UefiCpuPkg/Library/CpuCommonFeaturesLib/ClockModulation.c

   1 /** @file
   2   Clock Modulation feature.
   3
   4   Copyright (c) 2017 - 2018, 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 Clock Modulation 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     Clock Modulation feature is supported.
  29   @retval FALSE    Clock Modulation feature is not supported.
  30
  31   @note This service could be called by BSP/APs.
  32 **/
  33 BOOLEAN
  34 EFIAPI
  35 ClockModulationSupport (
  36   IN UINTN                             ProcessorNumber,
  37   IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  38   IN VOID                              *ConfigData  OPTIONAL
  39   )
  40 {
  41   return (CpuInfo->CpuIdVersionInfoEdx.Bits.ACPI == 1);
  42 }
  43
  44 /**
  45   Initializes Clock Modulation 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 Clock Modulation feature must be enabled.
  55                                If FALSE, then the Clock Modulation feature must be disabled.
  56
  57   @retval RETURN_SUCCESS       Clock Modulation feature is initialized.
  58
  59   @note This service could be called by BSP only.
  60 **/
  61 RETURN_STATUS
  62 EFIAPI
  63 ClockModulationInitialize (
  64   IN UINTN                             ProcessorNumber,
  65   IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  66   IN VOID                              *ConfigData,  OPTIONAL
  67   IN BOOLEAN                           State
  68   )
  69 {
  70   CPUID_THERMAL_POWER_MANAGEMENT_EAX   ThermalPowerManagementEax;
  71   AsmCpuid (CPUID_THERMAL_POWER_MANAGEMENT, &ThermalPowerManagementEax.Uint32, NULL, NULL, NULL);
  72
  73   CPU_REGISTER_TABLE_WRITE_FIELD (
  74     ProcessorNumber,
  75     Msr,
  76     MSR_IA32_CLOCK_MODULATION,
  77     MSR_IA32_CLOCK_MODULATION_REGISTER,
  78     Bits.OnDemandClockModulationDutyCycle,
  79     PcdGet8 (PcdCpuClockModulationDutyCycle) >> 1
  80     );
  81   if (ThermalPowerManagementEax.Bits.ECMD == 1) {
  82     CPU_REGISTER_TABLE_WRITE_FIELD (
  83       ProcessorNumber,
  84       Msr,
  85       MSR_IA32_CLOCK_MODULATION,
  86       MSR_IA32_CLOCK_MODULATION_REGISTER,
  87       Bits.ExtendedOnDemandClockModulationDutyCycle,
  88       PcdGet8 (PcdCpuClockModulationDutyCycle) & BIT0
  89       );
  90   }
  91   CPU_REGISTER_TABLE_WRITE_FIELD (
  92     ProcessorNumber,
  93     Msr,
  94     MSR_IA32_CLOCK_MODULATION,
  95     MSR_IA32_CLOCK_MODULATION_REGISTER,
  96     Bits.OnDemandClockModulationEnable,
  97     (State) ? 1 : 0
  98     );
  99   return RETURN_SUCCESS;
 100 }