linux-kernel - Re: [PATCH V1 1/6] ACPI: CPPC: Add get the highest performance cppc control

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Date:   Tue, 8 Aug 2023 10:43:09 -0500
From:   Mario Limonciello <mario.limonciello@....com>
To:     Meng Li <li.meng@....com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Huang Rui <ray.huang@....com>
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        x86@...nel.org, linux-acpi@...r.kernel.org,
        Shuah Khan <skhan@...uxfoundation.org>,
        linux-kselftest@...r.kernel.org,
        Nathan Fontenot <nathan.fontenot@....com>,
        Deepak Sharma <deepak.sharma@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Shimmer Huang <shimmer.huang@....com>,
        Perry Yuan <Perry.Yuan@....com>,
        Xiaojian Du <Xiaojian.Du@....com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Borislav Petkov <bp@...en8.de>
Subject: Re: [PATCH V1 1/6] ACPI: CPPC: Add get the highest performance cppc
 control

On 8/8/2023 03:09, Meng Li wrote:
> Add support for getting the highest performance to the
> generic CPPC driver. This enables downstream drivers
> such as amd-pstate to discover and use these values.
> 

I suggest adding this to commit message:

Link: 
https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html?highlight=cppc#cpc-continuous-performance-control

> Signed-off-by: Meng Li <li.meng@....com>

Reviewed-by: Mario Limonciello <mario.limonciello@....com>

> ---
>   drivers/acpi/cppc_acpi.c | 13 +++++++++++++
>   include/acpi/cppc_acpi.h |  5 +++++
>   2 files changed, 18 insertions(+)
> 
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index 7ff269a78c20..ad388a0e8484 100644
> --- a/drivers/acpi/cppc_acpi.c
> +++ b/drivers/acpi/cppc_acpi.c
> @@ -1154,6 +1154,19 @@ int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
>   	return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);
>   }
>   
> +/**
> + * cppc_get_highest_perf - Get the highest performance register value.
> + * @cpunum: CPU from which to get highest performance.
> + * @highest_perf: Return address.
> + *
> + * Return: 0 for success, -EIO otherwise.
> + */
> +int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
> +{
> +	return cppc_get_perf(cpunum, HIGHEST_PERF, highest_perf);
> +}
> +EXPORT_SYMBOL_GPL(cppc_get_highest_perf);
> +
>   /**
>    * cppc_get_epp_perf - Get the epp register value.
>    * @cpunum: CPU from which to get epp preference value.
> diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
> index 6126c977ece0..c0b69ffe7bdb 100644
> --- a/include/acpi/cppc_acpi.h
> +++ b/include/acpi/cppc_acpi.h
> @@ -139,6 +139,7 @@ struct cppc_cpudata {
>   #ifdef CONFIG_ACPI_CPPC_LIB
>   extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf);
>   extern int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf);
> +extern int cppc_get_highest_perf(int cpunum, u64 *highest_perf);
>   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);
> @@ -165,6 +166,10 @@ static inline int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
>   {
>   	return -ENOTSUPP;
>   }
> +static inline int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
> +{
> +	return -ENOTSUPP;
> +}
>   static inline int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
>   {
>   	return -ENOTSUPP;