Messages in this thread | | | Date | Mon, 7 Nov 2022 12:18:09 -0600 | Subject | Re: [PATCH v3 6/8] cpufreq: amd-pstate: implement suspend and resume callbacks | From | "Limonciello, Mario" <> |
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On 11/7/2022 11:57, Perry Yuan wrote: > add suspend and resume support for the AMD processors by amd_pstate_epp > driver instance. > > When the CPPC is suspended, EPP driver will set EPP profile to 'power' > profile and set max/min perf to lowest perf value. > When resume happens, it will restore the MSR registers with > previous cached value. > > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
> --- > drivers/cpufreq/amd-pstate.c | 40 ++++++++++++++++++++++++++++++++++++ > 1 file changed, 40 insertions(+) > > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c > index 6ce9fca0a128..841b1e2383b8 100644 > --- a/drivers/cpufreq/amd-pstate.c > +++ b/drivers/cpufreq/amd-pstate.c > @@ -1282,6 +1282,44 @@ static int amd_pstate_epp_cpu_offline(struct cpufreq_policy *policy) > return amd_pstate_cpu_offline(policy); > } > > +static int amd_pstate_epp_suspend(struct cpufreq_policy *policy) > +{ > + struct amd_cpudata *cpudata = all_cpu_data[policy->cpu]; > + int ret; > + > + /* avoid suspending when EPP is not enabled */ > + if (!cppc_active) > + return 0; > + > + /* set this flag to avoid setting core offline*/ > + cpudata->suspended = true; > + > + /* disable CPPC in lowlevel firmware */ > + ret = amd_pstate_enable(false); > + if (ret) > + pr_err("failed to suspend, return %d\n", ret); > + > + return 0; > +} > + > +static int amd_pstate_epp_resume(struct cpufreq_policy *policy) > +{ > + struct amd_cpudata *cpudata = all_cpu_data[policy->cpu]; > + > + if (cpudata->suspended) { > + mutex_lock(&amd_pstate_limits_lock); > + > + /* enable amd pstate from suspend state*/ > + amd_pstate_epp_reenable(cpudata); > + > + mutex_unlock(&amd_pstate_limits_lock); > + > + cpudata->suspended = false; > + } > + > + return 0; > +} > + > static void amd_pstate_verify_cpu_policy(struct amd_cpudata *cpudata, > struct cpufreq_policy_data *policy) > { > @@ -1318,6 +1356,8 @@ static struct cpufreq_driver amd_pstate_epp_driver = { > .update_limits = amd_pstate_epp_update_limits, > .offline = amd_pstate_epp_cpu_offline, > .online = amd_pstate_epp_cpu_online, > + .suspend = amd_pstate_epp_suspend, > + .resume = amd_pstate_epp_resume, > .name = "amd_pstate_epp", > .attr = amd_pstate_epp_attr, > };
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