linux-kernel - Re: [PATCH 2/7] cpufreq: amd-pstate: initialize new core precision boost state

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Date: Wed, 14 Feb 2024 12:07:11 +0530
From: "Gautham R. Shenoy" <gautham.shenoy@....com>
To: Perry Yuan <perry.yuan@....com>
Cc: rafael.j.wysocki@...el.com, Mario.Limonciello@....com,
	viresh.kumar@...aro.org, Ray.Huang@....com, Borislav.Petkov@....com,
	Alexander.Deucher@....com, Xinmei.Huang@....com,
	Xiaojian.Du@....com, Li.Meng@....com, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/7] cpufreq: amd-pstate: initialize new core precision
 boost state

Hello Perry,

On Fri, Jan 26, 2024 at 04:08:05PM +0800, Perry Yuan wrote:
> From: Perry Yuan <Perry.Yuan@....com>

[..snip..]

> @@ -632,18 +645,27 @@ static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
>  	return lowest_nonlinear_freq * 1000;
>  }
>  
> -static void amd_pstate_boost_init(struct amd_cpudata *cpudata)
> +static int amd_pstate_boost_init(struct amd_cpudata *cpudata)
>  {
> -	u32 highest_perf, nominal_perf;
> +	u64 boost_state, boost_val;


> +	int ret;
>  
> -	highest_perf = READ_ONCE(cpudata->highest_perf);
> -	nominal_perf = READ_ONCE(cpudata->nominal_perf);
> +	ret = rdmsrl_on_cpu(cpudata->cpu, MSR_K7_HWCR, &boost_val);

Use hwcr_val instead of boost_val ?

> +	if (ret) {
> +		pr_err_once("failed to read initial CPU boost state!\n");
> +		return ret;
> +	}
>  
> -	if (highest_perf <= nominal_perf)
> -		return;
> +	boost_state = (boost_val >> 25) & 0x1;

How about the following ?

        boost_disabled = (hwcr_val & MSR_K7_HWCR_CPB_DIS);



> +	if (!boost_state) {

        if (!boost_disabled) {

> +		global.cpb_supported = true;
> +		global.cpb_boost = true;
> +	} else {
> +		global.cpb_supported = false;
> +		global.cpb_boost = false;
> +	}
>  
> -	cpudata->boost_supported = true;
> -	current_pstate_driver->boost_enabled = true;
> +	return ret;
>  }
>  
>  static void amd_perf_ctl_reset(unsigned int cpu)
> @@ -676,6 +698,9 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  	if (ret)
>  		goto free_cpudata1;
>  
> +	/* initialize cpu cores boot state */
> +	amd_pstate_boost_init(cpudata);
> +
>  	min_freq = amd_get_min_freq(cpudata);
>  	max_freq = amd_get_max_freq(cpudata);
>  	nominal_freq = amd_get_nominal_freq(cpudata);
> @@ -725,7 +750,6 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  
>  	policy->driver_data = cpudata;
>  
> -	amd_pstate_boost_init(cpudata);
>  	if (!current_pstate_driver->adjust_perf)
>  		current_pstate_driver->adjust_perf = amd_pstate_adjust_perf;
>  
> @@ -1093,6 +1117,9 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  	if (ret)
>  		goto free_cpudata1;
>  
> +	/* initialize cpu cores boot state */
> +	amd_pstate_boost_init(cpudata);
> +
>  	min_freq = amd_get_min_freq(cpudata);
>  	max_freq = amd_get_max_freq(cpudata);
>  	nominal_freq = amd_get_nominal_freq(cpudata);
> @@ -1143,7 +1170,6 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  			return ret;
>  		WRITE_ONCE(cpudata->cppc_cap1_cached, value);
>  	}
> -	amd_pstate_boost_init(cpudata);
>  
>  	return 0;
>  
> diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> index 446394f84606..66d939a344b1 100644
> --- a/include/linux/amd-pstate.h
> +++ b/include/linux/amd-pstate.h
> @@ -80,7 +80,6 @@ struct amd_cpudata {
>  	struct amd_aperf_mperf prev;
>  
>  	u64	freq;
> -	bool	boost_supported;
>  
>  	/* EPP feature related attributes*/
>  	s16	epp_policy;
> -- 
> 2.34.1
> 

Otherwise looks good to me.
--
Thanks and Regards
gautham.