RealTimeClock.c

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#include <PiDxe.h>
#include <Library/DebugLib.h>
#include <Library/RealTimeClockLib.h>
#include <Library/TimeBaseLib.h>
#include <Library/UefiLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiRuntimeLib.h>
#include <Protocol/RealTimeClock.h>
 
EFI_HANDLE  mHandle = NULL;
 
//
// These values can be set by SetTime () and need to be returned by GetTime ()
// but cannot usually be kept by the RTC hardware, so we store them in a UEFI
// variable instead.
//
typedef struct {
  INT16    TimeZone;
  UINT8    Daylight;
} NON_VOLATILE_TIME_SETTINGS;
 
STATIC CONST CHAR16                mTimeSettingsVariableName[] = L"RtcTimeSettings";
STATIC NON_VOLATILE_TIME_SETTINGS  mTimeSettings;
 
EFI_STATUS
EFIAPI
GetTime (
  OUT EFI_TIME               *Time,
  OUT EFI_TIME_CAPABILITIES  *Capabilities
  )
{
  if (Time == NULL) {
    return EFI_INVALID_PARAMETER;
  }
 
  //
  // Set these first so the RealTimeClockLib implementation
  // can override them based on its own settings.
  //
  Time->TimeZone = mTimeSettings.TimeZone;
  Time->Daylight = mTimeSettings.Daylight;
 
  return LibGetTime (Time, Capabilities);
}
 
EFI_STATUS
EFIAPI
SetTime (
  IN EFI_TIME  *Time
  )
{
  EFI_STATUS  Status;
  BOOLEAN     TimeSettingsChanged;
 
  if ((Time == NULL) || !IsTimeValid (Time)) {
    return EFI_INVALID_PARAMETER;
  }
 
  TimeSettingsChanged = FALSE;
  if ((mTimeSettings.TimeZone != Time->TimeZone) ||
      (mTimeSettings.Daylight != Time->Daylight))
  {
    mTimeSettings.TimeZone = Time->TimeZone;
    mTimeSettings.Daylight = Time->Daylight;
    TimeSettingsChanged    = TRUE;
  }
 
  Status = LibSetTime (Time);
  if (EFI_ERROR (Status)) {
    return Status;
  }
 
  if (TimeSettingsChanged) {
    Status = EfiSetVariable (
               (CHAR16 *)mTimeSettingsVariableName,
               &gEfiCallerIdGuid,
               EFI_VARIABLE_NON_VOLATILE |
               EFI_VARIABLE_BOOTSERVICE_ACCESS |
               EFI_VARIABLE_RUNTIME_ACCESS,
               sizeof (mTimeSettings),
               (VOID *)&mTimeSettings
               );
    if (EFI_ERROR (Status)) {
      return EFI_DEVICE_ERROR;
    }
  }
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
GetWakeupTime (
  OUT BOOLEAN   *Enabled,
  OUT BOOLEAN   *Pending,
  OUT EFI_TIME  *Time
  )
{
  if ((Time == NULL) || (Enabled == NULL) || (Pending == NULL)) {
    return EFI_INVALID_PARAMETER;
  }
 
  //
  // Set these first so the RealTimeClockLib implementation
  // can override them based on its own settings.
  //
  Time->TimeZone = mTimeSettings.TimeZone;
  Time->Daylight = mTimeSettings.Daylight;
 
  return LibGetWakeupTime (Enabled, Pending, Time);
}
 
EFI_STATUS
EFIAPI
SetWakeupTime (
  IN BOOLEAN    Enabled,
  OUT EFI_TIME  *Time
  )
{
  return LibSetWakeupTime (Enabled, Time);
}
 
EFI_STATUS
EFIAPI
InitializeRealTimeClock (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS  Status;
  UINTN       Size;
 
  Status = LibRtcInitialize (ImageHandle, SystemTable);
  if (EFI_ERROR (Status)) {
    return Status;
  }
 
  Size   = sizeof (mTimeSettings);
  Status = EfiGetVariable (
             (CHAR16 *)mTimeSettingsVariableName,
             &gEfiCallerIdGuid,
             NULL,
             &Size,
             (VOID *)&mTimeSettings
             );
  if (EFI_ERROR (Status) ||
      !IsValidTimeZone (mTimeSettings.TimeZone) ||
      !IsValidDaylight (mTimeSettings.Daylight))
  {
    DEBUG ((
      DEBUG_WARN,
      "%a: using default timezone/daylight settings\n",
      __func__
      ));
 
    mTimeSettings.TimeZone = EFI_UNSPECIFIED_TIMEZONE;
    mTimeSettings.Daylight = 0;
  }
 
  SystemTable->RuntimeServices->GetTime       = GetTime;
  SystemTable->RuntimeServices->SetTime       = SetTime;
  SystemTable->RuntimeServices->GetWakeupTime = GetWakeupTime;
  SystemTable->RuntimeServices->SetWakeupTime = SetWakeupTime;
 
  Status = gBS->InstallMultipleProtocolInterfaces (
                  &mHandle,
                  &gEfiRealTimeClockArchProtocolGuid,
                  NULL,
                  NULL
                  );
 
  return Status;
}