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 <log.h>
  10 #include <asm/cpu.h>
  11 #include <asm/msr.h>
  12 #include <asm/processor.h>
  13 #include <asm/turbo.h>
  14
  15 DECLARE_GLOBAL_DATA_PTR;
  16
  17 #ifdef CONFIG_CPU_INTEL_TURBO_NOT_PACKAGE_SCOPED
  18 static inline int get_global_turbo_state(void)
  19 {
  20         return TURBO_UNKNOWN;
  21 }
  22
  23 static inline void set_global_turbo_state(int state)
  24 {
  25 }
  26 #else
  27 static inline int get_global_turbo_state(void)
  28 {
  29         return gd->arch.turbo_state;
  30 }
  31
  32 static inline void set_global_turbo_state(int state)
  33 {
  34         gd->arch.turbo_state = state;
  35 }
  36 #endif
  37
  38 /* gcc 7.3 does not wwant to drop strings, so use #ifdef */
  39 #ifndef CONFIG_TPL_BUILD
  40 static const char *const turbo_state_desc[] = {
  41         [TURBO_UNKNOWN]         = "unknown",
  42         [TURBO_UNAVAILABLE]     = "unavailable",
  43         [TURBO_DISABLED]        = "available but hidden",
  44         [TURBO_ENABLED]         = "available and visible"
  45 };
  46 #endif
  47
  48 /*
  49  * Determine the current state of Turbo and cache it for later.
  50  * Turbo is a package level config so it does not need to be
  51  * enabled on every core.
  52  */
  53 int turbo_get_state(void)
  54 {
  55         struct cpuid_result cpuid_regs;
  56         int turbo_en, turbo_cap;
  57         msr_t msr;
  58         int turbo_state = get_global_turbo_state();
  59
  60         /* Return cached state if available */
  61         if (turbo_state != TURBO_UNKNOWN)
  62                 return turbo_state;
  63
  64         cpuid_regs = cpuid(CPUID_LEAF_PM);
  65         turbo_cap = !!(cpuid_regs.eax & PM_CAP_TURBO_MODE);
  66
  67         msr = msr_read(MSR_IA32_MISC_ENABLE);
  68         turbo_en = !(msr.hi & MISC_DISABLE_TURBO);
  69
  70         if (!turbo_cap && turbo_en) {
  71                 /* Unavailable */
  72                 turbo_state = TURBO_UNAVAILABLE;
  73         } else if (!turbo_cap && !turbo_en) {
  74                 /* Available but disabled */
  75                 turbo_state = TURBO_DISABLED;
  76         } else if (turbo_cap && turbo_en) {
  77                 /* Available */
  78                 turbo_state = TURBO_ENABLED;
  79         }
  80
  81         set_global_turbo_state(turbo_state);
  82 #ifndef CONFIG_TPL_BUILD
  83         debug("Turbo is %s\n", turbo_state_desc[turbo_state]);
  84 #endif
  85         return turbo_state;
  86 }
  87
  88 void turbo_enable(void)
  89 {
  90         msr_t msr;
  91
  92         /* Only possible if turbo is available but hidden */
  93         if (turbo_get_state() == TURBO_DISABLED) {
  94                 /* Clear Turbo Disable bit in Misc Enables */
  95                 msr = msr_read(MSR_IA32_MISC_ENABLE);
  96                 msr.hi &= ~MISC_DISABLE_TURBO;
  97                 msr_write(MSR_IA32_MISC_ENABLE, msr);
  98
  99                 /* Update cached turbo state */
 100                 set_global_turbo_state(TURBO_ENABLED);
 101                 debug("Turbo has been enabled\n");
 102         }
 103 }