[v10,08/12] cpufreq: amd-pstate: add driver working mode switch support

  From: Perry Yuan <Perry.Yuan@amd.com>

While amd-pstate driver was loaded with specific driver mode, it will
need to check which mode is enabled for the pstate driver,add this sysfs
entry to show the current status

$ cat /sys/devices/system/cpu/amd-pstate/status
active

Meanwhile, user can switch the pstate driver mode with writing mode
string to sysfs entry as below.

Enable passive mode:
$ sudo bash -c "echo passive >  /sys/devices/system/cpu/amd-pstate/status"

Enable active mode (EPP driver mode):
$ sudo bash -c "echo active > /sys/devices/system/cpu/amd-pstate/status"

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 118 +++++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)
  

On Fri, Jan 06, 2023 at 02:14:16PM +0800, Yuan, Perry wrote:
> From: Perry Yuan <Perry.Yuan@amd.com>
> 
> While amd-pstate driver was loaded with specific driver mode, it will
> need to check which mode is enabled for the pstate driver,add this sysfs
> entry to show the current status
> 
> $ cat /sys/devices/system/cpu/amd-pstate/status
> active
> 
> Meanwhile, user can switch the pstate driver mode with writing mode
> string to sysfs entry as below.
> 
> Enable passive mode:
> $ sudo bash -c "echo passive >  /sys/devices/system/cpu/amd-pstate/status"
> 
> Enable active mode (EPP driver mode):
> $ sudo bash -c "echo active > /sys/devices/system/cpu/amd-pstate/status"
> 
> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>

Patch is Acked-by: Huang Rui <ray.huang@amd.com>

Wyes, may we have a ack or any comment from you of this patch, as you are
working on the new guided autonomous mode?

Thanks,
Ray

> ---
>  drivers/cpufreq/amd-pstate.c | 118 +++++++++++++++++++++++++++++++++++
>  1 file changed, 118 insertions(+)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 2c8b126cec5a..d3f4cdd803f3 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -63,6 +63,7 @@ static struct cpufreq_driver *current_pstate_driver;
>  static struct cpufreq_driver amd_pstate_driver;
>  static struct cpufreq_driver amd_pstate_epp_driver;
>  static int cppc_state = AMD_PSTATE_DISABLE;
> +struct kobject *amd_pstate_kobj;
>  
>  static inline int get_mode_idx_from_str(const char *str, size_t size)
>  {
> @@ -631,6 +632,8 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>  	policy->driver_data = cpudata;
>  
>  	amd_pstate_boost_init(cpudata);
> +	if (!current_pstate_driver->adjust_perf)
> +		current_pstate_driver->adjust_perf = amd_pstate_adjust_perf;
>  
>  	return 0;
>  
> @@ -771,12 +774,99 @@ static ssize_t show_energy_performance_preference(
>  	return sysfs_emit(buf, "%s\n", energy_perf_strings[preference]);
>  }
>  
> +static ssize_t amd_pstate_show_status(char *buf)
> +{
> +	if (!current_pstate_driver)
> +		return sysfs_emit(buf, "disable\n");
> +
> +	return sysfs_emit(buf, "%s\n", amd_pstate_mode_string[cppc_state]);
> +}
> +
> +static void amd_pstate_driver_cleanup(void)
> +{
> +	current_pstate_driver = NULL;
> +}
> +
> +static int amd_pstate_update_status(const char *buf, size_t size)
> +{
> +	int ret;
> +	int mode_idx;
> +
> +	if (size > 7 || size < 6)
> +		return -EINVAL;
> +	mode_idx = get_mode_idx_from_str(buf, size);
> +
> +	switch(mode_idx) {
> +	case AMD_PSTATE_DISABLE:
> +		if (!current_pstate_driver)
> +			return -EINVAL;
> +		if (cppc_state == AMD_PSTATE_ACTIVE)
> +			return -EBUSY;
> +		ret = cpufreq_unregister_driver(current_pstate_driver);
> +		amd_pstate_driver_cleanup();
> +		break;
> +	case AMD_PSTATE_PASSIVE:
> +		if (current_pstate_driver) {
> +			if (current_pstate_driver == &amd_pstate_driver)
> +				return 0;
> +			cpufreq_unregister_driver(current_pstate_driver);
> +			cppc_state = AMD_PSTATE_PASSIVE;
> +			current_pstate_driver = &amd_pstate_driver;
> +		}
> +
> +		ret = cpufreq_register_driver(current_pstate_driver);
> +		break;
> +	case AMD_PSTATE_ACTIVE:
> +		if (current_pstate_driver) {
> +			if (current_pstate_driver == &amd_pstate_epp_driver)
> +				return 0;
> +			cpufreq_unregister_driver(current_pstate_driver);
> +			current_pstate_driver = &amd_pstate_epp_driver;
> +			cppc_state = AMD_PSTATE_ACTIVE;
> +		}
> +
> +		ret = cpufreq_register_driver(current_pstate_driver);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static ssize_t show_status(struct kobject *kobj,
> +			   struct kobj_attribute *attr, char *buf)
> +{
> +	ssize_t ret;
> +
> +	mutex_lock(&amd_pstate_driver_lock);
> +	ret = amd_pstate_show_status(buf);
> +	mutex_unlock(&amd_pstate_driver_lock);
> +
> +	return ret;
> +}
> +
> +static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
> +			    const char *buf, size_t count)
> +{
> +	char *p = memchr(buf, '\n', count);
> +	int ret;
> +
> +	mutex_lock(&amd_pstate_driver_lock);
> +	ret = amd_pstate_update_status(buf, p ? p - buf : count);
> +	mutex_unlock(&amd_pstate_driver_lock);
> +
> +	return ret < 0 ? ret : count;
> +}
> +
>  cpufreq_freq_attr_ro(amd_pstate_max_freq);
>  cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
>  
>  cpufreq_freq_attr_ro(amd_pstate_highest_perf);
>  cpufreq_freq_attr_rw(energy_performance_preference);
>  cpufreq_freq_attr_ro(energy_performance_available_preferences);
> +define_one_global_rw(status);
>  
>  static struct freq_attr *amd_pstate_attr[] = {
>  	&amd_pstate_max_freq,
> @@ -794,6 +884,15 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
>  	NULL,
>  };
>  
> +static struct attribute *pstate_global_attributes[] = {
> +	&status.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group amd_pstate_global_attr_group = {
> +	.attrs = pstate_global_attributes,
> +};
> +
>  static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>  {
>  	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
> @@ -1153,6 +1252,25 @@ static int __init amd_pstate_init(void)
>  	if (ret)
>  		pr_err("failed to register with return %d\n", ret);
>  
> +	amd_pstate_kobj = kobject_create_and_add("amd_pstate", &cpu_subsys.dev_root->kobj);
> +	if (!amd_pstate_kobj) {
> +		ret = -EINVAL;
> +		pr_err("global sysfs registration failed.\n");
> +		goto kobject_free;
> +	}
> +
> +	ret = sysfs_create_group(amd_pstate_kobj, &amd_pstate_global_attr_group);
> +	if (ret) {
> +		pr_err("sysfs attribute export failed with error %d.\n", ret);
> +		goto global_attr_free;
> +	}
> +
> +	return ret;
> +
> +global_attr_free:
> +	kobject_put(amd_pstate_kobj);
> +kobject_free:
> +	cpufreq_unregister_driver(current_pstate_driver);
>  	return ret;
>  }
>  device_initcall(amd_pstate_init);
> -- 
> 2.34.1
>
  

Hi Ray, Perry,

On 1/17/2023 7:26 PM, Huang Rui wrote:
> On Fri, Jan 06, 2023 at 02:14:16PM +0800, Yuan, Perry wrote:
>> From: Perry Yuan <Perry.Yuan@amd.com>
>>
>> While amd-pstate driver was loaded with specific driver mode, it will
>> need to check which mode is enabled for the pstate driver,add this sysfs
>> entry to show the current status
>>
>> $ cat /sys/devices/system/cpu/amd-pstate/status
>> active
>>
>> Meanwhile, user can switch the pstate driver mode with writing mode
>> string to sysfs entry as below.
>>
>> Enable passive mode:
>> $ sudo bash -c "echo passive >  /sys/devices/system/cpu/amd-pstate/status"
>>
>> Enable active mode (EPP driver mode):
>> $ sudo bash -c "echo active > /sys/devices/system/cpu/amd-pstate/status"
>>
>> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
>> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> 
> Patch is Acked-by: Huang Rui <ray.huang@amd.com>
> 
> Wyes, may we have a ack or any comment from you of this patch, as you are
> working on the new guided autonomous mode?

This looks good to me.

Reviewed-by: Wyes Karny <wyes.karny@amd.com>

> 
> Thanks,
> Ray
> 
>> ---
>>  drivers/cpufreq/amd-pstate.c | 118 +++++++++++++++++++++++++++++++++++
>>  1 file changed, 118 insertions(+)
>>
>> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
>> index 2c8b126cec5a..d3f4cdd803f3 100644
>> --- a/drivers/cpufreq/amd-pstate.c
>> +++ b/drivers/cpufreq/amd-pstate.c
>> @@ -63,6 +63,7 @@ static struct cpufreq_driver *current_pstate_driver;
>>  static struct cpufreq_driver amd_pstate_driver;
>>  static struct cpufreq_driver amd_pstate_epp_driver;
>>  static int cppc_state = AMD_PSTATE_DISABLE;
>> +struct kobject *amd_pstate_kobj;
>>  
>>  static inline int get_mode_idx_from_str(const char *str, size_t size)
>>  {
>> @@ -631,6 +632,8 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>>  	policy->driver_data = cpudata;
>>  
>>  	amd_pstate_boost_init(cpudata);
>> +	if (!current_pstate_driver->adjust_perf)
>> +		current_pstate_driver->adjust_perf = amd_pstate_adjust_perf;
>>  
>>  	return 0;
>>  
>> @@ -771,12 +774,99 @@ static ssize_t show_energy_performance_preference(
>>  	return sysfs_emit(buf, "%s\n", energy_perf_strings[preference]);
>>  }
>>  
>> +static ssize_t amd_pstate_show_status(char *buf)
>> +{
>> +	if (!current_pstate_driver)
>> +		return sysfs_emit(buf, "disable\n");
>> +
>> +	return sysfs_emit(buf, "%s\n", amd_pstate_mode_string[cppc_state]);
>> +}
>> +
>> +static void amd_pstate_driver_cleanup(void)
>> +{
>> +	current_pstate_driver = NULL;
>> +}
>> +
>> +static int amd_pstate_update_status(const char *buf, size_t size)
>> +{
>> +	int ret;
>> +	int mode_idx;
>> +
>> +	if (size > 7 || size < 6)
>> +		return -EINVAL;
>> +	mode_idx = get_mode_idx_from_str(buf, size);
>> +
>> +	switch(mode_idx) {
>> +	case AMD_PSTATE_DISABLE:
>> +		if (!current_pstate_driver)
>> +			return -EINVAL;
>> +		if (cppc_state == AMD_PSTATE_ACTIVE)
>> +			return -EBUSY;
>> +		ret = cpufreq_unregister_driver(current_pstate_driver);
>> +		amd_pstate_driver_cleanup();
>> +		break;
>> +	case AMD_PSTATE_PASSIVE:
>> +		if (current_pstate_driver) {
>> +			if (current_pstate_driver == &amd_pstate_driver)
>> +				return 0;
>> +			cpufreq_unregister_driver(current_pstate_driver);
>> +			cppc_state = AMD_PSTATE_PASSIVE;
>> +			current_pstate_driver = &amd_pstate_driver;
>> +		}
>> +
>> +		ret = cpufreq_register_driver(current_pstate_driver);
>> +		break;
>> +	case AMD_PSTATE_ACTIVE:
>> +		if (current_pstate_driver) {
>> +			if (current_pstate_driver == &amd_pstate_epp_driver)
>> +				return 0;
>> +			cpufreq_unregister_driver(current_pstate_driver);
>> +			current_pstate_driver = &amd_pstate_epp_driver;
>> +			cppc_state = AMD_PSTATE_ACTIVE;
>> +		}
>> +
>> +		ret = cpufreq_register_driver(current_pstate_driver);
>> +		break;
>> +	default:
>> +		ret = -EINVAL;
>> +		break;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static ssize_t show_status(struct kobject *kobj,
>> +			   struct kobj_attribute *attr, char *buf)
>> +{
>> +	ssize_t ret;
>> +
>> +	mutex_lock(&amd_pstate_driver_lock);
>> +	ret = amd_pstate_show_status(buf);
>> +	mutex_unlock(&amd_pstate_driver_lock);
>> +
>> +	return ret;
>> +}
>> +
>> +static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
>> +			    const char *buf, size_t count)
>> +{
>> +	char *p = memchr(buf, '\n', count);
>> +	int ret;
>> +
>> +	mutex_lock(&amd_pstate_driver_lock);
>> +	ret = amd_pstate_update_status(buf, p ? p - buf : count);
>> +	mutex_unlock(&amd_pstate_driver_lock);
>> +
>> +	return ret < 0 ? ret : count;
>> +}
>> +
>>  cpufreq_freq_attr_ro(amd_pstate_max_freq);
>>  cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
>>  
>>  cpufreq_freq_attr_ro(amd_pstate_highest_perf);
>>  cpufreq_freq_attr_rw(energy_performance_preference);
>>  cpufreq_freq_attr_ro(energy_performance_available_preferences);
>> +define_one_global_rw(status);
>>  
>>  static struct freq_attr *amd_pstate_attr[] = {
>>  	&amd_pstate_max_freq,
>> @@ -794,6 +884,15 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
>>  	NULL,
>>  };
>>  
>> +static struct attribute *pstate_global_attributes[] = {
>> +	&status.attr,
>> +	NULL
>> +};
>> +
>> +static const struct attribute_group amd_pstate_global_attr_group = {
>> +	.attrs = pstate_global_attributes,
>> +};
>> +
>>  static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>>  {
>>  	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
>> @@ -1153,6 +1252,25 @@ static int __init amd_pstate_init(void)
>>  	if (ret)
>>  		pr_err("failed to register with return %d\n", ret);
>>  
>> +	amd_pstate_kobj = kobject_create_and_add("amd_pstate", &cpu_subsys.dev_root->kobj);
>> +	if (!amd_pstate_kobj) {
>> +		ret = -EINVAL;
>> +		pr_err("global sysfs registration failed.\n");
>> +		goto kobject_free;
>> +	}
>> +
>> +	ret = sysfs_create_group(amd_pstate_kobj, &amd_pstate_global_attr_group);
>> +	if (ret) {
>> +		pr_err("sysfs attribute export failed with error %d.\n", ret);
>> +		goto global_attr_free;
>> +	}
>> +
>> +	return ret;
>> +
>> +global_attr_free:
>> +	kobject_put(amd_pstate_kobj);
>> +kobject_free:
>> +	cpufreq_unregister_driver(current_pstate_driver);
>>  	return ret;
>>  }
>>  device_initcall(amd_pstate_init);
>> -- 
>> 2.34.1
>>
  

[AMD Official Use Only - General]

Hi Ray, Wyse.

> -----Original Message-----
> From: Karny, Wyes <Wyes.Karny@amd.com>
> Sent: Wednesday, January 18, 2023 2:35 PM
> To: Huang, Ray <Ray.Huang@amd.com>; Yuan, Perry <Perry.Yuan@amd.com>
> Cc: rafael.j.wysocki@intel.com; Limonciello, Mario
> <Mario.Limonciello@amd.com>; viresh.kumar@linaro.org; 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 v10 08/12] cpufreq: amd-pstate: add driver working mode
> switch support
> 
> Hi Ray, Perry,
> 
> On 1/17/2023 7:26 PM, Huang Rui wrote:
> > On Fri, Jan 06, 2023 at 02:14:16PM +0800, Yuan, Perry wrote:
> >> From: Perry Yuan <Perry.Yuan@amd.com>
> >>
> >> While amd-pstate driver was loaded with specific driver mode, it will
> >> need to check which mode is enabled for the pstate driver,add this
> >> sysfs entry to show the current status
> >>
> >> $ cat /sys/devices/system/cpu/amd-pstate/status
> >> active
> >>
> >> Meanwhile, user can switch the pstate driver mode with writing mode
> >> string to sysfs entry as below.
> >>
> >> Enable passive mode:
> >> $ sudo bash -c "echo passive >  /sys/devices/system/cpu/amd-pstate/status"
> >>
> >> Enable active mode (EPP driver mode):
> >> $ sudo bash -c "echo active > /sys/devices/system/cpu/amd-pstate/status"
> >>
> >> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
> >> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> >
> > Patch is Acked-by: Huang Rui <ray.huang@amd.com>
> >
> > Wyes, may we have a ack or any comment from you of this patch, as you
> > are working on the new guided autonomous mode?
> 
> This looks good to me.
> 
> Reviewed-by: Wyes Karny <wyes.karny@amd.com>
> 
> >
> > Thanks,
> > Ray

Thanks a lot for the ack and review flags,  I  will pick up all the new flags in v11. 

Perry. 

> >
> >> ---
> >>  drivers/cpufreq/amd-pstate.c | 118
> >> +++++++++++++++++++++++++++++++++++
> >>  1 file changed, 118 insertions(+)
> >>
> >> diff --git a/drivers/cpufreq/amd-pstate.c
> >> b/drivers/cpufreq/amd-pstate.c index 2c8b126cec5a..d3f4cdd803f3
> >> 100644
> >> --- a/drivers/cpufreq/amd-pstate.c
> >> +++ b/drivers/cpufreq/amd-pstate.c
> >> @@ -63,6 +63,7 @@ static struct cpufreq_driver
> >> *current_pstate_driver;  static struct cpufreq_driver
> >> amd_pstate_driver;  static struct cpufreq_driver
> >> amd_pstate_epp_driver;  static int cppc_state = AMD_PSTATE_DISABLE;
> >> +struct kobject *amd_pstate_kobj;
> >>
> >>  static inline int get_mode_idx_from_str(const char *str, size_t
> >> size)  { @@ -631,6 +632,8 @@ static int amd_pstate_cpu_init(struct
> >> cpufreq_policy *policy)
> >>  	policy->driver_data = cpudata;
> >>
> >>  	amd_pstate_boost_init(cpudata);
> >> +	if (!current_pstate_driver->adjust_perf)
> >> +		current_pstate_driver->adjust_perf = amd_pstate_adjust_perf;
> >>
> >>  	return 0;
> >>
> >> @@ -771,12 +774,99 @@ static ssize_t
> show_energy_performance_preference(
> >>  	return sysfs_emit(buf, "%s\n", energy_perf_strings[preference]);  }
> >>
> >> +static ssize_t amd_pstate_show_status(char *buf) {
> >> +	if (!current_pstate_driver)
> >> +		return sysfs_emit(buf, "disable\n");
> >> +
> >> +	return sysfs_emit(buf, "%s\n", amd_pstate_mode_string[cppc_state]);
> >> +}
> >> +
> >> +static void amd_pstate_driver_cleanup(void) {
> >> +	current_pstate_driver = NULL;
> >> +}
> >> +
> >> +static int amd_pstate_update_status(const char *buf, size_t size) {
> >> +	int ret;
> >> +	int mode_idx;
> >> +
> >> +	if (size > 7 || size < 6)
> >> +		return -EINVAL;
> >> +	mode_idx = get_mode_idx_from_str(buf, size);
> >> +
> >> +	switch(mode_idx) {
> >> +	case AMD_PSTATE_DISABLE:
> >> +		if (!current_pstate_driver)
> >> +			return -EINVAL;
> >> +		if (cppc_state == AMD_PSTATE_ACTIVE)
> >> +			return -EBUSY;
> >> +		ret = cpufreq_unregister_driver(current_pstate_driver);
> >> +		amd_pstate_driver_cleanup();
> >> +		break;
> >> +	case AMD_PSTATE_PASSIVE:
> >> +		if (current_pstate_driver) {
> >> +			if (current_pstate_driver == &amd_pstate_driver)
> >> +				return 0;
> >> +			cpufreq_unregister_driver(current_pstate_driver);
> >> +			cppc_state = AMD_PSTATE_PASSIVE;
> >> +			current_pstate_driver = &amd_pstate_driver;
> >> +		}
> >> +
> >> +		ret = cpufreq_register_driver(current_pstate_driver);
> >> +		break;
> >> +	case AMD_PSTATE_ACTIVE:
> >> +		if (current_pstate_driver) {
> >> +			if (current_pstate_driver == &amd_pstate_epp_driver)
> >> +				return 0;
> >> +			cpufreq_unregister_driver(current_pstate_driver);
> >> +			current_pstate_driver = &amd_pstate_epp_driver;
> >> +			cppc_state = AMD_PSTATE_ACTIVE;
> >> +		}
> >> +
> >> +		ret = cpufreq_register_driver(current_pstate_driver);
> >> +		break;
> >> +	default:
> >> +		ret = -EINVAL;
> >> +		break;
> >> +	}
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +static ssize_t show_status(struct kobject *kobj,
> >> +			   struct kobj_attribute *attr, char *buf) {
> >> +	ssize_t ret;
> >> +
> >> +	mutex_lock(&amd_pstate_driver_lock);
> >> +	ret = amd_pstate_show_status(buf);
> >> +	mutex_unlock(&amd_pstate_driver_lock);
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
> >> +			    const char *buf, size_t count) {
> >> +	char *p = memchr(buf, '\n', count);
> >> +	int ret;
> >> +
> >> +	mutex_lock(&amd_pstate_driver_lock);
> >> +	ret = amd_pstate_update_status(buf, p ? p - buf : count);
> >> +	mutex_unlock(&amd_pstate_driver_lock);
> >> +
> >> +	return ret < 0 ? ret : count;
> >> +}
> >> +
> >>  cpufreq_freq_attr_ro(amd_pstate_max_freq);
> >>  cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
> >>
> >>  cpufreq_freq_attr_ro(amd_pstate_highest_perf);
> >>  cpufreq_freq_attr_rw(energy_performance_preference);
> >>  cpufreq_freq_attr_ro(energy_performance_available_preferences);
> >> +define_one_global_rw(status);
> >>
> >>  static struct freq_attr *amd_pstate_attr[] = {
> >>  	&amd_pstate_max_freq,
> >> @@ -794,6 +884,15 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
> >>  	NULL,
> >>  };
> >>
> >> +static struct attribute *pstate_global_attributes[] = {
> >> +	&status.attr,
> >> +	NULL
> >> +};
> >> +
> >> +static const struct attribute_group amd_pstate_global_attr_group = {
> >> +	.attrs = pstate_global_attributes,
> >> +};
> >> +
> >>  static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)  {
> >>  	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
> >> @@ -1153,6 +1252,25 @@ static int __init amd_pstate_init(void)
> >>  	if (ret)
> >>  		pr_err("failed to register with return %d\n", ret);
> >>
> >> +	amd_pstate_kobj = kobject_create_and_add("amd_pstate",
> &cpu_subsys.dev_root->kobj);
> >> +	if (!amd_pstate_kobj) {
> >> +		ret = -EINVAL;
> >> +		pr_err("global sysfs registration failed.\n");
> >> +		goto kobject_free;
> >> +	}
> >> +
> >> +	ret = sysfs_create_group(amd_pstate_kobj,
> &amd_pstate_global_attr_group);
> >> +	if (ret) {
> >> +		pr_err("sysfs attribute export failed with error %d.\n", ret);
> >> +		goto global_attr_free;
> >> +	}
> >> +
> >> +	return ret;
> >> +
> >> +global_attr_free:
> >> +	kobject_put(amd_pstate_kobj);
> >> +kobject_free:
> >> +	cpufreq_unregister_driver(current_pstate_driver);
> >>  	return ret;
> >>  }
> >>  device_initcall(amd_pstate_init);
> >> --
> >> 2.34.1
> >>
> 
> --
> Thanks & Regards,
> Wyes