source: mainline/uspace/dist/src/bithenge/usbdesc.bh@ cf13b17

##
##
## USB DESCRIPTORS
##
##

# Originally by Vojtech Horky.

# Block prefixed with a byte length
transform block = (in.data) <- struct {
        .bLength <- uint8;
        .data <- known_length(.bLength - 1);
};

# USB configuration descriptor
# This is not the full configuration descriptor (i.e. with interface
# and endpoint descriptors included) but only the header. 
transform usb_configuration_descriptor_bare = struct {
        .wTotalLength <- uint16le;
        .bNumInterfaces <- uint8;
        .bConfigurationValue <- uint8;
        .iConfiguration <- uint8;
        .bmAttributes <- uint8;
        .MaxPower <- uint8;
};

# USB interface descriptor
transform usb_interface_descriptor = struct {
        .bInterfaceNumber <- uint8;
        .bAlternateSetting <- uint8;
        .bNumEndpoints <- uint8;
        .bInterfaceClass <- uint8;
        .bInterfaceSubClass <- uint8;
        .bInterfaceProtocol <- uint8;
        .iInterface <- uint8;
};

# USB endpoint descriptor
transform usb_endpoint_descriptor = struct {
        .bEndpointAddress  <- uint8;
        .bmAttributes <- uint8;
        .wMaxPacketSize <- uint16le;
        .bInterval <- uint8;
};

# USB HID descriptor
transform usb_hid_descriptor = struct {
        .bcdHID <- uint16le;
        .bCountryCode <- uint8;
        .bNumDescriptors <- uint8;
        <- repeat(.bNumDescriptors) { struct {
                .bDescriptorType <- uint8;
                .wDescriptorLength <- uint16le;
        } };
};

# USB descriptor
transform usb_descriptor = struct {
        .bDescriptorType <- uint8;
        <- switch (.bDescriptorType) {
                 2: usb_configuration_descriptor_bare;
                 4: usb_interface_descriptor;
                 5: usb_endpoint_descriptor;
                33: usb_hid_descriptor;
        };
} <- block;

transform main = repeat { usb_descriptor };