RE: [PATCH v3 5/8] cpufreq: amd_pstate: implement amd pstate cpu online and offline callback

[Yuan, Perry]

[AMD Official Use Only - General]



> -----Original Message-----
> From: Limonciello, Mario <Mario.Limonciello@xxxxxxx>
> Sent: Tuesday, November 8, 2022 2:22 AM
> To: Yuan, Perry <Perry.Yuan@xxxxxxx>; rafael.j.wysocki@xxxxxxxxx; Huang,
> Ray <Ray.Huang@xxxxxxx>; viresh.kumar@xxxxxxxxxx
> Cc: Sharma, Deepak <Deepak.Sharma@xxxxxxx>; Fontenot, Nathan
> <Nathan.Fontenot@xxxxxxx>; Deucher, Alexander
> <Alexander.Deucher@xxxxxxx>; Huang, Shimmer
> <Shimmer.Huang@xxxxxxx>; Du, Xiaojian <Xiaojian.Du@xxxxxxx>; Meng,
> Li (Jassmine) <Li.Meng@xxxxxxx>; linux-pm@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v3 5/8] cpufreq: amd_pstate: implement amd pstate cpu
> online and offline callback
> 
> On 11/7/2022 11:57, Perry Yuan wrote:
> > Adds online and offline driver callback support to allow cpu cores go
> > offline and help to restore the previous working states when core goes
> > back online later for EPP driver mode.
> >
> > Signed-off-by: Perry Yuan <Perry.Yuan@xxxxxxx>
> 
> Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx>

Thank you.
I pick up the RB tag in the V4.

Perry.

> 
> > ---
> >   drivers/cpufreq/amd-pstate.c | 89
> ++++++++++++++++++++++++++++++++++++
> >   include/linux/amd-pstate.h   |  1 +
> >   2 files changed, 90 insertions(+)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index eb82bc6a7f66..6ce9fca0a128 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -1195,6 +1195,93 @@ static int amd_pstate_epp_set_policy(struct
> cpufreq_policy *policy)
> >   	return 0;
> >   }
> >
> > +static void amd_pstate_epp_reenable(struct amd_cpudata *cpudata) {
> > +	struct cppc_perf_ctrls perf_ctrls;
> > +	u64 value, max_perf;
> > +	int ret;
> > +
> > +	ret = amd_pstate_enable(true);
> > +	if (ret)
> > +		pr_err("failed to enable amd pstate during resume,
> return %d\n",
> > +ret);
> > +
> > +	value = READ_ONCE(cpudata->cppc_req_cached);
> > +	max_perf = READ_ONCE(cpudata->highest_perf);
> > +
> > +	if (boot_cpu_has(X86_FEATURE_CPPC)) {
> > +		wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
> > +	} else {
> > +		perf_ctrls.max_perf = max_perf;
> > +		perf_ctrls.energy_perf =
> AMD_CPPC_ENERGY_PERF_PREF(cpudata->epp_cached);
> > +		cppc_set_perf(cpudata->cpu, &perf_ctrls);
> > +	}
> > +}
> > +
> > +static int amd_pstate_epp_cpu_online(struct cpufreq_policy *policy) {
> > +	struct amd_cpudata *cpudata = all_cpu_data[policy->cpu];
> > +
> > +	pr_debug("AMD CPU Core %d going online\n", cpudata->cpu);
> > +
> > +	if (cppc_active) {
> > +		amd_pstate_epp_reenable(cpudata);
> > +		cpudata->suspended = false;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static void amd_pstate_epp_offline(struct cpufreq_policy *policy) {
> > +	struct amd_cpudata *cpudata = all_cpu_data[policy->cpu];
> > +	struct cppc_perf_ctrls perf_ctrls;
> > +	int min_perf;
> > +	u64 value;
> > +
> > +	min_perf = READ_ONCE(cpudata->lowest_perf);
> > +	value = READ_ONCE(cpudata->cppc_req_cached);
> > +
> > +	mutex_lock(&amd_pstate_limits_lock);
> > +	if (boot_cpu_has(X86_FEATURE_CPPC)) {
> > +		cpudata->epp_policy = CPUFREQ_POLICY_UNKNOWN;
> > +
> > +		/* Set max perf same as min perf */
> > +		value &= ~AMD_CPPC_MAX_PERF(~0L);
> > +		value |= AMD_CPPC_MAX_PERF(min_perf);
> > +		value &= ~AMD_CPPC_MIN_PERF(~0L);
> > +		value |= AMD_CPPC_MIN_PERF(min_perf);
> > +		wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
> > +	} else {
> > +		perf_ctrls.desired_perf = 0;
> > +		perf_ctrls.max_perf = min_perf;
> > +		perf_ctrls.energy_perf =
> AMD_CPPC_ENERGY_PERF_PREF(AMD_CPPC_EPP_POWERSAVE);
> > +		cppc_set_perf(cpudata->cpu, &perf_ctrls);
> > +	}
> > +	mutex_unlock(&amd_pstate_limits_lock);
> > +}
> > +
> > +static int amd_pstate_cpu_offline(struct cpufreq_policy *policy) {
> > +	struct amd_cpudata *cpudata = all_cpu_data[policy->cpu];
> > +
> > +	pr_debug("AMD CPU Core %d going offline\n", cpudata->cpu);
> > +
> > +	if (cpudata->suspended)
> > +		return 0;
> > +
> > +	if (cppc_active)
> > +		amd_pstate_epp_offline(policy);
> > +
> > +	return 0;
> > +}
> > +
> > +static int amd_pstate_epp_cpu_offline(struct cpufreq_policy *policy)
> > +{
> > +	amd_pstate_clear_update_util_hook(policy->cpu);
> > +
> > +	return amd_pstate_cpu_offline(policy); }
> > +
> >   static void amd_pstate_verify_cpu_policy(struct amd_cpudata *cpudata,
> >   					   struct cpufreq_policy_data *policy)
> >   {
> > @@ -1229,6 +1316,8 @@ static struct cpufreq_driver
> amd_pstate_epp_driver = {
> >   	.init		= amd_pstate_epp_cpu_init,
> >   	.exit		= amd_pstate_epp_cpu_exit,
> >   	.update_limits	= amd_pstate_epp_update_limits,
> > +	.offline	= amd_pstate_epp_cpu_offline,
> > +	.online		= amd_pstate_epp_cpu_online,
> >   	.name		= "amd_pstate_epp",
> >   	.attr		= amd_pstate_epp_attr,
> >   };
> > diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> > index 7e6e8cab97b3..c0ad7eedcae3 100644
> > --- a/include/linux/amd-pstate.h
> > +++ b/include/linux/amd-pstate.h
> > @@ -99,6 +99,7 @@ struct amd_cpudata {
> >   	u64	cppc_cap1_cached;
> >   	struct	update_util_data update_util;
> >   	struct	amd_aperf_mperf sample;
> > +	bool suspended;
> >   };
> >
> >   /**