UefiCpuPkg/Library/CpuCommonFeaturesLib/Eist.c

   1 /** @file
   2   Enhanced Intel SpeedStep feature.
   3
   4   Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "CpuCommonFeatures.h"
  16
  17 /**
  18   Detects if Enhanced Intel SpeedStep feature supported on current processor.
  19
  20   @param[in]  ProcessorNumber  The index of the CPU executing this function.
  21   @param[in]  CpuInfo          A pointer to the REGISTER_CPU_FEATURE_INFORMATION
  22                                structure for the CPU executing this function.
  23   @param[in]  ConfigData       A pointer to the configuration buffer returned
  24                                by CPU_FEATURE_GET_CONFIG_DATA.  NULL if
  25                                CPU_FEATURE_GET_CONFIG_DATA was not provided in
  26                                RegisterCpuFeature().
  27
  28   @retval TRUE     Enhanced Intel SpeedStep feature is supported.
  29   @retval FALSE    Enhanced Intel SpeedStep feature is not supported.
  30
  31   @note This service could be called by BSP/APs.
  32 **/
  33 BOOLEAN
  34 EFIAPI
  35 EistSupport (
  36   IN UINTN                             ProcessorNumber,
  37   IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  38   IN VOID                              *ConfigData  OPTIONAL
  39   )
  40 {
  41   return (CpuInfo->CpuIdVersionInfoEcx.Bits.EIST == 1);
  42 }
  43
  44 /**
  45   Initializes Enhanced Intel SpeedStep feature to specific state.
  46
  47   @param[in]  ProcessorNumber  The index of the CPU executing this function.
  48   @param[in]  CpuInfo          A pointer to the REGISTER_CPU_FEATURE_INFORMATION
  49                                structure for the CPU executing this function.
  50   @param[in]  ConfigData       A pointer to the configuration buffer returned
  51                                by CPU_FEATURE_GET_CONFIG_DATA.  NULL if
  52                                CPU_FEATURE_GET_CONFIG_DATA was not provided in
  53                                RegisterCpuFeature().
  54   @param[in]  State            If TRUE, then the Enhanced Intel SpeedStep feature
  55                                must be enabled.
  56                                If FALSE, then the Enhanced Intel SpeedStep feature
  57                                must be disabled.
  58
  59   @retval RETURN_SUCCESS       Enhanced Intel SpeedStep feature is initialized.
  60
  61   @note This service could be called by BSP only.
  62 **/
  63 RETURN_STATUS
  64 EFIAPI
  65 EistInitialize (
  66   IN UINTN                             ProcessorNumber,
  67   IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  68   IN VOID                              *ConfigData,  OPTIONAL
  69   IN BOOLEAN                           State
  70   )
  71 {
  72   //
  73   // The scope of the MSR_IA32_MISC_ENABLE is core for below processor type, only program
  74   // MSR_IA32_MISC_ENABLE for thread 0 in each core.
  75   //
  76   if (IS_ATOM_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel) ||
  77       IS_CORE_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel) ||
  78       IS_CORE2_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel)) {
  79     if (CpuInfo->ProcessorInfo.Location.Thread != 0) {
  80       return RETURN_SUCCESS;
  81     }
  82   }
  83
  84   CPU_REGISTER_TABLE_WRITE_FIELD (
  85     ProcessorNumber,
  86     Msr,
  87     MSR_IA32_MISC_ENABLE,
  88     MSR_IA32_MISC_ENABLE_REGISTER,
  89     Bits.EIST,
  90     (State) ? 1 : 0
  91     );
  92   return RETURN_SUCCESS;
  93 }