2022-12-19 07:15:36

by Yuan, Perry

Subject: [PATCH v8 08/13] cpufreq: amd-pstate: implement suspend and resume callbacks

From: Perry Yuan <[email protected]>

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 <[email protected]>
Signed-off-by: Perry Yuan <[email protected]>
---
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

2022-12-23 08:26:03

by Huang Rui

Subject: Re: [PATCH v8 08/13] cpufreq: amd-pstate: implement suspend and resume callbacks

On Mon, Dec 19, 2022 at 02:40:37PM +0800, Yuan, Perry wrote:
> From: Perry Yuan <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: Perry Yuan <[email protected]>

Acked-by: Huang Rui <[email protected]>

> ---
> 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
>