ACPI: CPPC: Add three functions related to autonomous selection

cppc_set_epp() - write energy performance preference register value,
based on ACPI 6.5, s8.4.6.1.7

cppc_get_auto_act_window() - read autonomous activity window register
value, based on ACPI 6.5, s8.4.6.1.6

cppc_set_auto_act_window() - write autonomous activity window register
value, based on ACPI 6.5, s8.4.6.1.6

Reviewed-by: Pierre Gondois <pierre.gondois@arm.com>
Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://patch.msgid.link/20250411093855.982491-9-zhenglifeng1@huawei.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 83 insertions, 0 deletions

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 6163831b8c19..a9ae2fd62863 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1602,6 +1602,89 @@ int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
 EXPORT_SYMBOL_GPL(cppc_set_epp_perf);
 
 /**
+ * cppc_set_epp() - Write the EPP register.
+ * @cpu: CPU on which to write register.
+ * @epp_val: Value to write to the EPP register.
+ */
+int cppc_set_epp(int cpu, u64 epp_val)
+{
+	if (epp_val > CPPC_ENERGY_PERF_MAX)
+		return -EINVAL;
+
+	return cppc_set_reg_val(cpu, ENERGY_PERF, epp_val);
+}
+EXPORT_SYMBOL_GPL(cppc_set_epp);
+
+/**
+ * cppc_get_auto_act_window() - Read autonomous activity window register.
+ * @cpu: CPU from which to read register.
+ * @auto_act_window: Return address.
+ *
+ * According to ACPI 6.5, s8.4.6.1.6, the value read from the autonomous
+ * activity window register consists of two parts: a 7 bits value indicate
+ * significand and a 3 bits value indicate exponent.
+ */
+int cppc_get_auto_act_window(int cpu, u64 *auto_act_window)
+{
+	unsigned int exp;
+	u64 val, sig;
+	int ret;
+
+	if (auto_act_window == NULL)
+		return -EINVAL;
+
+	ret = cppc_get_reg_val(cpu, AUTO_ACT_WINDOW, &val);
+	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;
+	*auto_act_window = sig * int_pow(10, exp);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cppc_get_auto_act_window);
+
+/**
+ * cppc_set_auto_act_window() - Write autonomous activity window register.
+ * @cpu: CPU on which to write register.
+ * @auto_act_window: usec value to write to the autonomous activity window register.
+ *
+ * According to ACPI 6.5, s8.4.6.1.6, the value to write to the autonomous
+ * activity window register consists of two parts: a 7 bits value indicate
+ * significand and a 3 bits value indicate exponent.
+ */
+int cppc_set_auto_act_window(int cpu, u64 auto_act_window)
+{
+	/* The max value to store is 1270000000 */
+	u64 max_val = CPPC_AUTO_ACT_WINDOW_MAX_SIG * int_pow(10, CPPC_AUTO_ACT_WINDOW_MAX_EXP);
+	int exp = 0;
+	u64 val;
+
+	if (auto_act_window > max_val)
+		return -EINVAL;
+
+	/*
+	 * The max significand is 127, when auto_act_window is larger than
+	 * 129, discard the precision of the last digit and increase the
+	 * exponent by 1.
+	 */
+	while (auto_act_window > CPPC_AUTO_ACT_WINDOW_SIG_CARRY_THRESH) {
+		auto_act_window /= 10;
+		exp += 1;
+	}
+
+	/* For 128 and 129, cut it to 127. */
+	if (auto_act_window > CPPC_AUTO_ACT_WINDOW_MAX_SIG)
+		auto_act_window = CPPC_AUTO_ACT_WINDOW_MAX_SIG;
+
+	val = (exp << CPPC_AUTO_ACT_WINDOW_SIG_BIT_SIZE) + auto_act_window;
+
+	return cppc_set_reg_val(cpu, AUTO_ACT_WINDOW, val);
+}
+EXPORT_SYMBOL_GPL(cppc_set_auto_act_window);
+
+/**
  * cppc_get_auto_sel() - Read autonomous selection register.
  * @cpu: CPU from which to read register.
  * @enable: Return address.