Re: [RFC PATCH 03/38] arm64: mpam: Advertise the CPUs MPAM limits to the driver
From: Jonathan Cameron
Date: Thu Dec 18 2025 - 05:43:17 EST
On Fri, 5 Dec 2025 21:58:26 +0000
James Morse <james.morse@xxxxxxx> wrote:
> Requestors need to populate the MPAM fields for any traffic they send
> on the interconnect. For the CPUs these values are taken from the
> corresponding MPAMy_ELx register. Each requestor may have a limit on
> the largest PARTID or PMG value that can be used. The MPAM driver has
> to determine the system-wide minimum supported PARTID and PMG values.
>
> To do this, the driver needs to be told what each requestor's
> limit is.
Trivial but this commit message line wrap isn't very consistent.
>
> CPUs are special, but this infrastructure is also needed for the
> SMMU and GIC ITS. Call the helper to tell the MPAM driver what the
> CPUs can do.
>
> The return value can be ignored by the arch code as it runs well
> before the MPAM driver starts probing.
>
> Signed-off-by: James Morse <james.morse@xxxxxxx>