Re: [PATCH v2 3/3] perf/smmuv3: Synthesize IIDR from CoreSight ID registers

On 2021-12-07 09:14, John Garry wrote:

On 17/11/2021 14:48, Jean-Philippe Brucker wrote:

quoted

From: Robin Murphy<robin.murphy@arm.com>

The SMMU_PMCG_IIDR register was not present in older revisions of the
Arm SMMUv3 spec. On Arm Ltd. implementations, the IIDR value consists of
fields from several PIDR registers, allowing us to present a
standardized identifier to userspace.

So is there some userspace part to go with this now?

FWIW I've not looked into it - is it just a case of someone knocking out 
some JSON from the MMU-600/700 TRMs, or is there still mroe to do? I had 
the impression that *some* part of the process was stalled until 
implementations can start providing meaningful IIDRs, but I wasn't sure 
whether that was tooling or just data. I just work the low-level 
enablement angle :)

Robin.