UcxIoDeviceControl function (ucxcontroller.h)

Article
10/21/2021

Allows USB host controller extension (UCX) to handle an I/O control code (IOCTL) request from user mode.

Syntax

BOOLEAN UcxIoDeviceControl(
  [in] WDFDEVICE  Device,
  [in] WDFREQUEST Request,
  [in] size_t     OutputBufferLength,
  [in] size_t     InputBufferLength,
  [in] ULONG      IoControlCode
);

Parameters

[in] Device

A handle to the framework device object that the client driver retrieved in the previous call to WdfDeviceCreate.

[in] Request

A handle to a framework request object that represents the user-mode IOCTL request.

[in] OutputBufferLength

The length, in bytes, of the request's output buffer, if an output buffer is available.

[in] InputBufferLength

The length, in bytes, of the request's input buffer, if an input buffer is available.

[in] IoControlCode

The driver-defined or system-defined IOCTL that is associated with the request.

Return value

If the operation is successful, the method returns TRUE. Otherwise it returns FALSE.

Remarks

The client driver can call this method to allow UCX to handle IOCTLs listed in this table: User-Mode IOCTLs for USB. If the IOCTL code is IOCTL_USB_DIAGNOSTIC_MODE_OFF or IOCTL_USB_DIAGNOSTIC_MODE_ON, UCX completes the request successfully. For IOCTLS that are used to retrieve the USB host controllers driver key name, such as IOCTL_USB_GET_ROOT_HUB_NAME or IOCTL_GET_HCD_DRIVERKEY_NAME, UCX retrieves the Unicode string. If the user mode IOCTL is IOCTL_USB_USER_REQUEST, the input and output buffer lengths must be equal and the output buffer must contain the USBUSER_REQUEST_HEADER structure. For the remaining IOCTLs, UCX returns FALSE and the client driver can provide its own handling logic.

Examples

VOID
Controller_WdfEvtIoDeviceControl(
    WDFQUEUE    WdfQueue,
    WDFREQUEST  WdfRequest,
    size_t      OutputBufferLength,
    size_t      InputBufferLength,
    ULONG       IoControlCode
)
/*++

Routine Description:

    This routine is a callback function which is called by WDF when a driver
    receives an I/O control request from the queue this callback is registered
    with.

    The controller driver calls UcxIoDeviceControl() to allow UCX to try and
    handle the IOCTL.  If UCX cannot handle the IOCTL, the controller driver
    must handle it, perhaps by failing it.

    The default queue only expects to receive IOCTLs from user mode (via the
    interface defined by GUID_DEVINTERFACE_USB_HOST_CONTROLLER).

Arguments:

    WdfQueue - A handle to the framework I/O queue object.

    WdfRequest - A handle to the framework request object that contains the IOCTL.

    OutputBufferLength - Length of the IOCTL output buffer, if an output buffer
        is available.

    InputBufferLength - Length of the IOCTL input buffer, if an input buffer
        is available.

    IoControlCode - I/O control code associated with the request.

Return Value:

    None.

--*/
{
    KPROCESSOR_MODE requestorMode;

    //
    // Allow UCX to try and handle the request
    //
    if (UcxIoDeviceControl(WdfIoQueueGetDevice(WdfQueue),
                           WdfRequest,
                           OutputBufferLength,
                           InputBufferLength,
                           IoControlCode)) {
        DbgTrace(TL_VERBOSE, Controller, "IoControlCode 0x%x was handled by UCX", IoControlCode);
        goto WdfEvtIoDeviceControlEnd;
    }

    //
    // Check that the request is coming from user mode
    //
    requestorMode = WdfRequestGetRequestorMode(WdfRequest);

    if (requestorMode != UserMode) {
        DbgTrace(TL_WARNING, Controller, "Invalid RequestorMode %d", requestorMode);
    }

    //
    // UCX could not handle the request, so handle it here
    //
    switch (IoControlCode) {

    default:
        DbgTrace(TL_WARNING, Controller, "Unsupported IoControlCode 0x%x", IoControlCode);
        WdfRequestComplete(WdfRequest, STATUS_INVALID_DEVICE_REQUEST);
    }

WdfEvtIoDeviceControlEnd:

    return;
}

Requirements

Requirement	Value
Minimum supported client	Windows 10
Target Platform	Windows
Header	ucxcontroller.h (include Ucxclass.h)
IRQL	<=DISPATCH_LEVEL

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