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/global_data.h>
  12 #include <asm/msr.h>
  13 #include <asm/processor.h>
  14 #include <asm/turbo.h>
  15
  16 DECLARE_GLOBAL_DATA_PTR;
  17
  18 #ifdef CONFIG_CPU_INTEL_TURBO_NOT_PACKAGE_SCOPED
  19 static inline int get_global_turbo_state(void)
  20 {
  21         return TURBO_UNKNOWN;
  22 }
  23
  24 static inline void set_global_turbo_state(int state)
  25 {
  26 }
  27 #else
  28 static inline int get_global_turbo_state(void)
  29 {
  30         return gd->arch.turbo_state;
  31 }
  32
  33 static inline void set_global_turbo_state(int state)
  34 {
  35         gd->arch.turbo_state = state;
  36 }
  37 #endif
  38
  39 /* gcc 7.3 does not wwant to drop strings, so use #ifdef */
  40 #ifndef CONFIG_TPL_BUILD
  41 static const char *const turbo_state_desc[] = {
  42         [TURBO_UNKNOWN]         = "unknown",
  43         [TURBO_UNAVAILABLE]     = "unavailable",
  44         [TURBO_DISABLED]        = "available but hidden",
  45         [TURBO_ENABLED]         = "available and visible"
  46 };
  47 #endif
  48
  49 /*
  50  * Determine the current state of Turbo and cache it for later.
  51  * Turbo is a package level config so it does not need to be
  52  * enabled on every core.
  53  */
  54 int turbo_get_state(void)
  55 {
  56         struct cpuid_result cpuid_regs;
  57         int turbo_en, turbo_cap;
  58         msr_t msr;
  59         int turbo_state = get_global_turbo_state();
  60
  61         /* Return cached state if available */
  62         if (turbo_state != TURBO_UNKNOWN)
  63                 return turbo_state;
  64
  65         cpuid_regs = cpuid(CPUID_LEAF_PM);
  66         turbo_cap = !!(cpuid_regs.eax & PM_CAP_TURBO_MODE);
  67
  68         msr = msr_read(MSR_IA32_MISC_ENABLE);
  69         turbo_en = !(msr.hi & MISC_DISABLE_TURBO);
  70
  71         if (!turbo_cap && turbo_en) {
  72                 /* Unavailable */
  73                 turbo_state = TURBO_UNAVAILABLE;
  74         } else if (!turbo_cap && !turbo_en) {
  75                 /* Available but disabled */
  76                 turbo_state = TURBO_DISABLED;
  77         } else if (turbo_cap && turbo_en) {
  78                 /* Available */
  79                 turbo_state = TURBO_ENABLED;
  80         }
  81
  82         set_global_turbo_state(turbo_state);
  83 #ifndef CONFIG_TPL_BUILD
  84         debug("Turbo is %s\n", turbo_state_desc[turbo_state]);
  85 #endif
  86         return turbo_state;
  87 }
  88
  89 void turbo_enable(void)
  90 {
  91         msr_t msr;
  92
  93         /* Only possible if turbo is available but hidden */
  94         if (turbo_get_state() == TURBO_DISABLED) {
  95                 /* Clear Turbo Disable bit in Misc Enables */
  96                 msr = msr_read(MSR_IA32_MISC_ENABLE);
  97                 msr.hi &= ~MISC_DISABLE_TURBO;
  98                 msr_write(MSR_IA32_MISC_ENABLE, msr);
  99
 100                 /* Update cached turbo state */
 101                 set_global_turbo_state(TURBO_ENABLED);
 102                 debug("Turbo has been enabled\n");
 103         }
 104 }