Re: [PATCH v4 1/3] ACPI: CPPC: Factor out and export per-cpu cppc_perf_ctrs_in_pcc_cpu()

[Beata Michalska <beata.michalska@arm.com>]

On Wed, Dec 03, 2025 at 11:24:20AM +0800, Jie Zhan wrote:
> Factor out cppc_perf_ctrs_in_pcc_cpu() for checking whether per-cpu CPC
> regs are defined in PCC channels, and export it out for further use.
> 
> Signed-off-by: Jie Zhan <zhanjie9@hisilicon.com>
> ---
>  drivers/acpi/cppc_acpi.c | 45 +++++++++++++++++++++-------------------
>  include/acpi/cppc_acpi.h |  5 +++++
>  2 files changed, 29 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index 3bdeeee3414e..aa80dbcf42c0 100644
> --- a/drivers/acpi/cppc_acpi.c
> +++ b/drivers/acpi/cppc_acpi.c
> @@ -1422,6 +1422,29 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
>  }
>  EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
>  
> +bool cppc_perf_ctrs_in_pcc_cpu(unsigned int cpu)
> +{
> +	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
> +	struct cpc_register_resource *ref_perf_reg;
> +
> +	/*
> +	 * If reference perf register is not supported then we should use the
> +	 * nominal perf value
> +	 */
> +	ref_perf_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
> +	if (!CPC_SUPPORTED(ref_perf_reg))
> +		ref_perf_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
> +
> +	if (CPC_IN_PCC(&cpc_desc->cpc_regs[DELIVERED_CTR]) ||
> +	    CPC_IN_PCC(&cpc_desc->cpc_regs[REFERENCE_CTR]) ||
> +	    CPC_IN_PCC(&cpc_desc->cpc_regs[CTR_WRAP_TIME]) ||
> +	    CPC_IN_PCC(ref_perf_reg))
> +		return true;
> +
> +	return false;
> +}
> +EXPORT_SYMBOL_GPL(cppc_perf_ctrs_in_pcc_cpu);
It is minor, but I would prefer the earlier version when we grab the reference
performance reg only when none of the other regs is in the PCC.

---
BR
Beata
> +
>  /**
>   * cppc_perf_ctrs_in_pcc - Check if any perf counters are in a PCC region.
>   *
> @@ -1436,27 +1459,7 @@ bool cppc_perf_ctrs_in_pcc(void)
>  	int cpu;
>  
>  	for_each_online_cpu(cpu) {
> -		struct cpc_register_resource *ref_perf_reg;
> -		struct cpc_desc *cpc_desc;
> -
> -		cpc_desc = per_cpu(cpc_desc_ptr, cpu);
> -
> -		if (CPC_IN_PCC(&cpc_desc->cpc_regs[DELIVERED_CTR]) ||
> -		    CPC_IN_PCC(&cpc_desc->cpc_regs[REFERENCE_CTR]) ||
> -		    CPC_IN_PCC(&cpc_desc->cpc_regs[CTR_WRAP_TIME]))
> -			return true;
> -
> -
> -		ref_perf_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
> -
> -		/*
> -		 * If reference perf register is not supported then we should
> -		 * use the nominal perf value
> -		 */
> -		if (!CPC_SUPPORTED(ref_perf_reg))
> -			ref_perf_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
> -
> -		if (CPC_IN_PCC(ref_perf_reg))
> +		if (cppc_perf_ctrs_in_pcc_cpu(cpu))
>  			return true;
>  	}
>  
> diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
> index 13fa81504844..4bcdcaf8bf2c 100644
> --- a/include/acpi/cppc_acpi.h
> +++ b/include/acpi/cppc_acpi.h
> @@ -154,6 +154,7 @@ extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
>  extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
>  extern int cppc_set_enable(int cpu, bool enable);
>  extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps);
> +extern bool cppc_perf_ctrs_in_pcc_cpu(unsigned int cpu);
>  extern bool cppc_perf_ctrs_in_pcc(void);
>  extern unsigned int cppc_perf_to_khz(struct cppc_perf_caps *caps, unsigned int perf);
>  extern unsigned int cppc_khz_to_perf(struct cppc_perf_caps *caps, unsigned int freq);
> @@ -204,6 +205,10 @@ static inline int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps)
>  {
>  	return -EOPNOTSUPP;
>  }
> +static inline bool cppc_perf_ctrs_in_pcc_cpu(unsigned int cpu)
> +{
> +	return false;
> +}
>  static inline bool cppc_perf_ctrs_in_pcc(void)
>  {
>  	return false;
> -- 
> 2.33.0
>