C++ EFI_USB_IO_PROTOCOL::UsbGetConfigDescriptor方法代码示例

/**
  Initialize the USB mouse device.

  This function retrieves and parses HID report descriptor, and
  initializes state of USB_MOUSE_DEV. Then it sets indefinite idle
  rate for the device. Finally it creates event for delayed recovery,
  which deals with device error.

  @param  UsbMouseDev           Device instance to be initialized.

  @retval EFI_SUCCESS           USB mouse device successfully initialized..
  @retval EFI_UNSUPPORTED       HID descriptor type is not report descriptor.
  @retval Other                 USB mouse device was not initialized successfully.

**/
EFI_STATUS
InitializeUsbMouseDevice (
  IN OUT USB_MOUSE_DEV           *UsbMouseDev
  )
{
  EFI_USB_IO_PROTOCOL       *UsbIo;
  UINT8                     Protocol;
  EFI_STATUS                Status;
  EFI_USB_HID_DESCRIPTOR    *MouseHidDesc;
  UINT8                     *ReportDesc;
  EFI_USB_CONFIG_DESCRIPTOR ConfigDesc;
  VOID                      *Buf;
  UINT32                    TransferResult;
  UINT16                    Total;
  USB_DESC_HEAD             *Head;
  BOOLEAN                   Start;

  UsbIo = UsbMouseDev->UsbIo;

  //
  // Get the current configuration descriptor. Note that it doesn't include other descriptors.
  //
  Status = UsbIo->UsbGetConfigDescriptor (
                    UsbIo,
                    &ConfigDesc
                    );
  if (EFI_ERROR (Status)) {
    return Status;
  }

  //
  // By issuing Get_Descriptor(Configuration) request with total length, we get the Configuration descriptor,
  // all Interface descriptors, all Endpoint descriptors, and the HID descriptor for each interface.
  //
  Buf = AllocateZeroPool (ConfigDesc.TotalLength);
  if (Buf == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  Status = UsbGetDescriptor (
             UsbIo,
             (UINT16)((USB_DESC_TYPE_CONFIG << 8) | (ConfigDesc.ConfigurationValue - 1)),
             0,
             ConfigDesc.TotalLength,
             Buf,
             &TransferResult
             );
  if (EFI_ERROR (Status)) {
    FreePool (Buf);
    return Status;
  }

  Total = 0;
  Start = FALSE;
  Head  = (USB_DESC_HEAD *)Buf;
  MouseHidDesc = NULL;

  //
  // Get HID descriptor from the receipt of Get_Descriptor(Configuration) request.
  // This algorithm is based on the fact that the HID descriptor shall be interleaved
  // between the interface and endpoint descriptors for HID interfaces.
  //
  while (Total < ConfigDesc.TotalLength) {
    if (Head->Type == USB_DESC_TYPE_INTERFACE) {
      if ((((USB_INTERFACE_DESCRIPTOR *)Head)->InterfaceNumber == UsbMouseDev->InterfaceDescriptor.InterfaceNumber) &&
        (((USB_INTERFACE_DESCRIPTOR *)Head)->AlternateSetting == UsbMouseDev->InterfaceDescriptor.AlternateSetting)) {
        Start = TRUE;
      }
    }
    if (Start && (Head->Type == USB_DESC_TYPE_ENDPOINT)) {
      break;
    }
    if (Start && (Head->Type == USB_DESC_TYPE_HID)) {
      MouseHidDesc = (EFI_USB_HID_DESCRIPTOR *)Head;
      break;
    }
    Total = Total + (UINT16)Head->Len;
    Head  = (USB_DESC_HEAD*)((UINT8 *)Buf + Total);
  }

  if (MouseHidDesc == NULL) {
    FreePool (Buf);
    return EFI_UNSUPPORTED;
  }

//.........这里部分代码省略.........