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

[Yuan, Perry]

[AMD Official Use Only - General]

Hi Ray, Wyse.

> -----Original Message-----
> From: Karny, Wyes <Wyes.Karny@xxxxxxx>
> Sent: Wednesday, January 18, 2023 2:35 PM
> To: Huang, Ray <Ray.Huang@xxxxxxx>; Yuan, Perry <Perry.Yuan@xxxxxxx>
> Cc: rafael.j.wysocki@xxxxxxxxx; Limonciello, Mario
> <Mario.Limonciello@xxxxxxx>; viresh.kumar@xxxxxxxxxx; Sharma, Deepak
> <Deepak.Sharma@xxxxxxx>; Fontenot, Nathan
> <Nathan.Fontenot@xxxxxxx>; Deucher, Alexander
> <Alexander.Deucher@xxxxxxx>; Huang, Shimmer
> <Shimmer.Huang@xxxxxxx>; Du, Xiaojian <Xiaojian.Du@xxxxxxx>; Meng, Li
> (Jassmine) <Li.Meng@xxxxxxx>; linux-pm@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> 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@xxxxxxx>
> >>
> >> 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@xxxxxxx>
> >> Signed-off-by: Perry Yuan <Perry.Yuan@xxxxxxx>
> >
> > Patch is Acked-by: Huang Rui <ray.huang@xxxxxxx>
> >
> > 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@xxxxxxx>
> 
> >
> > 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