[PATCH v3 4/4] cpufreq: CPPC: Support for autonomous selection in cppc_cpufreq

[Lifeng Zheng]

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

Signed-off-by: Lifeng Zheng <zhenglifeng1@xxxxxxxxxx>
---
 .../ABI/testing/sysfs-devices-system-cpu      |  54 ++++++++
 drivers/cpufreq/cppc_cpufreq.c                | 129 ++++++++++++++++++
 include/acpi/cppc_acpi.h                      |   9 ++
 3 files changed, 192 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 206079d3bd5b..3d87c3bb3fe2 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:		October 2024
+Contact:	linux-pm@xxxxxxxxxxxxxxx
+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 only presents if the cppc-cpufreq driver is in use.
+
+What:		/sys/devices/system/cpu/cpuX/cpufreq/auto_act_window
+Date:		October 2024
+Contact:	linux-pm@xxxxxxxxxxxxxxx
+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 only presents if the cppc-cpufreq driver is in use.
+
+What:		/sys/devices/system/cpu/cpuX/cpufreq/energy_perf
+Date:		October 2024
+Contact:	linux-pm@xxxxxxxxxxxxxxx
+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 only presents 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 2b8708475ac7..111fab50b7a0 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -792,10 +792,139 @@ 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)
+{
+	u64 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, "%s\n", "<unsupported>");
+
+	if (ret)
+		return ret;
+
+	return sysfs_emit(buf, "%llu\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)
+{
+	unsigned int exp;
+	u64 val, sig;
+	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, "%s\n", "<unsupported>");
+
+	if (ret)
+		return ret;
+
+	sig = val & CPPC_AUTO_ACT_WINDOW_MAX_SIG;
+	exp = (val >> CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) & CPPC_AUTO_ACT_WINDOW_MAX_EXP;
+
+	return sysfs_emit(buf, "%llu\n", sig * int_pow(10, exp));
+}
+
+static ssize_t store_auto_act_window(struct cpufreq_policy *policy,
+				     const char *buf, size_t count)
+{
+	unsigned long usec;
+	int digits = 0;
+	int ret;
+
+	ret = kstrtoul(buf, 0, &usec);
+	if (ret)
+		return ret;
+
+	if (usec > CPPC_AUTO_ACT_WINDOW_MAX_SIG * int_pow(10, CPPC_AUTO_ACT_WINDOW_MAX_EXP))
+		return -EINVAL;
+
+	while (usec > CPPC_AUTO_ACT_WINDOW_SIG_CARRY_THRESH) {
+		usec /= 10;
+		digits += 1;
+	}
+
+	if (usec > CPPC_AUTO_ACT_WINDOW_MAX_SIG)
+		usec = CPPC_AUTO_ACT_WINDOW_MAX_SIG;
+
+	ret = cppc_set_auto_act_window(policy->cpu,
+				       (digits << CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) + usec);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t show_energy_perf(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, "%s\n", "<unsupported>");
+
+	if (ret)
+		return ret;
+
+	return sysfs_emit(buf, "%llu\n", val);
+}
+
+static ssize_t store_energy_perf(struct cpufreq_policy *policy,
+				 const char *buf, size_t count)
+{
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val > CPPC_ENERGY_PERF_MAX)
+		return -EINVAL;
+
+	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_perf);
 
 static struct freq_attr *cppc_cpufreq_attr[] = {
 	&freqdomain_cpus,
+	&auto_select,
+	&auto_act_window,
+	&energy_perf,
 	NULL,
 };
 
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 134931b081a0..8176fca4c86b 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -32,6 +32,15 @@
 #define	CMD_READ 0
 #define	CMD_WRITE 1
 
+#define CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE	(7)
+#define CPPC_AUTO_ACT_WINDOW_EXP_BIT_SIZE	(3)
+#define CPPC_AUTO_ACT_WINDOW_MAX_SIG	((1 << CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) - 1)
+#define CPPC_AUTO_ACT_WINDOW_MAX_EXP	((1 << CPPC_AUTO_ACT_WINDOW_EXP_BIT_SIZE) - 1)
+/* CPPC_AUTO_ACT_WINDOW_MAX_SIG is 127, so 128 and 129 will decay to 127 when writing */
+#define CPPC_AUTO_ACT_WINDOW_SIG_CARRY_THRESH 129
+
+#define CPPC_ENERGY_PERF_MAX	(0xFF)
+
 /* Each register has the folowing format. */
 struct cpc_reg {
 	u8 descriptor;
-- 
2.33.0