[PATCH v2 11/29] arm_mpam: Probe hardware to find the supported partid/pmg values

[Ben Horgan]

Hi James,

On 9/10/25 21:42, James Morse wrote:
> CPUs can generate traffic with a range of PARTID and PMG values,
> but each MSC may also have its own maximum size for these fields.
> Before MPAM can be used, the driver needs to probe each RIS on
> each MSC, to find the system-wide smallest value that can be used.
> The limits from requestors (e.g. CPUs) also need taking into account.
> 
> While doing this, RIS entries that firmware didn't describe are created
> under MPAM_CLASS_UNKNOWN.
> 
> While we're here, implement the mpam_register_requestor() call
> for the arch code to register the CPU limits. Future callers of this
> will tell us about the SMMU and ITS.
> 
> Signed-off-by: James Morse <james.morse at arm.com>
> ---
> Changes since v1:
>  * Change to lock ordering now that the list-lock mutex isn't held from
>    the cpuhp call.
>  * Removed irq-unmaksed assert in requestor register.
>  * Changed captialisation in print message.
> ---
>  drivers/resctrl/mpam_devices.c  | 150 +++++++++++++++++++++++++++++++-
>  drivers/resctrl/mpam_internal.h |   6 ++
>  include/linux/arm_mpam.h        |  14 +++
>  3 files changed, 169 insertions(+), 1 deletion(-)

Looks good to me. I think Jonathan's comment on getting rid of the local
variable, 'found', is worthwhile.

Reviewed-by: Ben Horgan <ben.horgan at arm.com>

Thanks,

Ben