Minoca-os/drivers/net/wireless/rtlw81xx/rtlw81.c

/*++

Copyright (c) 2015 Minoca Corp. All Rights Reserved

Module Name:

    rtlw81.c

Abstract:

    This module implements support for the driver portion of the RTL81xx
    family of USB WIFI Controllers.

Author:

    Chris Stevens 7-Oct-2015

Environment:

    Kernel

--*/

//
// ------------------------------------------------------------------- Includes
//

#include <minoca/kernel/driver.h>
#include <minoca/net/netdrv.h>
#include <minoca/net/net80211.h>
#include <minoca/usb/usb.h>
#include "rtlw81.h"

//
// ---------------------------------------------------------------- Definitions
//

//
// Known vendors and products.
//

#define RTLW81_USB_DEVICE_ID_FORMAT "VID_%x&PID_%x"

#define RTLW81_VENDOR_DLINK 0x2001
#define RTLW81_DLINK_DWA125D1 0x330F
#define RTLW81_DLINK_DWA123D1 0x3310

#define RTLW81_VENDOR_ELECOM 0x056E
#define RTLW81_ELECOM_WDC150SU2M 0x4008

#define RTLW81_VENDOR_REALTEK 0x0BDA
#define RTLW81_REALTEK_RTL8188ETV 0x0179
#define RTLW81_REALTEK_RTL8188EU 0x8179

//
// ------------------------------------------------------ Data Type Definitions
//

//
// ----------------------------------------------- Internal Function Prototypes
//

KSTATUS
Rtlw81AddDevice (
    PVOID Driver,
    PSTR DeviceId,
    PSTR ClassId,
    PSTR CompatibleIds,
    PVOID DeviceToken
    );

VOID
Rtlw81DispatchStateChange (
    PIRP Irp,
    PVOID DeviceContext,
    PVOID IrpContext
    );

VOID
Rtlw81DispatchOpen (
    PIRP Irp,
    PVOID DeviceContext,
    PVOID IrpContext
    );

VOID
Rtlw81DispatchClose (
    PIRP Irp,
    PVOID DeviceContext,
    PVOID IrpContext
    );

VOID
Rtlw81DispatchIo (
    PIRP Irp,
    PVOID DeviceContext,
    PVOID IrpContext
    );

VOID
Rtlw81DispatchSystemControl (
    PIRP Irp,
    PVOID DeviceContext,
    PVOID IrpContext
    );

VOID
Rtlw81DestroyLink (
    PVOID DeviceContext
    );

KSTATUS
Rtlw81pInitializeDeviceStructures (
    PVOID OsDevice,
    PRTLW81_DEVICE *NewDevice
    );

VOID
Rtlw81pDestroyDeviceStructures (
    PRTLW81_DEVICE Device
    );

VOID
Rtlw81pDeviceAddReference (
    PRTLW81_DEVICE Device
    );

VOID
Rtlw81pDeviceReleaseReference (
    PRTLW81_DEVICE Device
    );

KSTATUS
Rtlw81pSetUpUsbDevice (
    PRTLW81_DEVICE Device
    );

KSTATUS
Rtlw81pStartDevice (
    PIRP Irp,
    PRTLW81_DEVICE Device
    );

KSTATUS
Rtlw81pStopDevice (
    PIRP Irp,
    PRTLW81_DEVICE Device
    );

//
// -------------------------------------------------------------------- Globals
//

PDRIVER Rtlw81Driver = NULL;

//
// Store the default rate information for the RTL81xx wireless devices.
//

UCHAR RtlwDefaultRates[] = {
    NET80211_RATE_BASIC | 0x02,
    NET80211_RATE_BASIC | 0x04,
    NET80211_RATE_BASIC | 0x0B,
    NET80211_RATE_BASIC | 0x16,
    0x0C,
    0x12,
    0x18,
    0x24,
    0x30,
    0x48,
    0x60,
    0x6C
};

NET80211_RATE_INFORMATION RtlwDefaultRateInformation = {
    sizeof(RtlwDefaultRates) / sizeof(RtlwDefaultRates[0]),
    RtlwDefaultRates
};

//
// ------------------------------------------------------------------ Functions
//

KSTATUS
DriverEntry (
    PDRIVER Driver
    )

/*++

Routine Description:

    This routine is the entry point for the SMSC95xx driver. It registers its
    other dispatch functions, and performs driver-wide initialization.

Arguments:

    Driver - Supplies a pointer to the driver object.

Return Value:

    STATUS_SUCCESS on success.

    Failure code on error.

--*/

{

    DRIVER_FUNCTION_TABLE FunctionTable;
    KSTATUS Status;

    Rtlw81Driver = Driver;
    RtlZeroMemory(&FunctionTable, sizeof(DRIVER_FUNCTION_TABLE));
    FunctionTable.Version = DRIVER_FUNCTION_TABLE_VERSION;
    FunctionTable.AddDevice = Rtlw81AddDevice;
    FunctionTable.DispatchStateChange = Rtlw81DispatchStateChange;
    FunctionTable.DispatchOpen = Rtlw81DispatchOpen;
    FunctionTable.DispatchClose = Rtlw81DispatchClose;
    FunctionTable.DispatchIo = Rtlw81DispatchIo;
    FunctionTable.DispatchSystemControl = Rtlw81DispatchSystemControl;
    Status = IoRegisterDriverFunctions(Driver, &FunctionTable);
    return Status;
}

KSTATUS
Rtlw81AddDevice (
    PVOID Driver,
    PSTR DeviceId,
    PSTR ClassId,
    PSTR CompatibleIds,
    PVOID DeviceToken
    )

/*++

Routine Description:

    This routine is called when a device is detected for which the SMSC95xx
    driver acts as the function driver. The driver will attach itself to the
    stack.

Arguments:

    Driver - Supplies a pointer to the driver being called.

    DeviceId - Supplies a pointer to a string with the device ID.

    ClassId - Supplies a pointer to a string containing the device's class ID.

    CompatibleIds - Supplies a pointer to a string containing device IDs
        that would be compatible with this device.

    DeviceToken - Supplies an opaque token that the driver can use to identify
        the device in the system. This token should be used when attaching to
        the stack.

Return Value:

    STATUS_SUCCESS on success.

    Failure code if the driver was unsuccessful in attaching itself.

--*/

{

    PRTLW81_DEVICE Device;
    ULONG ItemsScanned;
    KSTATUS Status;
    USHORT UsbProductId;
    USHORT UsbVendorId;

    Status = Rtlw81pInitializeDeviceStructures(DeviceToken, &Device);
    if (!KSUCCESS(Status)) {
        goto AddDeviceEnd;
    }

    //
    // Detect variants by USB vendor and product ID.
    //

    Status = RtlStringScan(DeviceId,
                           RtlStringLength(DeviceId) + 1,
                           RTLW81_USB_DEVICE_ID_FORMAT,
                           sizeof(RTLW81_USB_DEVICE_ID_FORMAT),
                           CharacterEncodingDefault,
                           &ItemsScanned,
                           &UsbVendorId,
                           &UsbProductId);

    if (!KSUCCESS(Status)) {
        goto AddDeviceEnd;
    }

    if (ItemsScanned != 2) {
        Status = STATUS_INVALID_CONFIGURATION;
        goto AddDeviceEnd;
    }

    switch (UsbVendorId) {
    case RTLW81_VENDOR_DLINK:
        if ((UsbProductId == RTLW81_DLINK_DWA123D1) ||
            (UsbProductId == RTLW81_DLINK_DWA125D1)) {

            Device->Flags |= RTLW81_FLAG_8188E;
        }

        break;

    case RTLW81_VENDOR_ELECOM:
        if (UsbProductId == RTLW81_ELECOM_WDC150SU2M) {
            Device->Flags |= RTLW81_FLAG_8188E;
        }

        break;

    case RTLW81_VENDOR_REALTEK:
        if ((UsbProductId == RTLW81_REALTEK_RTL8188ETV) ||
            (UsbProductId == RTLW81_REALTEK_RTL8188EU)) {

            Device->Flags |= RTLW81_FLAG_8188E;
        }

        break;

    default:
        break;
    }

    Status = IoAttachDriverToDevice(Driver, DeviceToken, Device);
    if (!KSUCCESS(Status)) {
        goto AddDeviceEnd;
    }

AddDeviceEnd:
    if (!KSUCCESS(Status)) {
        if (Device != NULL) {
            Rtlw81pDeviceReleaseReference(Device);
        }
    }

    return Status;
}

VOID
Rtlw81DispatchStateChange (
    PIRP Irp,
    PVOID DeviceContext,
    PVOID IrpContext
    )

/*++

Routine Description:

    This routine handles State Change IRPs.

Arguments:

    Irp - Supplies a pointer to the I/O request packet.

    DeviceContext - Supplies the context pointer supplied by the driver when it
        attached itself to the driver stack. Presumably this pointer contains
        driver-specific device context.

    IrpContext - Supplies the context pointer supplied by the driver when
        the IRP was created.

Return Value:

    None.

--*/

{

    KSTATUS Status;

    ASSERT(Irp->MajorCode == IrpMajorStateChange);

    if (Irp->Direction == IrpUp) {
        switch (Irp->MinorCode) {
        case IrpMinorQueryResources:
        case IrpMinorQueryChildren:
            IoCompleteIrp(Rtlw81Driver, Irp, STATUS_SUCCESS);
            break;

        case IrpMinorStartDevice:
            Status = Rtlw81pStartDevice(Irp, DeviceContext);
            if (!KSUCCESS(Status)) {
                IoCompleteIrp(Rtlw81Driver, Irp, Status);
            }

            break;

        case IrpMinorRemoveDevice:
            Status = Rtlw81pStopDevice(Irp, DeviceContext);
            if (!KSUCCESS(Status)) {
                IoCompleteIrp(Rtlw81Driver, Irp, Status);
                break;
            }

            break;

        default:
            break;
        }
    }

    return;
}

VOID
Rtlw81DispatchOpen (
    PIRP Irp,
    PVOID DeviceContext,
    PVOID IrpContext
    )

/*++

Routine Description:

    This routine handles Open IRPs.

Arguments:

    Irp - Supplies a pointer to the I/O request packet.

    DeviceContext - Supplies the context pointer supplied by the driver when it
        attached itself to the driver stack. Presumably this pointer contains
        driver-specific device context.

    IrpContext - Supplies the context pointer supplied by the driver when
        the IRP was created.

Return Value:

    None.

--*/

{

    return;
}

VOID
Rtlw81DispatchClose (
    PIRP Irp,
    PVOID DeviceContext,
    PVOID IrpContext
    )

/*++

Routine Description:

    This routine handles Close IRPs.

Arguments:

    Irp - Supplies a pointer to the I/O request packet.

    DeviceContext - Supplies the context pointer supplied by the driver when it
        attached itself to the driver stack. Presumably this pointer contains
        driver-specific device context.

    IrpContext - Supplies the context pointer supplied by the driver when
        the IRP was created.

Return Value:

    None.

--*/

{

    return;
}

VOID
Rtlw81DispatchIo (
    PIRP Irp,
    PVOID DeviceContext,
    PVOID IrpContext
    )

/*++

Routine Description:

    This routine handles I/O IRPs.

Arguments:

    Irp - Supplies a pointer to the I/O request packet.

    DeviceContext - Supplies the context pointer supplied by the driver when it
        attached itself to the driver stack. Presumably this pointer contains
        driver-specific device context.

    IrpContext - Supplies the context pointer supplied by the driver when
        the IRP was created.

Return Value:

    None.

--*/

{

    return;
}

VOID
Rtlw81DispatchSystemControl (
    PIRP Irp,
    PVOID DeviceContext,
    PVOID IrpContext
    )

/*++

Routine Description:

    This routine handles System Control IRPs.

Arguments:

    Irp - Supplies a pointer to the I/O request packet.

    DeviceContext - Supplies the context pointer supplied by the driver when it
        attached itself to the driver stack. Presumably this pointer contains
        driver-specific device context.

    IrpContext - Supplies the context pointer supplied by the driver when
        the IRP was created.

Return Value:

    None.

--*/

{

    PRTLW81_DEVICE Device;
    PSYSTEM_CONTROL_DEVICE_INFORMATION DeviceInformationRequest;
    KSTATUS Status;

    ASSERT(Irp->MajorCode == IrpMajorSystemControl);

    Device = DeviceContext;
    if (Irp->Direction == IrpDown) {
        switch (Irp->MinorCode) {
        case IrpMinorSystemControlDeviceInformation:
            DeviceInformationRequest = Irp->U.SystemControl.SystemContext;
            Status = Net80211GetSetLinkDeviceInformation(
                                         Device->Net80211Link,
                                         &(DeviceInformationRequest->Uuid),
                                         DeviceInformationRequest->Data,
                                         &(DeviceInformationRequest->DataSize),
                                         DeviceInformationRequest->Set);

            IoCompleteIrp(Rtlw81Driver, Irp, Status);
            break;

        default:
            break;
        }
    }

    return;
}

KSTATUS
Rtlw81pAddNetworkDevice (
    PRTLW81_DEVICE Device
    )

/*++

Routine Description:

    This routine adds the device to 802.11 core networking's available links.

Arguments:

    Device - Supplies a pointer to the device to add.

Return Value:

    Status code.

--*/

{

    NET80211_LINK_PROPERTIES Properties;
    KSTATUS Status;

    if (Device->Net80211Link != NULL) {
        Status = STATUS_SUCCESS;
        goto AddNetworkDeviceEnd;
    }

    //
    // Add a link to the 802.11 core networking library.
    //

    RtlZeroMemory(&Properties, sizeof(NET80211_LINK_PROPERTIES));
    Properties.Version = NET80211_LINK_PROPERTIES_VERSION;
    Properties.TransmitAlignment = MmGetIoBufferAlignment();
    Properties.Device = Device->OsDevice;
    Properties.DeviceContext = Device;
    Properties.MaxChannel = RTLW81_MAX_CHANNEL;
    Properties.Capabilities = NET80211_CAPABILITY_FLAG_SHORT_PREAMBLE |
                              NET80211_CAPABILITY_FLAG_SHORT_SLOT_TIME;

    Properties.PacketSizeInformation.MaxPacketSize = RTLW81_MAX_PACKET_SIZE;
    Properties.PacketSizeInformation.HeaderSize = RTLW81_TRANSMIT_HEADER_SIZE;
    Properties.MaxPhysicalAddress = MAX_ULONG;
    Properties.PhysicalAddress.Domain = NetDomain80211;
    RtlCopyMemory(&(Properties.PhysicalAddress.Address),
                  &(Device->MacAddress),
                  sizeof(Device->MacAddress));

    Properties.SupportedRates = &RtlwDefaultRateInformation;
    Properties.Interface.Send = Rtlw81Send;
    Properties.Interface.GetSetInformation = Rtlw81GetSetInformation;
    Properties.Interface.DestroyLink = Rtlw81DestroyLink;
    Properties.Interface.SetChannel = Rtlw81SetChannel;
    Properties.Interface.SetState = Rtlw81SetState;
    Status = Net80211AddLink(&Properties, &(Device->Net80211Link));
    if (!KSUCCESS(Status)) {
        goto AddNetworkDeviceEnd;
    }

    //
    // The 802.11 core now has a pointer to the device context. Add a reference
    // for it.
    //

    Rtlw81pDeviceAddReference(Device);

AddNetworkDeviceEnd:
    if (!KSUCCESS(Status)) {
        if (Device->Net80211Link != NULL) {
            Net80211RemoveLink(Device->Net80211Link);
            Device->Net80211Link = NULL;
        }
    }

    return Status;
}

VOID
Rtlw81DestroyLink (
    PVOID DeviceContext
    )

/*++

Routine Description:

    This routine notifies the device layer that the 802.11 core is in the
    process of destroying the link and will no longer call into the device for
    this link. This allows the device layer to release any context that was
    supporting the device link interface.

Arguments:

    DeviceContext - Supplies a pointer to the device context associated with
        the link being destroyed.

Return Value:

    None.

--*/

{

    Rtlw81pDeviceReleaseReference(DeviceContext);
    return;
}

//
// --------------------------------------------------------- Internal Functions
//

KSTATUS
Rtlw81pInitializeDeviceStructures (
    PVOID OsDevice,
    PRTLW81_DEVICE *NewDevice
    )

/*++

Routine Description:

    This routine initializes an RTLW81xx device.

Arguments:

    OsDevice - Supplies a pointer to the system token that represents this
        device.

    NewDevice - Supplies a pointer where the new structure will be returned.

Return Value:

    Status code.

--*/

{

    ULONG BufferAlignment;
    PRTLW81_DEVICE Device;
    ULONG Index;
    ULONG IoBufferFlags;
    UINTN IoBufferSize;
    ULONG MaxBulkInTransferSize;
    ULONG MaxControlSize;
    PHYSICAL_ADDRESS PhysicalAddress;
    KSTATUS Status;
    PUSB_TRANSFER UsbTransfer;
    PVOID VirtualAddress;

    Device = MmAllocatePagedPool(sizeof(RTLW81_DEVICE), RTLW81_ALLOCATION_TAG);
    if (Device == NULL) {
        Status = STATUS_INSUFFICIENT_RESOURCES;
        goto InitializeDeviceStructuresEnd;
    }

    RtlZeroMemory(Device, sizeof(RTLW81_DEVICE));
    Device->OsDevice = OsDevice;
    Device->UsbCoreHandle = INVALID_HANDLE;
    Device->ReferenceCount = 1;
    for (Index = 0; Index < RTLW81_MAX_BULK_OUT_ENDPOINT_COUNT; Index += 1) {
        INITIALIZE_LIST_HEAD(&(Device->BulkOutFreeTransferList[Index]));
    }

    Device->BulkOutListLock = KeCreateQueuedLock();
    if (Device->BulkOutListLock == NULL) {
        Status = STATUS_INSUFFICIENT_RESOURCES;
        goto InitializeDeviceStructuresEnd;
    }

    //
    // Attempt to attach to the USB core.
    //

    Status = UsbDriverAttach(OsDevice, Rtlw81Driver, &(Device->UsbCoreHandle));
    if (!KSUCCESS(Status)) {
        goto InitializeDeviceStructuresEnd;
    }

    Status = Rtlw81pSetUpUsbDevice(Device);
    if (!KSUCCESS(Status)) {
        goto InitializeDeviceStructuresEnd;
    }

    //
    // Create an I/O buffer for the control and receive transfers.
    //

    BufferAlignment = MmGetIoBufferAlignment();
    MaxBulkInTransferSize = ALIGN_RANGE_UP(RTLW81_BULK_IN_TRANSFER_SIZE,
                                           BufferAlignment);

    MaxControlSize = ALIGN_RANGE_UP(RTLW81_MAX_CONTROL_TRANSFER_SIZE,
                                    BufferAlignment);

    IoBufferSize = (MaxBulkInTransferSize * RTLW81_BULK_IN_TRANSFER_COUNT) +
                   MaxControlSize;

    IoBufferFlags = IO_BUFFER_FLAG_PHYSICALLY_CONTIGUOUS;
    Device->IoBuffer = MmAllocateNonPagedIoBuffer(0,
                                                  MAX_ULONG,
                                                  BufferAlignment,
                                                  IoBufferSize,
                                                  IoBufferFlags);

    if (Device->IoBuffer == NULL) {
        Status = STATUS_INSUFFICIENT_RESOURCES;
        goto InitializeDeviceStructuresEnd;
    }

    ASSERT(Device->IoBuffer->FragmentCount == 1);
    ASSERT(Device->IoBuffer->Fragment[0].VirtualAddress != NULL);

    PhysicalAddress = Device->IoBuffer->Fragment[0].PhysicalAddress;
    VirtualAddress = Device->IoBuffer->Fragment[0].VirtualAddress;

    //
    // Set up the bulk in transfers that are used to receive packets.
    //

    for (Index = 0; Index < RTLW81_BULK_IN_TRANSFER_COUNT; Index += 1) {
        UsbTransfer = UsbAllocateTransfer(Device->UsbCoreHandle,
                                          Device->BulkInEndpoint,
                                          RTLW81_BULK_IN_TRANSFER_SIZE,
                                          0);

        if (UsbTransfer == NULL) {
            Status = STATUS_INSUFFICIENT_RESOURCES;
            goto InitializeDeviceStructuresEnd;
        }

        UsbTransfer->Buffer = VirtualAddress;
        UsbTransfer->BufferPhysicalAddress = PhysicalAddress;
        UsbTransfer->Direction = UsbTransferDirectionIn;
        UsbTransfer->Length = RTLW81_BULK_IN_TRANSFER_SIZE;
        UsbTransfer->BufferActualLength = MaxBulkInTransferSize;
        UsbTransfer->UserData = Device;
        UsbTransfer->CallbackRoutine = Rtlw81BulkInTransferCompletion;
        Device->BulkInTransfer[Index] = UsbTransfer;
        PhysicalAddress += MaxBulkInTransferSize;
        VirtualAddress += MaxBulkInTransferSize;
    }

    //
    // Set up the control transfer that's used for register reads and writes.
    //

    Device->ControlTransfer = UsbAllocateTransfer(
                                             Device->UsbCoreHandle,
                                             0,
                                             RTLW81_MAX_CONTROL_TRANSFER_SIZE,
                                             0);

    if (Device->ControlTransfer == NULL) {
        Status = STATUS_INSUFFICIENT_RESOURCES;
        goto InitializeDeviceStructuresEnd;
    }

    Device->ControlTransfer->Buffer = VirtualAddress;
    Device->ControlTransfer->BufferPhysicalAddress = PhysicalAddress;
    Device->ControlTransfer->BufferActualLength = MaxControlSize;
    VirtualAddress += MaxControlSize;
    PhysicalAddress += MaxControlSize;
    Status = STATUS_SUCCESS;

InitializeDeviceStructuresEnd:
    if (!KSUCCESS(Status)) {
        if (Device != NULL) {
            Rtlw81pDeviceReleaseReference(Device);
            Device = NULL;
        }
    }

    *NewDevice = Device;
    return Status;
}

VOID
Rtlw81pDestroyDeviceStructures (
    PRTLW81_DEVICE Device
    )

/*++

Routine Description:

    This routine destroys an RTLW81xx device structure.

Arguments:

    Device - Supplies a pointer to the device.

Return Value:

    None.

--*/

{

    ULONG Index;

    //
    // Destroy all the allocated transfers. For good measure, make sure they
    // are cancelled.
    //

    for (Index = 0; Index < RTLW81_BULK_IN_TRANSFER_COUNT; Index += 1) {
        if (Device->BulkInTransfer[Index] != NULL) {
            UsbCancelTransfer(Device->BulkInTransfer[Index], TRUE);
            UsbDestroyTransfer(Device->BulkInTransfer[Index]);
        }
    }

    if (Device->ControlTransfer != NULL) {
        UsbCancelTransfer(Device->ControlTransfer, TRUE);
        UsbDestroyTransfer(Device->ControlTransfer);
    }

    if (Device->IoBuffer != NULL) {
        MmFreeIoBuffer(Device->IoBuffer);
    }

    //
    // There should be no active bulk out transfers, so destroy all the free
    // transfers.
    //

    Rtlw81pDestroyBulkOutTransfers(Device);
    if (Device->BulkOutListLock != NULL) {
        KeDestroyQueuedLock(Device->BulkOutListLock);
    }

    MmFreePagedPool(Device);
    return;
}

VOID
Rtlw81pDeviceAddReference (
    PRTLW81_DEVICE Device
    )

/*++

Routine Description:

    This routine increments the reference count of the given RTLW81xx device.

Arguments:

    Device - Supplies a pointer to the SM95 device.

Return Value:

    None.

--*/

{

    ULONG OldReferenceCount;

    OldReferenceCount = RtlAtomicAdd32(&(Device->ReferenceCount), 1);

    ASSERT((OldReferenceCount != 0) & (OldReferenceCount < 0x20000000));

    return;
}

VOID
Rtlw81pDeviceReleaseReference (
    PRTLW81_DEVICE Device
    )

/*++

Routine Description:

    This routine decrements the reference count of the given RTLW81xx device.

Arguments:

    Device - Supplies a pointer to the SM95 device.

Return Value:

    None.

--*/

{

    ULONG OldReferenceCount;

    OldReferenceCount = RtlAtomicAdd32(&(Device->ReferenceCount), -1);

    ASSERT(OldReferenceCount != 0);

    if (OldReferenceCount == 1) {
        Rtlw81pDestroyDeviceStructures(Device);
    }

    return;
}

KSTATUS
Rtlw81pSetUpUsbDevice (
    PRTLW81_DEVICE Device
    )

/*++

Routine Description:

    This routine claims the proper interface for the device and finds the
    bulk in, bulk out, and interrupt endpoints.

Arguments:

    Device - Supplies a pointer to the device.

Return Value:

    Status code.

--*/

{

    ULONG BulkOutEndpointCount;
    PUSB_CONFIGURATION_DESCRIPTION Configuration;
    PLIST_ENTRY CurrentEntry;
    USB_TRANSFER_DIRECTION Direction;
    PUSB_ENDPOINT_DESCRIPTION Endpoint;
    UCHAR EndpointType;
    ULONG Index;
    PUSB_INTERFACE_DESCRIPTION Interface;
    KSTATUS Status;

    if (Device->InterfaceClaimed != FALSE) {

        ASSERT((Device->BulkInEndpoint != 0) &&
               (Device->BulkOutEndpointCount != 0));

        Status = STATUS_SUCCESS;
        goto SetUpUsbDeviceEnd;
    }

    //
    // If the configuration isn't yet set, set the first one.
    //

    Configuration = UsbGetActiveConfiguration(Device->UsbCoreHandle);
    if (Configuration == NULL) {
        Status = UsbSetConfiguration(Device->UsbCoreHandle, 0, TRUE);
        if (!KSUCCESS(Status)) {
            goto SetUpUsbDeviceEnd;
        }

        Configuration = UsbGetActiveConfiguration(Device->UsbCoreHandle);

        ASSERT(Configuration != NULL);

    }

    //
    // Get and verify the interface.
    //

    Interface = UsbGetDesignatedInterface(Device->OsDevice,
                                          Device->UsbCoreHandle);

    if (Interface == NULL) {
        Status = STATUS_NO_INTERFACE;
        goto SetUpUsbDeviceEnd;
    }

    if (Interface->Descriptor.Class != UsbInterfaceClassVendor) {
        Status = STATUS_NO_INTERFACE;
        goto SetUpUsbDeviceEnd;
    }

    //
    // Locate the IN and OUT bulk endpoints, and the interrupt endpoint.
    //

    BulkOutEndpointCount = 0;
    CurrentEntry = Interface->EndpointListHead.Next;
    while (CurrentEntry != &(Interface->EndpointListHead)) {
        if ((Device->BulkInEndpoint != 0) &&
            (BulkOutEndpointCount == RTLW81_MAX_BULK_OUT_ENDPOINT_COUNT)) {

            break;
        }

        Endpoint = LIST_VALUE(CurrentEntry,
                              USB_ENDPOINT_DESCRIPTION,
                              ListEntry);

        CurrentEntry = CurrentEntry->Next;

        //
        // Deconstruct the components of the endpoint descriptor.
        //

        EndpointType = Endpoint->Descriptor.Attributes &
                       USB_ENDPOINT_ATTRIBUTES_TYPE_MASK;

        if ((Endpoint->Descriptor.EndpointAddress &
             USB_ENDPOINT_ADDRESS_DIRECTION_IN) != 0) {

            Direction = UsbTransferDirectionIn;

        } else {
            Direction = UsbTransferDirectionOut;
        }

        //
        // Look to match the endpoint up to one of the required ones.
        //

        if (EndpointType == USB_ENDPOINT_ATTRIBUTES_TYPE_BULK) {
            if ((Device->BulkInEndpoint == 0) &&
                (Direction == UsbTransferDirectionIn)) {

                Device->BulkInEndpoint = Endpoint->Descriptor.EndpointAddress;

            } else if ((BulkOutEndpointCount <
                        RTLW81_MAX_BULK_OUT_ENDPOINT_COUNT) &&
                       (Direction == UsbTransferDirectionOut)) {

                Device->BulkOutEndpoint[BulkOutEndpointCount] =
                                          Endpoint->Descriptor.EndpointAddress;

                BulkOutEndpointCount += 1;
            }
        }
    }

    if ((Device->BulkInEndpoint == 0) ||
        (BulkOutEndpointCount == 0)) {

        Status = STATUS_INVALID_CONFIGURATION;
        goto SetUpUsbDeviceEnd;
    }

    //
    // Assign the bulk out endpoints based on how many there are.
    //

    if (BulkOutEndpointCount == 1) {
        for (Index = 0; Index < Rtlw81BulkOutTypeCount; Index += 1) {
            Device->BulkOutTypeEndpointIndex[Index] = 0;
        }

    } else if (BulkOutEndpointCount == 2) {
        Device->BulkOutTypeEndpointIndex[Rtlw81BulkOutBe] = 1;
        Device->BulkOutTypeEndpointIndex[Rtlw81BulkOutBk] = 1;
        Device->BulkOutTypeEndpointIndex[Rtlw81BulkOutVi] = 0;
        Device->BulkOutTypeEndpointIndex[Rtlw81BulkOutVo] = 0;

    } else {

        ASSERT(BulkOutEndpointCount == RTLW81_MAX_BULK_OUT_ENDPOINT_COUNT);

        Device->BulkOutTypeEndpointIndex[Rtlw81BulkOutBe] = 2;
        Device->BulkOutTypeEndpointIndex[Rtlw81BulkOutBk] = 2;
        Device->BulkOutTypeEndpointIndex[Rtlw81BulkOutVi] = 1;
        Device->BulkOutTypeEndpointIndex[Rtlw81BulkOutVo] = 0;
    }

    //
    // Everything's all ready, claim the interface.
    //

    Status = UsbClaimInterface(Device->UsbCoreHandle,
                               Interface->Descriptor.InterfaceNumber);

    if (!KSUCCESS(Status)) {
        goto SetUpUsbDeviceEnd;
    }

    Device->InterfaceNumber = Interface->Descriptor.InterfaceNumber;
    Device->InterfaceClaimed = TRUE;
    Status = STATUS_SUCCESS;

SetUpUsbDeviceEnd:
    return Status;
}

KSTATUS
Rtlw81pStartDevice (
    PIRP Irp,
    PRTLW81_DEVICE Device
    )

/*++

Routine Description:

    This routine starts the SMSC95xx LAN device.

Arguments:

    Irp - Supplies a pointer to the start IRP.

    Device - Supplies a pointer to the device information.

Return Value:

    Status code.

--*/

{

    KSTATUS Status;

    //
    // Start up the controller.
    //

    Status = Rtlw81pInitialize(Device, Irp);
    if (!KSUCCESS(Status)) {
        goto StartDeviceEnd;
    }

StartDeviceEnd:
    return Status;
}

KSTATUS
Rtlw81pStopDevice (
    PIRP Irp,
    PRTLW81_DEVICE Device
    )

/*++

Routine Description:

    This routine stops the SMSC95xx LAN device.

Arguments:

    Irp - Supplies a pointer to the removal IRP.

    Device - Supplies a pointer to the device information.

Return Value:

    Status code.

--*/

{

    //
    // Detach the device from USB core. This will cancel all transfer attached
    // to the device, including the in-flight bulk out transfers that this
    // driver does not track.
    //

    if (Device->UsbCoreHandle != INVALID_HANDLE) {
        UsbDetachDevice(Device->UsbCoreHandle);
    }

    if (Device->InterfaceClaimed != FALSE) {
        UsbReleaseInterface(Device->UsbCoreHandle, Device->InterfaceNumber);
    }

    if (Device->UsbCoreHandle != INVALID_HANDLE) {
        UsbDeviceClose(Device->UsbCoreHandle);
    }

    //
    // Remove the link from 802.11 core. It is no longer in service.
    //

    if (Device->Net80211Link != NULL) {
        Net80211RemoveLink(Device->Net80211Link);
        Device->Net80211Link = NULL;
    }

    Rtlw81pDeviceReleaseReference(Device);
    return STATUS_SUCCESS;
}