len, dev->sector_pos);
                    break;
                case GPCMD_VERIFY_12:
                case GPCMD_WRITE_12:
                case GPCMD_WRITE_AND_VERIFY_12:
                    dev->sector_len = (((uint32_t) cdb[6]) << 24) | (((uint32_t) cdb[7]) << 16) | (((uint32_t) cdb[8]) << 8) | ((uint32_t) cdb[9]);
                    dev->sector_pos = (((uint32_t) cdb[2]) << 24) | (((uint32_t) cdb[3]) << 16) | (((uint32_t) cdb[4]) << 8) | ((uint32_t) cdb[5]);
                    break;

                default:
                    break;
            }

            if ((dev->sector_pos > last_sector) /* ||
                 ((dev->sector_pos + dev->sector_len - 1) > last_sector)*/
            ) {
                scsi_disk_lba_out_of_range(dev);
                return;
            }

            if ((!dev->sector_len) || (*BufLen == 0)) {
                scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
                scsi_disk_log("SCSI HD %i: All done - callback set\n", dev->id);
                dev->packet_status = PHASE_COMPLETE;
                dev->callback      = 20.0 * SCSI_TIME;
                break;
            }

            max_len               = dev->sector_len;
            dev->requested_blocks = max_len;

            alloc_length = dev->packet_len = max_len << 9;
            scsi_disk_buf_alloc(dev, dev->packet_len);

            scsi_disk_set_buf_len(dev, BufLen, &alloc_length);
            scsi_disk_set_phase(dev, SCSI_PHASE_DATA_OUT);

            if (dev->requested_blocks > 1)
                scsi_disk_data_command_finish(dev, alloc_length, alloc_length / dev->requested_blocks, alloc_length, 1);
            else
                scsi_disk_data_command_finish(dev, alloc_length, alloc_length, alloc_length, 1);

            if (dev->packet_status != PHASE_COMPLETE)
                ui_sb_update_icon(SB_HDD | dev->drv->bus, 1);
            else
                ui_sb_update_icon(SB_HDD | dev->drv->bus, 0);
            return;

        case GPCMD_WRITE_SAME_10:
            scsi_disk_set_phase(dev, SCSI_PHASE_DATA_OUT);
            alloc_length = 512;

            if ((cdb[1] & 6) == 6) {
                scsi_disk_invalid_field(dev);
                return;
            }

            dev->sector_len = (cdb[7] << 8) | cdb[8];
            dev->sector_pos = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];

            if ((dev->sector_pos > last_sector) /* ||
                 ((dev->sector_pos + dev->sector_len - 1) > last_sector)*/
            ) {
                scsi_disk_lba_out_of_range(dev);
                return;
            }

            if ((!dev->sector_len) || (*BufLen == 0)) {
                scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
                scsi_disk_log("SCSI HD %i: All done - callback set\n", dev->id);
                dev->packet_status = PHASE_COMPLETE;
                dev->callback      = 20.0 * SCSI_TIME;
                break;
            }

            scsi_disk_buf_alloc(dev, alloc_length);
            scsi_disk_set_buf_len(dev, BufLen, &alloc_length);

            max_len               = 1;
            dev->requested_blocks = 1;

            scsi_disk_set_phase(dev, SCSI_PHASE_DATA_OUT);

            scsi_disk_data_command_finish(dev, 512, 512, alloc_length, 1);

            if (dev->packet_status != PHASE_COMPLETE)
                ui_sb_update_icon(SB_HDD | dev->drv->bus, 1);
            else
                ui_sb_update_icon(SB_HDD | dev->drv->bus, 0);
            return;

        case GPCMD_MODE_SENSE_6:
        case GPCMD_MODE_SENSE_10:
            scsi_disk_set_phase(dev, SCSI_PHASE_DATA_IN);

            block_desc = ((cdb[1] >> 3) & 1) ? 0 : 1;

            if (cdb[0] == GPCMD_MODE_SENSE_6) {
                len = cdb[4];
                scsi_disk_buf_alloc(dev, 256);
            } else {
                len = (cdb[8] | (cdb[7] << 8));
                scsi_disk_buf_alloc(dev, 65536);
            }

            memset(dev->temp_buffer, 0, len);
            alloc_length = len;

            if (cdb[0] == GPCMD_MODE_SENSE_6) {
                len = scsi_disk_mode_sense(dev, dev->temp_buffer, 4, cdb[2], block_desc);
                if (len > alloc_length)
                    len = alloc_length;
                dev->temp_buffer[0] = len - 1;
                dev->temp_buffer[1] = 0;
                if (block_desc)
                    dev->temp_buffer[3] = 8;
            } else {
                len = scsi_disk_mode_sense(dev, dev->temp_buffer, 8, cdb[2], block_desc);
                if (len > alloc_length)
                    len = alloc_length;
                dev->temp_buffer[0] = (len - 2) >> 8;
                dev->temp_buffer[1] = (len - 2) & 255;
                dev->temp_buffer[2] = 0;
                if (block_desc) {
                    dev->temp_buffer[6] = 0;
                    dev->temp_buffer[7] = 8;
                }
            }

            if (len > alloc_length)
                len = alloc_length;
            else if (len < alloc_length)
                alloc_length = len;

            scsi_disk_set_buf_len(dev, BufLen, &alloc_length);
            scsi_disk_log("SCSI HDD %i: Reading mode page: %02X...\n", dev->id, cdb[2]);

            scsi_disk_data_command_finish(dev, len, len, alloc_length, 0);
            return;

        case GPCMD_MODE_SELECT_6:
        case GPCMD_MODE_SELECT_10:
            scsi_disk_set_phase(dev, SCSI_PHASE_DATA_OUT);

            if (cdb[0] == GPCMD_MODE_SELECT_6) {
                len = cdb[4];
                scsi_disk_buf_alloc(dev, 256);
            } else {
                len = (cdb[7] << 8) | cdb[8];
                scsi_disk_buf_alloc(dev, 65536);
            }

            scsi_disk_set_buf_len(dev, BufLen, &len);
            dev->total_length = len;
            dev->do_page_save = cdb[1] & 1;
            scsi_disk_data_command_finish(dev, len, len, len, 1);
            return;

        case GPCMD_INQUIRY:
            max_len = cdb[3];
            max_len <<= 8;
            max_len |= cdb[4];

            if ((!max_len) || (*BufLen == 0)) {
                scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
                /* scsi_disk_log("SCSI HD %i: All done - callback set\n", dev->id); */
                dev->packet_status = PHASE_COMPLETE;
                dev->callback      = 20.0 * SCSI_TIME;
                break;
            }

            scsi_disk_buf_alloc(dev, 65536);

            if (cdb[1] & 1) {
                preamble_len = 4;
                size_idx     = 3;

                dev->temp_buffer[idx++] = 05;
                dev->temp_buffer[idx++] = cdb[2];
                dev->temp_buffer[idx++] = 0;

                idx++;

                switch (cdb[2]) {
                    case 0x00:
                        dev->temp_buffer[idx++] = 0x00;
                        dev->temp_buffer[idx++] = 0x83;
                        break;
                    case 0x83:
                        if (idx + 24 > max_len) {
                            scsi_disk_buf_free(dev);
                            scsi_disk_data_phase_error(dev);
                            return;
                        }

                        dev->temp_buffer[idx++] = 0x02;
                        dev->temp_buffer[idx++] = 0x00;
                        dev->temp_buffer[idx++] = 0x00;
                        dev->temp_buffer[idx++] = 20;
                        ide_padstr8(dev->temp_buffer + idx, 20, "53R141"); /* Serial */
                        idx += 20;

                        if (idx + 72 > cdb[4])
                            goto atapi_out;
                        dev->temp_buffer[idx++] = 0x02;
                        dev->temp_buffer[idx++] = 0x01;
                        dev->temp_buffer[idx++] = 0x00;
                        dev->temp_buffer[idx++] = 68;
                        ide_padstr8(dev->temp_buffer + idx, 8, EMU_NAME); /* Vendor */
                        idx += 8;
                        ide_padstr8(dev->temp_buffer + idx, 40, device_identify_ex); /* Product */
                        idx += 40;
                        ide_padstr8(dev->temp_buffer + idx, 20, "53R141"); /* Product */
                        idx += 20;
                        break;
                    default:
                        scsi_disk_log("INQUIRY: Invalid page: %02X\n", cdb[2]);
                        scsi_disk_invalid_field(dev);
                        scsi_disk_buf_free(dev);
                        return;
                }
            } else {
                preamble_len = 5;
                size_idx     = 4;

                memset(dev->temp_buffer, 0, 8);
                dev->temp_buffer[0] = 0;    /*SCSI HD*/
                dev->temp_buffer[1] = 0;    /*Fixed*/
                dev->temp_buffer[2] = 0x02; /*SCSI-2 compliant*/
                dev->temp_buffer[3] = 0x02;
                dev->temp_buffer[4] = 31;
                dev->temp_buffer[6] = 1;    /* 16-bit transfers supported */
                dev->temp_buffer[7] = 0x20; /* Wide bus supported */

                ide_padstr8(dev->temp_buffer + 8, 8, EMU_NAME);          /* Vendor */
                ide_padstr8(dev->temp_buffer + 16, 16, device_identify); /* Product */
                ide_padstr8(dev->temp_buffer + 32, 4, EMU_VERSION_EX);   /* Revision */
                idx = 36;

                if (max_len == 96) {
                    dev->temp_buffer[4] = 91;
                    idx                 = 96;
                }
            }

atapi_out:
            dev->temp_buffer[size_idx] = idx - preamble_len;
            len                        = idx;

            if (len > max_len)
                len = max_len;

            scsi_disk_set_buf_len(dev, BufLen, &len);

            if (len > *BufLen)
                len = *BufLen;

            scsi_disk_set_phase(dev, SCSI_PHASE_DATA_IN);
            scsi_disk_data_command_finish(dev, len, len, max_len, 0);
            break;

        case GPCMD_PREVENT_REMOVAL:
            scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
            scsi_disk_command_complete(dev);
            break;

        case GPCMD_SEEK_6:
        case GPCMD_SEEK_10:
            switch (cdb[0]) {
                case GPCMD_SEEK_6:
                    pos = (cdb[2] << 8) | cdb[3];
                    break;
                case GPCMD_SEEK_10:
                    pos = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
                    break;

                default:
                    break;
            }
            scsi_disk_seek(dev, pos);

            scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
            scsi_disk_command_complete(dev);
            break;

        case GPCMD_READ_CDROM_CAPACITY:
            scsi_disk_buf_alloc(dev, 8);

            max_len = hdd_image_get_last_sector(dev->id);
            memset(dev->temp_buffer, 0, 8);
            dev->temp_buffer[0] = (max_len >> 24) & 0xff;
            dev->temp_buffer[1] = (max_len >> 16) & 0xff;
            dev->temp_buffer[2] = (max_len >> 8) & 0xff;
            dev->temp_buffer[3] = max_len & 0xff;
            dev->temp_buffer[6] = 2;
            len                 = 8;

            scsi_disk_set_buf_len(dev, BufLen, &len);

            scsi_disk_set_phase(dev, SCSI_PHASE_DATA_IN);
            scsi_disk_data_command_finish(dev, len, len, len, 0);
            break;

        default:
            scsi_disk_illegal_opcode(dev);
            break;
    }

    /* scsi_disk_log("SCSI HD %i: Phase: %02X, request length: %i\n", dev->id, dev->phase, dev->request_length); */
}

static void
scsi_disk_command_stop(scsi_common_t *sc)
{
    scsi_disk_t *dev = (scsi_disk_t *) sc;

    scsi_disk_command_complete(dev);
    scsi_disk_buf_free(dev);
}

static uint8_t
scsi_disk_phase_data_out(scsi_common_t *sc)
{
    scsi_disk_t   *dev      = (scsi_disk_t *) sc;
    uint8_t        scsi_bus = (dev->drv->scsi_id >> 4) & 0x0f;
    uint8_t        scsi_id  = dev->drv->scsi_id & 0x0f;
    int            i;
    const int32_t *BufLen      = &scsi_devices[scsi_bus][scsi_id].buffer_length;
    uint32_t       last_sector = hdd_image_get_last_sector(dev->id);
    uint32_t       c;
    uint32_t       h;
    uint32_t       s;
    uint32_t       last_to_write = 0;
    uint16_t       block_desc_len;
    uint16_t       pos;
    uint16_t       param_list_len;
    uint8_t        hdr_len;
    uint8_t        val;
    uint8_t        old_val;
    uint8_t        ch;
    uint8_t        error = 0;
    uint8_t        page;
    uint8_t        page_len;

    if (!*BufLen) {
        scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);

        return 1;
    }

    switch (dev->current_cdb[0]) {
        case GPCMD_VERIFY_6:
        case GPCMD_VERIFY_10:
        case GPCMD_VERIFY_12:
            break;
        case GPCMD_WRITE_6:
        case GPCMD_WRITE_10:
        case GPCMD_WRITE_AND_VERIFY_10:
        case GPCMD_WRITE_12:
        case GPCMD_WRITE_AND_VERIFY_12:
            if ((dev->requested_blocks > 0) && (*BufLen > 0)) {
                if (dev->packet_len > (uint32_t) *BufLen)
                    hdd_image_write(dev->id, dev->sector_pos, *BufLen >> 9, dev->temp_buffer);
                else
                    hdd_image_write(dev->id, dev->sector_pos, dev->requested_blocks, dev->temp_buffer);
            }
            break;
        case GPCMD_WRITE_SAME_10:
            if (!dev->current_cdb[7] && !dev->current_cdb[8])
                last_to_write = last_sector;
            else
                last_to_write = dev->sector_pos + dev->sector_len - 1;

            for (i = dev->sector_pos; i <= (int) last_to_write; i++) {
                if (dev->current_cdb[1] & 2) {
                    dev->temp_buffer[0] = (i >> 24) & 0xff;
                    dev->temp_buffer[1] = (i >> 16) & 0xff;
                    dev->temp_buffer[2] = (i >> 8) & 0xff;
                    dev->temp_buffer[3] = i & 0xff;
                } else if (dev->current_cdb[1] & 4) {
                    s                   = (i % dev->drv->spt);
                    h                   = ((i - s) / dev->drv->spt) % dev->drv->hpc;
                    c                   = ((i - s) / dev->drv->spt) / dev->drv->hpc;
                    dev->temp_buffer[0] = (c >> 16) & 0xff;
                    dev->temp_buffer[1] = (c >> 8) & 0xff;
                    dev->temp_buffer[2] = c & 0xff;
                    dev->temp_buffer[3] = h & 0xff;
                    dev->temp_buffer[4] = (s >> 24) & 0xff;
                    dev->temp_buffer[5] = (s >> 16) & 0xff;
                    dev->temp_buffer[6] = (s >> 8) & 0xff;
                    dev->temp_buffer[7] = s & 0xff;
                }
                hdd_image_write(dev->id, i, 1, dev->temp_buffer);
            }
            break;
        case GPCMD_MODE_SELECT_6:
        case GPCMD_MODE_SELECT_10:
            if (dev->current_cdb[0] == GPCMD_MODE_SELECT_10) {
                hdr_len        = 8;
                param_list_len = dev->current_cdb[7];
                param_list_len <<= 8;
                param_list_len |= dev->current_cdb[8];
            } else {
                hdr_len        = 4;
                param_list_len = dev->current_cdb[4];
            }

            if (dev->current_cdb[0] == GPCMD_MODE_SELECT_6) {
                block_desc_len = dev->temp_buffer[2];
                block_desc_len <<= 8;
                block_desc_len |= dev->temp_buffer[3];
            } else {
                block_desc_len = dev->temp_buffer[6];
                block_desc_len <<= 8;
                block_desc_len |= dev->temp_buffer[7];
            }

            pos = hdr_len + block_desc_len;

            while (1) {
                if (pos >= param_list_len) {
                    scsi_disk_log("SCSI HD %i: Buffer has only block descriptor\n", dev->id);
                    break;
                }

                page     = dev->temp_buffer[pos] & 0x3F;
                page_len = dev->temp_buffer[pos + 1];

                pos += 2;

                if (!(scsi_disk_mode_sense_page_flags & (1LL << ((uint64_t) page))))
                    error |= 1;
                else {
                    for (i = 0; i < page_len; i++) {
                        ch      = scsi_disk_mode_sense_pages_changeable.pages[page][i + 2];
                        val     = dev->temp_buffer[pos + i];
                        old_val = dev->ms_pages_saved.pages[page][i + 2];
                        if (val != old_val) {
                            if (ch)
                                dev->ms_pages_saved.pages[page][i + 2] = val;
                            else
                                error |= 1;
                        }
                    }
                }

                pos += page_len;

                val = scsi_disk_mode_sense_pages_default.pages[page][0] & 0x80;
                if (dev->do_page_save && val)
                    scsi_disk_mode_sense_save(dev);

                if (pos >= dev->total_length)
                    break;
            }

            if (error) {
                scsi_disk_buf_free(dev);
                scsi_disk_invalid_field_pl(dev);
            }
            break;
        default:
            fatal("SCSI HDD %i: Bad Command for phase 2 (%02X)\n", dev->id, dev->current_cdb[0]);
            break;
    }

    scsi_disk_command_stop((scsi_common_t *) dev);
    return 1;
}

void
scsi_disk_hard_reset(void)
{
    scsi_disk_t   *dev;
    scsi_device_t *sd;
    uint8_t        scsi_bus;
    uint8_t        scsi_id;

    for (uint8_t c = 0; c < HDD_NUM; c++) {
        if (hdd[c].bus == HDD_BUS_SCSI) {
            scsi_disk_log("SCSI disk hard_reset drive=%d\n", c);

            scsi_bus = (hdd[c].scsi_id >> 4) & 0x0f;
            scsi_id  = hdd[c].scsi_id & 0x0f;

            /* Make sure to ignore any SCSI disk that has an out of range SCSI bus. */
            if (scsi_bus >= SCSI_BUS_MAX)
                continue;

            /* Make sure to ignore any SCSI disk that has an out of range ID. */
            if (scsi_id >= SCSI_ID_MAX)
                continue;

            /* Make sure to ignore any SCSI disk whose image file name is empty. */
            if (strlen(hdd[c].fn) == 0)
                continue;

            /* Make sure to ignore any SCSI disk whose image fails to load. */
            if (!hdd_image_load(c))
                continue;

            if (!hdd[c].priv) {
                hdd[c].priv = (scsi_disk_t *) malloc(sizeof(scsi_disk_t));
                memset(hdd[c].priv, 0, sizeof(scsi_disk_t));
            }

            dev = (scsi_disk_t *) hdd[c].priv;

            /* SCSI disk, attach to the SCSI bus. */
            sd = &scsi_devices[scsi_bus][scsi_id];

            sd->sc             = (scsi_common_t *) dev;
            sd->command        = scsi_disk_command;
            sd->request_sense  = scsi_disk_request_sense_for_scsi;
            sd->reset          = scsi_disk_reset;
            sd->phase_data_out = scsi_disk_phase_data_out;
            sd->command_stop   = scsi_disk_command_stop;
            sd->type           = SCSI_FIXED_DISK;

            dev->id  = c;
            dev->drv = &hdd[c];

            dev->cur_lun = SCSI_LUN_USE_CDB;

            scsi_disk_mode_sense_load(dev);

            scsi_disk_log("SCSI disk %i attached to SCSI ID %i\n", c, hdd[c].scsi_id);
        }
    }
}

void
scsi_disk_close(void)
{
    scsi_disk_t *dev;
    uint8_t      scsi_bus;
    uint8_t      scsi_id;

    for (uint8_t c = 0; c < HDD_NUM; c++) {
        if (hdd[c].bus == HDD_BUS_SCSI) {
            scsi_bus = (hdd[c].scsi_id >> 4) & 0x0f;
            scsi_id  = hdd[c].scsi_id & 0x0f;

            memset(&scsi_devices[scsi_bus][scsi_id], 0x00, sizeof(scsi_device_t));

            hdd_image_close(c);

            dev = hdd[c].priv;

            if (dev) {
                free(dev);
                hdd[c].priv = NULL;
            }
        }
    }
}