linux-kernel - Re: [PATCH 4/8] x86/amd: Move amd_get_highest

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Message-ID: <Zs3qOxud6Ny7nCcH@BLRRASHENOY1.amd.com>
Date: Tue, 27 Aug 2024 20:31:15 +0530
From: "Gautham R. Shenoy" <gautham.shenoy@....com>
To: Mario Limonciello <superm1@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>, Perry Yuan <perry.yuan@....com>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
	"Rafael J . Wysocki" <rafael@...nel.org>,
	"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <linux-kernel@...r.kernel.org>,
	"open list:ACPI" <linux-acpi@...r.kernel.org>,
	"open list:CPU FREQUENCY SCALING FRAMEWORK" <linux-pm@...r.kernel.org>,
	Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH 4/8] x86/amd: Move amd_get_highest_perf() out of
 amd-pstate

On Mon, Aug 26, 2024 at 04:13:54PM -0500, Mario Limonciello wrote:
> From: Mario Limonciello <mario.limonciello@....com>
> 
> amd_get_highest_perf() is a helper used to get the highest perf

Nit: amd_pstate_get_highest_perf() is the existing helper, that is
being moved to the cppc handling code and being renamed as
amd_get_highest_perf().


> value on AMD systems.  It's used in amd-pstate as part of preferred
> core handling, but applicable for acpi-cpufreq as well.
> 
> Move it out to cppc handling code.

Otherwise, looks good to me.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@....com>

--
Thanks and Regards
gautham.



> 
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
>  arch/x86/kernel/acpi/cppc.c  | 30 ++++++++++++++++++++++++++++++
>  drivers/cpufreq/amd-pstate.c | 34 ++--------------------------------
>  include/acpi/cppc_acpi.h     |  2 ++
>  3 files changed, 34 insertions(+), 32 deletions(-)
> 
> diff --git a/arch/x86/kernel/acpi/cppc.c b/arch/x86/kernel/acpi/cppc.c
> index e94507110ca24..5a6c01a1b0d95 100644
> --- a/arch/x86/kernel/acpi/cppc.c
> +++ b/arch/x86/kernel/acpi/cppc.c
> @@ -119,6 +119,36 @@ void init_freq_invariance_cppc(void)
>  	mutex_unlock(&freq_invariance_lock);
>  }
>  
> +/*
> + * Get the highest performance register value.
> + * @cpu: CPU from which to get highest performance.
> + * @highest_perf: Return address for highest performance value.
> + *
> + * Return: 0 for success, negative error code otherwise.
> + */
> +int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf)
> +{
> +	u64 val;
> +	int ret;
> +
> +	if (cpu_feature_enabled(X86_FEATURE_CPPC)) {
> +		ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1, &val);
> +		if (ret)
> +			goto out;
> +
> +		val = AMD_CPPC_HIGHEST_PERF(val);
> +	} else {
> +		ret = cppc_get_highest_perf(cpu, &val);
> +		if (ret)
> +			goto out;
> +	}
> +
> +	WRITE_ONCE(*highest_perf, (u32)val);
> +out:
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(amd_get_highest_perf);
> +
>  /**
>   * amd_get_boost_ratio_numerator: Get the numerator to use for boost ratio calculation
>   * @cpu: CPU to get numerator for.
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 89bda7a2bb8d1..f470b5700db58 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -803,36 +803,6 @@ static void amd_pstste_sched_prefcore_workfn(struct work_struct *work)
>  }
>  static DECLARE_WORK(sched_prefcore_work, amd_pstste_sched_prefcore_workfn);
>  
> -/*
> - * Get the highest performance register value.
> - * @cpu: CPU from which to get highest performance.
> - * @highest_perf: Return address.
> - *
> - * Return: 0 for success, -EIO otherwise.
> - */
> -static int amd_pstate_get_highest_perf(int cpu, u32 *highest_perf)
> -{
> -	int ret;
> -
> -	if (cpu_feature_enabled(X86_FEATURE_CPPC)) {
> -		u64 cap1;
> -
> -		ret = rdmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_CAP1, &cap1);
> -		if (ret)
> -			return ret;
> -		WRITE_ONCE(*highest_perf, AMD_CPPC_HIGHEST_PERF(cap1));
> -	} else {
> -		u64 cppc_highest_perf;
> -
> -		ret = cppc_get_highest_perf(cpu, &cppc_highest_perf);
> -		if (ret)
> -			return ret;
> -		WRITE_ONCE(*highest_perf, cppc_highest_perf);
> -	}
> -
> -	return (ret);
> -}
> -
>  #define CPPC_MAX_PERF	U8_MAX
>  
>  static void amd_pstate_init_prefcore(struct amd_cpudata *cpudata)
> @@ -840,7 +810,7 @@ static void amd_pstate_init_prefcore(struct amd_cpudata *cpudata)
>  	int ret, prio;
>  	u32 highest_perf;
>  
> -	ret = amd_pstate_get_highest_perf(cpudata->cpu, &highest_perf);
> +	ret = amd_get_highest_perf(cpudata->cpu, &highest_perf);
>  	if (ret)
>  		return;
>  
> @@ -879,7 +849,7 @@ static void amd_pstate_update_limits(unsigned int cpu)
>  	if ((!amd_pstate_prefcore) || (!cpudata->hw_prefcore))
>  		goto free_cpufreq_put;
>  
> -	ret = amd_pstate_get_highest_perf(cpu, &cur_high);
> +	ret = amd_get_highest_perf(cpu, &cur_high);
>  	if (ret)
>  		goto free_cpufreq_put;
>  
> diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
> index f25a881cd46dd..2246ce0630362 100644
> --- a/include/acpi/cppc_acpi.h
> +++ b/include/acpi/cppc_acpi.h
> @@ -137,8 +137,10 @@ struct cppc_cpudata {
>  };
>  
>  #ifdef CONFIG_CPU_SUP_AMD
> +extern int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf);
>  extern int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator);
>  #else /* !CONFIG_CPU_SUP_AMD */
> +static inline int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf) { return -ENODEV; }
>  static inline int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator) { return -ENODEV; }
>  #endif /* !CONFIG_CPU_SUP_AMD */
>  
> -- 
> 2.43.0
>