From 18739e2ccc66e13dba10a7cb4578910daf455f01 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Fri, 14 Nov 2014 18:18:43 -0700 Subject: 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 --- arch/x86/cpu/turbo.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 arch/x86/cpu/turbo.c (limited to 'arch/x86/cpu/turbo.c') 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 +#include +#include +#include +#include + +#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"); + } +} -- cgit v1.1