Deal with devices that just exist in memory space.

To follow the EFI driver model you need a root handle to start with. An EFI driver will have a driver binding protocol (Supported, Start, Stop) that is used to layer on top of a handle via a gBS->ConnectController. The first handle has to just be in the system to make that work. For PCI it is a PCI Root Bridge IO protocol that provides the root.

On an embedded system with MMIO device we need a handle to just show up. That handle will have this protocol and a device path protocol on it.

For an ethernet device the device path must contain a MAC address device path node.

SPDX-License-Identifier: BSD-2-Clause-Patent

PROTOCOL Information

PROTOCOL's Guid Name	PROTOCOL's Guid
gEmbeddedDeviceGuid	{ 0xbf4b9d10, 0x13ec, 0x43dd, { 0x88, 0x80, 0xe9, 0xb, 0x71, 0x8f, 0x27, 0xde } }

Refer to Header File

EmbeddedPkg/Include/Protocol/EmbeddedDevice.h