linux-kernel - Re: [PATCH v2 1/4] ACPI: CPPC: Add a symbol to check if the preferred profile is a server

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Message-ID: <ZJG8w8le9AyRWKzO@amd.com>
Date:   Tue, 20 Jun 2023 22:50:43 +0800
From:   Huang Rui <ray.huang@....com>
To:     "Yuan, Perry" <Perry.Yuan@....com>
Cc:     "rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>,
        "viresh.kumar@...aro.org" <viresh.kumar@...aro.org>,
        "Limonciello, Mario" <Mario.Limonciello@....com>,
        "Sharma, Deepak" <Deepak.Sharma@....com>,
        "Karny, Wyes" <Wyes.Karny@....com>,
        "Shenoy, Gautham Ranjal" <gautham.shenoy@....com>,
        "Li, Sun peng (Leo)" <Sunpeng.Li@....com>,
        "Huang, Shimmer" <Shimmer.Huang@....com>,
        "Du, Xiaojian" <Xiaojian.Du@....com>,
        "Meng, Li (Jassmine)" <Li.Meng@....com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/4] ACPI: CPPC: Add a symbol to check if the
 preferred profile is a server

On Thu, Jun 15, 2023 at 02:32:00PM +0800, Yuan, Perry wrote:
> From: Mario Limonciello <mario.limonciello@....com>
> 
> This symbol will be used by intel-pstate and amd-pstate for making
> decisions based on what the FADT indicates the system pm profile is.
> 
> Suggested-by: Gautham Ranjal Shenoy <gautham.shenoy@....com>
> Link: https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/05_ACPI_Software_Programming_Model/ACPI_Software_Programming_Model.html#fixed-acpi-description-table-fadt
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
>  drivers/acpi/cppc_acpi.c | 34 ++++++++++++++++++++++++++++++++++
>  include/acpi/actbl.h     |  3 ++-
>  include/acpi/processor.h | 10 ++++++++++
>  3 files changed, 46 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index 7ff269a78c20..d8827eae3ba4 100644
> --- a/drivers/acpi/cppc_acpi.c
> +++ b/drivers/acpi/cppc_acpi.c
> @@ -941,6 +941,40 @@ void acpi_cppc_processor_exit(struct acpi_processor *pr)
>  }
>  EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
>  
> +
> +/**
> + * acpi_pm_profile_server() - Check if the system is a server.
> + *
> + * Return: true for server profiles, false for anything else
> + */
> +bool acpi_pm_profile_server(void)
> +{
> +	switch (acpi_gbl_FADT.preferred_profile) {
> +	case PM_ENTERPRISE_SERVER:
> +	case PM_SOHO_SERVER:
> +	case PM_PERFORMANCE_SERVER:
> +		return true;
> +	}
> +	return false;
> +}
> +EXPORT_SYMBOL_GPL(acpi_pm_profile_server);
> +
> +/**
> + * acpi_pm_profile_undefined() - Check if the system is an undefined pm profile.
> + *
> + * Return: true for undefined profiles, false for anything else
> + */
> +bool acpi_pm_profile_undefined(void)
> +{
> +	if (acpi_gbl_FADT.preferred_profile == PM_UNSPECIFIED)
> +		return true;
> +	if (acpi_gbl_FADT.preferred_profile >= NR_PM_PROFILES)
> +		return true;

May I know the acpi_gbl_FADT.preferred_profile value of powerful desktop
such as threadripper or AM4/AM5 socket types of processors?

I am thinking whether we can use this way to differentiate powerful desktop
and mobile platforms.

Thanks,
Ray

> +	return false;
> +}
> +EXPORT_SYMBOL_GPL(acpi_pm_profile_undefined);
> +
> +
>  /**
>   * cpc_read_ffh() - Read FFH register
>   * @cpunum:	CPU number to read
> diff --git a/include/acpi/actbl.h b/include/acpi/actbl.h
> index e5dfb6f4de52..451f6276da49 100644
> --- a/include/acpi/actbl.h
> +++ b/include/acpi/actbl.h
> @@ -307,7 +307,8 @@ enum acpi_preferred_pm_profiles {
>  	PM_SOHO_SERVER = 5,
>  	PM_APPLIANCE_PC = 6,
>  	PM_PERFORMANCE_SERVER = 7,
> -	PM_TABLET = 8
> +	PM_TABLET = 8,
> +	NR_PM_PROFILES = 9
>  };
>  
>  /* Values for sleep_status and sleep_control registers (V5+ FADT) */
> diff --git a/include/acpi/processor.h b/include/acpi/processor.h
> index 94181fe9780a..05a45ebddaea 100644
> --- a/include/acpi/processor.h
> +++ b/include/acpi/processor.h
> @@ -360,6 +360,8 @@ int acpi_get_cpuid(acpi_handle, int type, u32 acpi_id);
>  #ifdef CONFIG_ACPI_CPPC_LIB
>  extern int acpi_cppc_processor_probe(struct acpi_processor *pr);
>  extern void acpi_cppc_processor_exit(struct acpi_processor *pr);
> +extern bool acpi_pm_profile_server(void);
> +extern bool acpi_pm_profile_undefined(void);
>  #else
>  static inline int acpi_cppc_processor_probe(struct acpi_processor *pr)
>  {
> @@ -369,6 +371,14 @@ static inline void acpi_cppc_processor_exit(struct acpi_processor *pr)
>  {
>  	return;
>  }
> +static inline bool acpi_pm_profile_server(void)
> +{
> +	return false;
> +}
> +static inline bool acpi_pm_profile_undefined(void)
> +{
> +	return true;
> +}
>  #endif	/* CONFIG_ACPI_CPPC_LIB */
>  
>  /* in processor_pdc.c */
> -- 
> 2.34.1
>