linux-kernel - Re: [PATCH 08/19] cpufreq: amd: add boost mode support for amd-pstate

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Message-ID: <a2718365-5975-5c91-350f-fe9098b4de7b@amd.com>
Date:   Wed, 8 Sep 2021 13:24:54 -0500
From:   "Fontenot, Nathan" <Nathan.Fontenot@....com>
To:     Huang Rui <ray.huang@....com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Shuah Khan <skhan@...uxfoundation.org>,
        Borislav Petkov <bp@...e.de>, Ingo Molnar <mingo@...nel.org>,
        linux-pm@...r.kernel.org
Cc:     Deepak Sharma <deepak.sharma@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Mario Limonciello <mario.limonciello@....com>,
        Jinzhou Su <Jinzhou.Su@....com>,
        Xiaojian Du <Xiaojian.Du@....com>,
        linux-kernel@...r.kernel.org, x86@...nel.org
Subject: Re: [PATCH 08/19] cpufreq: amd: add boost mode support for amd-pstate

On 9/8/2021 9:59 AM, Huang Rui wrote:
> If the sbios supports the boost mode of amd-pstate, let's switch to
> boost enabled by default.
> 
> Signed-off-by: Huang Rui <ray.huang@....com>
> ---
>  drivers/cpufreq/amd-pstate.c | 50 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index ea965a122431..67a9a117f524 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -75,6 +75,8 @@ struct amd_cpudata {
>  	u32	min_freq;
>  	u32	nominal_freq;
>  	u32	lowest_nonlinear_freq;
> +
> +	bool	boost_supported;
>  };
>  
>  struct amd_pstate_perf_funcs {
> @@ -229,6 +231,19 @@ amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
>  				      max_perf, fast_switch);
>  }
>  
> +static bool amd_pstate_boost_supported(struct amd_cpudata *cpudata)
> +{
> +	u32 highest_perf, nominal_perf;
> +
> +	highest_perf = READ_ONCE(cpudata->highest_perf);
> +	nominal_perf = READ_ONCE(cpudata->nominal_perf);
> +
> +	if (highest_perf > nominal_perf)
> +		return true;
> +
> +	return false;
> +}
> +
>  static int amd_pstate_verify(struct cpufreq_policy_data *policy)
>  {
>  	cpufreq_verify_within_cpu_limits(policy);
> @@ -402,6 +417,37 @@ static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
>  	return lowest_nonlinear_freq * 1000;
>  }
>  
> +static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state)
> +{
> +	struct amd_cpudata *cpudata = policy->driver_data;
> +	int ret;
> +
> +	if (!cpudata->boost_supported) {
> +		pr_err("Boost mode is not supported by this processor or SBIOS\n");
> +		return -EINVAL;
> +	}
> +
> +	if (state)
> +		policy->cpuinfo.max_freq = cpudata->max_freq;
> +	else
> +		policy->cpuinfo.max_freq = cpudata->nominal_freq;
> +
> +	policy->max = policy->cpuinfo.max_freq;
> +
> +	ret = freq_qos_update_request(&cpudata->req[1],
> +				      policy->cpuinfo.max_freq);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static void amd_pstate_boost_init(struct amd_cpudata *cpudata)
> +{
> +	cpudata->boost_supported = true;
> +	amd_pstate_driver.boost_enabled = true;
> +}
> +
>  static int amd_pstate_init_freqs_in_cpudata(struct amd_cpudata *cpudata,
>  					    u32 max_freq, u32 min_freq,
>  					    u32 nominal_freq,
> @@ -504,6 +550,9 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  
>  	policy->driver_data = cpudata;
>  
> +	if (amd_pstate_boost_supported(cpudata))
> +		amd_pstate_boost_init(cpudata);

Is there any reason to not merge amd_pstate_boost_supported() and
amd_pstate_boost_init() into a single function? I don't see that
amd_pstate_boost_supported() is called anywhere else.

-Nathan

> +
>  	return 0;
>  
>  free_cpudata3:
> @@ -535,6 +584,7 @@ static struct cpufreq_driver amd_pstate_driver = {
>  	.fast_switch    = amd_pstate_fast_switch,
>  	.init		= amd_pstate_cpu_init,
>  	.exit		= amd_pstate_cpu_exit,
> +	.set_boost	= amd_pstate_set_boost,
>  	.name		= "amd-pstate",
>  };
>  
> -- 
> 2.25.1
>