diff options
Diffstat (limited to 'src/cpu/intel/turbo')
| -rw-r--r-- | src/cpu/intel/turbo/Makefile.inc | 1 | ||||
| -rw-r--r-- | src/cpu/intel/turbo/turbo.c | 90 |
2 files changed, 91 insertions, 0 deletions
diff --git a/src/cpu/intel/turbo/Makefile.inc b/src/cpu/intel/turbo/Makefile.inc new file mode 100644 index 0000000000..48ec55db1d --- /dev/null +++ b/src/cpu/intel/turbo/Makefile.inc @@ -0,0 +1 @@ +ramstage-y += turbo.c diff --git a/src/cpu/intel/turbo/turbo.c b/src/cpu/intel/turbo/turbo.c new file mode 100644 index 0000000000..779550e26b --- /dev/null +++ b/src/cpu/intel/turbo/turbo.c @@ -0,0 +1,90 @@ +/* + * 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"); + } +} |