Commit 922607a2 authored by Lifeng Zheng's avatar Lifeng Zheng Committed by Rafael J. Wysocki
Browse files

cpufreq: CPPC: Add support for autonomous selection 



Add sysfs interfaces for CPPC autonomous selection in the cppc_cpufreq
driver.

Signed-off-by: default avatarLifeng Zheng <zhenglifeng1@huawei.com>
Reviewed-by: default avatarSumit Gupta <sumitg@nvidia.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Link: https://patch.msgid.link/20250507031941.2812701-1-zhenglifeng1@huawei.com


[ rjw: Subject edits ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 1da98dc5

Documentation/ABI/testing/sysfs-devices-system-cpu

+54 −0
Original line number Diff line number Diff line
@@ -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

drivers/cpufreq/cppc_cpufreq.c

+109 −0
Original line number Diff line number Diff line
@@ -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,

};