arch/x86/cpu/turbo.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * From Coreboot file of the same name
   4  *
   5  * Copyright (C) 2011 The Chromium Authors.
   6  */
   7
   8 #include <common.h>
   9 #include <asm/cpu.h>
  10 #include <asm/msr.h>
  11 #include <asm/processor.h>
  12 #include <asm/turbo.h>
  13
  14 DECLARE_GLOBAL_DATA_PTR;
  15
  16 #ifdef CONFIG_CPU_INTEL_TURBO_NOT_PACKAGE_SCOPED
  17 static inline int get_global_turbo_state(void)
  18 {
  19         return TURBO_UNKNOWN;
  20 }
  21
  22 static inline void set_global_turbo_state(int state)
  23 {
  24 }
  25 #else
  26 static inline int get_global_turbo_state(void)
  27 {
  28         return gd->arch.turbo_state;
  29 }
  30
  31 static inline void set_global_turbo_state(int state)
  32 {
  33         gd->arch.turbo_state = state;
  34 }
  35 #endif
  36
  37 static const char *const turbo_state_desc[] = {
  38         [TURBO_UNKNOWN]         = "unknown",
  39         [TURBO_UNAVAILABLE]     = "unavailable",
  40         [TURBO_DISABLED]        = "available but hidden",
  41         [TURBO_ENABLED]         = "available and visible"
  42 };
  43
  44 /*
  45  * Determine the current state of Turbo and cache it for later.
  46  * Turbo is a package level config so it does not need to be
  47  * enabled on every core.
  48  */
  49 int turbo_get_state(void)
  50 {
  51         struct cpuid_result cpuid_regs;
  52         int turbo_en, turbo_cap;
  53         msr_t msr;
  54         int turbo_state = get_global_turbo_state();
  55
  56         /* Return cached state if available */
  57         if (turbo_state != TURBO_UNKNOWN)
  58                 return turbo_state;
  59
  60         cpuid_regs = cpuid(CPUID_LEAF_PM);
  61         turbo_cap = !!(cpuid_regs.eax & PM_CAP_TURBO_MODE);
  62
  63         msr = msr_read(MSR_IA32_MISC_ENABLE);
  64         turbo_en = !(msr.hi & MISC_DISABLE_TURBO);
  65
  66         if (!turbo_cap && turbo_en) {
  67                 /* Unavailable */
  68                 turbo_state = TURBO_UNAVAILABLE;
  69         } else if (!turbo_cap && !turbo_en) {
  70                 /* Available but disabled */
  71                 turbo_state = TURBO_DISABLED;
  72         } else if (turbo_cap && turbo_en) {
  73                 /* Available */
  74                 turbo_state = TURBO_ENABLED;
  75         }
  76
  77         set_global_turbo_state(turbo_state);
  78         debug("Turbo is %s\n", turbo_state_desc[turbo_state]);
  79         return turbo_state;
  80 }
  81
  82 void turbo_enable(void)
  83 {
  84         msr_t msr;
  85
  86         /* Only possible if turbo is available but hidden */
  87         if (turbo_get_state() == TURBO_DISABLED) {
  88                 /* Clear Turbo Disable bit in Misc Enables */
  89                 msr = msr_read(MSR_IA32_MISC_ENABLE);
  90                 msr.hi &= ~MISC_DISABLE_TURBO;
  91                 msr_write(MSR_IA32_MISC_ENABLE, msr);
  92
  93                 /* Update cached turbo state */
  94                 set_global_turbo_state(TURBO_ENABLED);
  95                 debug("Turbo has been enabled\n");
  96         }
  97 }