The topology of a platform is represented in ACPI using the PPTT
table. It is possible to append information to CPUs/processor
containers using their associated AML nodes in a SSDT
table.
A platform might have multiple 'physical packages' (or top-level
nodes) in their PPTT topology representation. It can be assumed
from [1] that a 'physical packages' is always a 'top-level node',
and conversely.
The SSDT topology generator doesn't support having multiple top-level
nodes. The top-level node is also not generated in the SSDT topology
representation.
Add support to generate multiple top-level nodes in the SSDT topology
generator and generate an AML node for this top-level node. This will
allow to have matching PPTT and SSDT topology representations. Prior
to this patch, this top-level AML node was not generated.
Also factorize the flag checking in CheckProcNode() and add more
checks.
This patch takes inspiration from the discussion at:
- v1: https://edk2.groups.io/g/devel/message/99410
- v2: https://edk2.groups.io/g/devel/message/99615
[1]
ACPI 6.5, 5.2.30.1 Processor hierarchy node structure (Type 0):
- "Multiple trees may be described, covering for example multiple
packages. For the root of a tree, the parent pointer should be 0.""
- "Each valid processor must belong to exactly one package. That is,
the leaf must itself be a physical package or have an ancestor
marked as a physical package."
Suggested-by: Jeff Brasen <jbrasen@nvidia.com>
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: Jeff Brasen <jbrasen@nvidia.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
18f463edba