/* * This file is part of the coreboot project. * * Copyright (C) 2011 The ChromiumOS Authors. All rights reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; version 2 of * the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, * MA 02110-1301 USA */ #include <console/console.h> #include <cpu/intel/turbo.h> #include <cpu/x86/msr.h> #include <arch/cpu.h> static int turbo_state = TURBO_UNKNOWN; static const char *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 get_turbo_state(void) { struct cpuid_result cpuid_regs; int turbo_en, turbo_cap; msr_t msr; /* 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 = rdmsr(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; } printk(BIOS_INFO, "Turbo is %s\n", turbo_state_desc[turbo_state]); return turbo_state; } /* * Try to enable Turbo mode. */ void enable_turbo(void) { msr_t msr; /* Only possible if turbo is available but hidden */ if (get_turbo_state() == TURBO_DISABLED) { /* Clear Turbo Disable bit in Misc Enables */ msr = rdmsr(MSR_IA32_MISC_ENABLES); msr.hi &= ~H_MISC_DISABLE_TURBO; wrmsr(MSR_IA32_MISC_ENABLES, msr); /* Update cached turbo state */ turbo_state = TURBO_ENABLED; printk(BIOS_INFO, "Turbo has been enabled\n"); } }