/*++

Copyright (C) Microsoft Corporation, 1996 - 1999

Module Name:

    nsmmc.c

Abstract:

    This module contains device-specific routines for NSM Mercury Cd library devices

Environment:

    kernel mode only

Revision History:


--*/

#include "ntddk.h"
#include "mcd.h"
#include "nsmmc.h"


#define MERCURY_40 0x01


typedef struct _CHANGER_ADDRESS_MAPPING {

    //
    // Indicates the first element for each element type.
    // Used to map device-specific values into the 0-based
    // values that layers above expect.
    //

    USHORT  FirstElement[ChangerMaxElement];

    //
    // Indicates the number of each element type.
    //

    USHORT  NumberOfElements[ChangerMaxElement];

    //
    // Indicates the lowest element address for the device.
    //

    USHORT LowAddress;

    //
    // Indicates that the address mapping has been
    // completed successfully.
    //

    BOOLEAN Initialized;

} CHANGER_ADDRESS_MAPPING, *PCHANGER_ADDRESS_MAPPING;

typedef struct _CHANGER_DATA {

    //
    // Size, in bytes, of the structure.
    //

    ULONG Size;

    //
    // Indicates the unit being supported.
    //

    ULONG DeviceID;

    //
    // INTERLOCKED counter of the number of prevent/allows.
    // As the HP units lock the IEPort on these operations
    // MoveMedium/SetAccess might need to clear a prevent
    // to do the operation.
    //

    LONG LockCount;

    //
    // See Address mapping structure above.
    //

    CHANGER_ADDRESS_MAPPING AddressMapping;

    //
    // Cached unique serial number.
    //

    UCHAR SerialNumber[NSM_SERIAL_NUMBER_LENGTH];

    //
    // Pad out to ULONG.
    //

    UCHAR Reserved;

    //
    // Cached inquiry data.
    //

    INQUIRYDATA InquiryData;

} CHANGER_DATA, *PCHANGER_DATA;



NTSTATUS
NSMBuildAddressMapping(
    IN PDEVICE_OBJECT DeviceObject
    );

ULONG
MapExceptionCodes(
    IN PELEMENT_DESCRIPTOR ElementDescriptor
    );

BOOLEAN
ElementOutOfRange(
    IN PCHANGER_ADDRESS_MAPPING AddressMap,
    IN USHORT ElementOrdinal,
    IN ELEMENT_TYPE ElementType
    );


ULONG
ChangerAdditionalExtensionSize(
    VOID
    )

/*++

Routine Description:

    This routine returns the additional device extension size
    needed by the NSM changers.

Arguments:


Return Value:

    Size, in bytes.

--*/

{

    return sizeof(CHANGER_DATA);
}


NTSTATUS
ChangerInitialize(
    IN PDEVICE_OBJECT DeviceObject
    )
{
    PFUNCTIONAL_DEVICE_EXTENSION fdoExtension = DeviceObject->DeviceExtension;
    PCHANGER_DATA  changerData = (PCHANGER_DATA)(fdoExtension->CommonExtension.DriverData);
    NTSTATUS       status;
    PINQUIRYDATA   dataBuffer;
    PSERIALNUMBER  serialBuffer;
    PCDB           cdb;
    ULONG          length;
    SCSI_REQUEST_BLOCK srb;

    changerData->Size = sizeof(CHANGER_DATA);

    //
    // Build address mapping.
    //


    status = NSMBuildAddressMapping(DeviceObject);
    if (!NT_SUCCESS(status)) {
        return status;
    }

    //
    // Get inquiry data.
    //

    dataBuffer = ChangerClassAllocatePool(NonPagedPoolCacheAligned, sizeof(INQUIRYDATA));
    if (!dataBuffer) {
        return STATUS_INSUFFICIENT_RESOURCES;
    }

    //
    // Now get the full inquiry information for the device.
    //

    RtlZeroMemory(&srb, SCSI_REQUEST_BLOCK_SIZE);

    //
    // Set timeout value.
    //

    srb.TimeOutValue = 10;

    srb.CdbLength = 6;

    cdb = (PCDB)srb.Cdb;

    //
    // Set CDB operation code.
    //

    cdb->CDB6INQUIRY.OperationCode = SCSIOP_INQUIRY;

    //
    // Set allocation length to inquiry data buffer size.
    //

    cdb->CDB6INQUIRY.AllocationLength = sizeof(INQUIRYDATA);

    status = ClassSendSrbSynchronous(DeviceObject,
                                     &srb,
                                     dataBuffer,
                                     sizeof(INQUIRYDATA),
                                     FALSE);

    if (SRB_STATUS(srb.SrbStatus) == SRB_STATUS_SUCCESS ||
        SRB_STATUS(srb.SrbStatus) == SRB_STATUS_DATA_OVERRUN) {

        //
        // Updated the length actually transfered.
        //

        length = dataBuffer->AdditionalLength + FIELD_OFFSET(INQUIRYDATA, Reserved);

        if (length > srb.DataTransferLength) {
            length = srb.DataTransferLength;
        }


        RtlMoveMemory(&changerData->InquiryData, dataBuffer, length);

    }

    //
    // Determine drive type.
    //

    if (RtlCompareMemory(dataBuffer->ProductId,"Mercury-40S",11) == 11) {
        changerData->DeviceID = MERCURY_40;
    }

    //
    // Get the Vital Product Data page.
    //

    serialBuffer = ChangerClassAllocatePool(NonPagedPoolCacheAligned, sizeof(SERIALNUMBER));
    if (!serialBuffer) {
        DebugPrint((1, "BuildAddressMapping failed. %x\n", status));

        ChangerClassFreePool(dataBuffer);
        return STATUS_INSUFFICIENT_RESOURCES;
    }

    RtlZeroMemory(serialBuffer, sizeof(SERIALNUMBER));

    RtlZeroMemory(&srb, SCSI_REQUEST_BLOCK_SIZE);

    //
    // Set timeout value.
    //

    srb.TimeOutValue = 10;

    srb.CdbLength = 6;

    cdb = (PCDB)srb.Cdb;

    //
    // Set CDB operation code.
    //

    cdb->CDB6INQUIRY.OperationCode = SCSIOP_INQUIRY;

    //
    // Set EVPD
    //

    cdb->CDB6INQUIRY.Reserved1 = 1;

    //
    // Unit serial number page.
    //

    cdb->CDB6INQUIRY.PageCode = 0x80;

    //
    // Set allocation length to inquiry data buffer size.
    //

    cdb->CDB6INQUIRY.AllocationLength = sizeof(SERIALNUMBER);

    status = ClassSendSrbSynchronous(DeviceObject,
                                     &srb,
                                     serialBuffer,
                                     sizeof(SERIALNUMBER),
                                     FALSE);

    if (SRB_STATUS(srb.SrbStatus) == SRB_STATUS_SUCCESS ||
        SRB_STATUS(srb.SrbStatus) == SRB_STATUS_DATA_OVERRUN) {

        ULONG i;

        RtlMoveMemory(changerData->SerialNumber, serialBuffer->SerialNumber, NSM_SERIAL_NUMBER_LENGTH);

        DebugPrint((1,"DeviceType - %x\n", serialBuffer->DeviceType));
        DebugPrint((1,"PageCode - %x\n", serialBuffer->PageCode));
        DebugPrint((1,"Length - %x\n", serialBuffer->PageLength));

        DebugPrint((1,"Serial number "));

        for (i = 0; i < NSM_SERIAL_NUMBER_LENGTH; i++) {
            DebugPrint((1,"%x", serialBuffer->SerialNumber[i]));
        }

        DebugPrint((1,"\n"));

    }


    ChangerClassFreePool(serialBuffer);
    ChangerClassFreePool(dataBuffer);


    //
    // Send an allow to the unit to ensure that the LockCount and state of the unit
    // are in sync.
    //

    RtlZeroMemory(&srb, SCSI_REQUEST_BLOCK_SIZE);

    cdb = (PCDB)srb.Cdb;
    srb.CdbLength = CDB6GENERIC_LENGTH;
    srb.DataTransferLength = 0;
    srb.TimeOutValue = 10;
    cdb->MEDIA_REMOVAL.OperationCode = SCSIOP_MEDIUM_REMOVAL;
    cdb->MEDIA_REMOVAL.Prevent = 0;

    status = ClassSendSrbSynchronous(DeviceObject,
                                     &srb,
                                     NULL,
                                     0,
                                     FALSE);

    return STATUS_SUCCESS;
}


BOOLEAN
ChangerVerifyInquiry(
    PINQUIRYDATA InquiryData
    )
/*++

Routine Description:

    This routine determines whether the device specified in InquiryData
    should be supported by this module.

Arguments:

    InquiryData - Pointer to inquiry data.

Return Value:

    TRUE - If this is a supported device.

--*/

{


    if (RtlCompareMemory(InquiryData->VendorId,"NSM     ",8) == 8) {
        if (RtlCompareMemory(InquiryData->ProductId,"Mercury-40S",11) == 11) {

            return TRUE;

        }
    }

    return FALSE;
}


VOID
ChangerError(
    PDEVICE_OBJECT DeviceObject,
    PSCSI_REQUEST_BLOCK Srb,
    NTSTATUS *Status,
    BOOLEAN *Retry
    )

/*++

Routine Description:

    This routine executes any device-specific error handling needed.

Arguments:

    DeviceObject
    Irp

Return Value:

    NTSTATUS

--*/
{
    PFUNCTIONAL_DEVICE_EXTENSION fdoExtension = DeviceObject->DeviceExtension;
    PCHANGER_DATA changerData = (PCHANGER_DATA)(fdoExtension->CommonExtension.DriverData);
    PSENSE_DATA senseBuffer = Srb->SenseInfoBuffer;



    if (Srb->SrbStatus & SRB_STATUS_AUTOSENSE_VALID) {
        switch (senseBuffer->SenseKey) {
            case SCSI_SENSE_NOT_READY:
                if ((senseBuffer->AdditionalSenseCode == SCSI_ADSENSE_LUN_NOT_READY) &&
                    (senseBuffer->AdditionalSenseCodeQualifier == SCSI_SENSEQ_MANUAL_INTERVENTION_REQUIRED)) {

                    //
                    // Indicate that the door is open.
                    //

                    *Status = STATUS_DEVICE_DOOR_OPEN;
                }
                break;

            case SCSI_SENSE_UNIT_ATTENTION:

                InterlockedExchange(&changerData->LockCount, 0);

                if (senseBuffer->AdditionalSenseCode == SCSI_ADSENSE_POSITION_ERROR) {
                    if (senseBuffer->AdditionalSenseCodeQualifier == SCSI_SENSEQ_SOURCE_EMPTY) {

                        DebugPrint((1,
                                    "NSMMC: The specified source element has no media\n"));

                        //
                        // The indicated source address has no media.
                        //

                        *Status = STATUS_SOURCE_ELEMENT_EMPTY;

                    } else if (senseBuffer->AdditionalSenseCodeQualifier == SCSI_SENSEQ_DESTINATION_FULL) {

                        DebugPrint((1,
                                    "NSMMC: The specified destination element already has media.\n"));
                        //
                        // The indicated destination already contains media.
                        //

                        *Status = STATUS_DESTINATION_ELEMENT_FULL;
                    }
                }
            break;

        }

        DebugPrint((1,
                   "ChangerError: Sense Key - %x\n",
                   senseBuffer->SenseKey & 0x0f));
        DebugPrint((1,
                   "              AdditionalSenseCode - %x\n",
                   senseBuffer->AdditionalSenseCode));
        DebugPrint((1,
                   "              AdditionalSenseCodeQualifier - %x\n",
                   senseBuffer->AdditionalSenseCodeQualifier));
    }
    return;
}

NTSTATUS
ChangerGetParameters(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:

    This routine determines and returns the "drive parameters" of the
    DVL changers.

Arguments:

    DeviceObject
    Irp

Return Value:

    NTSTATUS

--*/

{
    PFUNCTIONAL_DEVICE_EXTENSION          fdoExtension = DeviceObject->DeviceExtension;
    PCHANGER_DATA              changerData = (PCHANGER_DATA)(fdoExtension->CommonExtension.DriverData);
    PCHANGER_ADDRESS_MAPPING   addressMapping = &(changerData->AddressMapping);
    PSCSI_REQUEST_BLOCK        srb;
    PGET_CHANGER_PARAMETERS    changerParameters;
    PMODE_ELEMENT_ADDRESS_PAGE elementAddressPage;
    PMODE_TRANSPORT_GEOMETRY_PAGE transportGeometryPage;
    PMODE_DEVICE_CAPABILITIES_PAGE capabilitiesPage;
    NTSTATUS status;
    PVOID    modeBuffer;
    PCDB     cdb;
    ULONG    i;

    srb = ChangerClassAllocatePool(NonPagedPool, SCSI_REQUEST_BLOCK_SIZE);

    if (srb == NULL) {

        return STATUS_INSUFFICIENT_RESOURCES;
    }

    RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);
    cdb = (PCDB)srb->Cdb;

    //
    // Build a mode sense - Element address assignment page.
    //

    modeBuffer = ChangerClassAllocatePool(NonPagedPoolCacheAligned, sizeof(MODE_PARAMETER_HEADER)
                                + sizeof(MODE_ELEMENT_ADDRESS_PAGE));
    if (!modeBuffer) {
        ChangerClassFreePool(srb);
        return STATUS_INSUFFICIENT_RESOURCES;
    }


    RtlZeroMemory(modeBuffer, sizeof(MODE_PARAMETER_HEADER) + sizeof(MODE_ELEMENT_ADDRESS_PAGE));
    srb->CdbLength = CDB6GENERIC_LENGTH;
    srb->TimeOutValue = 20;
    srb->DataTransferLength = sizeof(MODE_PARAMETER_HEADER) + sizeof(MODE_ELEMENT_ADDRESS_PAGE);
    srb->DataBuffer = modeBuffer;

    cdb->MODE_SENSE.OperationCode = SCSIOP_MODE_SENSE;
    cdb->MODE_SENSE.PageCode = MODE_PAGE_ELEMENT_ADDRESS;
    cdb->MODE_SENSE.Dbd = 1;
    cdb->MODE_SENSE.AllocationLength = (UCHAR)srb->DataTransferLength;

    //
    // Send the request.
    //

    status = ClassSendSrbSynchronous(DeviceObject,
                                     srb,
                                     srb->DataBuffer,
                                     srb->DataTransferLength,
                                     FALSE);

    if (!NT_SUCCESS(status)) {
        ChangerClassFreePool(srb);
        ChangerClassFreePool(modeBuffer);
        return status;
    }

    //
    // Fill in values.
    //

    changerParameters = Irp->AssociatedIrp.SystemBuffer;
    RtlZeroMemory(changerParameters, sizeof(GET_CHANGER_PARAMETERS));

    elementAddressPage = modeBuffer;
    (PCHAR)elementAddressPage += sizeof(MODE_PARAMETER_HEADER);

    changerParameters->Size = sizeof(GET_CHANGER_PARAMETERS);
    changerParameters->NumberTransportElements = elementAddressPage->NumberTransportElements[1];
    changerParameters->NumberTransportElements |= (elementAddressPage->NumberTransportElements[0] << 8);

    changerParameters->NumberStorageElements = elementAddressPage->NumberStorageElements[1];
    changerParameters->NumberStorageElements |= (elementAddressPage->NumberStorageElements[0] << 8);

    changerParameters->NumberIEElements = elementAddressPage->NumberIEPortElements[1];
    changerParameters->NumberIEElements |= (elementAddressPage->NumberIEPortElements[0] << 8);

    changerParameters->NumberDataTransferElements = elementAddressPage->NumberDataXFerElements[1];
    changerParameters->NumberDataTransferElements |= (elementAddressPage->NumberDataXFerElements[0] << 8);


    if (!addressMapping->Initialized) {

        //
        // Build address mapping.
        //

        addressMapping->FirstElement[ChangerTransport] = (elementAddressPage->MediumTransportElementAddress[0] << 8) |
                                                          elementAddressPage->MediumTransportElementAddress[1];
        addressMapping->FirstElement[ChangerDrive] = (elementAddressPage->FirstDataXFerElementAddress[0] << 8) |
                                                      elementAddressPage->FirstDataXFerElementAddress[1];

        addressMapping->FirstElement[ChangerIEPort] = (elementAddressPage->FirstIEPortElementAddress[0] << 8) |
                                                       elementAddressPage->FirstIEPortElementAddress[1];

        addressMapping->FirstElement[ChangerSlot] = (elementAddressPage->FirstStorageElementAddress[0] << 8) |
                                                     elementAddressPage->FirstStorageElementAddress[1];


        addressMapping->FirstElement[ChangerDoor] = 0;

        addressMapping->FirstElement[ChangerKeypad] = 0;

        addressMapping->NumberOfElements[ChangerTransport] = elementAddressPage->NumberTransportElements[1];
        addressMapping->NumberOfElements[ChangerTransport] |= (elementAddressPage->NumberTransportElements[0] << 8);

        addressMapping->NumberOfElements[ChangerDrive] = elementAddressPage->NumberDataXFerElements[1];
        addressMapping->NumberOfElements[ChangerDrive] |= (elementAddressPage->NumberDataXFerElements[0] << 8);

        addressMapping->NumberOfElements[ChangerIEPort] = elementAddressPage->NumberIEPortElements[1];
        addressMapping->NumberOfElements[ChangerIEPort] |= (elementAddressPage->NumberIEPortElements[0] << 8);

        addressMapping->NumberOfElements[ChangerSlot] = elementAddressPage->NumberStorageElements[1];
        addressMapping->NumberOfElements[ChangerSlot] |= (elementAddressPage->NumberStorageElements[0] << 8);

        //
        // Determine lowest address of all elements.
        //

        addressMapping->LowAddress = NSM_NO_ELEMENT;
        for (i = 0; i <= ChangerDrive; i++) {
            if (addressMapping->LowAddress > addressMapping->FirstElement[i]) {
                addressMapping->LowAddress = addressMapping->FirstElement[i];
            }
        }
    }

    DebugPrint((1,"GetParams: First addresses\n"));
    DebugPrint((1,"Transport: %x\n",
                elementAddressPage->MediumTransportElementAddress[1]));
    DebugPrint((1,"Slot: %x\n",
                elementAddressPage->FirstStorageElementAddress[1]));
    DebugPrint((1,"Ieport: %x\n",
                elementAddressPage->FirstIEPortElementAddress[1]));
    DebugPrint((1,"Drive: %x\n",
                elementAddressPage->FirstDataXFerElementAddress[1]));
    DebugPrint((1,"LowAddress: %x\n",
                addressMapping->LowAddress));

    changerParameters->NumberOfDoors = 1;
    changerParameters->NumberCleanerSlots = 0;

    changerParameters->FirstSlotNumber = 1;
    changerParameters->FirstDriveNumber =  1;
    changerParameters->FirstTransportNumber = 0;
    changerParameters->FirstIEPortNumber = 0;


    changerParameters->MagazineSize = 50;
    changerParameters->DriveCleanTimeout = 0;

    //
    // Free buffer.
    //

    ChangerClassFreePool(modeBuffer);

    //
    // Features based on manual, nothing programatic.
    //

    changerParameters->Features0 = CHANGER_EXCHANGE_MEDIA              |
                                   CHANGER_LOCK_UNLOCK                 |
                                   CHANGER_CARTRIDGE_MAGAZINE          |
                                   CHANGER_DEVICE_REINITIALIZE_CAPABLE |
                                   CHANGER_SERIAL_NUMBER_VALID;

    changerParameters->Features1 = CHANGER_IEPORT_USER_CONTROL_CLOSE | 
                                   CHANGER_MOVE_EXTENDS_IEPORT;

    changerParameters->PositionCapabilities = (CHANGER_TO_DRIVE | CHANGER_TO_SLOT | CHANGER_TO_IEPORT);
    changerParameters->LockUnlockCapabilities = (LOCK_UNLOCK_IEPORT);

    //
    // build device caps mode sense.
    //

    RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);
    cdb = (PCDB)srb->Cdb;

    modeBuffer = ChangerClassAllocatePool(NonPagedPoolCacheAligned, sizeof(MODE_PARAMETER_HEADER)
                                + sizeof(MODE_DEVICE_CAPABILITIES_PAGE));
    if (!modeBuffer) {
        ChangerClassFreePool(srb);
        return STATUS_INSUFFICIENT_RESOURCES;
    }

    RtlZeroMemory(modeBuffer, sizeof(MODE_PARAMETER_HEADER) + sizeof(MODE_DEVICE_CAPABILITIES_PAGE));
    srb->CdbLength = CDB6GENERIC_LENGTH;
    srb->TimeOutValue = 20;
    srb->DataTransferLength = sizeof(MODE_PARAMETER_HEADER) + sizeof(MODE_DEVICE_CAPABILITIES_PAGE);
    srb->DataBuffer = modeBuffer;

    cdb->MODE_SENSE.OperationCode = SCSIOP_MODE_SENSE;
    cdb->MODE_SENSE.PageCode = MODE_PAGE_DEVICE_CAPABILITIES;
    cdb->MODE_SENSE.Dbd = 1;
    cdb->MODE_SENSE.AllocationLength = (UCHAR)srb->DataTransferLength;

    //
    // Send the request.
    //

    status = ClassSendSrbSynchronous(DeviceObject,
                                     srb,
                                     srb->DataBuffer,
                                     srb->DataTransferLength,
                                     FALSE);

    if (!NT_SUCCESS(status)) {
        ChangerClassFreePool(srb);
        ChangerClassFreePool(modeBuffer);
        return status;
    }

    //
    // Get the systembuffer and by-pass the mode header for the mode sense data.
    //

    changerParameters = Irp->AssociatedIrp.SystemBuffer;
    capabilitiesPage = modeBuffer;
    (PCHAR)capabilitiesPage += sizeof(MODE_PARAMETER_HEADER);

    //
    // Fill in values in Features that are contained in this page.
    //

    changerParameters->Features0 |= capabilitiesPage->MediumTransport ? CHANGER_STORAGE_DRIVE : 0;
    changerParameters->Features0 |= capabilitiesPage->StorageLocation ? CHANGER_STORAGE_SLOT : 0;
    changerParameters->Features0 |= capabilitiesPage->IEPort ? CHANGER_STORAGE_IEPORT : 0;
    changerParameters->Features0 |= capabilitiesPage->DataXFer ? CHANGER_STORAGE_DRIVE : 0;

    //
    // Determine all the move from and exchange from capabilities of this device.
    //

    changerParameters->MoveFromTransport = capabilitiesPage->MTtoMT ? CHANGER_TO_TRANSPORT : 0;
    changerParameters->MoveFromTransport |= capabilitiesPage->MTtoST ? CHANGER_TO_SLOT : 0;
    changerParameters->MoveFromTransport |= capabilitiesPage->MTtoIE ? CHANGER_TO_IEPORT : 0;
    changerParameters->MoveFromTransport |= capabilitiesPage->MTtoDT ? CHANGER_TO_DRIVE : 0;

    changerParameters->MoveFromSlot = capabilitiesPage->STtoMT ? CHANGER_TO_TRANSPORT : 0;
    changerParameters->MoveFromSlot |= capabilitiesPage->STtoST ? CHANGER_TO_SLOT : 0;
    changerParameters->MoveFromSlot |= capabilitiesPage->STtoIE ? CHANGER_TO_IEPORT : 0;
    changerParameters->MoveFromSlot |= capabilitiesPage->STtoDT ? CHANGER_TO_DRIVE : 0;

    changerParameters->MoveFromIePort = capabilitiesPage->IEtoMT ? CHANGER_TO_TRANSPORT : 0;
    changerParameters->MoveFromIePort |= capabilitiesPage->IEtoST ? CHANGER_TO_SLOT : 0;
    changerParameters->MoveFromIePort |= capabilitiesPage->IEtoIE ? CHANGER_TO_IEPORT : 0;
    changerParameters->MoveFromIePort |= capabilitiesPage->IEtoDT ? CHANGER_TO_DRIVE : 0;

    changerParameters->MoveFromDrive = capabilitiesPage->DTtoMT ? CHANGER_TO_TRANSPORT : 0;
    changerParameters->MoveFromDrive |= capabilitiesPage->DTtoST ? CHANGER_TO_SLOT : 0;
    changerParameters->MoveFromDrive |= capabilitiesPage->DTtoIE ? CHANGER_TO_IEPORT : 0;
    changerParameters->MoveFromDrive |= capabilitiesPage->DTtoDT ? CHANGER_TO_DRIVE : 0;

    changerParameters->ExchangeFromTransport = capabilitiesPage->XMTtoMT ? CHANGER_TO_TRANSPORT : 0;
    changerParameters->ExchangeFromTransport |= capabilitiesPage->XMTtoST ? CHANGER_TO_SLOT : 0;
    changerParameters->ExchangeFromTransport |= capabilitiesPage->XMTtoIE ? CHANGER_TO_IEPORT : 0;
    changerParameters->ExchangeFromTransport |= capabilitiesPage->XMTtoDT ? CHANGER_TO_DRIVE : 0;

    changerParameters->ExchangeFromSlot = capabilitiesPage->XSTtoMT ? CHANGER_TO_TRANSPORT : 0;
    changerParameters->ExchangeFromSlot |= capabilitiesPage->XSTtoST ? CHANGER_TO_SLOT : 0;
    changerParameters->ExchangeFromSlot |= capabilitiesPage->XSTtoIE ? CHANGER_TO_IEPORT : 0;
    changerParameters->ExchangeFromSlot |= capabilitiesPage->XSTtoDT ? CHANGER_TO_DRIVE : 0;

    changerParameters->ExchangeFromIePort = capabilitiesPage->XIEtoMT ? CHANGER_TO_TRANSPORT : 0;
    changerParameters->ExchangeFromIePort |= capabilitiesPage->XIEtoST ? CHANGER_TO_SLOT : 0;
    changerParameters->ExchangeFromIePort |= capabilitiesPage->XIEtoIE ? CHANGER_TO_IEPORT : 0;
    changerParameters->ExchangeFromIePort |= capabilitiesPage->XIEtoDT ? CHANGER_TO_DRIVE : 0;

    changerParameters->ExchangeFromDrive = capabilitiesPage->XDTtoMT ? CHANGER_TO_TRANSPORT : 0;
    changerParameters->ExchangeFromDrive |= capabilitiesPage->XDTtoST ? CHANGER_TO_SLOT : 0;
    changerParameters->ExchangeFromDrive |= capabilitiesPage->XDTtoIE ? CHANGER_TO_IEPORT : 0;
    changerParameters->ExchangeFromDrive |= capabilitiesPage->XDTtoDT ? CHANGER_TO_DRIVE : 0;



    ChangerClassFreePool(srb);
    ChangerClassFreePool(modeBuffer);

    Irp->IoStatus.Information = sizeof(GET_CHANGER_PARAMETERS);

    return STATUS_SUCCESS;
}


NTSTATUS
ChangerGetStatus(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:

    This routine returns the status of the medium changer as determined through a TUR.

Arguments:

    DeviceObject
    Irp

Return Value:

    NTSTATUS

--*/

{
    PFUNCTIONAL_DEVICE_EXTENSION   fdoExtension = DeviceObject->DeviceExtension;
    PSCSI_REQUEST_BLOCK srb;
    PCDB     cdb;
    NTSTATUS status;

    srb = ChangerClassAllocatePool(NonPagedPool, SCSI_REQUEST_BLOCK_SIZE);

    if (!srb) {

        return STATUS_INSUFFICIENT_RESOURCES;
    }

    RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);
    cdb = (PCDB)srb->Cdb;

    //
    // Build TUR.
    //

    RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);
    cdb = (PCDB)srb->Cdb;

    srb->CdbLength = CDB6GENERIC_LENGTH;
    cdb->CDB6GENERIC.OperationCode = SCSIOP_TEST_UNIT_READY;
    srb->TimeOutValue = 20;

    //
    // Send SCSI command (CDB) to device
    //

    status = ClassSendSrbSynchronous(DeviceObject,
                                     srb,
                                     NULL,
                                     0,
                                     FALSE);

    ChangerClassFreePool(srb);
    return status;
}


NTSTATUS
ChangerGetProductData(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:

    This routine returns fields from the inquiry data useful for
    identifying the particular device.

Arguments:

    DeviceObject
    Irp

Return Value:

    NTSTATUS

--*/

{

    PFUNCTIONAL_DEVICE_EXTENSION fdoExtension = DeviceObject->DeviceExtension;
    PCHANGER_DATA changerData = (PCHANGER_DATA)(fdoExtension->CommonExtension.DriverData);
    PCHANGER_PRODUCT_DATA productData = Irp->AssociatedIrp.SystemBuffer;

    RtlZeroMemory(productData, sizeof(CHANGER_PRODUCT_DATA));

    //
    // Copy cached inquiry data fields into the system buffer.
    //

    RtlMoveMemory(productData->VendorId, changerData->InquiryData.VendorId, VENDOR_ID_LENGTH);
    RtlMoveMemory(productData->ProductId, changerData->InquiryData.ProductId, PRODUCT_ID_LENGTH);
    RtlMoveMemory(productData->Revision, changerData->InquiryData.ProductRevisionLevel, REVISION_LENGTH);
    RtlMoveMemory(productData->SerialNumber, changerData->SerialNumber, NSM_SERIAL_NUMBER_LENGTH);

    //
    // Indicate drive type.
    //

    productData->DeviceType = MEDIUM_CHANGER;

    Irp->IoStatus.Information = sizeof(CHANGER_PRODUCT_DATA);
    return STATUS_SUCCESS;
}



NTSTATUS
ChangerSetAccess(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:

    This routine sets the state of the IEPort/ Front panel.

Arguments:

    DeviceObject
    Irp

Return Value:

    NTSTATUS

--*/

{
    PFUNCTIONAL_DEVICE_EXTENSION   fdoExtension = DeviceObject->DeviceExtension;
    PCHANGER_DATA       changerData = (PCHANGER_DATA)(fdoExtension->CommonExtension.DriverData);
    PCHANGER_ADDRESS_MAPPING addressMapping = &(changerData->AddressMapping);
    PCHANGER_SET_ACCESS setAccess = Irp->AssociatedIrp.SystemBuffer;
    ULONG               controlOperation = setAccess->Control;
    NTSTATUS            status = STATUS_SUCCESS;
    PSCSI_REQUEST_BLOCK srb;
    PCDB                cdb;
    BOOLEAN             writeToDevice = FALSE;


    if (ElementOutOfRange(addressMapping, (USHORT)setAccess->Element.ElementAddress, setAccess->Element.ElementType)) {
        DebugPrint((1,
                   "ChangerSetAccess: Element out of range.\n"));

        return STATUS_ILLEGAL_ELEMENT_ADDRESS;
    }

    srb = ChangerClassAllocatePool(NonPagedPool, SCSI_REQUEST_BLOCK_SIZE);

    if (!srb) {

        return STATUS_INSUFFICIENT_RESOURCES;
    }

    RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);
    cdb = (PCDB)srb->Cdb;

    srb->CdbLength = CDB6GENERIC_LENGTH;
    cdb->MEDIA_REMOVAL.OperationCode = SCSIOP_MEDIUM_REMOVAL;

    srb->DataBuffer = NULL;
    srb->DataTransferLength = 0;
    srb->TimeOutValue = 10;

    switch (setAccess->Element.ElementType) {
        case ChangerIEPort:

            if (controlOperation == LOCK_ELEMENT) {

                //
                // Issue prevent media removal command to lock the door.
                //

                cdb->MEDIA_REMOVAL.Prevent = 1;

                //
                // Inc the lock count to indicate that a prevent is on the device.
                //

                InterlockedIncrement(&changerData->LockCount);

            } else if (controlOperation == UNLOCK_ELEMENT) {

                //
                // Issue allow media removal.
                //

                cdb->MEDIA_REMOVAL.Prevent = 0;

                InterlockedExchange(&changerData->LockCount, 0);

            } else {
                status = STATUS_INVALID_PARAMETER;
            }

            break;

        default:

            status = STATUS_INVALID_PARAMETER;
    }

    if (NT_SUCCESS(status)) {

        //
        // Issue the srb.
        //

        status = ClassSendSrbSynchronous(DeviceObject,
                                             srb,
                                             srb->DataBuffer,
                                             srb->DataTransferLength,
                                             writeToDevice);
    }

    if (srb->DataBuffer) {
        ChangerClassFreePool(srb->DataBuffer);
    }

    ChangerClassFreePool(srb);
    if (NT_SUCCESS(status)) {
        Irp->IoStatus.Information = sizeof(CHANGER_SET_ACCESS);
    }

    return status;
}



NTSTATUS
ChangerGetElementStatus(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:

    This routine builds and issues a read element status command for either all elements or the
    specified element type. The buffer returned is used to build the user buffer.

Arguments:

    DeviceObject
    Irp

Return Value:

    NTSTATUS

--*/

{

    PFUNCTIONAL_DEVICE_EXTENSION fdoExtension = DeviceObject->DeviceExtension;
    PCHANGER_DATA     changerData = (PCHANGER_DATA)(fdoExtension->CommonExtension.DriverData);
    PCHANGER_ADDRESS_MAPPING     addressMapping = &(changerData->AddressMapping);
    PCHANGER_READ_ELEMENT_STATUS readElementStatus = Irp->AssociatedIrp.SystemBuffer;
    PCHANGER_ELEMENT_STATUS      elementStatus;
    PCHANGER_ELEMENT    element;
    ELEMENT_TYPE        elementType;
    PSCSI_REQUEST_BLOCK srb;
    PCDB     cdb;
    ULONG    length;
    ULONG    statusPages;
    NTSTATUS status;
    PVOID    statusBuffer;

    //
    // Determine the element type.
    //

    elementType = readElementStatus->ElementList.Element.ElementType;
    element = &readElementStatus->ElementList.Element;


    if (readElementStatus->VolumeTagInfo) {

        return STATUS_INVALID_PARAMETER;
    }

    if (elementType == AllElements) {

        ULONG i;
        ULONG totalElements = 0;

        statusPages = 0;

        //
        // Run through and determine number of statuspages, based on
        // whether this device claims it supports an element type.
        // As everything past ChangerDrive is artificial, stop there.
        //

        for (i = 0; i <= ChangerDrive; i++) {
            statusPages += (addressMapping->NumberOfElements[i]) ? 1 : 0;

            //
            // Add these up instead of using the number passed in the user's buffer, as the driver
            // fakes that there are no IEPorts.
            //

            totalElements += addressMapping->NumberOfElements[i];
        }

        //
        // Determine length of the descriptors expected for the elements.
        //

        length = (sizeof(NSM_ELEMENT_DESCRIPTOR) * totalElements);

        //
        // Add in header and status pages.
        //

        length += sizeof(ELEMENT_STATUS_HEADER) + (sizeof(ELEMENT_STATUS_PAGE) * statusPages);


    } else {

        length = (sizeof(NSM_ELEMENT_DESCRIPTOR) * readElementStatus->ElementList.NumberOfElements);

        //
        // Add in length of header and status page.
        //

        length += sizeof(ELEMENT_STATUS_HEADER) + sizeof(ELEMENT_STATUS_PAGE);

    }

    statusBuffer = ChangerClassAllocatePool(NonPagedPoolCacheAligned, length);

    if (!statusBuffer) {
        return STATUS_INSUFFICIENT_RESOURCES;
    }

    RtlZeroMemory(statusBuffer, length);

    //
    // Build srb and cdb.
    //

    srb = ChangerClassAllocatePool(NonPagedPool, SCSI_REQUEST_BLOCK_SIZE);

    if (!srb) {

        ChangerClassFreePool(statusBuffer);
        return STATUS_INSUFFICIENT_RESOURCES;
    }

    RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);
    cdb = (PCDB)srb->Cdb;

    srb->CdbLength = CDB12GENERIC_LENGTH;
    srb->DataBuffer = statusBuffer;
    srb->DataTransferLength = length;
    srb->TimeOutValue = 200;

    cdb->READ_ELEMENT_STATUS.OperationCode = SCSIOP_READ_ELEMENT_STATUS;
    cdb->READ_ELEMENT_STATUS.ElementType = (UCHAR)elementType;
    cdb->READ_ELEMENT_STATUS.VolTag = readElementStatus->VolumeTagInfo;

    //
    // Fill in element addressing info based on the mapping values.
    //

    if (elementType == AllElements) {

        //
        // Ensure that starting address is valid.
        //

        cdb->READ_ELEMENT_STATUS.StartingElementAddress[0] =
            (UCHAR)((element->ElementAddress + addressMapping->LowAddress) >> 8);

        cdb->READ_ELEMENT_STATUS.StartingElementAddress[1] =
            (UCHAR)((element->ElementAddress + addressMapping->LowAddress) & 0xFF);

    } else {

        cdb->READ_ELEMENT_STATUS.StartingElementAddress[0] =
            (UCHAR)((element->ElementAddress + addressMapping->FirstElement[element->ElementType]) >> 8);

        cdb->READ_ELEMENT_STATUS.StartingElementAddress[1] =
            (UCHAR)((element->ElementAddress + addressMapping->FirstElement[element->ElementType]) & 0xFF);
    }

    cdb->READ_ELEMENT_STATUS.NumberOfElements[0] = (UCHAR)(readElementStatus->ElementList.NumberOfElements >> 8);
    cdb->READ_ELEMENT_STATUS.NumberOfElements[1] = (UCHAR)(readElementStatus->ElementList.NumberOfElements & 0xFF);

    cdb->READ_ELEMENT_STATUS.AllocationLength[0] = (UCHAR)(length >> 16);
    cdb->READ_ELEMENT_STATUS.AllocationLength[1] = (UCHAR)(length >> 8);
    cdb->READ_ELEMENT_STATUS.AllocationLength[2] = (UCHAR)(length & 0xFF);

    //
    // Send SCSI command (CDB) to device
    //

    status = ClassSendSrbSynchronous(DeviceObject,
                                     srb,
                                     srb->DataBuffer,
                                     srb->DataTransferLength,
                                     FALSE);

    if (NT_SUCCESS(status)) {

        PELEMENT_STATUS_HEADER statusHeader = statusBuffer;
        PELEMENT_STATUS_PAGE statusPage;
        PELEMENT_DESCRIPTOR elementDescriptor;
        ULONG numberElements = readElementStatus->ElementList.NumberOfElements;
        ULONG remainingElements;
        ULONG typeCount;
        BOOLEAN tagInfo = readElementStatus->VolumeTagInfo;
        ULONG i;
        ULONG descriptorLength;

        //
        // Determine total number elements returned.
        //

        remainingElements = statusHeader->NumberOfElements[1];
        remainingElements |= (statusHeader->NumberOfElements[0] << 8);

        //
        // The buffer is composed of a header, status page, and element descriptors.
        // Point each element to it's respective place in the buffer.
        //

        (PCHAR)statusPage = (PCHAR)statusHeader;
        (PCHAR)statusPage += sizeof(ELEMENT_STATUS_HEADER);

        elementType = statusPage->ElementType;

        (PCHAR)elementDescriptor = (PCHAR)statusPage;
        (PCHAR)elementDescriptor += sizeof(ELEMENT_STATUS_PAGE);

        descriptorLength = statusPage->ElementDescriptorLength[1];
        descriptorLength |= (statusPage->ElementDescriptorLength[0] << 8);

        //
        // Determine the number of elements of this type reported.
        //

        typeCount =  statusPage->DescriptorByteCount[2];
        typeCount |=  (statusPage->DescriptorByteCount[1] << 8);
        typeCount |=  (statusPage->DescriptorByteCount[0] << 16);

        if (typeCount > descriptorLength * remainingElements) {
            DebugPrint((1,
                        "ChangerGetElementStatus: DescriptorByteCount is hosed. Claimed: %x",
                        typeCount));

            typeCount = descriptorLength * remainingElements;

            DebugPrint((1," Actual: %x\n", typeCount));
        }

        typeCount /= descriptorLength;

        //
        // Fill in user buffer.
        //

        elementStatus = Irp->AssociatedIrp.SystemBuffer;

        do {

            for (i = 0; i < typeCount; i++, remainingElements--) {

                //
                // Get the address for this element.
                //

                elementStatus->Element.ElementAddress = elementDescriptor->ElementAddress[1];
                elementStatus->Element.ElementAddress |= (elementDescriptor->ElementAddress[0] << 8);

                //
                // Account for address mapping.
                //

                elementStatus->Element.ElementAddress -= addressMapping->FirstElement[elementType];

                //
                // Set the element type.
                //

                elementStatus->Element.ElementType = elementType;
                elementStatus->Flags = 0;

                if (elementType == ChangerDrive) {

                    //
                    // Source address
                    //

                    if (elementDescriptor->SValid) {

                        ULONG  j;
                        USHORT tmpAddress;


                        //
                        // Source address is valid. Determine the device specific address.
                        //

                        tmpAddress = elementDescriptor->SourceStorageElementAddress[1];
                        tmpAddress |= (elementDescriptor->SourceStorageElementAddress[0] << 8);

                        //
                        // Now convert to 0-based values.
                        //

                        for (j = 1; j <= ChangerDrive; j++) {
                            if (addressMapping->FirstElement[j] <= tmpAddress) {
                                if (tmpAddress < (addressMapping->NumberOfElements[j] + addressMapping->FirstElement[j])) {
                                    elementStatus->SrcElementAddress.ElementType = j;
                                    break;
                                }
                            }
                        }

                        elementStatus->SrcElementAddress.ElementAddress = tmpAddress - addressMapping->FirstElement[j];

                        elementStatus->Flags |= ELEMENT_STATUS_SVALID;

                    }

                    if (elementDescriptor->IdValid) {
                        elementStatus->TargetId = elementDescriptor->BusAddress;
                    }
                    if (elementDescriptor->LunValid) {
                        elementStatus->Lun = elementDescriptor->Lun;
                    }
                } else {

                    if (elementDescriptor->SValid) {

                        ULONG  j;
                        USHORT tmpAddress;


                        //
                        // Source address is valid. Determine the device specific address.
                        //

                        tmpAddress = elementDescriptor->SourceStorageElementAddress[1];
                        tmpAddress |= (elementDescriptor->SourceStorageElementAddress[0] << 8);

                        //
                        // Now convert to 0-based values.
                        //

                        for (j = 1; j <= ChangerDrive; j++) {
                            if (addressMapping->FirstElement[j] <= tmpAddress) {
                                if (tmpAddress < (addressMapping->NumberOfElements[j] + addressMapping->FirstElement[j])) {
                                    elementStatus->SrcElementAddress.ElementType = j;
                                    break;
                                }
                            }
                        }

                        elementStatus->SrcElementAddress.ElementAddress = tmpAddress - addressMapping->FirstElement[j];

                        elementStatus->Flags |= ELEMENT_STATUS_SVALID;

                    }
                }

                //
                // Build Flags field.
                //

                elementStatus->Flags |= elementDescriptor->Full;
                elementStatus->Flags |= (elementDescriptor->Exception << 2);
                elementStatus->Flags |= (elementDescriptor->Accessible << 3);

                elementStatus->Flags |= (elementDescriptor->LunValid << 12);
                elementStatus->Flags |= (elementDescriptor->IdValid << 13);
                elementStatus->Flags |= (elementDescriptor->NotThisBus << 15);

                elementStatus->Flags |= (elementDescriptor->Invert << 22);
                elementStatus->Flags |= (elementDescriptor->SValid << 23);


                //
                // Map the exceptions.
                //

                if (elementDescriptor->Exception) {
                    elementStatus->ExceptionCode = MapExceptionCodes(elementDescriptor);
                    if (elementStatus->ExceptionCode == 0) {

                        //
                        // For some reason an exception was noted that is not relevant.
                        //

                        elementStatus->Flags &=~ELEMENT_STATUS_EXCEPT;
                    }
                }

                //
                // Get next descriptor.
                //

                (PCHAR)elementDescriptor += descriptorLength;

                //
                // Advance to the next entry in the user buffer.
                //

                elementStatus += 1;
            }

            if (remainingElements) {

                //
                // Get next status page.
                //

                (PCHAR)statusPage = (PCHAR)elementDescriptor;

                elementType = statusPage->ElementType;

                //
                // Point to decriptors.
                //

                (PCHAR)elementDescriptor = (PCHAR)statusPage;
                (PCHAR)elementDescriptor += sizeof(ELEMENT_STATUS_PAGE);

                descriptorLength = statusPage->ElementDescriptorLength[1];
                descriptorLength |= (statusPage->ElementDescriptorLength[0] << 8);

                //
                // Determine the number of this element type reported.
                //

                typeCount =  statusPage->DescriptorByteCount[2];
                typeCount |=  (statusPage->DescriptorByteCount[1] << 8);
                typeCount |=  (statusPage->DescriptorByteCount[0] << 16);

                typeCount /= descriptorLength;
            }

        } while (remainingElements);

        Irp->IoStatus.Information = sizeof(CHANGER_ELEMENT_STATUS) * numberElements;

    }

    ChangerClassFreePool(srb);
    ChangerClassFreePool(statusBuffer);

    return status;
}


NTSTATUS
ChangerInitializeElementStatus(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:

    This routine issues the necessary command to either initialize all elements
    or the specified range of elements using the normal SCSI-2 command, or a vendor-unique
    range command.

Arguments:

    DeviceObject
    Irp

Return Value:

    NTSTATUS

--*/

{

    PFUNCTIONAL_DEVICE_EXTENSION   fdoExtension = DeviceObject->DeviceExtension;
    PCHANGER_DATA       changerData = (PCHANGER_DATA)(fdoExtension->CommonExtension.DriverData);
    PCHANGER_ADDRESS_MAPPING addressMapping = &(changerData->AddressMapping);
    PCHANGER_INITIALIZE_ELEMENT_STATUS initElementStatus = Irp->AssociatedIrp.SystemBuffer;
    PSCSI_REQUEST_BLOCK srb;
    PCDB                cdb;
    NTSTATUS            status;

    //
    // Build srb and cdb.
    //

    srb = ChangerClassAllocatePool(NonPagedPool, SCSI_REQUEST_BLOCK_SIZE);

    if (!srb) {

        return STATUS_INSUFFICIENT_RESOURCES;
    }

    RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);
    cdb = (PCDB)srb->Cdb;

    if (initElementStatus->ElementList.Element.ElementType == AllElements) {

        //
        // Build the normal SCSI-2 command for all elements.
        //

        srb->CdbLength = CDB6GENERIC_LENGTH;
        cdb->INIT_ELEMENT_STATUS.OperationCode = SCSIOP_INIT_ELEMENT_STATUS;

        srb->TimeOutValue = fdoExtension->TimeOutValue;
        srb->DataTransferLength = 0;

    } else {

        return STATUS_INVALID_PARAMETER;

    }

    //
    // Send SCSI command (CDB) to device
    //

    status = ClassSendSrbSynchronous(DeviceObject,
                                     srb,
                                     NULL,
                                     0,
                                     FALSE);

    if (NT_SUCCESS(status)) {
        Irp->IoStatus.Information = sizeof(CHANGER_INITIALIZE_ELEMENT_STATUS);
    }

    ChangerClassFreePool(srb);
    return status;
}


NTSTATUS
ChangerSetPosition(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:

    This routine issues the appropriate command to set the robotic mechanism to the specified
    element address. Normally used to optimize moves or exchanges by pre-positioning the picker.

Arguments:

    DeviceObject
    Irp

Return Value:

    NTSTATUS

--*/

{
    //
    // The Mercury doesn't support this.
    //

    return STATUS_INVALID_DEVICE_REQUEST;
}


NTSTATUS
ChangerExchangeMedium(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:

    Moves the media at source to dest1 and dest1 to dest2.

Arguments:

    DeviceObject
    Irp

Return Value:


--*/

{

    PFUNCTIONAL_DEVICE_EXTENSION   fdoExtension = DeviceObject->DeviceExtension;
    PCHANGER_DATA       changerData = (PCHANGER_DATA)(fdoExtension->CommonExtension.DriverData);
    PCHANGER_ADDRESS_MAPPING addressMapping = &(changerData->AddressMapping);
    PCHANGER_EXCHANGE_MEDIUM exchangeMedium = Irp->AssociatedIrp.SystemBuffer;
    USHORT              transport;
    USHORT              source;
    USHORT              destination1, destination2;
    PSCSI_REQUEST_BLOCK srb;
    PCDB                cdb;
    NTSTATUS            status;

    //
    // Verify transport, source, and dest. are within range.
    // Convert from 0-based to device-specific addressing.
    //

    transport = (USHORT)(exchangeMedium->Transport.ElementAddress);

    if (ElementOutOfRange(addressMapping, transport, ChangerTransport)) {

        DebugPrint((1,
                   "ChangerExchangeMedium: Transport element out of range.\n"));

        return STATUS_ILLEGAL_ELEMENT_ADDRESS;
    }

    source = (USHORT)(exchangeMedium->Source.ElementAddress);

    if (ElementOutOfRange(addressMapping, source, exchangeMedium->Source.ElementType)) {

        DebugPrint((1,
                   "ChangerExchangeMedium: Source element out of range.\n"));

        return STATUS_ILLEGAL_ELEMENT_ADDRESS;
    }

    destination1 = (USHORT)(exchangeMedium->Destination1.ElementAddress);

    if (ElementOutOfRange(addressMapping, destination1, exchangeMedium->Destination1.ElementType)) {
        DebugPrint((1,
                   "ChangerExchangeMedium: Destination1 element out of range.\n"));

        return STATUS_ILLEGAL_ELEMENT_ADDRESS;
    }

    destination2 = (USHORT)(exchangeMedium->Destination2.ElementAddress);

    if (ElementOutOfRange(addressMapping, destination2, exchangeMedium->Destination2.ElementType)) {
        DebugPrint((1,
                   "ChangerExchangeMedium: Destination1 element out of range.\n"));

        return STATUS_ILLEGAL_ELEMENT_ADDRESS;
    }

    //
    // Convert to device addresses.
    //

    transport += addressMapping->FirstElement[ChangerTransport];
    source += addressMapping->FirstElement[exchangeMedium->Source.ElementType];
    destination1 += addressMapping->FirstElement[exchangeMedium->Destination1.ElementType];
    destination2 += addressMapping->FirstElement[exchangeMedium->Destination2.ElementType];

    //
    // Build srb and cdb.
    //

    srb = ChangerClassAllocatePool(NonPagedPool, SCSI_REQUEST_BLOCK_SIZE);

    if (!srb) {

        return STATUS_INSUFFICIENT_RESOURCES;
    }

    RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);
    cdb = (PCDB)srb->Cdb;
    srb->CdbLength = CDB12GENERIC_LENGTH;
    srb->TimeOutValue = fdoExtension->TimeOutValue;

    cdb->EXCHANGE_MEDIUM.OperationCode = SCSIOP_EXCHANGE_MEDIUM;

    //
    // Build addressing values based on address map.
    //

    cdb->EXCHANGE_MEDIUM.TransportElementAddress[0] = (UCHAR)(transport >> 8);
    cdb->EXCHANGE_MEDIUM.TransportElementAddress[1] = (UCHAR)(transport & 0xFF);

    cdb->EXCHANGE_MEDIUM.SourceElementAddress[0] = (UCHAR)(source >> 8);
    cdb->EXCHANGE_MEDIUM.SourceElementAddress[1] = (UCHAR)(source & 0xFF);

    cdb->EXCHANGE_MEDIUM.Destination1ElementAddress[0] = (UCHAR)(destination1 >> 8);
    cdb->EXCHANGE_MEDIUM.Destination1ElementAddress[1] = (UCHAR)(destination1 & 0xFF);

    cdb->EXCHANGE_MEDIUM.Destination2ElementAddress[0] = (UCHAR)(destination2 >> 8);
    cdb->EXCHANGE_MEDIUM.Destination2ElementAddress[1] = (UCHAR)(destination2 & 0xFF);

    cdb->EXCHANGE_MEDIUM.Flip1 = exchangeMedium->Flip1;
    cdb->EXCHANGE_MEDIUM.Flip2 = exchangeMedium->Flip2;

    srb->DataTransferLength = 0;

    //
    // Send SCSI command (CDB) to device
    //

    status = ClassSendSrbSynchronous(DeviceObject,
                                     srb,
                                     NULL,
                                     0,
                                     FALSE);

    if (NT_SUCCESS(status)) {
        Irp->IoStatus.Information = sizeof(CHANGER_EXCHANGE_MEDIUM);
    }

    ChangerClassFreePool(srb);
    return status;
}


NTSTATUS
ChangerMoveMedium(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:


Arguments:

    DeviceObject
    Irp

Return Value:

    NTSTATUS

--*/


{
    PFUNCTIONAL_DEVICE_EXTENSION   fdoExtension = DeviceObject->DeviceExtension;
    PCHANGER_DATA       changerData = (PCHANGER_DATA)(fdoExtension->CommonExtension.DriverData);
    PCHANGER_ADDRESS_MAPPING addressMapping = &(changerData->AddressMapping);
    PCHANGER_MOVE_MEDIUM moveMedium = Irp->AssociatedIrp.SystemBuffer;
    USHORT              transport;
    USHORT              source;
    USHORT              destination;
    PSCSI_REQUEST_BLOCK srb;
    PCDB                cdb;
    NTSTATUS            status;
    LONG                lockValue = 0;

    //
    // Verify transport, source, and dest. are within range.
    //

    transport = (USHORT)(moveMedium->Transport.ElementAddress);

    if (ElementOutOfRange(addressMapping, transport, ChangerTransport)) {

        DebugPrint((1,
                   "ChangerMoveMedium: Transport element out of range.\n"));

        return STATUS_ILLEGAL_ELEMENT_ADDRESS;
    }

    source = (USHORT)(moveMedium->Source.ElementAddress);

    if (ElementOutOfRange(addressMapping, source, moveMedium->Source.ElementType)) {

        DebugPrint((1,
                   "ChangerMoveMedium: Source element out of range.\n"));

        return STATUS_ILLEGAL_ELEMENT_ADDRESS;
    }

    destination = (USHORT)(moveMedium->Destination.ElementAddress);

    if (ElementOutOfRange(addressMapping, destination, moveMedium->Destination.ElementType)) {
        DebugPrint((1,
                   "ChangerMoveMedium: Destination element out of range.\n"));

        return STATUS_ILLEGAL_ELEMENT_ADDRESS;
    }

    //
    // Convert to device addresses.
    //

    transport += addressMapping->FirstElement[ChangerTransport];
    source += addressMapping->FirstElement[moveMedium->Source.ElementType];
    destination += addressMapping->FirstElement[moveMedium->Destination.ElementType];

    //
    // Build srb and cdb.
    //

    srb = ChangerClassAllocatePool(NonPagedPool, SCSI_REQUEST_BLOCK_SIZE);

    if (!srb) {

        return STATUS_INSUFFICIENT_RESOURCES;
    }

    if ((moveMedium->Destination.ElementType == ChangerIEPort) ||
        (moveMedium->Source.ElementType == ChangerIEPort)) {

        //
        // Determine value of LockCount.
        //

        lockValue = changerData->LockCount;
        DebugPrint((1,
                   "MoveMedium: LockCount is %x\n",
                   lockValue));

        if (lockValue) {

            RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);

            //
            // Send an allow to clear the prevent for IEPORT extend/retract.
            //

            cdb = (PCDB)srb->Cdb;
            srb->CdbLength = CDB6GENERIC_LENGTH;
            srb->DataTransferLength = 0;
            srb->TimeOutValue = 10;
            cdb->MEDIA_REMOVAL.OperationCode = SCSIOP_MEDIUM_REMOVAL;
            cdb->MEDIA_REMOVAL.Prevent = 0;

            //
            // Ignore errors at this point. If this fails and the move doesn't happen, the LM will
            // clean things up.
            //

            status = ClassSendSrbSynchronous(DeviceObject,
                                             srb,
                                             NULL,
                                             0,
                                             FALSE);
            DebugPrint((1,
                       "MoveMedium: Allow sent. Status %x\n",
                       status));

            status = STATUS_SUCCESS;
        }
    }

    RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);
    cdb = (PCDB)srb->Cdb;
    srb->CdbLength = CDB12GENERIC_LENGTH;
    srb->TimeOutValue = fdoExtension->TimeOutValue;

    cdb->MOVE_MEDIUM.OperationCode = SCSIOP_MOVE_MEDIUM;

    //
    // Build addressing values based on address map.
    //

    cdb->MOVE_MEDIUM.TransportElementAddress[0] = (UCHAR)(transport >> 8);
    cdb->MOVE_MEDIUM.TransportElementAddress[1] = (UCHAR)(transport & 0xFF);

    cdb->MOVE_MEDIUM.SourceElementAddress[0] = (UCHAR)(source >> 8);
    cdb->MOVE_MEDIUM.SourceElementAddress[1] = (UCHAR)(source & 0xFF);

    cdb->MOVE_MEDIUM.DestinationElementAddress[0] = (UCHAR)(destination >> 8);
    cdb->MOVE_MEDIUM.DestinationElementAddress[1] = (UCHAR)(destination & 0xFF);

    cdb->MOVE_MEDIUM.Flip = moveMedium->Flip;

    srb->DataTransferLength = 0;

    //
    // Send SCSI command (CDB) to device
    //

    status = ClassSendSrbSynchronous(DeviceObject,
                                     srb,
                                     NULL,
                                     0,
                                     FALSE);

    if (NT_SUCCESS(status)) {
        Irp->IoStatus.Information = sizeof(CHANGER_MOVE_MEDIUM);
    }

    if (lockValue) {

        NTSTATUS preventStatus;

        //
        // Send the prevent to re-lock down the unit.
        //

        RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);
        cdb = (PCDB)srb->Cdb;
        srb->CdbLength = CDB6GENERIC_LENGTH;
        srb->DataTransferLength = 0;
        srb->TimeOutValue = 10;
        cdb->MEDIA_REMOVAL.OperationCode = SCSIOP_MEDIUM_REMOVAL;
        cdb->MEDIA_REMOVAL.Prevent = 1;

        //
        // Ignore any errors at this point. The LM will fixup any problems with
        // prevent/allow
        //

        preventStatus = ClassSendSrbSynchronous(DeviceObject,
                                srb,
                                NULL,
                                0,
                                FALSE);
        DebugPrint((1,
                   "MoveMedium: Prevent sent. Status %x\n",
                   preventStatus));
    }

    ChangerClassFreePool(srb);
    return status;
}


NTSTATUS
ChangerReinitializeUnit(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:


Arguments:

    DeviceObject
    Irp

Return Value:

    NTSTATUS

--*/

{
    PFUNCTIONAL_DEVICE_EXTENSION   fdoExtension = DeviceObject->DeviceExtension;
    PCHANGER_DATA       changerData = (PCHANGER_DATA)(fdoExtension->CommonExtension.DriverData);
    PCHANGER_ADDRESS_MAPPING addressMapping = &(changerData->AddressMapping);
    PSCSI_REQUEST_BLOCK srb;
    PCDB                cdb;
    NTSTATUS            status;


    //
    // Build srb and cdb.
    //

    srb = ChangerClassAllocatePool(NonPagedPool, SCSI_REQUEST_BLOCK_SIZE);

    if (!srb) {

        return STATUS_INSUFFICIENT_RESOURCES;
    }

    RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);
    cdb = (PCDB)srb->Cdb;



    //
    // Issue a rezero unit to the device.
    //

    srb->CdbLength = CDB6GENERIC_LENGTH;
    cdb->CDB6GENERIC.OperationCode = SCSIOP_REZERO_UNIT;
    srb->DataTransferLength = 0;
    srb->TimeOutValue = fdoExtension->TimeOutValue;


    //
    // Send SCSI command (CDB) to device
    //

    status = ClassSendSrbSynchronous(DeviceObject,
                                     srb,
                                     NULL,
                                     0,
                                     FALSE);

    if (NT_SUCCESS(status)) {
        Irp->IoStatus.Information = sizeof(CHANGER_ELEMENT);
    }

    ChangerClassFreePool(srb);
    return status;
}


NTSTATUS
ChangerQueryVolumeTags(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp
    )

/*++

Routine Description:


Arguments:

    DeviceObject
    Irp

Return Value:

    NTSTATUS

--*/

{

    return STATUS_INVALID_DEVICE_REQUEST;
}


NTSTATUS
NSMBuildAddressMapping(
    IN PDEVICE_OBJECT DeviceObject
    )

/*++

Routine Description:

    This routine issues the appropriate mode sense commands and builds an
    array of element addresses. These are used to translate between the device-specific
    addresses and the zero-based addresses of the API.

Arguments:

    DeviceObject

Return Value:

    NTSTATUS

--*/
{

    PFUNCTIONAL_DEVICE_EXTENSION      fdoExtension = DeviceObject->DeviceExtension;
    PCHANGER_DATA          changerData = (PCHANGER_DATA)(fdoExtension->CommonExtension.DriverData);
    PCHANGER_ADDRESS_MAPPING addressMapping = &changerData->AddressMapping;
    PSCSI_REQUEST_BLOCK    srb;
    PCDB                   cdb;
    NTSTATUS               status;
    PMODE_ELEMENT_ADDRESS_PAGE elementAddressPage;
    PVOID modeBuffer;
    ULONG i;

    //
    // Set all FirstElements to NO_ELEMENT.
    //

    for (i = 0; i < ChangerMaxElement; i++) {
        addressMapping->FirstElement[i] = NSM_NO_ELEMENT;
    }

    srb = ChangerClassAllocatePool(NonPagedPool, SCSI_REQUEST_BLOCK_SIZE);
    if (!srb) {
        return STATUS_INSUFFICIENT_RESOURCES;
    }

    RtlZeroMemory(srb, SCSI_REQUEST_BLOCK_SIZE);

    cdb = (PCDB)srb->Cdb;

    //
    // Build a mode sense - Element address assignment page.
    //

    modeBuffer = ChangerClassAllocatePool(NonPagedPoolCacheAligned, sizeof(MODE_PARAMETER_HEADER)
                                + sizeof(MODE_ELEMENT_ADDRESS_PAGE));
    if (!modeBuffer) {
        ChangerClassFreePool(srb);
        return STATUS_INSUFFICIENT_RESOURCES;
    }


    RtlZeroMemory(modeBuffer, sizeof(MODE_PARAMETER_HEADER) + sizeof(MODE_ELEMENT_ADDRESS_PAGE));
    srb->CdbLength = CDB6GENERIC_LENGTH;
    srb->TimeOutValue = 20;
    srb->DataTransferLength = sizeof(MODE_PARAMETER_HEADER) + sizeof(MODE_ELEMENT_ADDRESS_PAGE);
    srb->DataBuffer = modeBuffer;

    cdb->MODE_SENSE.OperationCode = SCSIOP_MODE_SENSE;
    cdb->MODE_SENSE.PageCode = MODE_PAGE_ELEMENT_ADDRESS;
    cdb->MODE_SENSE.Dbd = 1;
    cdb->MODE_SENSE.AllocationLength = (UCHAR)srb->DataTransferLength;

    //
    // Send the request.
    //

    status = ClassSendSrbSynchronous(DeviceObject,
                                     srb,
                                     srb->DataBuffer,
                                     srb->DataTransferLength,
                                     FALSE);

    elementAddressPage = modeBuffer;
    (PCHAR)elementAddressPage += sizeof(MODE_PARAMETER_HEADER);

    if (NT_SUCCESS(status)) {

        //
        // Build address mapping.
        //

        addressMapping->FirstElement[ChangerTransport] = (elementAddressPage->MediumTransportElementAddress[0] << 8) |
                                                          elementAddressPage->MediumTransportElementAddress[1];
        addressMapping->FirstElement[ChangerDrive] = (elementAddressPage->FirstDataXFerElementAddress[0] << 8) |
                                                      elementAddressPage->FirstDataXFerElementAddress[1];
        addressMapping->FirstElement[ChangerIEPort] = (elementAddressPage->FirstIEPortElementAddress[0] << 8) |
                                                       elementAddressPage->FirstIEPortElementAddress[1];
        addressMapping->FirstElement[ChangerSlot] = (elementAddressPage->FirstStorageElementAddress[0] << 8) |
                                                     elementAddressPage->FirstStorageElementAddress[1];


        //
        // Determine lowest address of all elements.
        //

        addressMapping->LowAddress = NSM_NO_ELEMENT;
        for (i = 0; i <= ChangerDrive; i++) {
            if (addressMapping->LowAddress > addressMapping->FirstElement[i]) {
                addressMapping->LowAddress = addressMapping->FirstElement[i];
            }
        }

        addressMapping->FirstElement[ChangerDoor] = 0;

        addressMapping->FirstElement[ChangerKeypad] = 0;

        addressMapping->NumberOfElements[ChangerTransport] = elementAddressPage->NumberTransportElements[1];
        addressMapping->NumberOfElements[ChangerTransport] |= (elementAddressPage->NumberTransportElements[0] << 8);

        addressMapping->NumberOfElements[ChangerDrive] = elementAddressPage->NumberDataXFerElements[1];
        addressMapping->NumberOfElements[ChangerDrive] |= (elementAddressPage->NumberDataXFerElements[0] << 8);

        addressMapping->NumberOfElements[ChangerIEPort] = elementAddressPage->NumberIEPortElements[1];
        addressMapping->NumberOfElements[ChangerIEPort] |= (elementAddressPage->NumberIEPortElements[0] << 8);

        addressMapping->NumberOfElements[ChangerSlot] = elementAddressPage->NumberStorageElements[1];
        addressMapping->NumberOfElements[ChangerSlot] |= (elementAddressPage->NumberStorageElements[0] << 8);

        addressMapping->NumberOfElements[ChangerDoor] = 1;
        addressMapping->NumberOfElements[ChangerKeypad] = 0;

        addressMapping->Initialized = TRUE;

    }


    //
    // Free buffer.
    //

    ChangerClassFreePool(modeBuffer);
    ChangerClassFreePool(srb);

    return status;
}


ULONG
MapExceptionCodes(
    IN PELEMENT_DESCRIPTOR ElementDescriptor
    )

/*++

Routine Description:

    This routine takes the sense data from the elementDescriptor and creates
    the appropriate bitmap of values.

Arguments:

   ElementDescriptor - pointer to the descriptor page.

Return Value:

    Bit-map of exception codes.

--*/

{
    UCHAR asc = ElementDescriptor->AdditionalSenseCode;
    UCHAR ascq = ElementDescriptor->AddSenseCodeQualifier;
    ULONG exceptionCode;

    switch (asc) {
        case 0x00:

            //
            // No error.
            //

            exceptionCode = 0;
            break;

        case 0x53:
            if (ascq == 0x02) {

                //
                // Reporting that medium removal is prevented.
                //

                exceptionCode = 0;

            }
            break;
        default:
            exceptionCode = ERROR_UNHANDLED_ERROR;
            break;
    }

    DebugPrint((1,
               "NSMMC: MapExceptionCode - ASC %x, ASCQ %x ExceptionCode %x\n",
               asc,
               ascq,
               exceptionCode));

    return exceptionCode;

}



BOOLEAN
ElementOutOfRange(
    IN PCHANGER_ADDRESS_MAPPING AddressMap,
    IN USHORT ElementOrdinal,
    IN ELEMENT_TYPE ElementType
    )
/*++

Routine Description:

    This routine determines whether the element address passed in is within legal range for
    the device.

Arguments:

    AddressMap - The dds' address map array
    ElementOrdinal - Zero-based address of the element to check.
    ElementType

Return Value:

    TRUE if out of range

--*/
{

    if (ElementOrdinal >= AddressMap->NumberOfElements[ElementType]) {

        DebugPrint((0,
                   "ElementOutOfRange: Type %x, Ordinal %x, Max %x\n",
                   ElementType,
                   ElementOrdinal,
                   AddressMap->NumberOfElements[ElementType]));
        return TRUE;
    } else if (AddressMap->FirstElement[ElementType] == NSM_NO_ELEMENT) {

        DebugPrint((1,
                   "ElementOutOfRange: No Type %x present\n",
                   ElementType));

        return TRUE;
    }

    return FALSE;
}

