Re: [PATCH v2 2/2] arm64: dts: qcom: kaanapali: fix traceNoC probe issue

[Leo Yan <leo.yan@arm.com>]

Hi Jie,

On Tue, Jun 30, 2026 at 09:03:52AM +0800, Jie Gan wrote:

[...]

> >    - How can you guarantee that a interconnect TraceNoC will never
> >      require ATID in the future?

> From a hardware perspective, there is no fundamental difference between an
> itnoc and an AG TraceNoC. They use the same TraceNoC hardware implementation
> and share the same AMBA bus type. The distinction is purely functional: an
> itnoc is used for local trace aggregation within a subsystem, whereas an AG
> TraceNoC serves as the top-level aggregation point for the SoC.

I'm still not convinced that adding "arm,primecell-periphid" is the
right approach.

From the description above, I'd expect either the hardware to expose
bits in a register to distinguish these two module types, or as I
suggested earlier, to use a DT property to indicate the module type (or
whether ATID is required).

Or have you tried to detect the last tnoc on a path and allocate ID for
it? (You can retrieve csdev->path).

Thanks,
Leo