How can I use USBmakebmRequestType with DriverKit

Question

I'm building a driver in C++ for my iPad using DriverKit.

I'm trying to make a request to a control endpoint, so I'm trying to use IOUSBHostInterface::DeviceRequest(). For the first parameter, bmRequestType, the documentation states:

bmRequestType

The characteristics of the device request. See the USBmakebmRequestType macro for information about how to construct this request.

But this macro USBmakebmRequestType is defined in IOKit > USB.h

I tried to #include <IOKit/USB.h> but it doesn't find the header.

Any idea?

Answer 1

As far as I'm aware, that macro isn't available in USBDriverKit. I think the documentation is just a copy-paste from elsewhere. (kernel headers, most likely)

In my code I've simply bitwise or'd (|) different combinations of the various relevant constants from the header <USBDriverKit/AppleUSBDefinitions.h>:

enum tIOUSBDeviceRequest
{
    // […]
    // Pick one each of direction…
    kIOUSBDeviceRequestDirectionOut       = (kIOUSBDeviceRequestDirectionValueOut << kIOUSBDeviceRequestDirectionPhase),
    kIOUSBDeviceRequestDirectionIn        = (kIOUSBDeviceRequestDirectionValueIn << kIOUSBDeviceRequestDirectionPhase),
    // […]
    // …request type…
    kIOUSBDeviceRequestTypeStandard       = (kIOUSBDeviceRequestTypeValueStandard << kIOUSBDeviceRequestTypePhase),
    kIOUSBDeviceRequestTypeClass          = (kIOUSBDeviceRequestTypeValueClass << kIOUSBDeviceRequestTypePhase),
    kIOUSBDeviceRequestTypeVendor         = (kIOUSBDeviceRequestTypeValueVendor << kIOUSBDeviceRequestTypePhase),
    // […]
    // …and recipient:
    kIOUSBDeviceRequestRecipientDevice    = (kIOUSBDeviceRequestRecipientValueDevice << kIOUSBDeviceRequestRecipientPhase),
    kIOUSBDeviceRequestRecipientInterface = (kIOUSBDeviceRequestRecipientValueInterface << kIOUSBDeviceRequestRecipientPhase),
    kIOUSBDeviceRequestRecipientEndpoint  = (kIOUSBDeviceRequestRecipientValueEndpoint << kIOUSBDeviceRequestRecipientPhase),
    kIOUSBDeviceRequestRecipientOther     = (kIOUSBDeviceRequestRecipientValueOther << kIOUSBDeviceRequestRecipientPhase),
}

So, something like:

const uint8_t request_type =
  kIOUSBDeviceRequestTypeVendor
  | kIOUSBDeviceRequestRecipientDevice
  | kIOUSBDeviceRequestDirectionIn;