UefiCpuPkg/Library/CpuCommonFeaturesLib/ClockModulation.c

   1 /** @file
   2   Clock Modulation feature.
   3
   4   Copyright (c) 2017 - 2018, Intel Corporation. All rights reserved.<BR>
   5   SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 #include "CpuCommonFeatures.h"
  10
  11 /**
  12   Detects if Clock Modulation feature supported on current processor.
  13
  14   @param[in]  ProcessorNumber  The index of the CPU executing this function.
  15   @param[in]  CpuInfo          A pointer to the REGISTER_CPU_FEATURE_INFORMATION
  16                                structure for the CPU executing this function.
  17   @param[in]  ConfigData       A pointer to the configuration buffer returned
  18                                by CPU_FEATURE_GET_CONFIG_DATA.  NULL if
  19                                CPU_FEATURE_GET_CONFIG_DATA was not provided in
  20                                RegisterCpuFeature().
  21
  22   @retval TRUE     Clock Modulation feature is supported.
  23   @retval FALSE    Clock Modulation feature is not supported.
  24
  25   @note This service could be called by BSP/APs.
  26 **/
  27 BOOLEAN
  28 EFIAPI
  29 ClockModulationSupport (
  30   IN UINTN                             ProcessorNumber,
  31   IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  32   IN VOID                              *ConfigData  OPTIONAL
  33   )
  34 {
  35   return (CpuInfo->CpuIdVersionInfoEdx.Bits.ACPI == 1);
  36 }
  37
  38 /**
  39   Initializes Clock Modulation feature to specific state.
  40
  41   @param[in]  ProcessorNumber  The index of the CPU executing this function.
  42   @param[in]  CpuInfo          A pointer to the REGISTER_CPU_FEATURE_INFORMATION
  43                                structure for the CPU executing this function.
  44   @param[in]  ConfigData       A pointer to the configuration buffer returned
  45                                by CPU_FEATURE_GET_CONFIG_DATA.  NULL if
  46                                CPU_FEATURE_GET_CONFIG_DATA was not provided in
  47                                RegisterCpuFeature().
  48   @param[in]  State            If TRUE, then the Clock Modulation feature must be enabled.
  49                                If FALSE, then the Clock Modulation feature must be disabled.
  50
  51   @retval RETURN_SUCCESS       Clock Modulation feature is initialized.
  52
  53   @note This service could be called by BSP only.
  54 **/
  55 RETURN_STATUS
  56 EFIAPI
  57 ClockModulationInitialize (
  58   IN UINTN                             ProcessorNumber,
  59   IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  60   IN VOID                              *ConfigData,  OPTIONAL
  61   IN BOOLEAN                           State
  62   )
  63 {
  64   CPUID_THERMAL_POWER_MANAGEMENT_EAX   ThermalPowerManagementEax;
  65   AsmCpuid (CPUID_THERMAL_POWER_MANAGEMENT, &ThermalPowerManagementEax.Uint32, NULL, NULL, NULL);
  66
  67   CPU_REGISTER_TABLE_WRITE_FIELD (
  68     ProcessorNumber,
  69     Msr,
  70     MSR_IA32_CLOCK_MODULATION,
  71     MSR_IA32_CLOCK_MODULATION_REGISTER,
  72     Bits.OnDemandClockModulationDutyCycle,
  73     PcdGet8 (PcdCpuClockModulationDutyCycle) >> 1
  74     );
  75   if (ThermalPowerManagementEax.Bits.ECMD == 1) {
  76     CPU_REGISTER_TABLE_WRITE_FIELD (
  77       ProcessorNumber,
  78       Msr,
  79       MSR_IA32_CLOCK_MODULATION,
  80       MSR_IA32_CLOCK_MODULATION_REGISTER,
  81       Bits.ExtendedOnDemandClockModulationDutyCycle,
  82       PcdGet8 (PcdCpuClockModulationDutyCycle) & BIT0
  83       );
  84   }
  85   CPU_REGISTER_TABLE_WRITE_FIELD (
  86     ProcessorNumber,
  87     Msr,
  88     MSR_IA32_CLOCK_MODULATION,
  89     MSR_IA32_CLOCK_MODULATION_REGISTER,
  90     Bits.OnDemandClockModulationEnable,
  91     (State) ? 1 : 0
  92     );
  93   return RETURN_SUCCESS;
  94 }