diff mbox series

[v3,6/8] cpufreq: amd-pstate: implement suspend and resume callbacks

Message ID 20221107175705.2207842-7-Perry.Yuan@amd.com
State New
Headers
Series Implement AMD Pstate EPP Driver |

Commit Message

Yuan, Perry Nov. 7, 2022, 5:57 p.m. UTC 
  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>
---
 drivers/cpufreq/amd-pstate.c | 40 ++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

Comments

Mario Limonciello Nov. 7, 2022, 6:18 p.m. UTC | #1 
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,
>   };
Nathan Fontenot Nov. 10, 2022, 4:19 p.m. UTC | #2 
On 11/7/22 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>
> ---
>  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;

Shouldn't we set this only after the amd_pstate_enable(false) call succeeds?

> +
> +	/* disable CPPC in lowlevel firmware */
> +	ret = amd_pstate_enable(false);
> +	if (ret)
> +		pr_err("failed to suspend, return %d\n", ret);
> +
> +	return 0;

You could drop the checking of ret here and just return ret. The caller
cpufreq.c:cpufreq_suspend() already does a check of the return code and
prints an error message.

> +}
> +
> +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);

This call can fail, we should check the return code.

-Nathan

> +
> +		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,
>  };
Yuan, Perry Nov. 13, 2022, 4:19 p.m. UTC | #3 
[AMD Official Use Only - General]

Hi Mario. 

> -----Original Message-----
> From: Limonciello, Mario <Mario.Limonciello@amd.com>
> Sent: Tuesday, November 8, 2022 2:18 AM
> To: Yuan, Perry <Perry.Yuan@amd.com>; rafael.j.wysocki@intel.com; Huang,
> Ray <Ray.Huang@amd.com>; viresh.kumar@linaro.org
> Cc: Sharma, Deepak <Deepak.Sharma@amd.com>; Fontenot, Nathan
> <Nathan.Fontenot@amd.com>; Deucher, Alexander
> <Alexander.Deucher@amd.com>; Huang, Shimmer
> <Shimmer.Huang@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>; Meng,
> Li (Jassmine) <Li.Meng@amd.com>; linux-pm@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH v3 6/8] cpufreq: amd-pstate: implement suspend and
> resume callbacks
> 
> 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>

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

Perry. 

> 
> > ---
> >   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,
> >   };
diff mbox series

Patch

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,
 };