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 <inttypes.h>
#include <math.h>
#ifdef ENABLE_SCSI_DISK_LOG
#include <stdarg.h>
#endif
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <86box/86box.h>
#include <86box/timer.h>
#include <86box/device.h>
#include <86box/log.h>
#include <86box/scsi.h>
#include <86box/scsi_device.h>
#include <86box/machine.h>
#include <86box/nvr.h>
#include <86box/hdc_ide.h>
#include <86box/plat.h>
#include <86box/ui.h>
#include <86box/hdd.h>
#include <86box/scsi_disk.h>
#include <86box/version.h>

#define IDE_ATAPI_IS_EARLY             id->sc->pad0

#define scsi_disk_sense_error dev->sense[0]
#define scsi_disk_sense_key   dev->sense[2]
#define scsi_disk_info        *(uint32_t *) &(dev->sense[3])
#define scsi_disk_asc         dev->sense[12]
#define scsi_disk_ascq        dev->sense[13]

// clang-format off
/*
   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] = {
    [0x00]          = IMPLEMENTED | CHECK_READY,
    [0x01]          = IMPLEMENTED | ALLOW_UA | SCSI_ONLY,
    [0x03]          = IMPLEMENTED | ALLOW_UA,
    [0x04]          = IMPLEMENTED | CHECK_READY | ALLOW_UA | SCSI_ONLY,
    [0x08]          = IMPLEMENTED | CHECK_READY,
    [0x0a ... 0x0b] = IMPLEMENTED | CHECK_READY,
    [0x12]          = IMPLEMENTED | ALLOW_UA,
    [0x13]          = IMPLEMENTED | CHECK_READY | SCSI_ONLY,
    [0x15]          = IMPLEMENTED,
    [0x16 ... 0x17] = IMPLEMENTED | SCSI_ONLY,
    [0x1a]          = IMPLEMENTED,
    [0x1d]          = IMPLEMENTED,
    [0x1e]          = IMPLEMENTED | CHECK_READY,
    [0x25]          = IMPLEMENTED | CHECK_READY,
    [0x28]          = IMPLEMENTED | CHECK_READY,
    [0x2a ... 0x2b] = IMPLEMENTED | CHECK_READY,
    [0x2e]          = IMPLEMENTED | CHECK_READY,
    [0x2f]          = IMPLEMENTED | CHECK_READY | SCSI_ONLY,
    [0x41]          = IMPLEMENTED | CHECK_READY,
    [0x55]          = IMPLEMENTED,
    [0x5a]          = IMPLEMENTED,
    [0xa8]          = IMPLEMENTED | CHECK_READY,
    [0xaa]          = IMPLEMENTED | CHECK_READY,
    [0xae]          = IMPLEMENTED | CHECK_READY,
    [0xaf]          = IMPLEMENTED | CHECK_READY | SCSI_ONLY,
    [0xbd]          = IMPLEMENTED
};

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

static const mode_sense_pages_t scsi_disk_mode_sense_pages_default = {
    { [0x03] = { GPMODE_FORMAT_DEVICE_PAGE,           0x16, 0x00, 0x01, 0x00, 0x01, 0x00, 0x01,
                 0x00,                                0x01, 0x01, 0x00, 0x02, 0x00, 0x00, 0x00,
                 0x00,                                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      [0x04] = { GPMODE_RIGID_DISK_PAGE,              0x16, 0x00, 0x10, 0x00, 0x40, 0x00, 0x00,
                  0x00,                               0x00, 0x00, 0x00, 0x00, 0xc8, 0xff, 0xff,
                  0xff,                               0x00, 0x00, 0x00, 0x15, 0x18, 0x00, 0x00 },
      [0x30] = { GPMODE_UNK_VENDOR_PAGE | 0x80,       0x16, '8' , '6' , 'B' , 'o' , 'x' , ' ' ,
                  ' ' ,                               ' ' , ' ' , ' ' , ' ' , ' ' , ' ' , ' ' ,
                  ' ' ,                               ' ' , ' ' , ' ' , ' ' , ' ' , ' ' , ' '  } }
};

static const mode_sense_pages_t scsi_disk_mode_sense_pages_changeable = {
    { [0x03] = { GPMODE_FORMAT_DEVICE_PAGE,           0x16, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                 0x00,                                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                 0x00,                                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      [0x04] = { GPMODE_RIGID_DISK_PAGE,              0x16, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                 0x00,                                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                 0x00,                                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
      [0x30] = { GPMODE_UNK_VENDOR_PAGE | 0x80,       0x16, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                 0xff,                                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                 0xff,                                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff } }
};
// clang-format on

static void scsi_disk_command_complete(scsi_disk_t *dev);

static void scsi_disk_mode_sense_load(scsi_disk_t *dev);

static void scsi_disk_init(scsi_disk_t *dev);

#ifdef ENABLE_SCSI_DISK_LOG
int scsi_disk_do_log = ENABLE_SCSI_DISK_LOG;

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

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

static void
scsi_disk_set_callback(const scsi_disk_t *dev)
{
    if (dev->drv->bus_type != HDD_BUS_SCSI)
        ide_set_callback(ide_drives[dev->drv->ide_channel], dev->callback);
}

static void
scsi_disk_init(scsi_disk_t *dev)
{
    if (dev != NULL) {
        /* Do a reset (which will also rezero it). */
        scsi_disk_reset((scsi_common_t *) dev);

        /* Configure the drive. */
        dev->requested_blocks = 1;

        dev->drv->bus_mode = 0;
        if (dev->drv->bus_type >= HDD_BUS_ATAPI)
            dev->drv->bus_mode |= 2;
        if (dev->drv->bus_type < HDD_BUS_SCSI)
            dev->drv->bus_mode |= 1;
        scsi_disk_log(dev->log, "Bus type %i, bus mode %i\n",
                      dev->drv->bus_type, dev->drv->bus_mode);

        dev->sense[0] = 0xf0;
        dev->sense[7] = 10;

        dev->tf->status      = 0;
        dev->tf->pos         = 0;
        dev->packet_status   = PHASE_NONE;
        scsi_disk_sense_key = scsi_disk_asc = scsi_disk_ascq = dev->unit_attention = 0;
        scsi_disk_info      = 0x00;
        scsi_disk_mode_sense_load(dev);
    }
}

/* Returns: 0 for none, 1 for PIO, 2 for DMA. */
static int
scsi_disk_current_mode(const scsi_disk_t *dev)
{
   int ret = 0;

    if (dev->drv->bus_type == HDD_BUS_SCSI)
        ret = 2;
    else if (dev->drv->bus_type == HDD_BUS_ATAPI) {
        scsi_disk_log(dev->log, "ATAPI drive, setting to %s\n",
                      (dev->tf->features & 1) ? "DMA" : "PIO",
                      dev->id);
        ret = (dev->tf->features & 1) ? 2 : 1;
    }

    return ret;
}

static void
scsi_disk_mode_sense_load(scsi_disk_t *dev)
{
    char  file_name[512] = { 0 };

    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));

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

static void
scsi_disk_mode_sense_save(const scsi_disk_t *dev)
{
    char  file_name[512] = { 0 };

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

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

    if (page == GPMODE_RIGID_DISK_PAGE)
        switch (pgctl) {
            /* 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 (pgctl) {
            /* 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 (pgctl) {
            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(const scsi_disk_t *dev, uint8_t *buf, uint32_t pos,
                     uint8_t page, const uint8_t block_descriptor_len)
{
    int     size = hdd_image_get_last_sector(dev->id);

    page &= 0x3f;

    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)) {
                const uint8_t pgctl  = (page >> 6) & 3;
                const uint8_t msplen = scsi_disk_mode_sense_read(dev, pgctl, i, 1);
                buf[pos++]           = scsi_disk_mode_sense_read(dev, pgctl, i, 0);
                buf[pos++]           = msplen;
                scsi_disk_log(dev->log, "MODE SENSE: Page [%02X] length %i\n",
                              i, msplen);
                for (uint8_t j = 0; j < msplen; j++)
                    buf[pos++] = scsi_disk_mode_sense_read(dev, pgctl, i, 2 + j);
            }
        }
    }

    return pos;
}

static void
scsi_disk_update_request_length(scsi_disk_t *dev, int len, const int block_len)
{
    int bt;
    int min_len = 0;

    dev->max_transfer_len = dev->tf->request_length;

    /* For media access commands, make sure the requested DRQ length matches the block length. */
    switch (dev->current_cdb[0]) {
        case 0x08:
        case 0x0a:
        case 0x28:
        case 0x2a:
        case 0xa8:
        case 0xaa:
            /* Round it to the nearest 2048 bytes. */
            dev->max_transfer_len = (dev->max_transfer_len >> 9) << 9;

            /* Make sure total length is not bigger than sum of the lengths of
               all the requested blocks. */
            bt = (dev->requested_blocks * block_len);
            if (len > bt)
                len = bt;

            min_len = block_len;

            if (len <= block_len) {
                /* Total length is less or equal to block length. */
                if (dev->max_transfer_len < block_len) {
                    /* Transfer a minimum of (block size) bytes. */
                    dev->max_transfer_len = block_len;
                    dev->packet_len       = block_len;
                    break;
                }
            }
            fallthrough;

        default:
            dev->packet_len = len;
            break;
    }
    /* If the DRQ length is odd, and the total remaining length is bigger, make sure it's even. */
    if ((dev->max_transfer_len & 1) && (dev->max_transfer_len < len))
        dev->max_transfer_len &= 0xfffe;
    /* If the DRQ length is smaller or equal in size to the total remaining length, set it to that. */
    if (!dev->max_transfer_len)
        dev->max_transfer_len = 65534;

    if ((len <= dev->max_transfer_len) && (len >= min_len))
        dev->tf->request_length = dev->max_transfer_len = len;
    else if (len > dev->max_transfer_len)
        dev->tf->request_length = dev->max_transfer_len;

    return;
}

static double
scsi_disk_bus_speed(scsi_disk_t *dev)
{
    double ret = -1.0;

    if (dev && dev->drv && (dev->drv->bus_type == HDD_BUS_SCSI)) {
        dev->callback = -1.0; /* Speed depends on SCSI controller */
        return 0.0;
    } else {
        if (dev && dev->drv)
            ret = ide_atapi_get_period(dev->drv->ide_channel);
        if (ret == -1.0) {
            if (dev)
                dev->callback = -1.0;
            return 0.0;
        } else
            return ret * 1000000.0;
    }
}

void
scsi_disk_command_common(scsi_disk_t *dev)
{
    double bytes_per_second;
    double period;

    /* MAP: BUSY_STAT, no DRQ, phase 1. */
    dev->tf->status    = BUSY_STAT;
    dev->tf->phase     = 1;
    dev->tf->pos       = 0;
    dev->callback      = 0;

    if (dev->packet_status == PHASE_COMPLETE) {

        switch (dev->current_cdb[0]) {
            case GPCMD_VERIFY_6:
            case GPCMD_VERIFY_10:
            case GPCMD_VERIFY_12:
            case GPCMD_WRITE_6:
            case GPCMD_WRITE_10:
            case GPCMD_WRITE_AND_VERIFY_10:
            case GPCMD_WRITE_12:
            case GPCMD_WRITE_AND_VERIFY_12:
            case GPCMD_WRITE_SAME_10:
                /* Seek time is in us. */
                period = hdd_timing_write(dev->drv, dev->drv->seek_pos,
                                          dev->drv->seek_len);
                scsi_disk_log(dev->log, "Seek period: %" PRIu64 " us\n",
                              (uint64_t) period);
                dev->callback += period;
                /* Account for seek time. */
                bytes_per_second = scsi_bus_get_speed(dev->drv->scsi_id >> 4);

                period = 1000000.0 / bytes_per_second;
                scsi_disk_log(dev->log, "Byte transfer period: %" PRIu64 " us\n",
                              (uint64_t) period);
                period = period * (double) (dev->packet_len);
                scsi_disk_log(dev->log, "Sector transfer period: %" PRIu64 " us\n",
                              (uint64_t) period);
                dev->callback += period;
                break;
            default:
                dev->callback = 0;
                break;
        }
    } else {
        switch (dev->current_cdb[0]) {
            case GPCMD_REZERO_UNIT:
            case 0x0b:
            case 0x2b:
                /* Seek time is in us. */
                period = hdd_seek_get_time(dev->drv, (dev->current_cdb[0] == GPCMD_REZERO_UNIT) ?
                                           0 : dev->sector_pos, HDD_OP_SEEK, 0, 0.0);
                scsi_disk_log(dev->log, "Seek period: %" PRIu64 " us\n",
                              (uint64_t) period);
                dev->callback += period;
                scsi_disk_set_callback(dev);
                return;
            case 0x08:
            case 0x28:
            case 0xa8:
                /* Seek time is in us. */
                period = hdd_timing_read(dev->drv, dev->drv->seek_pos,
                                         dev->drv->seek_len);
                scsi_disk_log(dev->log, "Seek period: %" PRIu64 " us\n",
                              (uint64_t) period);
                dev->callback += period;
                /* Account for seek time. */
                bytes_per_second = scsi_bus_get_speed(dev->drv->scsi_id >> 4);
                break;
            case 0x25:
            default:
                bytes_per_second = scsi_disk_bus_speed(dev);
                if (bytes_per_second == 0.0) {
                    dev->callback = -1; /* Speed depends on SCSI controller */
                    return;
                }
                break;
        }

        period = 1000000.0 / bytes_per_second;
        scsi_disk_log(dev->log, "Byte transfer period: %" PRIu64 " us\n",
                      (uint64_t) period);
        period = period * (double) (dev->packet_len);
        scsi_disk_log(dev->log, "Sector transfer period: %" PRIu64 " us\n",
                      (uint64_t) period);
        dev->callback += period;
    }
    scsi_disk_set_callback(dev);
}

static void
scsi_disk_command_complete(scsi_disk_t *dev)
{
    dev->packet_status = PHASE_COMPLETE;
    scsi_disk_command_common(dev);
}

static void
scsi_disk_command_read(scsi_disk_t *dev)
{
    dev->packet_status = PHASE_DATA_IN;
    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(scsi_disk_t *dev)
{
    dev->packet_status = PHASE_DATA_OUT;
    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);
}

/*
   dev = Pointer to current SCSI disk device;
   len = Total transfer length;
   block_len = Length of a single block (why does it matter?!);
   alloc_len = Allocated transfer length;
   direction = Transfer direction (0 = read from host, 1 = write to host).
 */
static void
scsi_disk_data_command_finish(scsi_disk_t *dev, int len, const int block_len,
                              const int alloc_len, const int direction)
{
    scsi_disk_log(dev->log, "Finishing command (%02X): %i, %i, %i, %i, %i\n",
                 dev->current_cdb[0], len, block_len, alloc_len, direction,
                 dev->tf->request_length);
    dev->tf->pos = 0;
    if (alloc_len >= 0) {
        if (alloc_len < len)
            len = alloc_len;
    }
    if ((len == 0) || (scsi_disk_current_mode(dev) == 0)) {
        if (dev->drv->bus_type != HDD_BUS_SCSI)
            dev->packet_len = 0;

        scsi_disk_command_complete(dev);
    } else {
        if (scsi_disk_current_mode(dev) == 2) {
            if (dev->drv->bus_type != HDD_BUS_SCSI)
                dev->packet_len = alloc_len;

            if (direction == 0)
                scsi_disk_command_read_dma(dev);
            else
                scsi_disk_command_write_dma(dev);
        } else {
            scsi_disk_update_request_length(dev, len, block_len);
            if (direction == 0)
                scsi_disk_command_read(dev);
            else
                scsi_disk_command_write(dev);
        }
    }

    scsi_disk_log(dev->log, "Status: %i, cylinder %i, packet length: %i, position: %i, "
                  "phase: %i\n",
                  dev->packet_status, dev->tf->request_length, dev->packet_len,
                  dev->tf->pos, dev->tf->phase);
}

static void
scsi_disk_sense_clear(scsi_disk_t *dev, UNUSED(int command))
{
    scsi_disk_sense_key = scsi_disk_asc = scsi_disk_ascq = 0;
    scsi_disk_info      = 0x00000000;
}

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

    if (dev->drv->bus_type == HDD_BUS_SCSI)
        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->tf->error     = ((scsi_disk_sense_key & 0xf) << 4) | ABRT_ERR;
    dev->tf->status    = READY_STAT | ERR_STAT;
    dev->tf->phase     = 3;
    dev->packet_status = PHASE_ERROR;
    dev->callback      = 50.0 * SCSI_TIME;
    scsi_disk_set_callback(dev);
    ui_sb_update_icon(SB_HDD | dev->drv->bus_type, 0);
    scsi_disk_log(dev->log, "ERROR: %02X/%02X/%02X\n", scsi_disk_sense_key,
                  scsi_disk_asc, scsi_disk_ascq);
}

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

static void
scsi_disk_buf_free(scsi_disk_t *dev)
{
    if (dev->temp_buffer) {
        scsi_disk_log(dev->log, "Freeing buffer...\n");
        free(dev->temp_buffer);
        dev->temp_buffer = NULL;
    }
}

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

    scsi_disk_buf_free(dev);
    scsi_disk_sense_key = scsi_disk_asc = scsi_disk_ascq = 0;
    scsi_disk_info      =  (dev->sector_pos >> 24)        |
                          ((dev->sector_pos >> 16) <<  8) |
                          ((dev->sector_pos >> 8)  << 16) |
                          ( dev->sector_pos        << 24);
    scsi_disk_cmd_error(dev);
}

static void
scsi_disk_write_error(scsi_disk_t *dev)
{
    scsi_disk_sense_key = SENSE_MEDIUM_ERROR;
    scsi_disk_asc       = ASC_WRITE_ERROR;
    scsi_disk_ascq      = 0;
    scsi_disk_info      =  (dev->sector_pos >> 24)        |
                          ((dev->sector_pos >> 16) <<  8) |
                          ((dev->sector_pos >> 8)  << 16) |
                          ( dev->sector_pos        << 24);
    scsi_disk_cmd_error(dev);
}

static void
scsi_disk_read_error(scsi_disk_t *dev)
{
    scsi_disk_sense_key = SENSE_MEDIUM_ERROR;
    scsi_disk_asc       = ASC_UNRECOVERED_READ_ERROR;
    scsi_disk_ascq      = 0;
    scsi_disk_info      =  (dev->sector_pos >> 24)        |
                          ((dev->sector_pos >> 16) <<  8) |
                          ((dev->sector_pos >> 8)  << 16) |
                          ( dev->sector_pos        << 24);
    scsi_disk_cmd_error(dev);
}

static void
scsi_disk_invalid_lun(scsi_disk_t *dev, const uint8_t lun)
{
    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_info      = lun << 24;
    scsi_disk_cmd_error(dev);
}

static void
scsi_disk_illegal_opcode(scsi_disk_t *dev, const uint8_t opcode)
{
    scsi_disk_sense_key = SENSE_ILLEGAL_REQUEST;
    scsi_disk_asc       = ASC_ILLEGAL_OPCODE;
    scsi_disk_ascq      = 0;
    scsi_disk_info      = opcode << 24;
    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_info      =  (dev->sector_pos >> 24)        |
                          ((dev->sector_pos >> 16) <<  8) |
                          ((dev->sector_pos >> 8)  << 16) |
                          ( dev->sector_pos        << 24);
    scsi_disk_cmd_error(dev);
}

static void
scsi_disk_invalid_field(scsi_disk_t *dev, const uint32_t field)
{
    scsi_disk_sense_key = SENSE_ILLEGAL_REQUEST;
    scsi_disk_asc       = ASC_INV_FIELD_IN_CMD_PACKET;
    scsi_disk_ascq      = 0;
    scsi_disk_info      =  (field >> 24)        |
                          ((field >> 16) <<  8) |
                          ((field >> 8)  << 16) |
                          ( field        << 24);
    scsi_disk_cmd_error(dev);
    dev->tf->status     = 0x53;
}

static void
scsi_disk_invalid_field_pl(scsi_disk_t *dev, const uint32_t field)
{
    scsi_disk_sense_key = SENSE_ILLEGAL_REQUEST;
    scsi_disk_asc       = ASC_INV_FIELD_IN_PARAMETER_LIST;
    scsi_disk_ascq      = 0;
    scsi_disk_info      =  (field >> 24)        |
                          ((field >> 16) <<  8) |
                          ((field >> 8)  << 16) |
                          ( field        << 24);
    scsi_disk_cmd_error(dev);
    dev->tf->status     = 0x53;
}

static void
scsi_disk_data_phase_error(scsi_disk_t *dev, const uint32_t info)
{
    scsi_disk_sense_key = SENSE_ILLEGAL_REQUEST;
    scsi_disk_asc       = ASC_DATA_PHASE_ERROR;
    scsi_disk_ascq      = 0;
    scsi_disk_info      =  (info >> 24)        |
                          ((info >> 16) <<  8) |
                          ((info >> 8)  << 16) |
                          ( info        << 24);
    scsi_disk_cmd_error(dev);
}

static int
scsi_disk_blocks(scsi_disk_t *dev, int32_t *len, UNUSED(int first_batch), const int out)
{
    const uint32_t medium_size = hdd_image_get_last_sector(dev->id) + 1;

    *len = 0;

    if (!dev->sector_len) {
        scsi_disk_command_complete(dev);
        return -1;
    }

    scsi_disk_log(dev->log, "%sing %i blocks starting from %i...\n", out ? "Writ" : "Read",
                  dev->requested_blocks, dev->sector_pos);

    if (dev->sector_pos >= medium_size) {
        scsi_disk_log(dev->log, "Trying to %s beyond the end of disk\n",
                      out ? "write" : "read");
        scsi_disk_lba_out_of_range(dev);
        return 0;
    }

    *len = dev->requested_blocks << 9;

    for (int i = 0; i < dev->requested_blocks; i++) {
        if (out) {
            if (hdd_image_write(dev->id, dev->sector_pos, 1, dev->temp_buffer +
                                (i << 9)) < 0) {
                scsi_disk_write_error(dev);
                return -1;
            }
        } else {
            if (hdd_image_read(dev->id, dev->sector_pos, 1, dev->temp_buffer +
                               (i << 9)) < 0) {
                scsi_disk_read_error(dev);
                return -1;
            }
        }
        dev->sector_pos++;
    }

    scsi_disk_log(dev->log, "%s %i bytes of blocks...\n", out ? "Written" : "Read", *len);

    dev->sector_len -= dev->requested_blocks;

    return 1;
}

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

    if (!(scsi_disk_command_flags[cdb[0]] & IMPLEMENTED)) {
        scsi_disk_log(dev->log, "Attempting to execute unknown "
                      "command %02X over %s\n", cdb[0],
                      (dev->drv->bus_type == HDD_BUS_SCSI) ? "SCSI" : "ATAPI");
        scsi_disk_illegal_opcode(dev, cdb[0]);
        return 0;
    }

    if ((dev->drv->bus_type < HDD_BUS_SCSI) &&
        (scsi_disk_command_flags[cdb[0]] & SCSI_ONLY)) {
        scsi_disk_log(dev->log, "Attempting to execute SCSI-only command %02X "
                      "over ATAPI\n", cdb[0]);
        scsi_disk_illegal_opcode(dev, cdb[0]);
        return 0;
    }

    if ((dev->drv->bus_type == HDD_BUS_SCSI) &&
        (scsi_disk_command_flags[cdb[0]] & ATAPI_ONLY)) {
        scsi_disk_log(dev->log, "Attempting to execute ATAPI-only command %02X "
                      "over SCSI\n", cdb[0]);
        scsi_disk_illegal_opcode(dev, cdb[0]);
        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(dev->log, "Continuing with command %02X\n", cdb[0]);

    return 1;
}

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

static void
scsi_disk_rezero(scsi_disk_t *dev)
{
    if (dev->id != 0xff) {
        dev->sector_pos = dev->sector_len = 0;
        scsi_disk_seek(dev, 0);
    }
}

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

    scsi_disk_rezero(dev);
    dev->tf->status         = 0;
    dev->callback           = 0.0;
    scsi_disk_set_callback(dev);
    dev->tf->phase          = 1;
    dev->tf->request_length = 0xEB14;
    dev->packet_status      = PHASE_NONE;
    dev->unit_attention     = 0;
    dev->cur_lun            = SCSI_LUN_USE_CDB;
    scsi_disk_sense_key = scsi_disk_asc = scsi_disk_ascq = dev->unit_attention = 0;
    scsi_disk_info      = 0x00;
}

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

        buffer[0] = desc ? 0x70 : 0xf0;
        buffer[7] = 10;

        scsi_disk_log(dev->log, "Reporting sense: %02X %02X %02X\n",
                      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,
                                 const 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(const scsi_disk_t *dev, int32_t *BufLen, int32_t *src_len)
{
    if (dev->drv->bus_type == HDD_BUS_SCSI) {
        if (*BufLen == -1)
            *BufLen = *src_len;
        else {
            *BufLen  = MIN(*src_len, *BufLen);
            *src_len = *BufLen;
        }
        scsi_disk_log(dev->log, "Actual transfer length: %i\n", *BufLen);
    }
}

static void
scsi_disk_command(scsi_common_t *sc, const uint8_t *cdb)
{
    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 };
    scsi_disk_t *  dev                    = (scsi_disk_t *) sc;
    const uint32_t last_sector            = hdd_image_get_last_sector(dev->id);
    const uint8_t  scsi_bus               = (dev->drv->scsi_id >> 4) & 0x0f;
    const uint8_t  scsi_id                = dev->drv->scsi_id & 0x0f;
    int32_t        blen                   = 0;
    int            pos                    = 0;
    int            idx                    = 0;
    int            block_desc;
    int            ret;
    int32_t *      BufLen;
    int32_t        len;
    int32_t        max_len;
    int32_t        alloc_length;
    unsigned       size_idx;
    unsigned       preamble_len;

    if (dev->drv->bus_type == HDD_BUS_SCSI) {
        BufLen = &scsi_devices[scsi_bus][scsi_id].buffer_length;
        dev->tf->status &= ~ERR_STAT;
    } else {
        BufLen           = &blen;
        dev->tf->error   = 0;
    }

    dev->packet_len = 0;
    dev->request_pos = 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(dev->log, "Command 0x%02X, Sense Key %02X, Asc %02X, Ascq %02X\n",
                      cdb[0], scsi_disk_sense_key, scsi_disk_asc, scsi_disk_ascq);
        scsi_disk_log(dev->log, "Request length: %04X\n", dev->tf->request_length);

        scsi_disk_log(dev->log, "CDB: %02X %02X %02X %02X %02X %02X %02X %02X "
                      "%02X %02X %02X %02X\n",
                      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, cdb[1]);
                return;
            }
            fallthrough;
        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;

            dev->drv->seek_pos = dev->sector_pos;
            dev->drv->seek_len = dev->sector_len;

            scsi_disk_seek(dev, 0);
            scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
            break;

        case GPCMD_REQUEST_SENSE:
            len = cdb[4];

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

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

            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, *BufLen, 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:
            scsi_disk_set_phase(dev, SCSI_PHASE_DATA_IN);
            alloc_length = 512;

            switch (cdb[0]) {
                case GPCMD_READ_6:
                    dev->sector_len = cdb[4];
                    /*
                       For READ (6) and WRITE (6), a length of 0 indicates a
                       transfer of 256 sectors.
                     */
                    if (dev->sector_len == 0)
                        dev->sector_len = 256;
                    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)
                scsi_disk_lba_out_of_range(dev);
            else {
                if (dev->sector_len) {
                    max_len               = dev->sector_len;
                    dev->requested_blocks = max_len;

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

                    dev->drv->seek_pos = dev->sector_pos;
                    dev->drv->seek_len = dev->sector_len;

                    ret          = scsi_disk_blocks(dev, &alloc_length, 1, 0);
                    alloc_length = dev->requested_blocks * 512;

                    if (ret > 0) {
                        dev->requested_blocks = max_len;
                        dev->packet_len       = alloc_length;

                        scsi_disk_set_buf_len(dev, BufLen, (int32_t *) &dev->packet_len);

                        scsi_disk_data_command_finish(dev, alloc_length, 512, alloc_length, 0);

                        ui_sb_update_icon(SB_HDD | dev->drv->bus_type, dev->packet_status != PHASE_COMPLETE);
                    } else {
                        scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
                        dev->packet_status = (ret < 0) ? PHASE_ERROR : PHASE_COMPLETE;
                        dev->callback      = 20.0 * SCSI_TIME;
                        scsi_disk_set_callback(dev);
                        scsi_disk_buf_free(dev);
                    }
                } else {
                    scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
                    scsi_disk_log(dev->log, "All done - callback set\n");
                    dev->packet_status = PHASE_COMPLETE;
                    dev->callback      = 20.0 * SCSI_TIME;
                    scsi_disk_set_callback(dev);
                }
            }
            break;

        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;
            }
            fallthrough;
        case GPCMD_WRITE_6:
        case GPCMD_WRITE_10:
        case GPCMD_WRITE_AND_VERIFY_10:
        case GPCMD_WRITE_12:
        case GPCMD_WRITE_AND_VERIFY_12:
            scsi_disk_set_phase(dev, SCSI_PHASE_DATA_OUT);
            alloc_length = 512;

            switch (cdb[0]) {
                case GPCMD_VERIFY_6:
                case GPCMD_WRITE_6:
                    dev->sector_len = cdb[4];
                    /*
                       For READ (6) and WRITE (6), a length of 0 indicates a
                       transfer of 256 sectors.
                     */
                    if (dev->sector_len == 0)
                        dev->sector_len = 256;
                    dev->sector_pos = ((((uint32_t) cdb[1]) & 0x1f) << 16) |
                                      (((uint32_t) cdb[2]) << 8) | ((uint32_t) cdb[3]);
                    scsi_disk_log(dev->log, "Length: %i, LBA: %i\n",
                                  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(dev->log, "Length: %i, LBA: %i\n",
                                  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)
                scsi_disk_lba_out_of_range(dev);
            else {
                if (dev->sector_len) {
                    dev->drv->seek_pos = dev->sector_pos;
                    dev->drv->seek_len = dev->sector_len;

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

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

                    dev->requested_blocks = max_len;
                    dev->packet_len       = max_len << 9;

                    scsi_disk_set_buf_len(dev, BufLen, (int32_t *) &dev->packet_len);

                    scsi_disk_data_command_finish(dev, dev->packet_len, 512, dev->packet_len, 1);

                    ui_sb_update_icon(SB_HDD | dev->drv->bus_type, dev->packet_status != PHASE_COMPLETE);
                } else {
                    scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
                    scsi_disk_log(dev->log, "All done - callback set\n");
                    dev->packet_status = PHASE_COMPLETE;
                    dev->callback      = 20.0 * SCSI_TIME;
                    scsi_disk_set_callback(dev);
                }
            }
            break;

        case GPCMD_WRITE_SAME_10:
            alloc_length = 512;

            if ((cdb[1] & 6) == 6)
                scsi_disk_invalid_field(dev, cdb[1]);
            else {
                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)
                    scsi_disk_lba_out_of_range(dev);
                else {
                    if (dev->sector_len) {
                        scsi_disk_buf_alloc(dev, alloc_length);
                        scsi_disk_set_buf_len(dev, BufLen, (int32_t *) &dev->packet_len);

                        dev->requested_blocks = 1;

                        dev->packet_len = alloc_length;

                        scsi_disk_set_phase(dev, SCSI_PHASE_DATA_OUT);

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

                        ui_sb_update_icon(SB_HDD | dev->drv->bus_type,
                                          dev->packet_status != PHASE_COMPLETE);
                    } else {
                        scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
                        scsi_disk_log(dev->log, "All done - callback set\n");
                        dev->packet_status = PHASE_COMPLETE;
                        dev->callback      = 20.0 * SCSI_TIME;
                        scsi_disk_set_callback(dev);
                    }
                }
            }
            break;

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

            if (dev->drv->bus_type == HDD_BUS_SCSI)
                block_desc = ((cdb[1] >> 3) & 1) ? 0 : 1;
            else
                block_desc = 0;

            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(dev->log, "Reading mode page: %02X...\n", cdb[2]);

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

        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);
            break;

        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(dev->log, "All done - callback set\n"); */
                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, idx + 24);
                            return;
                        }

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

                memset(dev->temp_buffer, 0, 8);
                if ((cdb[1] & 0xe0) || ((dev->cur_lun > 0x00) && (dev->cur_lun < 0xff)))
                    dev->temp_buffer[0] = 0x7f;    /* No physical device on this LUN */
                else
                    dev->temp_buffer[0] = 0;       /* SCSI HD */
                dev->temp_buffer[1] = 0;           /* Fixed */
                /* SCSI-2 compliant */
                dev->temp_buffer[2] = (dev->drv->bus_type == HDD_BUS_SCSI) ? 0x02 : 0x00;
                dev->temp_buffer[3] = (dev->drv->bus_type == HDD_BUS_SCSI) ? 0x02 : 0x21;
                dev->temp_buffer[4] = 31;
                dev->temp_buffer[6] = 1;           /* 16-bit transfers supported */
                dev->temp_buffer[7] = 0x20;        /* Wide bus supported */

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

            dev->drv->seek_pos = dev->sector_pos;
            dev->drv->seek_len = 0;

            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, cdb[0]);
            break;
    }

    /* scsi_disk_log(dev->log, "Phase: %02X, request length: %i\n",
                     dev->tf->phase, dev->tf->request_length); */

    if ((dev->packet_status == PHASE_COMPLETE) || (dev->packet_status == PHASE_ERROR))
        scsi_disk_buf_free(dev);
}

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;
    const uint8_t  scsi_bus      = (dev->drv->scsi_id >> 4) & 0x0f;
    const uint8_t  scsi_id       = dev->drv->scsi_id & 0x0f;
    const int32_t *BufLen        = &scsi_devices[scsi_bus][scsi_id].buffer_length;
    const uint32_t last_sector   = hdd_image_get_last_sector(dev->id);
    int            len           = 0;
    uint8_t        error         = 0;
    int            ret           = 1;
    int            i;
    uint32_t       last_to_write;
    uint16_t       block_desc_len;
    uint16_t       pos;
    uint16_t       param_list_len;
    uint8_t        hdr_len;
    uint8_t        val;

    if (!*BufLen)
        scsi_disk_set_phase(dev, SCSI_PHASE_STATUS);
    else  switch (dev->current_cdb[0]) {
        default:
            log_fatal(dev->log, "Bad Command for phase 2 (%02X)\n", dev->current_cdb[0]);
            ret = 0;
        break;

        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)
                scsi_disk_blocks(dev, &len, 1, 1);
            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) {
                    uint32_t s          = (i % dev->drv->spt);
                    uint32_t h          = ((i - s) / dev->drv->spt) % dev->drv->hpc;
                    uint32_t 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;
                }
                if (hdd_image_write(dev->id, i, 1, dev->temp_buffer) < 0)
                    scsi_disk_write_error(dev);
            }
            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->drv->bus_type == HDD_BUS_SCSI) {
                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];
                }
            } else
                block_desc_len = 0;

            pos = hdr_len + block_desc_len;

            while (1) {
                if (pos >= param_list_len) {
                    scsi_disk_log(dev->log, "Buffer has only block descriptor\n");
                    break;
                }

                const uint8_t page     = dev->temp_buffer[pos] & 0x3f;
                const uint8_t 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++) {
                    const uint8_t old  = dev->ms_pages_saved.pages[page][i + 2];
                    const uint8_t ch   = scsi_disk_mode_sense_pages_changeable.pages[page][i + 2];

                    val     = dev->temp_buffer[pos + i];

                    if (val != old) {
                        if (ch)
                            dev->ms_pages_saved.pages[page][i + 2] = val;
                        else {
                            scsi_disk_invalid_field_pl(dev, val);
                            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);
            break;
    }

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

static int
scsi_disk_get_max(UNUSED(const ide_t *ide), int ide_has_dma, const int type)
{
    int ret;

    switch (type) {
        case TYPE_PIO:
            ret = ide_has_dma ? 4 : 0;
            break;
        case TYPE_SDMA:
            ret = ide_has_dma ? 2 : -1;
            break;
        case TYPE_MDMA:
            ret = ide_has_dma ? 2 : -1;
            break;
        case TYPE_UDMA:
            ret = ide_has_dma ? 5 : -1;
            break;
        default:
            ret = -1;
            break;
    }

    return ret;
}

static int
scsi_disk_get_timings(UNUSED(const ide_t *ide), const int ide_has_dma, const int type)
{
    int ret;

    switch (type) {
        case TIMINGS_DMA:
            ret = ide_has_dma ? 120 : 0;
            break;
        case TIMINGS_PIO:
            ret = ide_has_dma ? 120 : 0;
            break;
        case TIMINGS_PIO_FC:
            ret = 0;
            break;
        default:
            ret = 0;
            break;
    }

    return ret;
}

/*
   Fill in ide->buffer with the output of the "IDENTIFY PACKET DEVICE" command
 */
static void
scsi_disk_identify(const ide_t *ide, const int ide_has_dma)
{
    const scsi_disk_t *dev                = (scsi_disk_t *) ide->sc;
    char               device_identify[9] = { '8', '6', 'B', '_', 'H', 'D', '0', '0', 0 };

    device_identify[7] = dev->id + 0x30;
    scsi_disk_log(dev->log, "ATAPI Identify: %s\n", device_identify);

    /* ATAPI device, direct-access device, non-removable media, accelerated DRQ */
    ide->buffer[0] = 0x8000 | (0 << 8) | 0x00 | (2 << 5);
    ide_padstr((char *) (ide->buffer + 10), "", 20);               /* Serial Number */

    ide_padstr((char *) (ide->buffer + 23), EMU_VERSION_EX, 8);    /* Firmware */
    ide_padstr((char *) (ide->buffer + 27), device_identify, 40);     /* Model */

    ide->buffer[49]  = 0x200;                                            /* LBA supported */
    /* Interpret zero byte count limit as maximum length. */
    ide->buffer[126] = 0xfffe;

    if (ide_has_dma) {
        ide->buffer[71] = 30;
        ide->buffer[72] = 30;
        ide->buffer[80] = 0x7e; /*ATA-1 to ATA-6 supported*/
        ide->buffer[81] = 0x19; /*ATA-6 revision 3a supported*/
    }
}

void
scsi_disk_hard_reset(void)
{
    scsi_disk_t   *dev;

    for (uint8_t c = 0; c < HDD_NUM; c++) {
        uint8_t valid = 0;

        if (hdd[c].bus_type == HDD_BUS_SCSI) {
            const uint8_t scsi_bus = (hdd[c].scsi_id >> 4) & 0x0f;
            const uint8_t 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;

            valid = 1;

            hdd_preset_apply(c);

            if (hdd[c].priv == NULL) {
                hdd[c].priv  = (scsi_disk_t *) calloc(1, sizeof(scsi_disk_t));
                dev          = (scsi_disk_t *) hdd[c].priv;

                char n[1024] = { 0 };

                sprintf(n, "HDD %i SCSI ", c + 1);
                dev->log     = log_open(n);
            }

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

            scsi_disk_log(dev->log, "SCSI disk hard_reset drive=%d\n", c);

            if (dev->tf == NULL)
                dev->tf     = (ide_tf_t *) calloc(1, sizeof(ide_tf_t));

            /* SCSI disk, attach to the SCSI bus. */
            scsi_device_t *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;

            scsi_disk_log(dev->log, "SCSI disk %i attached to SCSI ID %i\n", c, hdd[c].scsi_id);
        } else if (hdd[c].bus_type == HDD_BUS_ATAPI) {
            /* 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. */

            /* ATAPI hard disk, attach to the IDE bus. */
            ide_t *id = ide_get_drive(hdd[c].ide_channel);

            /*
               If the IDE channel is initialized, we attach to it,
               otherwise, we do nothing - it's going to be a drive
               that's not attached to anything.
             */
            if (id) {
                if (!hdd_image_load(c))
                    continue;

                valid = 1;

                hdd_preset_apply(c);

                if (hdd[c].priv == NULL)
                    hdd[c].priv = (scsi_disk_t *) calloc(1, sizeof(scsi_disk_t));

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

                id->sc               = (scsi_common_t *) dev;
                dev->tf              = id->tf;
                IDE_ATAPI_IS_EARLY   = 0;
                id->get_max          = scsi_disk_get_max;
                id->get_timings      = scsi_disk_get_timings;
                id->identify         = scsi_disk_identify;
                id->stop             = NULL;
                id->packet_command   = scsi_disk_command;
                id->device_reset     = scsi_disk_reset;
                id->phase_data_out   = scsi_disk_phase_data_out;
                id->command_stop     = scsi_disk_command_stop;
                id->bus_master_error = scsi_disk_bus_master_error;
                id->interrupt_drq    = 0;

                ide_atapi_attach(id);

                scsi_disk_log(dev->log, "ATAPI hard disk drive %i attached to IDE channel %i\n",
                              c, hdd[c].ide_channel);
            }
        }

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

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

            dev->cur_lun = SCSI_LUN_USE_CDB;

            scsi_disk_init(dev);

            scsi_disk_mode_sense_load(dev);
        }
    }
}

void
scsi_disk_close(void)
{
    for (uint8_t c = 0; c < HDD_NUM; c++) {
        if ((hdd[c].bus_type == HDD_BUS_SCSI) || (hdd[c].bus_type == HDD_BUS_ATAPI)) {
            if (hdd[c].bus_type == HDD_BUS_SCSI) {
                const uint8_t scsi_bus = (hdd[c].scsi_id >> 4) & 0x0f;
                const uint8_t scsi_id  = hdd[c].scsi_id & 0x0f;

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

            hdd_image_close(c);

            scsi_disk_t *dev = hdd[c].priv;

            if (dev) {
                if (dev->tf)
                    free(dev->tf);

                if (dev->log != NULL) {
                    scsi_disk_log(dev->log, "Log closed\n");

                    log_close(dev->log);
                    dev->log = NULL;
                }

                free(dev);

                hdd[c].priv = NULL;
            }
        }
    }
}