Message-ID: <20250507031941.2812701-1-zhenglifeng1@huawei.com>
Date: Wed, 7 May 2025 11:19:41 +0800
From: Lifeng Zheng <zhenglifeng1@...wei.com>
To: <rafael@...nel.org>, <viresh.kumar@...aro.org>, <pierre.gondois@....com>,
	<sumitg@...dia.com>
CC: <linux-kernel@...r.kernel.org>, <linux-pm@...r.kernel.org>,
	<linuxarm@...wei.com>, <mario.limonciello@....com>,
	<yumpusamongus@...il.com>, <srinivas.pandruvada@...ux.intel.com>,
	<jonathan.cameron@...wei.com>, <zhanjie9@...ilicon.com>,
	<lihuisong@...wei.com>, <cenxinghai@...artners.com>, <yubowen8@...wei.com>,
	<zhenglifeng1@...wei.com>, <hepeng68@...wei.com>
Subject: [PATCH] cpufreq: CPPC: Support for autonomous selection in cppc_cpufreq

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

Signed-off-by: Lifeng Zheng <zhenglifeng1@...wei.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@...r.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@...r.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@...r.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

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