On Fri, Aug 04, 2017 at 10:41:32PM +0200, Mark Kettenis wrote: [...]
..and what you're sketching out here should work with recent enough versions of our bootloader.
However, to me having an ACPI Device Path component in there doesn't make much sense on a board without ACPI. It certainly doesn't help mapping a boot path back to an actual hardware device. Wouldn't it be more logical to a Hardware Device Path there instead? In particular a Memory Mapped Device Path would make a lot of sense as the start address would make it fairly easy to do the mapping.
It was really an arbitrary choice, as Rob said. I don't think there's any big problem with changing it, but I'm not sure Memory Mapped is correct. As I read it, StartingAddress and EndingAddress in that class should be pointing at some window into a memory map entry that is holding the thing described /by/ the node, but there's really nothing here. It's just an arbitrary root node.
If we want something other than the ACPI path I made up, we should probably just go with a Vendor Specific Device Path with a constant well-known GUID of our choosing. e61d73b9-a384-4acc-aeab-82e828f3628b, say.