Re: [PATCH v3 3/4] ACPI: CPPC: Add autonomous selection ABIs

[Mario Limonciello <mario.limonciello@amd.com>]

On 12/17/2024 07:48, Pierre Gondois wrote:
> Hello Lifeng, Huang, Gautham, Mario,
> 
> On 12/16/24 10:16, Lifeng Zheng wrote:
>> cppc_set_epp - write energy performance preference register
>>
>> cppc_get_auto_act_window - read autonomous activity window register
>>
>> cppc_set_auto_act_window - write autonomous activity window register
>>
>> cppc_get_auto_sel - read autonomous selection enable register
>>
>> Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
>> ---
>>   drivers/acpi/cppc_acpi.c | 44 ++++++++++++++++++++++++++++++++++++++++
>>   include/acpi/cppc_acpi.h | 20 ++++++++++++++++++
>>   2 files changed, 64 insertions(+)
>>
>> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
>> index 83c7fcad74ad..645f2366c888 100644
>> --- a/drivers/acpi/cppc_acpi.c
>> +++ b/drivers/acpi/cppc_acpi.c
>> @@ -1595,6 +1595,50 @@ int cppc_set_epp_perf(int cpu, struct 
>> cppc_perf_ctrls *perf_ctrls, bool enable)
>>   }
>>   EXPORT_SYMBOL_GPL(cppc_set_epp_perf);
>> +/**
>> + * cppc_set_epp() - Write the EPP register.
>> + * @cpu: CPU on which to write register.
>> + * @epp_val: Value to write to the EPP register.
>> + */
>> +int cppc_set_epp(int cpu, u64 epp_val)
>> +{
>> +    return cppc_set_reg_val(cpu, ENERGY_PERF, epp_val);
>> +}
>> +EXPORT_SYMBOL_GPL(cppc_set_epp);
>> +
>> +/**
>> + * cppc_get_auto_act_window() - Read autonomous activity window 
>> register.
>> + * @cpu: CPU from which to read register.
>> + * @auto_act_window: Return address.
>> + */
>> +int cppc_get_auto_act_window(int cpu, u64 *auto_act_window)
> 
> As there is only one way to interpret the value of the
> 'Autonomous Activity Window Register', maybe the logic to convert
> from/to the register value to a value in us should be placed here
> rather than in the cppc_cpufreq driver.
> Meaning, maybe the prototype should be:
> 
> int cppc_get_auto_act_window(int cpu, unsigned int *auto_act_window);
> 
> Similar remark for cppc_set_epp() and other functions.
> 
>> +{
>> +    return cppc_get_reg_val(cpu, AUTO_ACT_WINDOW, auto_act_window);
>> +}
>> +EXPORT_SYMBOL_GPL(cppc_get_auto_act_window);
>> +
>> +/**
>> + * cppc_set_auto_act_window() - Write autonomous activity window 
>> register.
>> + * @cpu: CPU on which to write register.
>> + * @auto_act_window: Value to write to the autonomous activity window 
>> register.
>> + */
>> +int cppc_set_auto_act_window(int cpu, u64 auto_act_window)
>> +{
>> +    return cppc_set_reg_val(cpu, AUTO_ACT_WINDOW, auto_act_window);
>> +}
>> +EXPORT_SYMBOL_GPL(cppc_set_auto_act_window);
>> +
>> +/**
>> + * cppc_get_auto_sel() - Read autonomous selection register.
>> + * @cpu: CPU from which to read register.
>> + * @auto_sel: Return address.
>> + */
>> +int cppc_get_auto_sel(int cpu, u64 *auto_sel)
> 
> Similarly, maybe it would be better to use:
> int cppc_get_auto_sel(int cpu, bool *auto_sel);
> 
>> +{
>> +    return cppc_get_reg_val(cpu, AUTO_SEL_ENABLE, auto_sel);
>> +}
>> +EXPORT_SYMBOL_GPL(cppc_get_auto_sel);
>> +
>>   /**
>>    * cppc_get_auto_sel_caps - Read autonomous selection register.
>>    * @cpunum : CPU from which to read register.
>> diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
>> index 62d368bcd9ec..134931b081a0 100644
>> --- a/include/acpi/cppc_acpi.h
>> +++ b/include/acpi/cppc_acpi.h
>> @@ -159,6 +159,10 @@ extern int cpc_read_ffh(int cpunum, struct 
>> cpc_reg *reg, u64 *val);
>>   extern int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val);
>>   extern int cppc_get_epp_perf(int cpunum, u64 *epp_perf);
>>   extern int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls 
>> *perf_ctrls, bool enable);
>> +extern int cppc_set_epp(int cpu, u64 epp_val);
>> +extern int cppc_get_auto_act_window(int cpu, u64 *auto_act_window);
>> +extern int cppc_set_auto_act_window(int cpu, u64 auto_act_window);
>> +extern int cppc_get_auto_sel(int cpu, u64 *auto_sel);
>>   extern int cppc_get_auto_sel_caps(int cpunum, struct cppc_perf_caps 
>> *perf_caps);
> 
> This is a bit annoying, but maybe only one function between:
> - cppc_get_auto_sel_caps()
> - cppc_get_auto_sel()
> is necessary.
> 
> I added the owners of the amd-pstate driver to ask if this would
> be ok to replace cppc_get_auto_sel_caps() by cppc_get_auto_sel().

Yeah I have no concerns with this if that's the direction this patch 
series goes.  Feel free to change amd-pstate in the patch that 
introduces cppc_get_auto_sel().

I'll be out around the US holiday, so I might not be able to review it 
for a while, but CC Gautham on the series and he may be able to.

> 
>>   extern int cppc_set_auto_sel(int cpu, bool enable);
>>   extern int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf);
>> @@ -225,6 +229,22 @@ static inline int cppc_set_epp_perf(int cpu, 
>> struct cppc_perf_ctrls *perf_ctrls,
>>   {
>>       return -EOPNOTSUPP;
>>   }
>> +static inline int cppc_set_epp(int cpu, u64 epp_val)
>> +{
>> +    return -EOPNOTSUPP;
>> +}
>> +static inline int cppc_get_auto_act_window(int cpu, u64 
>> *auto_act_window)
>> +{
>> +    return -EOPNOTSUPP;
>> +}
>> +static inline int cppc_set_auto_act_window(int cpu, u64 auto_act_window)
>> +{
>> +    return -EOPNOTSUPP;
>> +}
>> +static inline int cppc_get_auto_sel(int cpu, u64 *auto_sel)
>> +{
>> +    return -EOPNOTSUPP;
>> +}
>>   static inline int cppc_get_epp_perf(int cpunum, u64 *epp_perf)
>>   {
>>       return -EOPNOTSUPP;