1 files changed, 102 insertions, 0 deletions
diff --git a/arch/x86/kernel/acpi/cppc.c b/arch/x86/kernel/acpi/cppc.c
new file mode 100644
index 000000000000..8b8cbf22461a
--- /dev/null
+++ b/arch/x86/kernel/acpi/cppc.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * cppc.c: CPPC Interface for x86
+ * Copyright (c) 2016, Intel Corporation.
+ */
+
+#include <acpi/cppc_acpi.h>
+#include <asm/msr.h>
+#include <asm/processor.h>
+#include <asm/topology.h>
+
+/* Refer to drivers/acpi/cppc_acpi.c for the description of functions */
+
+bool cpc_ffh_supported(void)
+{
+	return true;
+}
+
+int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
+{
+	int err;
+
+	err = rdmsrl_safe_on_cpu(cpunum, reg->address, val);
+	if (!err) {
+		u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1,
+				       reg->bit_offset);
+
+		*val &= mask;
+		*val >>= reg->bit_offset;
+	}
+	return err;
+}
+
+int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
+{
+	u64 rd_val;
+	int err;
+
+	err = rdmsrl_safe_on_cpu(cpunum, reg->address, &rd_val);
+	if (!err) {
+		u64 mask = GENMASK_ULL(reg->bit_offset + reg->bit_width - 1,
+				       reg->bit_offset);
+
+		val <<= reg->bit_offset;
+		val &= mask;
+		rd_val &= ~mask;
+		rd_val |= val;
+		err = wrmsrl_safe_on_cpu(cpunum, reg->address, rd_val);
+	}
+	return err;
+}
+
+static void amd_set_max_freq_ratio(void)
+{
+	struct cppc_perf_caps perf_caps;
+	u64 highest_perf, nominal_perf;
+	u64 perf_ratio;
+	int rc;
+
+	rc = cppc_get_perf_caps(0, &perf_caps);
+	if (rc) {
+		pr_debug("Could not retrieve perf counters (%d)\n", rc);
+		return;
+	}
+
+	highest_perf = amd_get_highest_perf();
+	nominal_perf = perf_caps.nominal_perf;
+
+	if (!highest_perf || !nominal_perf) {
+		pr_debug("Could not retrieve highest or nominal performance\n");
+		return;
+	}
+
+	perf_ratio = div_u64(highest_perf * SCHED_CAPACITY_SCALE, nominal_perf);
+	/* midpoint between max_boost and max_P */
+	perf_ratio = (perf_ratio + SCHED_CAPACITY_SCALE) >> 1;
+	if (!perf_ratio) {
+		pr_debug("Non-zero highest/nominal perf values led to a 0 ratio\n");
+		return;
+	}
+
+	freq_invariance_set_perf_ratio(perf_ratio, false);
+}
+
+static DEFINE_MUTEX(freq_invariance_lock);
+
+void init_freq_invariance_cppc(void)
+{
+	static bool init_done;
+
+	if (!cpu_feature_enabled(X86_FEATURE_APERFMPERF))
+		return;
+
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+		return;
+
+	mutex_lock(&freq_invariance_lock);
+	if (!init_done)
+		amd_set_max_freq_ratio();
+	init_done = true;
+	mutex_unlock(&freq_invariance_lock);
+}