SCSILS120.cc

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/* Ported from:
** Source: /cvsroot/bluemsx/blueMSX/Src/IoDevice/ScsiDevice.c,v
** Revision: 1.10
** Date: 2007-05-21 21:38:29 +0200 (Mon, 21 May 2007)
**
** More info: http://www.bluemsx.com
**
** Copyright (C) 2003-2007 Daniel Vik, white cat
*/
 
/*
 * Notes:
 *  It follows the SCSI1(CCS) standard or the SCSI2 standard.
 *  Only the direct access device is supported now.
 *  Message system might be imperfect.
 *
 *  NOTE: this version supports a removable LS-120 disk, as the class
 *  name suggests. Refer to revision 6526 of SCSIHD.cc to see what was removed
 *  from the generic/parameterized code.
 */
 
#include "SCSILS120.hh"
#include "FileOperations.hh"
#include "FileException.hh"
#include "FilePool.hh"
#include "LedStatus.hh"
#include "MSXMotherBoard.hh"
#include "DeviceConfig.hh"
#include "RecordedCommand.hh"
#include "MSXCliComm.hh"
#include "TclObject.hh"
#include "CommandException.hh"
#include "FileContext.hh"
#include "endian.hh"
#include "narrow.hh"
#include "one_of.hh"
#include "serialize.hh"
#include <algorithm>
#include <array>
#include <cstring>
#include <memory>
#include <vector>
 
namespace openmsx {
 
// Medium type (value like LS-120)
static constexpr uint8_t MT_UNKNOWN   = 0x00;
static constexpr uint8_t MT_2DD_UN    = 0x10;
static constexpr uint8_t MT_2DD       = 0x11;
static constexpr uint8_t MT_2HD_UN    = 0x20;
static constexpr uint8_t MT_2HD_12_98 = 0x22;
static constexpr uint8_t MT_2HD_12    = 0x23;
static constexpr uint8_t MT_2HD_144   = 0x24;
static constexpr uint8_t MT_LS120     = 0x31;
static constexpr uint8_t MT_NO_DISK   = 0x70;
static constexpr uint8_t MT_DOOR_OPEN = 0x71;
static constexpr uint8_t MT_FMT_ERROR = 0x72;
 
static constexpr std::array<uint8_t, 36> inqData = {
          0,   // bit5-0 device type code.
          0,   // bit7 = 1 removable device
          2,   // bit7,6 ISO version. bit5,4,3 ECMA version.
               // bit2,1,0 ANSI Version (001=SCSI1, 010=SCSI2)
          2,   // bit7 AENC. bit6 TrmIOP.
               // bit3-0 Response Data Format. (0000=SCSI1, 0001=CCS, 0010=SCSI2)
         51,   // additional length
          0, 0,// reserved
          0,   // bit7 RelAdr, bit6 WBus32, bit5 Wbus16, bit4 Sync, bit3 Linked,
               // bit2 reserved bit1 CmdQue, bit0 SftRe
        'o', 'p', 'e', 'n', 'M', 'S', 'X', ' ',    // vendor ID (8bytes)
        'S', 'C', 'S', 'I', '2', ' ', 'L', 'S',    // product ID (16bytes)
        '-', '1', '2', '0', 'd', 'i', 's', 'k',
        '0', '1', '0', 'a'                         // product version (ASCII 4bytes)
};
 
// for FDSFORM.COM
static constexpr std::string_view fds120 = "IODATA  LS-120 COSM     0001";
 
static constexpr unsigned BUFFER_BLOCK_SIZE = SCSIDevice::BUFFER_SIZE /
                                              SectorAccessibleDisk::SECTOR_SIZE;
 
SCSILS120::SCSILS120(const DeviceConfig& targetConfig,
                     AlignedBuffer& buf, unsigned mode_)
        : motherBoard(targetConfig.getMotherBoard())
        , buffer(buf)
        , name("lsX")
        , mode(mode_)
        , scsiId(narrow_cast<uint8_t>(targetConfig.getAttributeValueAsInt("id", 0)))
{
        lsInUse = motherBoard.getSharedStuff<LSInUse>("lsInUse");
 
        unsigned id = 0;
        while ((*lsInUse)[id]) {
                ++id;
                if (id == MAX_LS) {
                        throw MSXException("Too many LSs");
                }
        }
        name[2] = char('a' + id);
        (*lsInUse)[id] = true;
        lsxCommand.emplace(
                motherBoard.getCommandController(),
                motherBoard.getStateChangeDistributor(),
                motherBoard.getScheduler(), *this);
 
        lun = 0; // TODO move to reset() ?
        message = 0;
        reset();
 
        motherBoard.registerMediaInfo(name, *this);
        motherBoard.getMSXCliComm().update(CliComm::HARDWARE, name, "add");
}
 
SCSILS120::~SCSILS120()
{
        motherBoard.unregisterMediaInfo(*this);
        motherBoard.getMSXCliComm().update(CliComm::HARDWARE, name, "remove");
 
        unsigned id = name[2] - 'a';
        assert((*lsInUse)[id]);
        (*lsInUse)[id] = false;
}
 
 
void SCSILS120::getMediaInfo(TclObject& result)
{
        result.addDictKeyValue("target", file.is_open() ? file.getURL() : std::string_view{});
}
 
void SCSILS120::reset()
{
        mediaChanged  = false;
        currentSector = 0;
        currentLength = 0;
        busReset();
}
 
void SCSILS120::busReset()
{
        keycode = 0;
        unitAttention = (mode & MODE_UNITATTENTION) != 0;
}
 
void SCSILS120::disconnect()
{
        motherBoard.getLedStatus().setLed(LedStatus::FDD, false);
}
 
// Check the initiator in the call origin.
bool SCSILS120::isSelected()
{
        lun = 0;
        return file.is_open();
}
 
bool SCSILS120::getReady()
{
        if (file.is_open()) return true;
        keycode = SCSI::SENSE_MEDIUM_NOT_PRESENT;
        return false;
}
 
void SCSILS120::testUnitReady()
{
        if ((mode & MODE_NOVAXIS) == 0) {
                if (getReady() && mediaChanged && (mode & MODE_MEGASCSI)) {
                        // Disk change is surely sent for the driver of MEGA-SCSI.
                        keycode = SCSI::SENSE_POWER_ON;
                }
        }
        mediaChanged = false;
}
 
void SCSILS120::startStopUnit()
{
        switch (cdb[4]) {
        case 2: // Eject
                eject();
                break;
        case 3: // Insert  TODO: how can this happen?
                //if (!diskPresent(diskId)) {
                //      *disk = disk;
                //      updateExtendedDiskName(diskId, disk->fileName, disk->fileNameInZip);
                //      boardChangeDiskette(diskId, disk->fileName, disk->fileNameInZip);
                //}
                break;
        }
}
 
unsigned SCSILS120::inquiry()
{
        auto total      = getNbSectors();
        unsigned length = currentLength;
 
        bool fdsMode = (total > 0) && (total <= 2880);
 
        if (length == 0) return 0;
 
        buffer[0] = SCSI::DT_DirectAccess;
        buffer[1] = 0x80; // removable
        if (fdsMode) {
                ranges::copy(subspan<6>(inqData, 2), &buffer[2]);
                ranges::copy(fds120, &buffer[8]);
        } else {
                ranges::copy(subspan(inqData, 2), &buffer[2]);
        }
 
        if (!(mode & BIT_SCSI2)) {
                buffer[2] = 1;
                buffer[3] = 1;
                if (!fdsMode) buffer[20] = '1';
        } else {
                if (mode & BIT_SCSI3) {
                        buffer[2] = 5;
                        if (!fdsMode) buffer[20] = '3';
                }
        }
 
        if (mode & BIT_SCSI3) {
                length = std::min(length, 96u);
                buffer[4] = 91;
                if (length > 56) {
                        memset(buffer + 56, 0, 40);
                        buffer[58] = 0x03;
                        buffer[60] = 0x01;
                        buffer[61] = 0x80;
                }
        } else {
                length = std::min(length, 56u);
        }
 
        if (length > 36) {
                std::string filename(FileOperations::getFilename(file.getURL()));
                filename.resize(20, ' ');
                ranges::copy(filename, &buffer[36]);
        }
        return length;
}
 
unsigned SCSILS120::modeSense()
{
        uint8_t* pBuffer = buffer;
 
        if ((currentLength > 0) && (cdb[2] == 3)) {
                auto total       = getNbSectors();
                uint8_t media       = MT_UNKNOWN;
                uint8_t sectors     = 64;
                uint8_t blockLength = SECTOR_SIZE >> 8;
                uint8_t tracks      = 8;
                uint8_t size        = 4 + 24;
                uint8_t removable   = 0xa0;
 
                memset(pBuffer + 2, 0, 34);
 
                if (total == 0) {
                        media = MT_NO_DISK;
                } else {
                        if (total == 1440) {
                                media       = MT_2DD;
                                sectors     = 9;
                                blockLength = 2048 >> 8; // FDS-120 value
                                tracks      = 160;
                        } else {
                                if (total == 2880) {
                                        media       = MT_2HD_144;
                                        sectors     = 18;
                                        blockLength = 2048 >> 8;
                                        tracks      = 160;
                                }
                        }
                }
 
                // Mode Parameter Header 4bytes
                pBuffer[1] = media; // Medium Type
                pBuffer[3] = 8;     // block descriptor length
                pBuffer += 4;
 
                // Disable Block Descriptor check
                if (!(cdb[1] & 0x08)) {
                        // Block Descriptor 8bytes
                        pBuffer[1] = (total >> 16) & 0xff; // 1..3 Number of Blocks
                        pBuffer[2] = (total >>  8) & 0xff;
                        pBuffer[3] = (total >>  0) & 0xff;
                        pBuffer[6] = blockLength & 0xff;   // 5..7 Block Length in Bytes
                        pBuffer += 8;
                        size   += 8;
                }
 
                // Format Device Page 24bytes
                pBuffer[ 0] = 3;           //     0 Page
                pBuffer[ 1] = 0x16;        //     1 Page Length
                pBuffer[ 3] = tracks;      //  2, 3 Tracks per Zone
                pBuffer[11] = sectors;     // 10,11 Sectors per Track
                pBuffer[12] = blockLength; // 12,13 Data Bytes per Physical Sector
                pBuffer[20] = removable;   // 20    bit7 Soft Sector bit5 Removable
 
                buffer[0] = size - 1;    // sense data length
 
                return std::min<unsigned>(currentLength, size);
        }
        keycode = SCSI::SENSE_INVALID_COMMAND_CODE;
        return 0;
}
 
unsigned SCSILS120::requestSense()
{
        unsigned length = currentLength;
        unsigned tmpKeycode = unitAttention ? SCSI::SENSE_POWER_ON : keycode;
        unitAttention = false;
 
        keycode = SCSI::SENSE_NO_SENSE;
 
        memset(buffer + 1, 0, 17);
        if (length == 0) {
                if (mode & BIT_SCSI2) {
                        return 0;
                }
                buffer[ 0] = (tmpKeycode >>  8) & 0xff; // Sense code
                length = 4;
        } else {
                buffer[ 0] = 0x70;
                buffer[ 2] = (tmpKeycode >> 16) & 0xff; // Sense key
                buffer[ 7] = 10;                        // Additional sense length
                buffer[12] = (tmpKeycode >>  8) & 0xff; // Additional sense code
                buffer[13] = (tmpKeycode >>  0) & 0xff; // Additional sense code qualifier
                length = std::min(length, 18u);
        }
        return length;
}
 
bool SCSILS120::checkReadOnly()
{
        if (file.isReadOnly()) {
                keycode = SCSI::SENSE_WRITE_PROTECT;
                return true;
        }
        return false;
}
 
unsigned SCSILS120::readCapacity()
{
        auto block = unsigned(getNbSectors());
 
        if (block == 0) {
                // drive not ready
                keycode = SCSI::SENSE_MEDIUM_NOT_PRESENT;
                return 0;
        }
 
        --block;
        Endian::writeB32(&buffer[0], block);
        Endian::writeB32(&buffer[4], SECTOR_SIZE); // TODO see SCSIHD
 
        return 8;
}
 
bool SCSILS120::checkAddress()
{
        auto total = unsigned(getNbSectors());
        if (total == 0) {
                // drive not ready
                keycode = SCSI::SENSE_MEDIUM_NOT_PRESENT;
                return false;
        }
 
        if ((currentLength > 0) && (currentSector + currentLength <= total)) {
                return true;
        }
        keycode = SCSI::SENSE_ILLEGAL_BLOCK_ADDRESS;
        return false;
}
 
// Execute scsiDeviceCheckAddress previously.
unsigned SCSILS120::readSector(unsigned& blocks)
{
        motherBoard.getLedStatus().setLed(LedStatus::FDD, true);
 
        unsigned numSectors = std::min(currentLength, BUFFER_BLOCK_SIZE);
        unsigned counter = currentLength * SECTOR_SIZE;
 
        try {
                // TODO: somehow map this to SectorAccessibleDisk::readSector?
                file.seek(SECTOR_SIZE * currentSector);
                file.read(std::span{buffer.data(), SECTOR_SIZE * numSectors});
                currentSector += numSectors;
                currentLength -= numSectors;
                blocks = currentLength;
                return counter;
        } catch (FileException&) {
                blocks = 0;
                keycode = SCSI::SENSE_UNRECOVERED_READ_ERROR;
                return 0;
        }
}
 
unsigned SCSILS120::dataIn(unsigned& blocks)
{
        if (cdb[0] == SCSI::OP_READ10) {
                unsigned counter = readSector(blocks);
                if (counter) {
                        return counter;
                }
        }
        // error
        blocks = 0;
        return 0;
}
 
// Execute scsiDeviceCheckAddress and scsiDeviceCheckReadOnly previously.
unsigned SCSILS120::writeSector(unsigned& blocks)
{
        motherBoard.getLedStatus().setLed(LedStatus::FDD, true);
 
        unsigned numSectors = std::min(currentLength, BUFFER_BLOCK_SIZE);
 
        // TODO: somehow map this to SectorAccessibleDisk::writeSector?
        try {
                file.seek(SECTOR_SIZE * currentSector);
                file.write(std::span{buffer.data(), SECTOR_SIZE * numSectors});
                currentSector += numSectors;
                currentLength -= numSectors;
 
                unsigned tmp = std::min(currentLength, BUFFER_BLOCK_SIZE);
                blocks = currentLength - tmp;
                unsigned counter = tmp * SECTOR_SIZE;
                return counter;
        } catch (FileException&) {
                keycode = SCSI::SENSE_WRITE_FAULT;
                blocks = 0;
                return 0;
        }
}
 
unsigned SCSILS120::dataOut(unsigned& blocks)
{
        if (cdb[0] == SCSI::OP_WRITE10) {
                return writeSector(blocks);
        }
        // error
        blocks = 0;
        return 0;
}
 
//  MBR erase only
void SCSILS120::formatUnit()
{
        if (getReady() && !checkReadOnly()) {
                memset(buffer, 0, SECTOR_SIZE);
                try {
                        file.seek(0);
                        file.write(std::span{buffer.data(), SECTOR_SIZE});
                        unitAttention = true;
                        mediaChanged = true;
                } catch (FileException&) {
                        keycode = SCSI::SENSE_WRITE_FAULT;
                }
        }
}
 
uint8_t SCSILS120::getStatusCode()
{
        return keycode ? SCSI::ST_CHECK_CONDITION : SCSI::ST_GOOD;
}
 
void SCSILS120::eject()
{
        file.close();
        mediaChanged = true;
        if (mode & MODE_UNITATTENTION) {
                unitAttention = true;
        }
        motherBoard.getMSXCliComm().update(CliComm::MEDIA, name, {});
}
 
void SCSILS120::insert(const std::string& filename)
{
        file = File(filename);
        mediaChanged = true;
        if (mode & MODE_UNITATTENTION) {
                unitAttention = true;
        }
        motherBoard.getMSXCliComm().update(CliComm::MEDIA, name, filename);
}
 
unsigned SCSILS120::executeCmd(std::span<const uint8_t, 12> cdb_, SCSI::Phase& phase, unsigned& blocks)
{
        ranges::copy(cdb_, cdb);
        message = 0;
        phase = SCSI::STATUS;
        blocks = 0;
 
        // check unit attention
        if (unitAttention && (mode & MODE_UNITATTENTION) &&
            (cdb[0] != one_of(SCSI::OP_INQUIRY, SCSI::OP_REQUEST_SENSE))) {
                unitAttention = false;
                keycode = SCSI::SENSE_POWER_ON;
                if (cdb[0] == SCSI::OP_TEST_UNIT_READY) {
                        mediaChanged = false;
                }
                // Unit Attention. This command is not executed.
                return 0;
        }
 
        // check LUN
        if (((cdb[1] & 0xe0) || lun) && (cdb[0] != SCSI::OP_REQUEST_SENSE) &&
            !(cdb[0] == SCSI::OP_INQUIRY && !(mode & MODE_NOVAXIS))) {
                keycode = SCSI::SENSE_INVALID_LUN;
                // check LUN error
                return 0;
        }
 
        if (cdb[0] != SCSI::OP_REQUEST_SENSE) {
                keycode = SCSI::SENSE_NO_SENSE;
        }
 
        if (cdb[0] < SCSI::OP_GROUP1) {
                currentSector = ((cdb[1] & 0x1f) << 16) | (cdb[2] << 8) | cdb[3];
                currentLength = cdb[4];
 
                switch (cdb[0]) {
                case SCSI::OP_TEST_UNIT_READY:
                        testUnitReady();
                        return 0;
 
                case SCSI::OP_INQUIRY: {
                        unsigned counter = inquiry();
                        if (counter) {
                                phase = SCSI::DATA_IN;
                        }
                        return counter;
                }
                case SCSI::OP_REQUEST_SENSE: {
                        unsigned counter = requestSense();
                        if (counter) {
                                phase = SCSI::DATA_IN;
                        }
                        return counter;
                }
                case SCSI::OP_READ6:
                        if (currentLength == 0) {
                                currentLength = SECTOR_SIZE >> 1;
                        }
                        if (checkAddress()) {
                                unsigned counter = readSector(blocks);
                                if (counter) {
                                        cdb[0] = SCSI::OP_READ10;
                                        phase = SCSI::DATA_IN;
                                        return counter;
                                }
                        }
                        return 0;
 
                case SCSI::OP_WRITE6:
                        if (currentLength == 0) {
                                currentLength = SECTOR_SIZE >> 1;
                        }
                        if (checkAddress() && !checkReadOnly()) {
                                motherBoard.getLedStatus().setLed(LedStatus::FDD, true);
                                unsigned tmp = std::min(currentLength, BUFFER_BLOCK_SIZE);
                                blocks = currentLength - tmp;
                                unsigned counter = tmp * SECTOR_SIZE;
                                cdb[0] = SCSI::OP_WRITE10;
                                phase = SCSI::DATA_OUT;
                                return counter;
                        }
                        return 0;
 
                case SCSI::OP_SEEK6:
                        motherBoard.getLedStatus().setLed(LedStatus::FDD, true);
                        currentLength = 1;
                        (void)checkAddress();
                        return 0;
 
                case SCSI::OP_MODE_SENSE: {
                        unsigned counter = modeSense();
                        if (counter) {
                                phase = SCSI::DATA_IN;
                        }
                        return counter;
                }
                case SCSI::OP_FORMAT_UNIT:
                        formatUnit();
                        return 0;
 
                case SCSI::OP_START_STOP_UNIT:
                        startStopUnit();
                        return 0;
 
                case SCSI::OP_REZERO_UNIT:
                case SCSI::OP_REASSIGN_BLOCKS:
                case SCSI::OP_RESERVE_UNIT:
                case SCSI::OP_RELEASE_UNIT:
                case SCSI::OP_SEND_DIAGNOSTIC:
                        // SCSI_Group0 dummy
                        return 0;
                }
        } else {
                currentSector = Endian::read_UA_B32(&cdb[2]);
                currentLength = Endian::read_UA_B16(&cdb[7]);
 
                switch (cdb[0]) {
                case SCSI::OP_READ10:
                        if (checkAddress()) {
                                unsigned counter = readSector(blocks);
                                if (counter) {
                                        phase = SCSI::DATA_IN;
                                        return counter;
                                }
                        }
                        return 0;
 
                case SCSI::OP_WRITE10:
                        if (checkAddress() && !checkReadOnly()) {
                                unsigned tmp = std::min(currentLength, BUFFER_BLOCK_SIZE);
                                blocks = currentLength - tmp;
                                unsigned counter = tmp * SECTOR_SIZE;
                                phase = SCSI::DATA_OUT;
                                return counter;
                        }
                        return 0;
 
                case SCSI::OP_READ_CAPACITY: {
                        unsigned counter = readCapacity();
                        if (counter) {
                                phase = SCSI::DATA_IN;
                        }
                        return counter;
                }
                case SCSI::OP_SEEK10:
                        motherBoard.getLedStatus().setLed(LedStatus::FDD, true);
                        currentLength = 1;
                        (void)checkAddress();
                        return 0;
                }
        }
 
        // unsupported command
        keycode = SCSI::SENSE_INVALID_COMMAND_CODE;
        return 0;
}
 
unsigned SCSILS120::executingCmd(SCSI::Phase& phase, unsigned& blocks)
{
        phase = SCSI::EXECUTE;
        blocks = 0;
        return 0; // we're very fast
}
 
uint8_t SCSILS120::msgIn()
{
        uint8_t result = message;
        message = 0;
        return result;
}
 
/*
scsiDeviceMsgOut()
Notes:
    [out]
          -1: Busfree demand. (Please process it in the call origin.)
        bit2: Status phase demand. Error happened.
        bit1: Make it to a busfree if ATN has not been released.
        bit0: There is a message(MsgIn).
*/
int SCSILS120::msgOut(uint8_t value)
{
        if (value & 0x80) {
                lun = value & 7;
                return 0;
        }
 
        switch (value) {
        case SCSI::MSG_INITIATOR_DETECT_ERROR:
                keycode = SCSI::SENSE_INITIATOR_DETECTED_ERR;
                return 6;
 
        case SCSI::MSG_BUS_DEVICE_RESET:
                busReset();
                [[fallthrough]];
        case SCSI::MSG_ABORT:
                return -1;
 
        case SCSI::MSG_REJECT:
        case SCSI::MSG_PARITY_ERROR:
        case SCSI::MSG_NO_OPERATION:
                return 2;
        }
        message = SCSI::MSG_REJECT;
        return ((value >= 0x04) && (value <= 0x11)) ? 3 : 1;
}
 
size_t SCSILS120::getNbSectorsImpl() const
{
        return file.is_open() ? (const_cast<File&>(file).getSize() / SECTOR_SIZE) : 0;
}
 
bool SCSILS120::isWriteProtectedImpl() const
{
        return false;
}
 
Sha1Sum SCSILS120::getSha1SumImpl(FilePool& filePool)
{
        if (hasPatches()) {
                return SectorAccessibleDisk::getSha1SumImpl(filePool);
        }
        return filePool.getSha1Sum(file);
}
 
void SCSILS120::readSectorsImpl(
        std::span<SectorBuffer> buffers, size_t startSector)
{
        file.seek(startSector * sizeof(SectorBuffer));
        file.read(buffers);
}
 
void SCSILS120::writeSectorImpl(size_t sector, const SectorBuffer& buf)
{
        file.seek(sizeof(buf) * sector);
        file.write(buf.raw);
}
 
SectorAccessibleDisk* SCSILS120::getSectorAccessibleDisk()
{
        return this;
}
 
std::string_view SCSILS120::getContainerName() const
{
        return name;
}
 
bool SCSILS120::diskChanged()
{
        return mediaChanged; // TODO not reset on read
}
 
int SCSILS120::insertDisk(const std::string& filename)
{
        try {
                insert(filename);
                return 0;
        } catch (MSXException&) {
                return -1;
        }
}
 
 
// class LSXCommand
 
LSXCommand::LSXCommand(CommandController& commandController_,
                       StateChangeDistributor& stateChangeDistributor_,
                       Scheduler& scheduler_, SCSILS120& ls_)
        : RecordedCommand(commandController_, stateChangeDistributor_,
                          scheduler_, ls_.name)
        , ls(ls_)
{
}
 
void LSXCommand::execute(std::span<const TclObject> tokens, TclObject& result,
                         EmuTime::param /*time*/)
{
        if (tokens.size() == 1) {
                auto& file = ls.file;
                result.addListElement(tmpStrCat(ls.name, ':'),
                                      file.is_open() ? file.getURL() : std::string{});
                if (!file.is_open()) result.addListElement("empty");
        } else if ((tokens.size() == 2) && (tokens[1] == one_of("eject", "-eject"))) {
                ls.eject();
                // TODO check for locked tray
                if (tokens[1] == "-eject") {
                        result = "Warning: use of '-eject' is deprecated, "
                                 "instead use the 'eject' subcommand";
                }
        } else if ((tokens.size() == 2) ||
                   ((tokens.size() == 3) && (tokens[1] == "insert"))) {
                int fileToken = 1;
                if (tokens[1] == "insert") {
                        if (tokens.size() > 2) {
                                fileToken = 2;
                        } else {
                                throw CommandException(
                                        "Missing argument to insert subcommand");
                        }
                }
                try {
                        ls.insert(userFileContext().resolve(tokens[fileToken].getString()));
                } catch (FileException& e) {
                        throw CommandException("Can't change disk image: ",
                                               e.getMessage());
                }
        } else {
                throw CommandException("Too many or wrong arguments.");
        }
}
 
std::string LSXCommand::help(std::span<const TclObject> /*tokens*/) const
{
        return strCat(
                ls.name, "                   : display the disk image for this LS-120 drive\n",
                ls.name, " eject             : eject the disk image from this LS-120 drive\n",
                ls.name, " insert <filename> : change the disk image for this LS-120 drive\n",
                ls.name, " <filename>        : change the disk image for this LS-120 drive\n");
}
 
void LSXCommand::tabCompletion(std::vector<std::string>& tokens) const
{
        using namespace std::literals;
        static constexpr std::array extra = {"eject"sv, "insert"sv};
        completeFileName(tokens, userFileContext(), extra);
}
 
 
template<typename Archive>
void SCSILS120::serialize(Archive& ar, unsigned /*version*/)
{
        std::string filename = file.is_open() ? file.getURL() : std::string{};
        ar.serialize("filename", filename);
        if constexpr (Archive::IS_LOADER) {
                // re-insert disk before restoring 'mediaChanged'
                if (filename.empty()) {
                        eject();
                } else {
                        insert(filename);
                }
        }
 
        ar.serialize("keycode",       keycode,
                     "currentSector", currentSector,
                     "currentLength", currentLength,
                     "unitAttention", unitAttention,
                     "mediaChanged",  mediaChanged,
                     "message",       message,
                     "lun",           lun);
        ar.serialize_blob("cdb", cdb);
}
INSTANTIATE_SERIALIZE_METHODS(SCSILS120);
REGISTER_POLYMORPHIC_INITIALIZER(SCSIDevice, SCSILS120, "SCSILS120");
 
} // namespace openmsx