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Date: Fri, 3 Nov 2023 11:00:23 +0800
From: Huang Rui <ray.huang@....com>
To: Wyes Karny <wyes.karny@....com>
Cc: "rafael@...nel.org" <rafael@...nel.org>,
"viresh.kumar@...aro.org" <viresh.kumar@...aro.org>,
"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"Yuan, Perry" <Perry.Yuan@....com>
Subject: Re: [PATCH] cpufreq/amd-pstate: Fix scaling_min_freq and
scaling_max_freq update
On Fri, Sep 22, 2023 at 02:12:29PM +0800, Wyes Karny wrote:
> When amd_pstate is running, writing to scaling_min_freq and
> scaling_max_freq has no effect. These values are only passed to the
> policy level, but not to the platform level. This means that the
> platform does not know about the frequency limits set by the user. To
> fix this, update the min_perf and max_perf values at the platform level
> whenever the user changes the scaling_min_freq and scaling_max_freq
> values.
>
> Signed-off-by: Wyes Karny <wyes.karny@....com>
Acked-by: Huang Rui <ray.huang@....com>
> ---
> drivers/cpufreq/amd-pstate.c | 60 ++++++++++++++++++++++++++++--------
> include/linux/amd-pstate.h | 4 +++
> 2 files changed, 51 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 9a1e194d5cf8..4839cdd2715e 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -307,11 +307,11 @@ static int pstate_init_perf(struct amd_cpudata *cpudata)
> highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);
>
> WRITE_ONCE(cpudata->highest_perf, highest_perf);
> -
> + WRITE_ONCE(cpudata->max_limit_perf, highest_perf);
> WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1));
> WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1));
> WRITE_ONCE(cpudata->lowest_perf, AMD_CPPC_LOWEST_PERF(cap1));
> -
> + WRITE_ONCE(cpudata->min_limit_perf, AMD_CPPC_LOWEST_PERF(cap1));
> return 0;
> }
>
> @@ -329,11 +329,12 @@ static int cppc_init_perf(struct amd_cpudata *cpudata)
> highest_perf = cppc_perf.highest_perf;
>
> WRITE_ONCE(cpudata->highest_perf, highest_perf);
> -
> + WRITE_ONCE(cpudata->max_limit_perf, highest_perf);
> WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);
> WRITE_ONCE(cpudata->lowest_nonlinear_perf,
> cppc_perf.lowest_nonlinear_perf);
> WRITE_ONCE(cpudata->lowest_perf, cppc_perf.lowest_perf);
> + WRITE_ONCE(cpudata->min_limit_perf, cppc_perf.lowest_perf);
>
> if (cppc_state == AMD_PSTATE_ACTIVE)
> return 0;
> @@ -432,6 +433,10 @@ static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
> u64 prev = READ_ONCE(cpudata->cppc_req_cached);
> u64 value = prev;
>
> + min_perf = clamp_t(unsigned long, min_perf, cpudata->min_limit_perf,
> + cpudata->max_limit_perf);
> + max_perf = clamp_t(unsigned long, max_perf, cpudata->min_limit_perf,
> + cpudata->max_limit_perf);
> des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf);
>
> if ((cppc_state == AMD_PSTATE_GUIDED) && (gov_flags & CPUFREQ_GOV_DYNAMIC_SWITCHING)) {
> @@ -470,6 +475,22 @@ static int amd_pstate_verify(struct cpufreq_policy_data *policy)
> return 0;
> }
>
> +static int amd_pstate_update_min_max_limit(struct cpufreq_policy *policy)
> +{
> + u32 max_limit_perf, min_limit_perf;
> + struct amd_cpudata *cpudata = policy->driver_data;
> +
> + max_limit_perf = div_u64(policy->max * cpudata->highest_perf, cpudata->max_freq);
> + min_limit_perf = div_u64(policy->min * cpudata->highest_perf, cpudata->max_freq);
> +
> + WRITE_ONCE(cpudata->max_limit_perf, max_limit_perf);
> + WRITE_ONCE(cpudata->min_limit_perf, min_limit_perf);
> + WRITE_ONCE(cpudata->max_limit_freq, policy->max);
> + WRITE_ONCE(cpudata->min_limit_freq, policy->min);
> +
> + return 0;
> +}
> +
> static int amd_pstate_update_freq(struct cpufreq_policy *policy,
> unsigned int target_freq, bool fast_switch)
> {
> @@ -480,6 +501,9 @@ static int amd_pstate_update_freq(struct cpufreq_policy *policy,
> if (!cpudata->max_freq)
> return -ENODEV;
>
> + 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);
> min_perf = READ_ONCE(cpudata->lowest_perf);
> max_perf = cap_perf;
> @@ -532,6 +556,10 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
> struct amd_cpudata *cpudata = policy->driver_data;
> unsigned int target_freq;
>
> + 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);
> lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf);
> max_freq = READ_ONCE(cpudata->max_freq);
> @@ -745,6 +773,8 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
> /* Initial processor data capability frequencies */
> cpudata->max_freq = max_freq;
> cpudata->min_freq = min_freq;
> + cpudata->max_limit_freq = max_freq;
> + cpudata->min_limit_freq = min_freq;
> cpudata->nominal_freq = nominal_freq;
> cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq;
>
> @@ -1183,16 +1213,25 @@ static int amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy)
> return 0;
> }
>
> -static void amd_pstate_epp_init(unsigned int cpu)
> +static void amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
> {
> - struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
> struct amd_cpudata *cpudata = policy->driver_data;
> - u32 max_perf, min_perf;
> + u32 max_perf, min_perf, min_limit_perf, max_limit_perf;
> u64 value;
> s16 epp;
>
> max_perf = READ_ONCE(cpudata->highest_perf);
> min_perf = READ_ONCE(cpudata->lowest_perf);
> + max_limit_perf = div_u64(policy->max * cpudata->highest_perf, cpudata->max_freq);
> + min_limit_perf = div_u64(policy->min * cpudata->highest_perf, cpudata->max_freq);
> +
> + max_perf = clamp_t(unsigned long, max_perf, cpudata->min_limit_perf,
> + cpudata->max_limit_perf);
> + min_perf = clamp_t(unsigned long, min_perf, cpudata->min_limit_perf,
> + cpudata->max_limit_perf);
> +
> + WRITE_ONCE(cpudata->max_limit_perf, max_limit_perf);
> + WRITE_ONCE(cpudata->min_limit_perf, min_limit_perf);
>
> value = READ_ONCE(cpudata->cppc_req_cached);
>
> @@ -1210,9 +1249,6 @@ static void amd_pstate_epp_init(unsigned int cpu)
> value &= ~AMD_CPPC_DES_PERF(~0L);
> value |= AMD_CPPC_DES_PERF(0);
>
> - if (cpudata->epp_policy == cpudata->policy)
> - goto skip_epp;
> -
> cpudata->epp_policy = cpudata->policy;
>
> /* Get BIOS pre-defined epp value */
> @@ -1222,7 +1258,7 @@ static void amd_pstate_epp_init(unsigned int cpu)
> * This return value can only be negative for shared_memory
> * systems where EPP register read/write not supported.
> */
> - goto skip_epp;
> + return;
> }
>
> if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
> @@ -1236,8 +1272,6 @@ static void amd_pstate_epp_init(unsigned int cpu)
>
> WRITE_ONCE(cpudata->cppc_req_cached, value);
> amd_pstate_set_epp(cpudata, epp);
> -skip_epp:
> - cpufreq_cpu_put(policy);
> }
>
> static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
> @@ -1252,7 +1286,7 @@ static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
>
> cpudata->policy = policy->policy;
>
> - amd_pstate_epp_init(policy->cpu);
> + amd_pstate_epp_update_limit(policy);
>
> return 0;
> }
> diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> index 446394f84606..6ad02ad9c7b4 100644
> --- a/include/linux/amd-pstate.h
> +++ b/include/linux/amd-pstate.h
> @@ -70,6 +70,10 @@ struct amd_cpudata {
> u32 nominal_perf;
> u32 lowest_nonlinear_perf;
> u32 lowest_perf;
> + u32 min_limit_perf;
> + u32 max_limit_perf;
> + u32 min_limit_freq;
> + u32 max_limit_freq;
>
> u32 max_freq;
> u32 min_freq;
> --
> 2.34.1
>
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