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

[Jie Zhan]

On 12/9/2025 12:17 AM, Beata Michalska wrote:
> 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 at 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.
Why?

It could return a little bit earlier for the PCC reg case, but this is only
called in initialization so efficiency is not that important I guess.
> 
> ---
> BR
> Beata

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