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authorSimon Glass <sjg@chromium.org>2014-11-14 18:18:43 -0700
committerSimon Glass <sjg@chromium.org>2014-11-25 06:34:02 -0700
commit18739e2ccc66e13dba10a7cb4578910daf455f01 (patch)
tree3b80e9bd185f69041ad4cd1686d1bf95c08762f4 /arch/x86/cpu
parenta6d4c453069303c3d1a499d2282f423b35c8f3b0 (diff)
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x86: Add Intel speedstep and turbo mode code
Intel chips have a turbo mode where they can run faster for a short period until they reach thermal limits. Add code to adjust and query this feature. Signed-off-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'arch/x86/cpu')
-rw-r--r--arch/x86/cpu/Makefile1
-rw-r--r--arch/x86/cpu/turbo.c98
2 files changed, 99 insertions, 0 deletions
diff --git a/arch/x86/cpu/Makefile b/arch/x86/cpu/Makefile
index 818969f..3839262 100644
--- a/arch/x86/cpu/Makefile
+++ b/arch/x86/cpu/Makefile
@@ -16,3 +16,4 @@ obj-$(CONFIG_SYS_COREBOOT) += coreboot/
obj-$(CONFIG_NORTHBRIDGE_INTEL_SANDYBRIDGE) += ivybridge/
obj-$(CONFIG_NORTHBRIDGE_INTEL_IVYBRIDGE) += ivybridge/
obj-$(CONFIG_PCI) += pci.o
+obj-y += turbo.o
diff --git a/arch/x86/cpu/turbo.c b/arch/x86/cpu/turbo.c
new file mode 100644
index 0000000..254d0de
--- /dev/null
+++ b/arch/x86/cpu/turbo.c
@@ -0,0 +1,98 @@
+/*
+ * From Coreboot file of the same name
+ *
+ * Copyright (C) 2011 The Chromium Authors.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <common.h>
+#include <asm/cpu.h>
+#include <asm/msr.h>
+#include <asm/processor.h>
+#include <asm/turbo.h>
+
+#if CONFIG_CPU_INTEL_TURBO_NOT_PACKAGE_SCOPED
+static inline int get_global_turbo_state(void)
+{
+ return TURBO_UNKNOWN;
+}
+
+static inline void set_global_turbo_state(int state)
+{
+}
+#else
+static int g_turbo_state = TURBO_UNKNOWN;
+
+static inline int get_global_turbo_state(void)
+{
+ return g_turbo_state;
+}
+
+static inline void set_global_turbo_state(int state)
+{
+ g_turbo_state = state;
+}
+#endif
+
+static const char *const turbo_state_desc[] = {
+ [TURBO_UNKNOWN] = "unknown",
+ [TURBO_UNAVAILABLE] = "unavailable",
+ [TURBO_DISABLED] = "available but hidden",
+ [TURBO_ENABLED] = "available and visible"
+};
+
+/*
+ * Determine the current state of Turbo and cache it for later.
+ * Turbo is a package level config so it does not need to be
+ * enabled on every core.
+ */
+int turbo_get_state(void)
+{
+ struct cpuid_result cpuid_regs;
+ int turbo_en, turbo_cap;
+ msr_t msr;
+ int turbo_state = get_global_turbo_state();
+
+ /* Return cached state if available */
+ if (turbo_state != TURBO_UNKNOWN)
+ return turbo_state;
+
+ cpuid_regs = cpuid(CPUID_LEAF_PM);
+ turbo_cap = !!(cpuid_regs.eax & PM_CAP_TURBO_MODE);
+
+ msr = msr_read(MSR_IA32_MISC_ENABLES);
+ turbo_en = !(msr.hi & H_MISC_DISABLE_TURBO);
+
+ if (!turbo_cap && turbo_en) {
+ /* Unavailable */
+ turbo_state = TURBO_UNAVAILABLE;
+ } else if (!turbo_cap && !turbo_en) {
+ /* Available but disabled */
+ turbo_state = TURBO_DISABLED;
+ } else if (turbo_cap && turbo_en) {
+ /* Available */
+ turbo_state = TURBO_ENABLED;
+ }
+
+ set_global_turbo_state(turbo_state);
+ debug("Turbo is %s\n", turbo_state_desc[turbo_state]);
+ return turbo_state;
+}
+
+void turbo_enable(void)
+{
+ msr_t msr;
+
+ /* Only possible if turbo is available but hidden */
+ if (turbo_get_state() == TURBO_DISABLED) {
+ /* Clear Turbo Disable bit in Misc Enables */
+ msr = msr_read(MSR_IA32_MISC_ENABLES);
+ msr.hi &= ~H_MISC_DISABLE_TURBO;
+ msr_write(MSR_IA32_MISC_ENABLES, msr);
+
+ /* Update cached turbo state */
+ set_global_turbo_state(TURBO_ENABLED);
+ debug("Turbo has been enabled\n");
+ }
+}