Re: [PATCH] arm_mpam: Do not access MPAMF_ESR on MSCs that do not have it

[Ping Li]

Hi Ben,

You are right, thanks for the pointers to the spec.

Our MSC is an MPAM v1.0 implementation without MPAMF_ESR, and the RTL
responds to accesses of unimplemented registers with a bus error
instead of RAZ/WI - which is what motivated the patch. Reading
MPAMF_ESR from the CPU therefore raises an external abort rather than
reading as zero.

Per RLNXX this implementation is not compliant, so the fix belongs in
hardware: the MSC design team will change accesses to unimplemented
registers to be RAZ/WI, as the specification requires.

With that in place the existing driver code is safe, so I am
withdrawing this patch.

Thanks,
Ping