[PATCH v2 13/29] arm_mpam: Probe the hardware features resctrl supports

[Ben Horgan]

Hi James,

On 9/10/25 21:42, James Morse wrote:
> Expand the probing support with the control and monitor types
> we can use with resctrl.
> 
> CC: Dave Martin <Dave.Martin at arm.com>
> Signed-off-by: James Morse <james.morse at arm.com>
> ---
> Changes since v1:
>  * added an underscore to a variable name.
> 
> Changes since RFC:
>  * Made mpam_ris_hw_probe_hw_nrdy() more in C.
>  * Added static assert on features bitmap size.
> ---
>  drivers/resctrl/mpam_devices.c  | 151 ++++++++++++++++++++++++++++++++
>  drivers/resctrl/mpam_internal.h |  53 +++++++++++
>  2 files changed, 204 insertions(+)
> 
[snip]
>  
>  	spin_lock(&partid_max_lock);
> diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
> index 4cc44d4e21c4..5ae5d4eee8ec 100644
> --- a/drivers/resctrl/mpam_internal.h
> +++ b/drivers/resctrl/mpam_internal.h
> @@ -112,6 +112,55 @@ static inline void mpam_mon_sel_lock_init(struct mpam_msc *msc)
>  	raw_spin_lock_init(&msc->_mon_sel_lock);
>  }
>  
> +/*
> + * When we compact the supported features, we don't care what they are.
> + * Storing them as a bitmap makes life easy.
> + */
> +typedef u16 mpam_features_t;
> +
> +/* Bits for mpam_features_t */
> +enum mpam_device_features {
> +	mpam_feat_ccap_part = 0,
> +	mpam_feat_cpor_part,
> +	mpam_feat_mbw_part,
> +	mpam_feat_mbw_min,
> +	mpam_feat_mbw_max,
> +	mpam_feat_mbw_prop,
> +	mpam_feat_msmon,
> +	mpam_feat_msmon_csu,
> +	mpam_feat_msmon_csu_capture,
> +	mpam_feat_msmon_csu_hw_nrdy,
> +	mpam_feat_msmon_mbwu,
> +	mpam_feat_msmon_mbwu_capture,
> +	mpam_feat_msmon_mbwu_rwbw,
> +	mpam_feat_msmon_mbwu_hw_nrdy,
> +	mpam_feat_msmon_capt,
> +	MPAM_FEATURE_LAST,
> +};

I added a garbled comment about this for v1. What I was trying to say is
that I don't think this quite matches what resctrl supports. For
instance, I don't think mpam_feat_ccap_part matches a resctrl feature.

Thanks,

Ben