Messages in this thread Patch in this message |  | | From | Perry Yuan <> | Subject | [PATCH v8 08/13] cpufreq: amd-pstate: implement suspend and resume callbacks | Date | Mon, 19 Dec 2022 14:40:37 +0800 |
| |
From: Perry Yuan <Perry.Yuan@amd.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.
Reviewed-by: Mario Limonciello <Mario.Limonciello@amd.com> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com> --- drivers/cpufreq/amd-pstate.c | 41 ++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index cb647f55a169..fc12d35bc7bd 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -1107,6 +1107,45 @@ static int amd_pstate_epp_verify_policy(struct cpufreq_policy_data *policy) return 0; } +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_state != AMD_PSTATE_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 struct cpufreq_driver amd_pstate_driver = { .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_NEED_UPDATE_LIMITS, .verify = amd_pstate_verify, @@ -1129,6 +1168,8 @@ 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
|  |