On 3/22/24 08:14, Marcin Juszkiewicz wrote:
W dniu 22.03.2024 o 05:55, Alistair Francis pisze:
I see no mention of device trees in the spec, but I do see ACPI. Do we
really expect a server platform to use DTs?
This platform "kind of" follows sbsa-ref where we have very minimalistic
device tree sharing information qemu->firmware.
libfdt is small, format is known and describes hardware. Firmware is
free to make use of it in any way it wants.
On sbsa-ref we parse DT in TF-A (base firmware) and provide hardware
information to higher level (edk2) via SMC mechanism. Then EDK2 creates
ACPI tables and provide them to the Operating System.
We should ensure that only either an ACPI table or a device-tree
description is passed to the OS and not both, e.g. when using
qemu-system-riscv64 -kernel vmlinux -M sbsa-ref
But that requirement is not machine specific.
Best regards
Heinrich
In physical system some parts of information provided in DT would be
read by firmware from onboard Embedded Controller chip.
These functions should be shared with the virt machine if we really do
want DTs, but I'm not convinced we do
