Re: [PATCH RFC 2/3] arch_topology: Parse die nodes in /cpu-map

["Troy Mitchell" <troy.mitchell@linux.dev>]

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> Where is the associated bindings ? Am I missing to check it in the series
> or it is really missing ? It is essential to add any code using the binding.

I left the binding out to get initial feedback on the topology model,
but I agree it should be available for review alongside the code.

The cpu-map binding lives in dt-schema. I have now opened a draft PR [1]
with the proposed dieN hierarchy. The PR also links back to this kernel
series.

> Also how does it align with ACPI implementation ? It is preferred to be
> in parity here, so we need some binding there as well IMHO.

This series does not implement ACPI die discovery and leaves die_id at
-1 on that path. I agree that DT and ACPI should describe the same
topology model.

RISC-V does not define topology fields in hart IDs. PPTT can describe
intermediate processor hierarchy nodes, but I could not find an explicit
die indicator in the ACPI 6.6 processor-node flags. Is there an existing
PPTT convention for identifying die boundaries that we should follow?

Would it be acceptable to add DT support first, keeping ACPI die IDs
unknown until that mapping is agreed, or should the ACPI mapping be
defined as part of this RFC?

Link: https://github.com/devicetree-org/dt-schema/pull/208 [1].

-- 
Troy Mitchell

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