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>

Author: Lifeng Zheng

drivers/acpi/cppc_acpi.c

@@ -1601,6 +1601,89 @@ 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.

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;
@@ -159,6 +168,9 @@ extern int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val);
 extern int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val);
 extern int cppc_get_epp_perf(int cpunum, u64 *epp_perf);
 extern int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable);
+extern int cppc_set_epp(int cpu, u64 epp_val);
+extern int cppc_get_auto_act_window(int cpu, u64 *auto_act_window);
+extern int cppc_set_auto_act_window(int cpu, u64 auto_act_window);
 extern int cppc_get_auto_sel(int cpu, bool *enable);
 extern int cppc_set_auto_sel(int cpu, bool enable);
 extern int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf);
@@ -229,6 +241,18 @@ static inline int cppc_get_epp_perf(int cpunum, u64 *epp_perf)
 {
 	return -EOPNOTSUPP;
 }
+static inline int cppc_set_epp(int cpu, u64 epp_val)
+{
+	return -EOPNOTSUPP;
+}
+static inline int cppc_get_auto_act_window(int cpu, u64 *auto_act_window)
+{
+	return -EOPNOTSUPP;
+}
+static inline int cppc_set_auto_act_window(int cpu, u64 auto_act_window)
+{
+	return -EOPNOTSUPP;
+}
 static inline int cppc_get_auto_sel(int cpu, bool *enable)
 {
 	return -EOPNOTSUPP;