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Message-ID: <0785e275-5c0b-4cf8-b8db-4396a81949ed@amd.com>
Date: Wed, 5 Feb 2025 11:46:37 -0600
From: Mario Limonciello <mario.limonciello@....com>
To: Dhananjay Ugwekar <dhananjay.ugwekar@....com>, gautham.shenoy@....com,
rafael@...nel.org, viresh.kumar@...aro.org
Cc: linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH 07/12] cpufreq/amd-pstate: Modularize perf<->freq
conversion
On 2/5/2025 05:25, Dhananjay Ugwekar wrote:
> Delegate the perf<->frequency conversion to helper functions to reduce
> code duplication, and improve readability.
>
> Signed-off-by: Dhananjay Ugwekar <dhananjay.ugwekar@....com>
Reviewed-by: Mario Limonciello <mario.limonciello@....com>
I'll queue this for 6.15.
> ---
> drivers/cpufreq/amd-pstate.c | 57 +++++++++++++++++++-----------------
> 1 file changed, 30 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index dd4f23fa2587..346fac646eba 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -142,6 +142,20 @@ static struct quirk_entry quirk_amd_7k62 = {
> .lowest_freq = 550,
> };
>
> +static inline u8 freq_to_perf(struct amd_cpudata *cpudata, unsigned int freq_val)
> +{
> + u8 perf_val = DIV_ROUND_UP_ULL((u64)freq_val * cpudata->nominal_perf,
> + cpudata->nominal_freq);
> +
> + return clamp_t(u8, perf_val, cpudata->lowest_perf, cpudata->highest_perf);
> +}
> +
> +static inline u32 perf_to_freq(struct amd_cpudata *cpudata, u8 perf_val)
> +{
> + return DIV_ROUND_UP_ULL((u64)cpudata->nominal_freq * perf_val,
> + cpudata->nominal_perf);
> +}
> +
> static int __init dmi_matched_7k62_bios_bug(const struct dmi_system_id *dmi)
> {
> /**
> @@ -534,14 +548,12 @@ static inline bool amd_pstate_sample(struct amd_cpudata *cpudata)
> static void amd_pstate_update(struct amd_cpudata *cpudata, u8 min_perf,
> u8 des_perf, u8 max_perf, bool fast_switch, int gov_flags)
> {
> - unsigned long max_freq;
> struct cpufreq_policy *policy = cpufreq_cpu_get(cpudata->cpu);
> u8 nominal_perf = READ_ONCE(cpudata->nominal_perf);
>
> des_perf = clamp_t(u8, des_perf, min_perf, max_perf);
>
> - max_freq = READ_ONCE(cpudata->max_limit_freq);
> - policy->cur = div_u64(des_perf * max_freq, max_perf);
> + policy->cur = perf_to_freq(cpudata, des_perf);
>
> if ((cppc_state == AMD_PSTATE_GUIDED) && (gov_flags & CPUFREQ_GOV_DYNAMIC_SWITCHING)) {
> min_perf = des_perf;
> @@ -591,14 +603,11 @@ static int amd_pstate_verify(struct cpufreq_policy_data *policy_data)
>
> static int amd_pstate_update_min_max_limit(struct cpufreq_policy *policy)
> {
> - u8 max_limit_perf, min_limit_perf, max_perf;
> - u32 max_freq;
> + u8 max_limit_perf, min_limit_perf;
> struct amd_cpudata *cpudata = policy->driver_data;
>
> - max_perf = READ_ONCE(cpudata->highest_perf);
> - max_freq = READ_ONCE(cpudata->max_freq);
> - max_limit_perf = div_u64(policy->max * max_perf, max_freq);
> - min_limit_perf = div_u64(policy->min * max_perf, max_freq);
> + max_limit_perf = freq_to_perf(cpudata, policy->max);
> + min_limit_perf = freq_to_perf(cpudata, policy->min);
>
> if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
> min_limit_perf = min(cpudata->nominal_perf, max_limit_perf);
> @@ -616,21 +625,15 @@ static int amd_pstate_update_freq(struct cpufreq_policy *policy,
> {
> struct cpufreq_freqs freqs;
> struct amd_cpudata *cpudata = policy->driver_data;
> - u8 des_perf, cap_perf;
> -
> - if (!cpudata->max_freq)
> - return -ENODEV;
> + u8 des_perf;
>
> if (policy->min != cpudata->min_limit_freq || policy->max != cpudata->max_limit_freq)
> amd_pstate_update_min_max_limit(policy);
>
> - cap_perf = READ_ONCE(cpudata->highest_perf);
> -
> freqs.old = policy->cur;
> freqs.new = target_freq;
>
> - des_perf = DIV_ROUND_CLOSEST(target_freq * cap_perf,
> - cpudata->max_freq);
> + des_perf = freq_to_perf(cpudata, target_freq);
>
> WARN_ON(fast_switch && !policy->fast_switch_enabled);
> /*
> @@ -904,7 +907,6 @@ static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
> {
> int ret;
> u32 min_freq, max_freq;
> - u8 highest_perf, nominal_perf, lowest_nonlinear_perf;
> u32 nominal_freq, lowest_nonlinear_freq;
> struct cppc_perf_caps cppc_perf;
>
> @@ -922,16 +924,17 @@ static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
> else
> nominal_freq = cppc_perf.nominal_freq;
>
> - highest_perf = READ_ONCE(cpudata->highest_perf);
> - nominal_perf = READ_ONCE(cpudata->nominal_perf);
> - max_freq = div_u64((u64)highest_perf * nominal_freq, nominal_perf);
> + min_freq *= 1000;
> + nominal_freq *= 1000;
> +
> + WRITE_ONCE(cpudata->nominal_freq, nominal_freq);
> + WRITE_ONCE(cpudata->min_freq, min_freq);
> +
> + max_freq = perf_to_freq(cpudata, cpudata->highest_perf);
> + lowest_nonlinear_freq = perf_to_freq(cpudata, cpudata->lowest_nonlinear_perf);
>
> - lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf);
> - lowest_nonlinear_freq = div_u64((u64)nominal_freq * lowest_nonlinear_perf, nominal_perf);
> - WRITE_ONCE(cpudata->min_freq, min_freq * 1000);
> - WRITE_ONCE(cpudata->lowest_nonlinear_freq, lowest_nonlinear_freq * 1000);
> - WRITE_ONCE(cpudata->nominal_freq, nominal_freq * 1000);
> - WRITE_ONCE(cpudata->max_freq, max_freq * 1000);
> + WRITE_ONCE(cpudata->lowest_nonlinear_freq, lowest_nonlinear_freq);
> + WRITE_ONCE(cpudata->max_freq, max_freq);
>
> /**
> * Below values need to be initialized correctly, otherwise driver will fail to load
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