I almost wrote the same comment — the first part, anyways.

In theory, it should be feasible to provide a "shim" to bridge the API gap between Linux and Windows internal APIs. The catch here is that Linux is a moving target.

AMDGPU (the Linux kernel module) has its roots in a shared Linux/Windows codebase from AMD, so hopefully it didn't get _too_ tightly integrated (I know some parts got integrated, IIRC it used to ship its own i2c driver).