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Date: Thu, 8 Dec 2022 19:18:46 +0800 From: Perry Yuan <perry.yuan@....com> To: <rafael.j.wysocki@...el.com>, <Mario.Limonciello@....com>, <ray.huang@....com>, <viresh.kumar@...aro.org> CC: <Deepak.Sharma@....com>, <Nathan.Fontenot@....com>, <Alexander.Deucher@....com>, <Shimmer.Huang@....com>, <Xiaojian.Du@....com>, <Li.Meng@....com>, <wyes.karny@....com>, <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org> Subject: [PATCH v7 07/13] cpufreq: amd-pstate: implement suspend and resume callbacks From: Perry Yuan <Perry.Yuan@....com> 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@....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 412accab7bda..ea9255bdc9ac 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -1273,6 +1273,44 @@ 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) { @@ -1309,6 +1347,8 @@ 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, }; -- 2.34.1
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