PcRtc.c

Go to the documentation of this file.

 
#include "PcRtc.h"
 
extern UINTN   mRtcIndexRegister;
extern UINTN   mRtcTargetRegister;
extern UINT16  mRtcDefaultYear;
extern UINT16  mMinimalValidYear;
extern UINT16  mMaximalValidYear;
//
// Days of month.
//
UINTN  mDayOfMonth[] = { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
 
//
// The name of NV variable to store the timezone and daylight saving information.
//
CHAR16  mTimeZoneVariableName[] = L"RTC";
 
INTN
CompareHMS (
  IN EFI_TIME  *From,
  IN EFI_TIME  *To
  );
 
BOOLEAN
IsWithinOneDay (
  IN EFI_TIME  *From,
  IN EFI_TIME  *To
  );
 
STATIC
UINT8
IoRtcRead (
  IN  UINTN  Address
  )
{
  IoWrite8 (
    mRtcIndexRegister,
    (UINT8)(Address | (UINT8)(IoRead8 (mRtcIndexRegister) & 0x80))
    );
  return IoRead8 (mRtcTargetRegister);
}
 
STATIC
VOID
IoRtcWrite (
  IN  UINTN  Address,
  IN  UINT8  Data
  )
{
  IoWrite8 (
    mRtcIndexRegister,
    (UINT8)(Address | (UINT8)(IoRead8 (mRtcIndexRegister) & 0x80))
    );
  IoWrite8 (mRtcTargetRegister, Data);
}
 
STATIC
UINT8
MmioRtcRead (
  IN  UINTN  Address
  )
{
  MmioWrite8 (
    mRtcIndexRegister,
    (UINT8)(Address | (UINT8)(MmioRead8 (mRtcIndexRegister) & 0x80))
    );
  return MmioRead8 (mRtcTargetRegister);
}
 
STATIC
VOID
MmioRtcWrite (
  IN  UINTN  Address,
  IN  UINT8  Data
  )
{
  MmioWrite8 (
    mRtcIndexRegister,
    (UINT8)(Address | (UINT8)(MmioRead8 (mRtcIndexRegister) & 0x80))
    );
  MmioWrite8 (mRtcTargetRegister, Data);
}
 
STATIC
UINT8
RtcRead (
  IN  UINTN  Address
  )
{
  if (FeaturePcdGet (PcdRtcUseMmio)) {
    return MmioRtcRead (Address);
  }
 
  return IoRtcRead (Address);
}
 
STATIC
VOID
RtcWrite (
  IN  UINTN  Address,
  IN  UINT8  Data
  )
{
  if (FeaturePcdGet (PcdRtcUseMmio)) {
    MmioRtcWrite (Address, Data);
  } else {
    IoRtcWrite (Address, Data);
  }
}
 
EFI_STATUS
PcRtcSetTimeZone (
  IN INT16                  TimeZone,
  IN UINT8                  Daylight,
  IN PC_RTC_MODULE_GLOBALS  *Global
  )
{
  EFI_STATUS  Status;
  UINT32      TimerVar;
 
  ASSERT ((TimeZone == EFI_UNSPECIFIED_TIMEZONE) || ((TimeZone >= -1440) && (TimeZone <= 1440)));
  ASSERT ((Daylight & (~(EFI_TIME_ADJUST_DAYLIGHT | EFI_TIME_IN_DAYLIGHT))) == 0);
 
  //
  // Write timezone and daylight to RTC variable
  //
  if ((TimeZone == EFI_UNSPECIFIED_TIMEZONE) && (Daylight == 0)) {
    Status = EfiSetVariable (
               mTimeZoneVariableName,
               &gEfiCallerIdGuid,
               0,
               0,
               NULL
               );
    if (Status == EFI_NOT_FOUND) {
      Status = EFI_SUCCESS;
    }
  } else {
    TimerVar = Daylight;
    TimerVar = (UINT32)((TimerVar << 16) | (UINT16)(TimeZone));
    Status   = EfiSetVariable (
                 mTimeZoneVariableName,
                 &gEfiCallerIdGuid,
                 EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_NON_VOLATILE,
                 sizeof (TimerVar),
                 &TimerVar
                 );
  }
 
  //
  // Set the variable that contains the TimeZone and Daylight fields
  //
  if (!EFI_ERROR (Status)) {
    Global->SavedTimeZone = TimeZone;
    Global->Daylight      = Daylight;
  }
 
  return Status;
}
 
EFI_STATUS
PcRtcInit (
  IN PC_RTC_MODULE_GLOBALS  *Global
  )
{
  EFI_STATUS      Status;
  RTC_REGISTER_A  RegisterA;
  RTC_REGISTER_B  RegisterB;
  RTC_REGISTER_D  RegisterD;
  EFI_TIME        Time;
  UINTN           DataSize;
  UINT32          TimerVar;
  BOOLEAN         Enabled;
  BOOLEAN         Pending;
  BOOLEAN         NeedRtcUpdate;
 
  NeedRtcUpdate = FALSE;
 
  //
  // Acquire RTC Lock to make access to RTC atomic
  //
  if (!EfiAtRuntime ()) {
    EfiAcquireLock (&Global->RtcLock);
  }
 
  //
  // Initialize RTC Register
  //
  // Make sure Division Chain is properly configured,
  // or RTC clock won't "tick" -- time won't increment
  //
  RegisterA.Data = FixedPcdGet8 (PcdInitialValueRtcRegisterA);
  RtcWrite (RTC_ADDRESS_REGISTER_A, RegisterA.Data);
 
  //
  // Read Register B
  //
  RegisterB.Data = RtcRead (RTC_ADDRESS_REGISTER_B);
 
  //
  // Clear RTC flag register
  //
  RtcRead (RTC_ADDRESS_REGISTER_C);
 
  //
  // Clear RTC register D
  //
  RegisterD.Data = FixedPcdGet8 (PcdInitialValueRtcRegisterD);
  RtcWrite (RTC_ADDRESS_REGISTER_D, RegisterD.Data);
 
  //
  // Wait for up to 0.1 seconds for the RTC to be updated
  //
  Status = RtcWaitToUpdate (PcdGet32 (PcdRealTimeClockUpdateTimeout));
  if (EFI_ERROR (Status)) {
    //
    // Set the variable with default value if the RTC is functioning incorrectly.
    //
    Global->SavedTimeZone = EFI_UNSPECIFIED_TIMEZONE;
    Global->Daylight      = 0;
    if (!EfiAtRuntime ()) {
      EfiReleaseLock (&Global->RtcLock);
    }
 
    return EFI_DEVICE_ERROR;
  }
 
  //
  // Get the Time/Date/Daylight Savings values.
  //
  Time.Second = RtcRead (RTC_ADDRESS_SECONDS);
  Time.Minute = RtcRead (RTC_ADDRESS_MINUTES);
  Time.Hour   = RtcRead (RTC_ADDRESS_HOURS);
  Time.Day    = RtcRead (RTC_ADDRESS_DAY_OF_THE_MONTH);
  Time.Month  = RtcRead (RTC_ADDRESS_MONTH);
  Time.Year   = RtcRead (RTC_ADDRESS_YEAR);
 
  //
  // Release RTC Lock.
  //
  if (!EfiAtRuntime ()) {
    EfiReleaseLock (&Global->RtcLock);
  }
 
  //
  // Get the data of Daylight saving and time zone, if they have been
  // stored in NV variable during previous boot.
  //
  DataSize = sizeof (UINT32);
  Status   = EfiGetVariable (
               mTimeZoneVariableName,
               &gEfiCallerIdGuid,
               NULL,
               &DataSize,
               &TimerVar
               );
  if (!EFI_ERROR (Status)) {
    Time.TimeZone = (INT16)TimerVar;
    Time.Daylight = (UINT8)(TimerVar >> 16);
  } else {
    Time.TimeZone = EFI_UNSPECIFIED_TIMEZONE;
    Time.Daylight = 0;
  }
 
  //
  // Validate time fields
  //
  Status = ConvertRtcTimeToEfiTime (&Time, RegisterB);
  if (!EFI_ERROR (Status)) {
    Status = RtcTimeFieldsValid (&Time);
  }
 
  if (EFI_ERROR (Status)) {
    //
    // Report Status Code to indicate that the RTC has bad date and time
    //
    REPORT_STATUS_CODE (
      EFI_ERROR_CODE | EFI_ERROR_MINOR,
      (EFI_SOFTWARE_DXE_RT_DRIVER | EFI_SW_EC_BAD_DATE_TIME)
      );
    Time.Second     = RTC_INIT_SECOND;
    Time.Minute     = RTC_INIT_MINUTE;
    Time.Hour       = RTC_INIT_HOUR;
    Time.Day        = RTC_INIT_DAY;
    Time.Month      = RTC_INIT_MONTH;
    Time.Year       = MAX (mRtcDefaultYear, mMinimalValidYear);
    Time.Year       = MIN (Time.Year, mMaximalValidYear);
    Time.Nanosecond = 0;
    Time.TimeZone   = EFI_UNSPECIFIED_TIMEZONE;
    Time.Daylight   = 0;
    NeedRtcUpdate   = TRUE;
  }
 
  //
  // Set RTC configuration after get original time
  // The value of bit AIE should be reserved.
  //
  if ((RegisterB.Data | BIT5) != (FixedPcdGet8 (PcdInitialValueRtcRegisterB) | BIT5)) {
    RegisterB.Data = FixedPcdGet8 (PcdInitialValueRtcRegisterB) | (RegisterB.Data & BIT5);
    RtcWrite (RTC_ADDRESS_REGISTER_B, RegisterB.Data);
    NeedRtcUpdate = TRUE;
  }
 
  //
  // Reset time value according to new RTC configuration
  //
  if (NeedRtcUpdate) {
    Status = PcRtcSetTime (&Time, Global);
    if (EFI_ERROR (Status)) {
      return EFI_DEVICE_ERROR;
    }
  } else {
    Status = PcRtcSetTimeZone (Time.TimeZone, Time.Daylight, Global);
    if (EFI_ERROR (Status)) {
      return EFI_DEVICE_ERROR;
    }
  }
 
  //
  // Reset wakeup time value to valid state when wakeup alarm is disabled and wakeup time is invalid.
  // Global variable has already had valid SavedTimeZone and Daylight,
  // so we can use them to get and set wakeup time.
  //
  Status = PcRtcGetWakeupTime (&Enabled, &Pending, &Time, Global);
  if ((!EFI_ERROR (Status)) || (Enabled)) {
    return EFI_SUCCESS;
  }
 
  //
  // When wakeup time is disabled and invalid, reset wakeup time register to valid state
  // but keep wakeup alarm disabled.
  //
  Time.Second     = RTC_INIT_SECOND;
  Time.Minute     = RTC_INIT_MINUTE;
  Time.Hour       = RTC_INIT_HOUR;
  Time.Day        = RTC_INIT_DAY;
  Time.Month      = RTC_INIT_MONTH;
  Time.Year       = MAX (mRtcDefaultYear, mMinimalValidYear);
  Time.Year       = MIN (Time.Year, mMaximalValidYear);
  Time.Nanosecond = 0;
  Time.TimeZone   = Global->SavedTimeZone;
  Time.Daylight   = Global->Daylight;
 
  //
  // Acquire RTC Lock to make access to RTC atomic
  //
  if (!EfiAtRuntime ()) {
    EfiAcquireLock (&Global->RtcLock);
  }
 
  //
  // Wait for up to 0.1 seconds for the RTC to be updated
  //
  Status = RtcWaitToUpdate (PcdGet32 (PcdRealTimeClockUpdateTimeout));
  if (EFI_ERROR (Status)) {
    if (!EfiAtRuntime ()) {
      EfiReleaseLock (&Global->RtcLock);
    }
 
    return EFI_DEVICE_ERROR;
  }
 
  ConvertEfiTimeToRtcTime (&Time, RegisterB);
 
  //
  // Set the Y/M/D info to variable as it has no corresponding hw registers.
  //
  Status =  EfiSetVariable (
              L"RTCALARM",
              &gEfiCallerIdGuid,
              EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_NON_VOLATILE,
              sizeof (Time),
              &Time
              );
  if (EFI_ERROR (Status)) {
    if (!EfiAtRuntime ()) {
      EfiReleaseLock (&Global->RtcLock);
    }
 
    return EFI_DEVICE_ERROR;
  }
 
  //
  // Inhibit updates of the RTC
  //
  RegisterB.Bits.Set = 1;
  RtcWrite (RTC_ADDRESS_REGISTER_B, RegisterB.Data);
 
  //
  // Set RTC alarm time registers
  //
  RtcWrite (RTC_ADDRESS_SECONDS_ALARM, Time.Second);
  RtcWrite (RTC_ADDRESS_MINUTES_ALARM, Time.Minute);
  RtcWrite (RTC_ADDRESS_HOURS_ALARM, Time.Hour);
 
  //
  // Allow updates of the RTC registers
  //
  RegisterB.Bits.Set = 0;
  RtcWrite (RTC_ADDRESS_REGISTER_B, RegisterB.Data);
 
  //
  // Release RTC Lock.
  //
  if (!EfiAtRuntime ()) {
    EfiReleaseLock (&Global->RtcLock);
  }
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
PcRtcGetTime (
  OUT  EFI_TIME               *Time,
  OUT  EFI_TIME_CAPABILITIES  *Capabilities   OPTIONAL,
  IN   PC_RTC_MODULE_GLOBALS  *Global
  )
{
  EFI_STATUS      Status;
  RTC_REGISTER_B  RegisterB;
 
  //
  // Check parameters for null pointer
  //
  if (Time == NULL) {
    return EFI_INVALID_PARAMETER;
  }
 
  //
  // Acquire RTC Lock to make access to RTC atomic
  //
  if (!EfiAtRuntime ()) {
    EfiAcquireLock (&Global->RtcLock);
  }
 
  //
  // Wait for up to 0.1 seconds for the RTC to be updated
  //
  Status = RtcWaitToUpdate (PcdGet32 (PcdRealTimeClockUpdateTimeout));
  if (EFI_ERROR (Status)) {
    if (!EfiAtRuntime ()) {
      EfiReleaseLock (&Global->RtcLock);
    }
 
    return Status;
  }
 
  //
  // Read Register B
  //
  RegisterB.Data = RtcRead (RTC_ADDRESS_REGISTER_B);
 
  //
  // Get the Time/Date/Daylight Savings values.
  //
  Time->Second = RtcRead (RTC_ADDRESS_SECONDS);
  Time->Minute = RtcRead (RTC_ADDRESS_MINUTES);
  Time->Hour   = RtcRead (RTC_ADDRESS_HOURS);
  Time->Day    = RtcRead (RTC_ADDRESS_DAY_OF_THE_MONTH);
  Time->Month  = RtcRead (RTC_ADDRESS_MONTH);
  Time->Year   = RtcRead (RTC_ADDRESS_YEAR);
 
  //
  // Release RTC Lock.
  //
  if (!EfiAtRuntime ()) {
    EfiReleaseLock (&Global->RtcLock);
  }
 
  //
  // Get the variable that contains the TimeZone and Daylight fields
  //
  Time->TimeZone = Global->SavedTimeZone;
  Time->Daylight = Global->Daylight;
 
  //
  // Make sure all field values are in correct range
  //
  Status = ConvertRtcTimeToEfiTime (Time, RegisterB);
  if (!EFI_ERROR (Status)) {
    Status = RtcTimeFieldsValid (Time);
  }
 
  if (EFI_ERROR (Status)) {
    return EFI_DEVICE_ERROR;
  }
 
  //
  //  Fill in Capabilities if it was passed in
  //
  if (Capabilities != NULL) {
    Capabilities->Resolution = 1;
    //
    // 1 hertz
    //
    Capabilities->Accuracy = 50000000;
    //
    // 50 ppm
    //
    Capabilities->SetsToZero = FALSE;
  }
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
PcRtcSetTime (
  IN EFI_TIME               *Time,
  IN PC_RTC_MODULE_GLOBALS  *Global
  )
{
  EFI_STATUS      Status;
  EFI_TIME        RtcTime;
  RTC_REGISTER_A  RegisterA;
  RTC_REGISTER_B  RegisterB;
 
  if (Time == NULL) {
    return EFI_INVALID_PARAMETER;
  }
 
  //
  // Make sure that the time fields are valid
  //
  Status = RtcTimeFieldsValid (Time);
  if (EFI_ERROR (Status)) {
    return Status;
  }
 
  CopyMem (&RtcTime, Time, sizeof (EFI_TIME));
 
  //
  // Acquire RTC Lock to make access to RTC atomic
  //
  if (!EfiAtRuntime ()) {
    EfiAcquireLock (&Global->RtcLock);
  }
 
  //
  // Wait for up to 0.1 seconds for the RTC to be updated
  //
  Status = RtcWaitToUpdate (PcdGet32 (PcdRealTimeClockUpdateTimeout));
  if (EFI_ERROR (Status)) {
    if (!EfiAtRuntime ()) {
      EfiReleaseLock (&Global->RtcLock);
    }
 
    return Status;
  }
 
  Status = PcRtcSetTimeZone (Time->TimeZone, Time->Daylight, Global);
 
  if (EFI_ERROR (Status)) {
    if (!EfiAtRuntime ()) {
      EfiReleaseLock (&Global->RtcLock);
    }
 
    return EFI_DEVICE_ERROR;
  }
 
  //
  // Read Register B, and inhibit updates of the RTC
  //
  RegisterB.Data     = RtcRead (RTC_ADDRESS_REGISTER_B);
  RegisterB.Bits.Set = 1;
  RtcWrite (RTC_ADDRESS_REGISTER_B, RegisterB.Data);
 
  RegisterA.Data = RtcRead (RTC_ADDRESS_REGISTER_A);
  //
  // Set Divider in Reset status, RTC stops
  //
  RtcWrite (RTC_ADDRESS_REGISTER_A, RegisterA.Data | RTC_DIV_RESET);
  //
  // Store the century value to RTC before converting to BCD format.
  //
  if (Global->CenturyRtcAddress != 0) {
    RtcWrite (Global->CenturyRtcAddress, DecimalToBcd8 ((UINT8)(RtcTime.Year / 100)));
  }
 
  ConvertEfiTimeToRtcTime (&RtcTime, RegisterB);
 
  RtcWrite (RTC_ADDRESS_SECONDS, RtcTime.Second);
  RtcWrite (RTC_ADDRESS_MINUTES, RtcTime.Minute);
  RtcWrite (RTC_ADDRESS_HOURS, RtcTime.Hour);
  RtcWrite (RTC_ADDRESS_DAY_OF_THE_MONTH, RtcTime.Day);
  RtcWrite (RTC_ADDRESS_MONTH, RtcTime.Month);
  RtcWrite (RTC_ADDRESS_YEAR, (UINT8)RtcTime.Year);
 
  //
  // Allow updates of the RTC registers
  //
  RegisterB.Bits.Set = 0;
  RtcWrite (RTC_ADDRESS_REGISTER_B, RegisterB.Data);
 
  //
  // Restore Divider status
  //
  RtcWrite (RTC_ADDRESS_REGISTER_A, RegisterA.Data);
  //
  // Release RTC Lock.
  //
  if (!EfiAtRuntime ()) {
    EfiReleaseLock (&Global->RtcLock);
  }
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
PcRtcGetWakeupTime (
  OUT BOOLEAN                *Enabled,
  OUT BOOLEAN                *Pending,
  OUT EFI_TIME               *Time,
  IN  PC_RTC_MODULE_GLOBALS  *Global
  )
{
  EFI_STATUS      Status;
  RTC_REGISTER_B  RegisterB;
  RTC_REGISTER_C  RegisterC;
  EFI_TIME        RtcTime;
  UINTN           DataSize;
 
  //
  // Check parameters for null pointers
  //
  if ((Enabled == NULL) || (Pending == NULL) || (Time == NULL)) {
    return EFI_INVALID_PARAMETER;
  }
 
  //
  // Acquire RTC Lock to make access to RTC atomic
  //
  if (!EfiAtRuntime ()) {
    EfiAcquireLock (&Global->RtcLock);
  }
 
  //
  // Wait for up to 0.1 seconds for the RTC to be updated
  //
  Status = RtcWaitToUpdate (PcdGet32 (PcdRealTimeClockUpdateTimeout));
  if (EFI_ERROR (Status)) {
    if (!EfiAtRuntime ()) {
      EfiReleaseLock (&Global->RtcLock);
    }
 
    return EFI_DEVICE_ERROR;
  }
 
  //
  // Read Register B and Register C
  //
  RegisterB.Data = RtcRead (RTC_ADDRESS_REGISTER_B);
  RegisterC.Data = RtcRead (RTC_ADDRESS_REGISTER_C);
 
  //
  // Get the Time/Date/Daylight Savings values.
  //
  *Enabled = RegisterB.Bits.Aie;
  *Pending = RegisterC.Bits.Af;
 
  Time->Second   = RtcRead (RTC_ADDRESS_SECONDS_ALARM);
  Time->Minute   = RtcRead (RTC_ADDRESS_MINUTES_ALARM);
  Time->Hour     = RtcRead (RTC_ADDRESS_HOURS_ALARM);
  Time->Day      = RtcRead (RTC_ADDRESS_DAY_OF_THE_MONTH);
  Time->Month    = RtcRead (RTC_ADDRESS_MONTH);
  Time->Year     = RtcRead (RTC_ADDRESS_YEAR);
  Time->TimeZone = Global->SavedTimeZone;
  Time->Daylight = Global->Daylight;
 
  //
  // Get the alarm info from variable
  //
  DataSize = sizeof (EFI_TIME);
  Status   = EfiGetVariable (
               L"RTCALARM",
               &gEfiCallerIdGuid,
               NULL,
               &DataSize,
               &RtcTime
               );
  if (!EFI_ERROR (Status)) {
    //
    // The alarm variable exists. In this case, we read variable to get info.
    //
    Time->Day   = RtcTime.Day;
    Time->Month = RtcTime.Month;
    Time->Year  = RtcTime.Year;
  }
 
  //
  // Release RTC Lock.
  //
  if (!EfiAtRuntime ()) {
    EfiReleaseLock (&Global->RtcLock);
  }
 
  //
  // Make sure all field values are in correct range
  //
  Status = ConvertRtcTimeToEfiTime (Time, RegisterB);
  if (!EFI_ERROR (Status)) {
    Status = RtcTimeFieldsValid (Time);
  }
 
  if (EFI_ERROR (Status)) {
    return EFI_DEVICE_ERROR;
  }
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
PcRtcSetWakeupTime (
  IN BOOLEAN                Enable,
  IN EFI_TIME               *Time    OPTIONAL,
  IN PC_RTC_MODULE_GLOBALS  *Global
  )
{
  EFI_STATUS             Status;
  EFI_TIME               RtcTime;
  RTC_REGISTER_B         RegisterB;
  EFI_TIME_CAPABILITIES  Capabilities;
 
  ZeroMem (&RtcTime, sizeof (RtcTime));
 
  if (Enable) {
    if (Time == NULL) {
      return EFI_INVALID_PARAMETER;
    }
 
    //
    // Make sure that the time fields are valid
    //
    Status = RtcTimeFieldsValid (Time);
    if (EFI_ERROR (Status)) {
      return EFI_INVALID_PARAMETER;
    }
 
    //
    // Just support set alarm time within 24 hours
    //
    Status = PcRtcGetTime (&RtcTime, &Capabilities, Global);
    if (!EFI_ERROR (Status)) {
      Status = RtcTimeFieldsValid (&RtcTime);
    }
 
    if (EFI_ERROR (Status)) {
      return EFI_DEVICE_ERROR;
    }
 
    if (!IsWithinOneDay (&RtcTime, Time)) {
      return EFI_UNSUPPORTED;
    }
 
    //
    // Make a local copy of the time and date
    //
    CopyMem (&RtcTime, Time, sizeof (EFI_TIME));
  }
 
  //
  // Acquire RTC Lock to make access to RTC atomic
  //
  if (!EfiAtRuntime ()) {
    EfiAcquireLock (&Global->RtcLock);
  }
 
  //
  // Wait for up to 0.1 seconds for the RTC to be updated
  //
  Status = RtcWaitToUpdate (PcdGet32 (PcdRealTimeClockUpdateTimeout));
  if (EFI_ERROR (Status)) {
    if (!EfiAtRuntime ()) {
      EfiReleaseLock (&Global->RtcLock);
    }
 
    return EFI_DEVICE_ERROR;
  }
 
  //
  // Read Register B
  //
  RegisterB.Data = RtcRead (RTC_ADDRESS_REGISTER_B);
 
  if (Enable) {
    ConvertEfiTimeToRtcTime (&RtcTime, RegisterB);
  } else {
    //
    // if the alarm is disable, record the current setting.
    //
    RtcTime.Second   = RtcRead (RTC_ADDRESS_SECONDS_ALARM);
    RtcTime.Minute   = RtcRead (RTC_ADDRESS_MINUTES_ALARM);
    RtcTime.Hour     = RtcRead (RTC_ADDRESS_HOURS_ALARM);
    RtcTime.Day      = RtcRead (RTC_ADDRESS_DAY_OF_THE_MONTH);
    RtcTime.Month    = RtcRead (RTC_ADDRESS_MONTH);
    RtcTime.Year     = RtcRead (RTC_ADDRESS_YEAR);
    RtcTime.TimeZone = Global->SavedTimeZone;
    RtcTime.Daylight = Global->Daylight;
  }
 
  //
  // Set the Y/M/D info to variable as it has no corresponding hw registers.
  //
  Status =  EfiSetVariable (
              L"RTCALARM",
              &gEfiCallerIdGuid,
              EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_NON_VOLATILE,
              sizeof (RtcTime),
              &RtcTime
              );
  if (EFI_ERROR (Status)) {
    if (!EfiAtRuntime ()) {
      EfiReleaseLock (&Global->RtcLock);
    }
 
    return EFI_DEVICE_ERROR;
  }
 
  //
  // Inhibit updates of the RTC
  //
  RegisterB.Bits.Set = 1;
  RtcWrite (RTC_ADDRESS_REGISTER_B, RegisterB.Data);
 
  if (Enable) {
    //
    // Set RTC alarm time
    //
    RtcWrite (RTC_ADDRESS_SECONDS_ALARM, RtcTime.Second);
    RtcWrite (RTC_ADDRESS_MINUTES_ALARM, RtcTime.Minute);
    RtcWrite (RTC_ADDRESS_HOURS_ALARM, RtcTime.Hour);
 
    RegisterB.Bits.Aie = 1;
  } else {
    RegisterB.Bits.Aie = 0;
  }
 
  //
  // Allow updates of the RTC registers
  //
  RegisterB.Bits.Set = 0;
  RtcWrite (RTC_ADDRESS_REGISTER_B, RegisterB.Data);
 
  //
  // Release RTC Lock.
  //
  if (!EfiAtRuntime ()) {
    EfiReleaseLock (&Global->RtcLock);
  }
 
  return EFI_SUCCESS;
}
 
UINT8
CheckAndConvertBcd8ToDecimal8 (
  IN  UINT8  Value
  )
{
  if ((Value < 0xa0) && ((Value & 0xf) < 0xa)) {
    return BcdToDecimal8 (Value);
  }
 
  return 0xff;
}
 
EFI_STATUS
ConvertRtcTimeToEfiTime (
  IN OUT EFI_TIME        *Time,
  IN     RTC_REGISTER_B  RegisterB
  )
{
  BOOLEAN  IsPM;
  UINT8    Century;
 
  // IsPM only makes sense for 12-hour format.
  if (RegisterB.Bits.Mil == 0) {
    if ((Time->Hour & 0x80) != 0) {
      IsPM = TRUE;
    } else {
      IsPM = FALSE;
    }
 
    Time->Hour = (UINT8)(Time->Hour & 0x7f);
  }
 
  if (RegisterB.Bits.Dm == 0) {
    Time->Year   = CheckAndConvertBcd8ToDecimal8 ((UINT8)Time->Year);
    Time->Month  = CheckAndConvertBcd8ToDecimal8 (Time->Month);
    Time->Day    = CheckAndConvertBcd8ToDecimal8 (Time->Day);
    Time->Hour   = CheckAndConvertBcd8ToDecimal8 (Time->Hour);
    Time->Minute = CheckAndConvertBcd8ToDecimal8 (Time->Minute);
    Time->Second = CheckAndConvertBcd8ToDecimal8 (Time->Second);
  }
 
  if ((Time->Year == 0xff) || (Time->Month == 0xff) || (Time->Day == 0xff) ||
      (Time->Hour == 0xff) || (Time->Minute == 0xff) || (Time->Second == 0xff))
  {
    return EFI_INVALID_PARAMETER;
  }
 
  //
  // For minimal/maximum year range [1970, 2069],
  //   Century is 19 if RTC year >= 70,
  //   Century is 20 otherwise.
  //
  Century = (UINT8)(mMinimalValidYear / 100);
  if (Time->Year < mMinimalValidYear % 100) {
    Century++;
  }
 
  Time->Year = (UINT16)(Century * 100 + Time->Year);
 
  //
  // If time is in 12 hour format, convert it to 24 hour format
  //
  if (RegisterB.Bits.Mil == 0) {
    if (IsPM && (Time->Hour < 12)) {
      Time->Hour = (UINT8)(Time->Hour + 12);
    }
 
    if (!IsPM && (Time->Hour == 12)) {
      Time->Hour = 0;
    }
  }
 
  Time->Nanosecond = 0;
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
RtcWaitToUpdate (
  UINTN  Timeout
  )
{
  RTC_REGISTER_A  RegisterA;
  RTC_REGISTER_D  RegisterD;
 
  //
  // See if the RTC is functioning correctly
  //
  RegisterD.Data = RtcRead (RTC_ADDRESS_REGISTER_D);
 
  if (RegisterD.Bits.Vrt == 0) {
    return EFI_DEVICE_ERROR;
  }
 
  //
  // Wait for up to 0.1 seconds for the RTC to be ready.
  //
  Timeout        = (Timeout / 10) + 1;
  RegisterA.Data = RtcRead (RTC_ADDRESS_REGISTER_A);
  while (RegisterA.Bits.Uip == 1 && Timeout > 0) {
    MicroSecondDelay (10);
    RegisterA.Data = RtcRead (RTC_ADDRESS_REGISTER_A);
    Timeout--;
  }
 
  RegisterD.Data = RtcRead (RTC_ADDRESS_REGISTER_D);
  if ((Timeout == 0) || (RegisterD.Bits.Vrt == 0)) {
    return EFI_DEVICE_ERROR;
  }
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
RtcTimeFieldsValid (
  IN EFI_TIME  *Time
  )
{
  if ((Time->Year < mMinimalValidYear) ||
      (Time->Year > mMaximalValidYear) ||
      (Time->Month < 1) ||
      (Time->Month > 12) ||
      (!DayValid (Time)) ||
      (Time->Hour > 23) ||
      (Time->Minute > 59) ||
      (Time->Second > 59) ||
      (Time->Nanosecond > 999999999) ||
      (!((Time->TimeZone == EFI_UNSPECIFIED_TIMEZONE) || ((Time->TimeZone >= -1440) && (Time->TimeZone <= 1440)))) ||
      ((Time->Daylight & (~(EFI_TIME_ADJUST_DAYLIGHT | EFI_TIME_IN_DAYLIGHT))) != 0))
  {
    return EFI_INVALID_PARAMETER;
  }
 
  return EFI_SUCCESS;
}
 
BOOLEAN
DayValid (
  IN  EFI_TIME  *Time
  )
{
  //
  // The validity of Time->Month field should be checked before
  //
  ASSERT (Time->Month >= 1);
  ASSERT (Time->Month <= 12);
  if ((Time->Day < 1) ||
      (Time->Day > mDayOfMonth[Time->Month - 1]) ||
      ((Time->Month == 2) && (!IsLeapYear (Time) && (Time->Day > 28)))
      )
  {
    return FALSE;
  }
 
  return TRUE;
}
 
BOOLEAN
IsLeapYear (
  IN EFI_TIME  *Time
  )
{
  if (Time->Year % 4 == 0) {
    if (Time->Year % 100 == 0) {
      if (Time->Year % 400 == 0) {
        return TRUE;
      } else {
        return FALSE;
      }
    } else {
      return TRUE;
    }
  } else {
    return FALSE;
  }
}
 
VOID
ConvertEfiTimeToRtcTime (
  IN OUT EFI_TIME        *Time,
  IN     RTC_REGISTER_B  RegisterB
  )
{
  BOOLEAN  IsPM;
 
  IsPM = TRUE;
  //
  // Adjust hour field if RTC is in 12 hour mode
  //
  if (RegisterB.Bits.Mil == 0) {
    if (Time->Hour < 12) {
      IsPM = FALSE;
    }
 
    if (Time->Hour >= 13) {
      Time->Hour = (UINT8)(Time->Hour - 12);
    } else if (Time->Hour == 0) {
      Time->Hour = 12;
    }
  }
 
  //
  // Set the Time/Date values.
  //
  Time->Year = (UINT16)(Time->Year % 100);
 
  if (RegisterB.Bits.Dm == 0) {
    Time->Year   = DecimalToBcd8 ((UINT8)Time->Year);
    Time->Month  = DecimalToBcd8 (Time->Month);
    Time->Day    = DecimalToBcd8 (Time->Day);
    Time->Hour   = DecimalToBcd8 (Time->Hour);
    Time->Minute = DecimalToBcd8 (Time->Minute);
    Time->Second = DecimalToBcd8 (Time->Second);
  }
 
  //
  // If we are in 12 hour mode and PM is set, then set bit 7 of the Hour field.
  //
  if ((RegisterB.Bits.Mil == 0) && IsPM) {
    Time->Hour = (UINT8)(Time->Hour | 0x80);
  }
}
 
INTN
CompareHMS (
  IN EFI_TIME  *From,
  IN EFI_TIME  *To
  )
{
  if ((From->Hour > To->Hour) ||
      ((From->Hour == To->Hour) && (From->Minute > To->Minute)) ||
      ((From->Hour == To->Hour) && (From->Minute == To->Minute) && (From->Second > To->Second)))
  {
    return 1;
  } else if ((From->Hour == To->Hour) && (From->Minute == To->Minute) && (From->Second == To->Second)) {
    return 0;
  } else {
    return -1;
  }
}
 
BOOLEAN
IsWithinOneDay (
  IN EFI_TIME  *From,
  IN EFI_TIME  *To
  )
{
  BOOLEAN  Adjacent;
 
  Adjacent = FALSE;
 
  //
  // The validity of From->Month field should be checked before
  //
  ASSERT (From->Month >= 1);
  ASSERT (From->Month <= 12);
 
  if (From->Year == To->Year) {
    if (From->Month == To->Month) {
      if ((From->Day + 1) == To->Day) {
        if ((CompareHMS (From, To) >= 0)) {
          Adjacent = TRUE;
        }
      } else if (From->Day == To->Day) {
        if ((CompareHMS (From, To) <= 0)) {
          Adjacent = TRUE;
        }
      }
    } else if (((From->Month + 1) == To->Month) && (To->Day == 1)) {
      if ((From->Month == 2) && !IsLeapYear (From)) {
        if (From->Day == 28) {
          if ((CompareHMS (From, To) >= 0)) {
            Adjacent = TRUE;
          }
        }
      } else if (From->Day == mDayOfMonth[From->Month - 1]) {
        if ((CompareHMS (From, To) >= 0)) {
          Adjacent = TRUE;
        }
      }
    }
  } else if (((From->Year + 1) == To->Year) &&
             (From->Month == 12) &&
             (From->Day   == 31) &&
             (To->Month   == 1)  &&
             (To->Day     == 1))
  {
    if ((CompareHMS (From, To) >= 0)) {
      Adjacent = TRUE;
    }
  }
 
  return Adjacent;
}
 
UINT8
GetCenturyRtcAddress (
  VOID
  )
{
  EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE  *Fadt;
 
  Fadt = (EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE *)EfiLocateFirstAcpiTable (
                                                        EFI_ACPI_2_0_FIXED_ACPI_DESCRIPTION_TABLE_SIGNATURE
                                                        );
 
  if ((Fadt != NULL) &&
      (Fadt->Century > RTC_ADDRESS_REGISTER_D) && (Fadt->Century < 0x80)
      )
  {
    return Fadt->Century;
  } else {
    return 0;
  }
}
 
VOID
EFIAPI
PcRtcAcpiTableChangeCallback (
  IN EFI_EVENT  Event,
  IN VOID       *Context
  )
{
  EFI_STATUS  Status;
  EFI_TIME    Time;
  UINT8       CenturyRtcAddress;
  UINT8       Century;
 
  CenturyRtcAddress = GetCenturyRtcAddress ();
  if ((CenturyRtcAddress != 0) && (mModuleGlobal.CenturyRtcAddress != CenturyRtcAddress)) {
    mModuleGlobal.CenturyRtcAddress = CenturyRtcAddress;
    Status                          = PcRtcGetTime (&Time, NULL, &mModuleGlobal);
    if (!EFI_ERROR (Status)) {
      Century = (UINT8)(Time.Year / 100);
      Century = DecimalToBcd8 (Century);
      DEBUG ((DEBUG_INFO, "PcRtc: Write 0x%x to CMOS location 0x%x\n", Century, mModuleGlobal.CenturyRtcAddress));
      RtcWrite (mModuleGlobal.CenturyRtcAddress, Century);
    }
  }
}