Re: [PATCH 10/19] cpufreq: amd: add amd-pstate frequencies attributes

From: "Fontenot, Nathan" <Nathan.Fontenot@amd.com>
To: Huang Rui <ray.huang@amd.com>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Shuah Khan <skhan@linuxfoundation.org>,
	Borislav Petkov <bp@suse.de>, Ingo Molnar <mingo@kernel.org>,
	linux-pm@vger.kernel.org
Cc: Deepak Sharma <deepak.sharma@amd.com>,
	Alex Deucher <alexander.deucher@amd.com>,
	Mario Limonciello <mario.limonciello@amd.com>,
	Jinzhou Su <Jinzhou.Su@amd.com>,
	Xiaojian Du <Xiaojian.Du@amd.com>,
	linux-kernel@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH 10/19] cpufreq: amd: add amd-pstate frequencies attributes
Date: Wed, 8 Sep 2021 13:13:41 -0500	[thread overview]
Message-ID: <25cbd9b4-f7f3-9b84-096a-5b2bffbd3e40@amd.com> (raw)
In-Reply-To: <20210908150001.3702552-11-ray.huang@amd.com>

On 9/8/2021 9:59 AM, Huang Rui wrote:
> Introduce sysfs attributes to get the different level processor
> frequencies.
> 
> Signed-off-by: Huang Rui <ray.huang@amd.com>
> ---
>  drivers/cpufreq/amd-pstate.c | 80 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 79 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 48dedd5af101..3c727a22cb69 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -577,16 +577,94 @@ static int amd_pstate_cpu_exit(struct cpufreq_policy *policy)
>  	return 0;
>  }
>  
> -static ssize_t show_is_amd_pstate_enabled(struct cpufreq_policy *policy,
> +/* Sysfs attributes */
> +
> +static ssize_t show_amd_pstate_max_freq(struct cpufreq_policy *policy,
>  					char *buf)
> +{
> +	int ret = 0, max_freq;
> +	struct amd_cpudata *cpudata;
> +
> +	cpudata = policy->driver_data;
> +
> +	max_freq = amd_get_max_freq(cpudata);
> +	if (max_freq < 0)
> +		return max_freq;
> +
> +	ret += sprintf(&buf[ret], "%u\n", max_freq);
> +
> +	return ret;

Here, and in the functions below, you could just do

	return sprintf(&buf[ret], "%u\n", max_freq);

and get rid of the intermediary 'ret' variable.

-Nathan

> +}
> +
> +static ssize_t show_amd_pstate_nominal_freq(struct cpufreq_policy *policy,
> +					    char *buf)
> +{
> +	int ret = 0, nominal_freq;
> +	struct amd_cpudata *cpudata;
> +
> +	cpudata = policy->driver_data;
> +
> +	nominal_freq = amd_get_nominal_freq(cpudata);
> +	if (nominal_freq < 0)
> +		return nominal_freq;
> +
> +	ret += sprintf(&buf[ret], "%u\n", nominal_freq);
> +
> +	return ret;
> +}
> +
> +static ssize_t
> +show_amd_pstate_lowest_nonlinear_freq(struct cpufreq_policy *policy, char *buf)
> +{
> +	int ret = 0, freq;
> +	struct amd_cpudata *cpudata;
> +
> +	cpudata = policy->driver_data;
> +
> +	freq = amd_get_lowest_nonlinear_freq(cpudata);
> +	if (freq < 0)
> +		return freq;
> +
> +	ret += sprintf(&buf[ret], "%u\n", freq);
> +
> +	return ret;
> +}
> +
> +static ssize_t show_amd_pstate_min_freq(struct cpufreq_policy *policy, char *buf)
> +{
> +	int ret = 0;
> +	int freq;
> +	struct amd_cpudata *cpudata;
> +
> +	cpudata = policy->driver_data;
> +
> +	freq = amd_get_min_freq(cpudata);
> +	if (freq < 0)
> +		return freq;
> +
> +	ret += sprintf(&buf[ret], "%u\n", freq);
> +
> +	return ret;
> +}
> +
> +static ssize_t show_is_amd_pstate_enabled(struct cpufreq_policy *policy,
> +					  char *buf)
>  {
>  	return sprintf(&buf[0], "%d\n", acpi_cpc_valid() ?  1 : 0);
>  }
>  
>  cpufreq_freq_attr_ro(is_amd_pstate_enabled);
> +cpufreq_freq_attr_ro(amd_pstate_max_freq);
> +cpufreq_freq_attr_ro(amd_pstate_nominal_freq);
> +cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
> +cpufreq_freq_attr_ro(amd_pstate_min_freq);
>  
>  static struct freq_attr *amd_pstate_attr[] = {
>  	&is_amd_pstate_enabled,
> +	&amd_pstate_max_freq,
> +	&amd_pstate_nominal_freq,
> +	&amd_pstate_lowest_nonlinear_freq,
> +	&amd_pstate_min_freq,
>  	NULL,
>  };
>  
> -- 
> 2.25.1
> 