[PATCH] cpufreq: CPPC: Support for autonomous selection in cppc_cpufreq

Lifeng Zheng posted 1 patch 7 months, 1 week ago
.../ABI/testing/sysfs-devices-system-cpu      |  54 +++++++++
drivers/cpufreq/cppc_cpufreq.c                | 109 ++++++++++++++++++
2 files changed, 163 insertions(+)
[PATCH] cpufreq: CPPC: Support for autonomous selection in cppc_cpufreq
Posted by Lifeng Zheng 7 months, 1 week ago
Add sysfs interfaces for CPPC autonomous selection in the cppc_cpufreq
driver.

Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
---
Hi Rafael,

This patch is the 8th patch in [1]. After the discussion in [2], Sumit
is OK with adding sysfs entries under cpufreq sysfs node, so I resend
this patch. He will later send his updated patch after.

Any comments appreciated!

Lifeng

[1] https://lore.kernel.org/all/20250206131428.3261578-1-zhenglifeng1@huawei.com/
[2] https://lore.kernel.org/all/20250211103737.447704-1-sumitg@nvidia.com/

 .../ABI/testing/sysfs-devices-system-cpu      |  54 +++++++++
 drivers/cpufreq/cppc_cpufreq.c                | 109 ++++++++++++++++++
 2 files changed, 163 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 206079d3bd5b..37065e1b8ebc 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -268,6 +268,60 @@ Description:	Discover CPUs in the same CPU frequency coordination domain
 		This file is only present if the acpi-cpufreq or the cppc-cpufreq
 		drivers are in use.
 
+What:		/sys/devices/system/cpu/cpuX/cpufreq/auto_select
+Date:		May 2025
+Contact:	linux-pm@vger.kernel.org
+Description:	Autonomous selection enable
+
+		Read/write interface to control autonomous selection enable
+			Read returns autonomous selection status:
+				0: autonomous selection is disabled
+				1: autonomous selection is enabled
+
+			Write 'y' or '1' or 'on' to enable autonomous selection.
+			Write 'n' or '0' or 'off' to disable autonomous selection.
+
+		This file is only present if the cppc-cpufreq driver is in use.
+
+What:		/sys/devices/system/cpu/cpuX/cpufreq/auto_act_window
+Date:		May 2025
+Contact:	linux-pm@vger.kernel.org
+Description:	Autonomous activity window
+
+		This file indicates a moving utilization sensitivity window to
+		the platform's autonomous selection policy.
+
+		Read/write an integer represents autonomous activity window (in
+		microseconds) from/to this file. The max value to write is
+		1270000000 but the max significand is 127. This means that if 128
+		is written to this file, 127 will be stored. If the value is
+		greater than 130, only the first two digits will be saved as
+		significand.
+
+		Writing a zero value to this file enable the platform to
+		determine an appropriate Activity Window depending on the workload.
+
+		Writing to this file only has meaning when Autonomous Selection is
+		enabled.
+
+		This file is only present if the cppc-cpufreq driver is in use.
+
+What:		/sys/devices/system/cpu/cpuX/cpufreq/energy_performance_preference_val
+Date:		May 2025
+Contact:	linux-pm@vger.kernel.org
+Description:	Energy performance preference
+
+		Read/write an 8-bit integer from/to this file. This file
+		represents a range of values from 0 (performance preference) to
+		0xFF (energy efficiency preference) that influences the rate of
+		performance increase/decrease and the result of the hardware's
+		energy efficiency and performance optimization policies.
+
+		Writing to this file only has meaning when Autonomous Selection is
+		enabled.
+
+		This file is only present if the cppc-cpufreq driver is in use.
+
 
 What:		/sys/devices/system/cpu/cpu*/cache/index3/cache_disable_{0,1}
 Date:		August 2008
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index b3d74f9adcf0..3c3d00cec298 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -808,10 +808,119 @@ static ssize_t show_freqdomain_cpus(struct cpufreq_policy *policy, char *buf)
 
 	return cpufreq_show_cpus(cpu_data->shared_cpu_map, buf);
 }
+
+static ssize_t show_auto_select(struct cpufreq_policy *policy, char *buf)
+{
+	bool val;
+	int ret;
+
+	ret = cppc_get_auto_sel(policy->cpu, &val);
+
+	/* show "<unsupported>" when this register is not supported by cpc */
+	if (ret == -EOPNOTSUPP)
+		return sysfs_emit(buf, "<unsupported>\n");
+
+	if (ret)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", val);
+}
+
+static ssize_t store_auto_select(struct cpufreq_policy *policy,
+				 const char *buf, size_t count)
+{
+	bool val;
+	int ret;
+
+	ret = kstrtobool(buf, &val);
+	if (ret)
+		return ret;
+
+	ret = cppc_set_auto_sel(policy->cpu, val);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t show_auto_act_window(struct cpufreq_policy *policy, char *buf)
+{
+	u64 val;
+	int ret;
+
+	ret = cppc_get_auto_act_window(policy->cpu, &val);
+
+	/* show "<unsupported>" when this register is not supported by cpc */
+	if (ret == -EOPNOTSUPP)
+		return sysfs_emit(buf, "<unsupported>\n");
+
+	if (ret)
+		return ret;
+
+	return sysfs_emit(buf, "%llu\n", val);
+}
+
+static ssize_t store_auto_act_window(struct cpufreq_policy *policy,
+				     const char *buf, size_t count)
+{
+	u64 usec;
+	int ret;
+
+	ret = kstrtou64(buf, 0, &usec);
+	if (ret)
+		return ret;
+
+	ret = cppc_set_auto_act_window(policy->cpu, usec);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t show_energy_performance_preference_val(struct cpufreq_policy *policy, char *buf)
+{
+	u64 val;
+	int ret;
+
+	ret = cppc_get_epp_perf(policy->cpu, &val);
+
+	/* show "<unsupported>" when this register is not supported by cpc */
+	if (ret == -EOPNOTSUPP)
+		return sysfs_emit(buf, "<unsupported>\n");
+
+	if (ret)
+		return ret;
+
+	return sysfs_emit(buf, "%llu\n", val);
+}
+
+static ssize_t store_energy_performance_preference_val(struct cpufreq_policy *policy,
+						       const char *buf, size_t count)
+{
+	u64 val;
+	int ret;
+
+	ret = kstrtou64(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	ret = cppc_set_epp(policy->cpu, val);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
 cpufreq_freq_attr_ro(freqdomain_cpus);
+cpufreq_freq_attr_rw(auto_select);
+cpufreq_freq_attr_rw(auto_act_window);
+cpufreq_freq_attr_rw(energy_performance_preference_val);
 
 static struct freq_attr *cppc_cpufreq_attr[] = {
 	&freqdomain_cpus,
+	&auto_select,
+	&auto_act_window,
+	&energy_performance_preference_val,
 	NULL,
 };
 
-- 
2.33.0
Re: [PATCH] cpufreq: CPPC: Support for autonomous selection in cppc_cpufreq
Posted by Sumit Gupta 6 months, 4 weeks ago

On 07/05/25 08:49, Lifeng Zheng wrote:
> External email: Use caution opening links or attachments
> 
> 
> Add sysfs interfaces for CPPC autonomous selection in the cppc_cpufreq
> driver.
> 
> Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>

Looks good to me.

Reviewed-by: Sumit Gupta <sumitg@nvidia.com>

> ---
> Hi Rafael,
> 
> This patch is the 8th patch in [1]. After the discussion in [2], Sumit
> is OK with adding sysfs entries under cpufreq sysfs node, so I resend
> this patch. He will later send his updated patch after.
> 
> Any comments appreciated!
> 
> Lifeng
> 
> [1] https://lore.kernel.org/all/20250206131428.3261578-1-zhenglifeng1@huawei.com/
> [2] https://lore.kernel.org/all/20250211103737.447704-1-sumitg@nvidia.com/
> 
>   .../ABI/testing/sysfs-devices-system-cpu      |  54 +++++++++
>   drivers/cpufreq/cppc_cpufreq.c                | 109 ++++++++++++++++++
>   2 files changed, 163 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
> index 206079d3bd5b..37065e1b8ebc 100644
> --- a/Documentation/ABI/testing/sysfs-devices-system-cpu
> +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
> @@ -268,6 +268,60 @@ Description:       Discover CPUs in the same CPU frequency coordination domain
>                  This file is only present if the acpi-cpufreq or the cppc-cpufreq
>                  drivers are in use.
> 
> +What:          /sys/devices/system/cpu/cpuX/cpufreq/auto_select
> +Date:          May 2025
> +Contact:       linux-pm@vger.kernel.org
> +Description:   Autonomous selection enable
> +
> +               Read/write interface to control autonomous selection enable
> +                       Read returns autonomous selection status:
> +                               0: autonomous selection is disabled
> +                               1: autonomous selection is enabled
> +
> +                       Write 'y' or '1' or 'on' to enable autonomous selection.
> +                       Write 'n' or '0' or 'off' to disable autonomous selection.
> +
> +               This file is only present if the cppc-cpufreq driver is in use.
> +
> +What:          /sys/devices/system/cpu/cpuX/cpufreq/auto_act_window
> +Date:          May 2025
> +Contact:       linux-pm@vger.kernel.org
> +Description:   Autonomous activity window
> +
> +               This file indicates a moving utilization sensitivity window to
> +               the platform's autonomous selection policy.
> +
> +               Read/write an integer represents autonomous activity window (in
> +               microseconds) from/to this file. The max value to write is
> +               1270000000 but the max significand is 127. This means that if 128
> +               is written to this file, 127 will be stored. If the value is
> +               greater than 130, only the first two digits will be saved as
> +               significand.
> +
> +               Writing a zero value to this file enable the platform to
> +               determine an appropriate Activity Window depending on the workload.
> +
> +               Writing to this file only has meaning when Autonomous Selection is
> +               enabled.
> +
> +               This file is only present if the cppc-cpufreq driver is in use.
> +
> +What:          /sys/devices/system/cpu/cpuX/cpufreq/energy_performance_preference_val
> +Date:          May 2025
> +Contact:       linux-pm@vger.kernel.org
> +Description:   Energy performance preference
> +
> +               Read/write an 8-bit integer from/to this file. This file
> +               represents a range of values from 0 (performance preference) to
> +               0xFF (energy efficiency preference) that influences the rate of
> +               performance increase/decrease and the result of the hardware's
> +               energy efficiency and performance optimization policies.
> +
> +               Writing to this file only has meaning when Autonomous Selection is
> +               enabled.
> +
> +               This file is only present if the cppc-cpufreq driver is in use.
> +
> 
>   What:          /sys/devices/system/cpu/cpu*/cache/index3/cache_disable_{0,1}
>   Date:          August 2008
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index b3d74f9adcf0..3c3d00cec298 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -808,10 +808,119 @@ static ssize_t show_freqdomain_cpus(struct cpufreq_policy *policy, char *buf)
> 
>          return cpufreq_show_cpus(cpu_data->shared_cpu_map, buf);
>   }
> +
> +static ssize_t show_auto_select(struct cpufreq_policy *policy, char *buf)
> +{
> +       bool val;
> +       int ret;
> +
> +       ret = cppc_get_auto_sel(policy->cpu, &val);
> +
> +       /* show "<unsupported>" when this register is not supported by cpc */
> +       if (ret == -EOPNOTSUPP)
> +               return sysfs_emit(buf, "<unsupported>\n");
> +
> +       if (ret)
> +               return ret;
> +
> +       return sysfs_emit(buf, "%d\n", val);
> +}
> +
> +static ssize_t store_auto_select(struct cpufreq_policy *policy,
> +                                const char *buf, size_t count)
> +{
> +       bool val;
> +       int ret;
> +
> +       ret = kstrtobool(buf, &val);
> +       if (ret)
> +               return ret;
> +
> +       ret = cppc_set_auto_sel(policy->cpu, val);
> +       if (ret)
> +               return ret;
> +
> +       return count;
> +}
> +
> +static ssize_t show_auto_act_window(struct cpufreq_policy *policy, char *buf)
> +{
> +       u64 val;
> +       int ret;
> +
> +       ret = cppc_get_auto_act_window(policy->cpu, &val);
> +
> +       /* show "<unsupported>" when this register is not supported by cpc */
> +       if (ret == -EOPNOTSUPP)
> +               return sysfs_emit(buf, "<unsupported>\n");
> +
> +       if (ret)
> +               return ret;
> +
> +       return sysfs_emit(buf, "%llu\n", val);
> +}
> +
> +static ssize_t store_auto_act_window(struct cpufreq_policy *policy,
> +                                    const char *buf, size_t count)
> +{
> +       u64 usec;
> +       int ret;
> +
> +       ret = kstrtou64(buf, 0, &usec);
> +       if (ret)
> +               return ret;
> +
> +       ret = cppc_set_auto_act_window(policy->cpu, usec);
> +       if (ret)
> +               return ret;
> +
> +       return count;
> +}
> +
> +static ssize_t show_energy_performance_preference_val(struct cpufreq_policy *policy, char *buf)
> +{
> +       u64 val;
> +       int ret;
> +
> +       ret = cppc_get_epp_perf(policy->cpu, &val);
> +
> +       /* show "<unsupported>" when this register is not supported by cpc */
> +       if (ret == -EOPNOTSUPP)
> +               return sysfs_emit(buf, "<unsupported>\n");
> +
> +       if (ret)
> +               return ret;
> +
> +       return sysfs_emit(buf, "%llu\n", val);
> +}
> +
> +static ssize_t store_energy_performance_preference_val(struct cpufreq_policy *policy,
> +                                                      const char *buf, size_t count)
> +{
> +       u64 val;
> +       int ret;
> +
> +       ret = kstrtou64(buf, 0, &val);
> +       if (ret)
> +               return ret;
> +
> +       ret = cppc_set_epp(policy->cpu, val);
> +       if (ret)
> +               return ret;
> +
> +       return count;
> +}
> +
>   cpufreq_freq_attr_ro(freqdomain_cpus);
> +cpufreq_freq_attr_rw(auto_select);
> +cpufreq_freq_attr_rw(auto_act_window);
> +cpufreq_freq_attr_rw(energy_performance_preference_val);
> 
>   static struct freq_attr *cppc_cpufreq_attr[] = {
>          &freqdomain_cpus,
> +       &auto_select,
> +       &auto_act_window,
> +       &energy_performance_preference_val,
>          NULL,
>   };
> 
> --
> 2.33.0
>
Re: [PATCH] cpufreq: CPPC: Support for autonomous selection in cppc_cpufreq
Posted by Viresh Kumar 6 months, 4 weeks ago
On 21-05-25, 16:13, Sumit Gupta wrote:
> 
> 
> On 07/05/25 08:49, Lifeng Zheng wrote:
> > External email: Use caution opening links or attachments
> > 
> > 
> > Add sysfs interfaces for CPPC autonomous selection in the cppc_cpufreq
> > driver.
> > 
> > Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
> 
> Looks good to me.
> 
> Reviewed-by: Sumit Gupta <sumitg@nvidia.com>

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

Rafael, since I have already sent the pull request, can you please
take it directly ? Thanks.

-- 
viresh
Re: [PATCH] cpufreq: CPPC: Support for autonomous selection in cppc_cpufreq
Posted by Rafael J. Wysocki 6 months, 4 weeks ago
On Wed, May 21, 2025 at 12:48 PM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> On 21-05-25, 16:13, Sumit Gupta wrote:
> >
> >
> > On 07/05/25 08:49, Lifeng Zheng wrote:
> > > External email: Use caution opening links or attachments
> > >
> > >
> > > Add sysfs interfaces for CPPC autonomous selection in the cppc_cpufreq
> > > driver.
> > >
> > > Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
> >
> > Looks good to me.
> >
> > Reviewed-by: Sumit Gupta <sumitg@nvidia.com>
>
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
>
> Rafael, since I have already sent the pull request, can you please
> take it directly ? Thanks.

Done, thanks!
Re: [PATCH] cpufreq: CPPC: Support for autonomous selection in cppc_cpufreq
Posted by Viresh Kumar 7 months ago
On 07-05-25, 11:19, Lifeng Zheng wrote:
> Add sysfs interfaces for CPPC autonomous selection in the cppc_cpufreq
> driver.
> 
> Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>

Sumit, can you provide your tag if it looks fine to you ?

> diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
> index 206079d3bd5b..37065e1b8ebc 100644
> --- a/Documentation/ABI/testing/sysfs-devices-system-cpu
> +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
> @@ -268,6 +268,60 @@ Description:	Discover CPUs in the same CPU frequency coordination domain
>  		This file is only present if the acpi-cpufreq or the cppc-cpufreq
>  		drivers are in use.
>  
> +What:		/sys/devices/system/cpu/cpuX/cpufreq/auto_select

Is the path correct? Should this be cpufreq/policyN/auto_select ?

> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index b3d74f9adcf0..3c3d00cec298 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -808,10 +808,119 @@ static ssize_t show_freqdomain_cpus(struct cpufreq_policy *policy, char *buf)
>  
>  	return cpufreq_show_cpus(cpu_data->shared_cpu_map, buf);
>  }
> +
> +static ssize_t show_auto_select(struct cpufreq_policy *policy, char *buf)
> +{
> +	bool val;
> +	int ret;
> +
> +	ret = cppc_get_auto_sel(policy->cpu, &val);
> +
> +	/* show "<unsupported>" when this register is not supported by cpc */

s/cpc/cppc/ ?

-- 
viresh
Re: [PATCH] cpufreq: CPPC: Support for autonomous selection in cppc_cpufreq
Posted by zhenglifeng (A) 7 months ago
On 2025/5/19 16:18, Viresh Kumar wrote:
> On 07-05-25, 11:19, Lifeng Zheng wrote:
>> Add sysfs interfaces for CPPC autonomous selection in the cppc_cpufreq
>> driver.
>>
>> Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
> 
> Sumit, can you provide your tag if it looks fine to you ?
> 
>> diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
>> index 206079d3bd5b..37065e1b8ebc 100644
>> --- a/Documentation/ABI/testing/sysfs-devices-system-cpu
>> +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
>> @@ -268,6 +268,60 @@ Description:	Discover CPUs in the same CPU frequency coordination domain
>>  		This file is only present if the acpi-cpufreq or the cppc-cpufreq
>>  		drivers are in use.
>>  
>> +What:		/sys/devices/system/cpu/cpuX/cpufreq/auto_select
> 
> Is the path correct? Should this be cpufreq/policyN/auto_select ?

cpufreq/policyN/ is linked to cpuX/cpufreq/, both paths correct. The
description of freqdomain_cpus uses cpuX/cpufreq/, so I followed.

> 
>> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
>> index b3d74f9adcf0..3c3d00cec298 100644
>> --- a/drivers/cpufreq/cppc_cpufreq.c
>> +++ b/drivers/cpufreq/cppc_cpufreq.c
>> @@ -808,10 +808,119 @@ static ssize_t show_freqdomain_cpus(struct cpufreq_policy *policy, char *buf)
>>  
>>  	return cpufreq_show_cpus(cpu_data->shared_cpu_map, buf);
>>  }
>> +
>> +static ssize_t show_auto_select(struct cpufreq_policy *policy, char *buf)
>> +{
>> +	bool val;
>> +	int ret;
>> +
>> +	ret = cppc_get_auto_sel(policy->cpu, &val);
>> +
>> +	/* show "<unsupported>" when this register is not supported by cpc */
> 
> s/cpc/cppc/ ?

It means Continuous Performance Control, you can see that in ACPI 6.5,
s8.4.6.1 _CPC (Continuous Performance Control). Use "_CPC" might be better.
Re: [PATCH] cpufreq: CPPC: Support for autonomous selection in cppc_cpufreq
Posted by Viresh Kumar 7 months ago
On 19-05-25, 17:29, zhenglifeng (A) wrote:
> cpufreq/policyN/ is linked to cpuX/cpufreq/, both paths correct.

Ahh, my bad.

> It means Continuous Performance Control, you can see that in ACPI 6.5,
> s8.4.6.1 _CPC (Continuous Performance Control). Use "_CPC" might be better.

Okay.

This looks fine to me then, let Sumit reply and then I can apply it.

-- 
viresh
Re: [PATCH] cpufreq: CPPC: Support for autonomous selection in cppc_cpufreq
Posted by Rafael J. Wysocki 7 months, 1 week ago
On Wed, May 7, 2025 at 5:19 AM Lifeng Zheng <zhenglifeng1@huawei.com> wrote:
>
> Add sysfs interfaces for CPPC autonomous selection in the cppc_cpufreq
> driver.
>
> Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
> ---
> Hi Rafael,
>
> This patch is the 8th patch in [1]. After the discussion in [2], Sumit
> is OK with adding sysfs entries under cpufreq sysfs node, so I resend
> this patch. He will later send his updated patch after.
>
> Any comments appreciated!
>
> Lifeng
>
> [1] https://lore.kernel.org/all/20250206131428.3261578-1-zhenglifeng1@huawei.com/
> [2] https://lore.kernel.org/all/20250211103737.447704-1-sumitg@nvidia.com/

This is for Viresh and when all of the ACPI CPPC patches settle down.
I think that it would be better to get back to it after the 6.16 merge
window.

>
>  .../ABI/testing/sysfs-devices-system-cpu      |  54 +++++++++
>  drivers/cpufreq/cppc_cpufreq.c                | 109 ++++++++++++++++++
>  2 files changed, 163 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
> index 206079d3bd5b..37065e1b8ebc 100644
> --- a/Documentation/ABI/testing/sysfs-devices-system-cpu
> +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
> @@ -268,6 +268,60 @@ Description:       Discover CPUs in the same CPU frequency coordination domain
>                 This file is only present if the acpi-cpufreq or the cppc-cpufreq
>                 drivers are in use.
>
> +What:          /sys/devices/system/cpu/cpuX/cpufreq/auto_select
> +Date:          May 2025
> +Contact:       linux-pm@vger.kernel.org
> +Description:   Autonomous selection enable
> +
> +               Read/write interface to control autonomous selection enable
> +                       Read returns autonomous selection status:
> +                               0: autonomous selection is disabled
> +                               1: autonomous selection is enabled
> +
> +                       Write 'y' or '1' or 'on' to enable autonomous selection.
> +                       Write 'n' or '0' or 'off' to disable autonomous selection.
> +
> +               This file is only present if the cppc-cpufreq driver is in use.
> +
> +What:          /sys/devices/system/cpu/cpuX/cpufreq/auto_act_window
> +Date:          May 2025
> +Contact:       linux-pm@vger.kernel.org
> +Description:   Autonomous activity window
> +
> +               This file indicates a moving utilization sensitivity window to
> +               the platform's autonomous selection policy.
> +
> +               Read/write an integer represents autonomous activity window (in
> +               microseconds) from/to this file. The max value to write is
> +               1270000000 but the max significand is 127. This means that if 128
> +               is written to this file, 127 will be stored. If the value is
> +               greater than 130, only the first two digits will be saved as
> +               significand.
> +
> +               Writing a zero value to this file enable the platform to
> +               determine an appropriate Activity Window depending on the workload.
> +
> +               Writing to this file only has meaning when Autonomous Selection is
> +               enabled.
> +
> +               This file is only present if the cppc-cpufreq driver is in use.
> +
> +What:          /sys/devices/system/cpu/cpuX/cpufreq/energy_performance_preference_val
> +Date:          May 2025
> +Contact:       linux-pm@vger.kernel.org
> +Description:   Energy performance preference
> +
> +               Read/write an 8-bit integer from/to this file. This file
> +               represents a range of values from 0 (performance preference) to
> +               0xFF (energy efficiency preference) that influences the rate of
> +               performance increase/decrease and the result of the hardware's
> +               energy efficiency and performance optimization policies.
> +
> +               Writing to this file only has meaning when Autonomous Selection is
> +               enabled.
> +
> +               This file is only present if the cppc-cpufreq driver is in use.
> +
>
>  What:          /sys/devices/system/cpu/cpu*/cache/index3/cache_disable_{0,1}
>  Date:          August 2008
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index b3d74f9adcf0..3c3d00cec298 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -808,10 +808,119 @@ static ssize_t show_freqdomain_cpus(struct cpufreq_policy *policy, char *buf)
>
>         return cpufreq_show_cpus(cpu_data->shared_cpu_map, buf);
>  }
> +
> +static ssize_t show_auto_select(struct cpufreq_policy *policy, char *buf)
> +{
> +       bool val;
> +       int ret;
> +
> +       ret = cppc_get_auto_sel(policy->cpu, &val);
> +
> +       /* show "<unsupported>" when this register is not supported by cpc */
> +       if (ret == -EOPNOTSUPP)
> +               return sysfs_emit(buf, "<unsupported>\n");
> +
> +       if (ret)
> +               return ret;
> +
> +       return sysfs_emit(buf, "%d\n", val);
> +}
> +
> +static ssize_t store_auto_select(struct cpufreq_policy *policy,
> +                                const char *buf, size_t count)
> +{
> +       bool val;
> +       int ret;
> +
> +       ret = kstrtobool(buf, &val);
> +       if (ret)
> +               return ret;
> +
> +       ret = cppc_set_auto_sel(policy->cpu, val);
> +       if (ret)
> +               return ret;
> +
> +       return count;
> +}
> +
> +static ssize_t show_auto_act_window(struct cpufreq_policy *policy, char *buf)
> +{
> +       u64 val;
> +       int ret;
> +
> +       ret = cppc_get_auto_act_window(policy->cpu, &val);
> +
> +       /* show "<unsupported>" when this register is not supported by cpc */
> +       if (ret == -EOPNOTSUPP)
> +               return sysfs_emit(buf, "<unsupported>\n");
> +
> +       if (ret)
> +               return ret;
> +
> +       return sysfs_emit(buf, "%llu\n", val);
> +}
> +
> +static ssize_t store_auto_act_window(struct cpufreq_policy *policy,
> +                                    const char *buf, size_t count)
> +{
> +       u64 usec;
> +       int ret;
> +
> +       ret = kstrtou64(buf, 0, &usec);
> +       if (ret)
> +               return ret;
> +
> +       ret = cppc_set_auto_act_window(policy->cpu, usec);
> +       if (ret)
> +               return ret;
> +
> +       return count;
> +}
> +
> +static ssize_t show_energy_performance_preference_val(struct cpufreq_policy *policy, char *buf)
> +{
> +       u64 val;
> +       int ret;
> +
> +       ret = cppc_get_epp_perf(policy->cpu, &val);
> +
> +       /* show "<unsupported>" when this register is not supported by cpc */
> +       if (ret == -EOPNOTSUPP)
> +               return sysfs_emit(buf, "<unsupported>\n");
> +
> +       if (ret)
> +               return ret;
> +
> +       return sysfs_emit(buf, "%llu\n", val);
> +}
> +
> +static ssize_t store_energy_performance_preference_val(struct cpufreq_policy *policy,
> +                                                      const char *buf, size_t count)
> +{
> +       u64 val;
> +       int ret;
> +
> +       ret = kstrtou64(buf, 0, &val);
> +       if (ret)
> +               return ret;
> +
> +       ret = cppc_set_epp(policy->cpu, val);
> +       if (ret)
> +               return ret;
> +
> +       return count;
> +}
> +
>  cpufreq_freq_attr_ro(freqdomain_cpus);
> +cpufreq_freq_attr_rw(auto_select);
> +cpufreq_freq_attr_rw(auto_act_window);
> +cpufreq_freq_attr_rw(energy_performance_preference_val);
>
>  static struct freq_attr *cppc_cpufreq_attr[] = {
>         &freqdomain_cpus,
> +       &auto_select,
> +       &auto_act_window,
> +       &energy_performance_preference_val,
>         NULL,
>  };
>
> --
> 2.33.0
>
>