EmbeddedPkg/Library/VirtualRealTimeClockLib/VirtualRealTimeClockLib.c

   1 /** @file
   2  *
   3  *  Implement virtual EFI RealTimeClock runtime services.
   4  *
   5  *  Coypright (c) 2019, Pete Batard <pete@akeo.ie>
   6  *  Copyright (c) 2018, Andrei Warkentin <andrey.warkentin@gmail.com>
   7  *  Copyright (c) 2011-2014, ARM Ltd. All rights reserved.
   8  *  Copyright (c) 2008-2010, Apple Inc. All rights reserved.
   9  *  Copyright (c) Microsoft Corporation. All rights reserved.
  10  *
  11  *  This program and the accompanying materials
  12  *  are licensed and made available under the terms and conditions of the BSD License
  13  *  which accompanies this distribution.  The full text of the license may be found at
  14  *  http://opensource.org/licenses/bsd-license.php
  15  *
  16  *  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  17  *  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  18  *
  19  *  Based on ArmPlatformPkg/Library/PL031RealTimeClockLib/PL031RealTimeClockLib.inf
  20  *
  21  **/
  22
  23 #include <PiDxe.h>
  24 #include <Library/BaseLib.h>
  25 #include <Library/DebugLib.h>
  26 #include <Library/IoLib.h>
  27 #include <Library/RealTimeClockLib.h>
  28 #include <Library/TimerLib.h>
  29 #include <Library/TimeBaseLib.h>
  30 #include <Library/UefiRuntimeLib.h>
  31
  32 STATIC CONST CHAR16  mEpochVariableName[]     = L"RtcEpochSeconds";
  33 STATIC CONST CHAR16  mTimeZoneVariableName[]  = L"RtcTimeZone";
  34 STATIC CONST CHAR16  mDaylightVariableName[]  = L"RtcDaylight";
  35
  36 /**
  37    Returns the current time and date information, and the time-keeping capabilities
  38    of the virtual RTC.
  39
  40    @param  Time                  A pointer to storage to receive a snapshot of the current time.
  41    @param  Capabilities          An optional pointer to a buffer to receive the real time clock
  42                                  device's capabilities.
  43
  44    @retval EFI_SUCCESS           The operation completed successfully.
  45    @retval EFI_INVALID_PARAMETER Time is NULL.
  46    @retval EFI_DEVICE_ERROR      The time could not be retrieved due to hardware error.
  47
  48 **/
  49 EFI_STATUS
  50 EFIAPI
  51 LibGetTime (
  52   OUT EFI_TIME               *Time,
  53   OUT EFI_TIME_CAPABILITIES  *Capabilities
  54   )
  55 {
  56   EFI_STATUS  Status;
  57   UINT32      EpochSeconds;
  58   INT16       TimeZone;
  59   UINT8       Daylight;
  60   UINT64      Freq;
  61   UINT64      Counter;
  62   UINT64      Remainder;
  63   UINTN       ElapsedSeconds;
  64   UINTN       Size;
  65
  66   if (Time == NULL) {
  67     return EFI_INVALID_PARAMETER;
  68   }
  69
  70   // Get the counter frequency
  71   Freq = GetPerformanceCounterProperties (NULL, NULL);
  72   if (Freq == 0) {
  73     return EFI_DEVICE_ERROR;
  74   }
  75
  76   // Get the epoch time from non-volatile storage
  77   Size = sizeof (UINTN);
  78   ElapsedSeconds = 0;
  79   Status = EfiGetVariable (
  80              (CHAR16 *)mEpochVariableName,
  81              &gEfiCallerIdGuid,
  82              NULL,
  83              &Size,
  84              (VOID *)&ElapsedSeconds
  85              );
  86   // Fall back to compilation-time epoch if not set
  87   if (EFI_ERROR (Status)) {
  88     ASSERT(Status != EFI_INVALID_PARAMETER);
  89     ASSERT(Status != EFI_BUFFER_TOO_SMALL);
  90     //
  91     // The following is intended to produce a compilation error on build
  92     // environments where BUILD_EPOCH can not be set from inline shell.
  93     // If you are attempting to use this library on such an environment, please
  94     // contact the edk2 mailing list, so we can try to add support for it.
  95     //
  96     ElapsedSeconds = BUILD_EPOCH;
  97     DEBUG ((
  98       DEBUG_INFO,
  99       "LibGetTime: %s non volatile variable was not found - Using compilation time epoch.\n",
 100       mEpochVariableName
 101       ));
 102   }
 103   Counter = GetPerformanceCounter ();
 104   ElapsedSeconds += DivU64x64Remainder (Counter, Freq, &Remainder);
 105
 106   // Get the current time zone information from non-volatile storage
 107   Size = sizeof (TimeZone);
 108   Status = EfiGetVariable (
 109              (CHAR16 *)mTimeZoneVariableName,
 110              &gEfiCallerIdGuid,
 111              NULL,
 112              &Size,
 113              (VOID *)&TimeZone
 114              );
 115
 116   if (EFI_ERROR (Status)) {
 117     ASSERT(Status != EFI_INVALID_PARAMETER);
 118     ASSERT(Status != EFI_BUFFER_TOO_SMALL);
 119
 120     if (Status != EFI_NOT_FOUND) {
 121       return Status;
 122     }
 123
 124     // The time zone variable does not exist in non-volatile storage, so create it.
 125     Time->TimeZone = EFI_UNSPECIFIED_TIMEZONE;
 126     // Store it
 127     Status = EfiSetVariable (
 128                (CHAR16 *)mTimeZoneVariableName,
 129                &gEfiCallerIdGuid,
 130                EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
 131                Size,
 132                (VOID *)&(Time->TimeZone)
 133                );
 134     if (EFI_ERROR (Status)) {
 135       DEBUG ((
 136         DEBUG_ERROR,
 137         "LibGetTime: Failed to save %s variable to non-volatile storage, Status = %r\n",
 138         mTimeZoneVariableName,
 139         Status
 140         ));
 141       return Status;
 142     }
 143   } else {
 144     // Got the time zone
 145     Time->TimeZone = TimeZone;
 146
 147     // Check TimeZone bounds: -1440 to 1440 or 2047
 148     if (((Time->TimeZone < -1440) || (Time->TimeZone > 1440))
 149         && (Time->TimeZone != EFI_UNSPECIFIED_TIMEZONE)) {
 150       Time->TimeZone = EFI_UNSPECIFIED_TIMEZONE;
 151     }
 152
 153     // Adjust for the correct time zone
 154     if (Time->TimeZone != EFI_UNSPECIFIED_TIMEZONE) {
 155       EpochSeconds += Time->TimeZone * SEC_PER_MIN;
 156     }
 157   }
 158
 159   // Get the current daylight information from non-volatile storage
 160   Size = sizeof (Daylight);
 161   Status = EfiGetVariable (
 162              (CHAR16 *)mDaylightVariableName,
 163              &gEfiCallerIdGuid,
 164              NULL,
 165              &Size,
 166              (VOID *)&Daylight
 167            );
 168
 169   if (EFI_ERROR (Status)) {
 170     ASSERT(Status != EFI_INVALID_PARAMETER);
 171     ASSERT(Status != EFI_BUFFER_TOO_SMALL);
 172
 173     if (Status != EFI_NOT_FOUND) {
 174       return Status;
 175     }
 176
 177     // The daylight variable does not exist in non-volatile storage, so create it.
 178     Time->Daylight = 0;
 179     // Store it
 180     Status = EfiSetVariable (
 181                (CHAR16 *)mDaylightVariableName,
 182                &gEfiCallerIdGuid,
 183                EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
 184                Size,
 185                (VOID *)&(Time->Daylight)
 186                );
 187     if (EFI_ERROR (Status)) {
 188       DEBUG ((
 189         DEBUG_ERROR,
 190         "LibGetTime: Failed to save %s variable to non-volatile storage, Status = %r\n",
 191         mDaylightVariableName,
 192         Status
 193         ));
 194       return Status;
 195     }
 196   } else {
 197     // Got the daylight information
 198     Time->Daylight = Daylight;
 199
 200     // Adjust for the correct period
 201     if ((Time->Daylight & EFI_TIME_IN_DAYLIGHT) == EFI_TIME_IN_DAYLIGHT) {
 202       // Convert to adjusted time, i.e. spring forwards one hour
 203       EpochSeconds += SEC_PER_HOUR;
 204     }
 205   }
 206
 207   EpochToEfiTime (ElapsedSeconds, Time);
 208
 209   // Because we use the performance counter, we can fill the Nanosecond attribute
 210   // provided that the remainder doesn't overflow 64-bit during multiplication.
 211   if (Remainder <= 18446744073U) {
 212     Time->Nanosecond = MultU64x64 (Remainder, 1000000000U) / Freq;
 213   } else {
 214     DEBUG ((DEBUG_WARN, "LibGetTime: Nanosecond value not set (64-bit overflow).\n"));
 215   }
 216
 217   if (Capabilities) {
 218     Capabilities->Accuracy   = 0;
 219     Capabilities->Resolution = Freq;
 220     Capabilities->SetsToZero = FALSE;
 221   }
 222
 223   return EFI_SUCCESS;
 224 }
 225
 226 /**
 227    Sets the current local time and date information.
 228
 229    @param  Time                  A pointer to the current time.
 230
 231    @retval EFI_SUCCESS           The operation completed successfully.
 232    @retval EFI_INVALID_PARAMETER A time field is out of range.
 233    @retval EFI_DEVICE_ERROR      The time could not be set due due to hardware error.
 234
 235 **/
 236 EFI_STATUS
 237 EFIAPI
 238 LibSetTime (
 239   IN EFI_TIME  *Time
 240   )
 241 {
 242   EFI_STATUS  Status;
 243   UINTN       EpochSeconds;
 244
 245   if (!IsTimeValid (Time)) {
 246     return EFI_INVALID_PARAMETER;
 247   }
 248
 249   EpochSeconds = EfiTimeToEpoch (Time);
 250
 251   // Adjust for the correct time zone, i.e. convert to UTC time zone
 252   if (Time->TimeZone != EFI_UNSPECIFIED_TIMEZONE) {
 253     EpochSeconds -= Time->TimeZone * SEC_PER_MIN;
 254   }
 255
 256   // Adjust for the correct period
 257   if ((Time->Daylight & EFI_TIME_IN_DAYLIGHT) == EFI_TIME_IN_DAYLIGHT) {
 258     // Convert to un-adjusted time, i.e. fall back one hour
 259     EpochSeconds -= SEC_PER_HOUR;
 260   }
 261
 262   // Save the current time zone information into non-volatile storage
 263   Status = EfiSetVariable (
 264              (CHAR16 *)mTimeZoneVariableName,
 265              &gEfiCallerIdGuid,
 266              EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
 267              sizeof (Time->TimeZone),
 268              (VOID *)&(Time->TimeZone)
 269              );
 270   if (EFI_ERROR (Status)) {
 271     DEBUG ((
 272       DEBUG_ERROR,
 273       "LibSetTime: Failed to save %s variable to non-volatile storage, Status = %r\n",
 274       mTimeZoneVariableName,
 275       Status
 276       ));
 277     return Status;
 278   }
 279
 280   // Save the current daylight information into non-volatile storage
 281   Status = EfiSetVariable (
 282              (CHAR16 *)mDaylightVariableName,
 283              &gEfiCallerIdGuid,
 284              EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
 285              sizeof(Time->Daylight),
 286              (VOID *)&(Time->Daylight)
 287            );
 288   if (EFI_ERROR (Status)) {
 289     DEBUG ((
 290       DEBUG_ERROR,
 291       "LibSetTime: Failed to save %s variable to non-volatile storage, Status = %r\n",
 292       mDaylightVariableName,
 293       Status
 294       ));
 295     return Status;
 296   }
 297
 298   Status = EfiSetVariable (
 299              (CHAR16 *)mEpochVariableName,
 300              &gEfiCallerIdGuid,
 301              EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
 302              sizeof (EpochSeconds),
 303              &EpochSeconds
 304              );
 305   if (EFI_ERROR (Status)) {
 306     DEBUG ((
 307       DEBUG_ERROR,
 308       "LibSetTime: Failed to save %s variable to non-volatile storage, Status = %r\n",
 309       mDaylightVariableName,
 310       Status
 311       ));
 312     return Status;
 313   }
 314
 315   return EFI_SUCCESS;
 316 }
 317
 318 /**
 319    Returns the current wakeup alarm clock setting.
 320
 321    @param  Enabled               Indicates if the alarm is currently enabled or disabled.
 322    @param  Pending               Indicates if the alarm signal is pending and requires acknowledgement.
 323    @param  Time                  The current alarm setting.
 324
 325    @retval EFI_SUCCESS           The alarm settings were returned.
 326    @retval EFI_INVALID_PARAMETER Any parameter is NULL.
 327    @retval EFI_DEVICE_ERROR      The wakeup time could not be retrieved due to a hardware error.
 328
 329 **/
 330 EFI_STATUS
 331 EFIAPI
 332 LibGetWakeupTime (
 333   OUT BOOLEAN   *Enabled,
 334   OUT BOOLEAN   *Pending,
 335   OUT EFI_TIME  *Time
 336   )
 337 {
 338   return EFI_UNSUPPORTED;
 339 }
 340
 341 /**
 342    Sets the system wakeup alarm clock time.
 343
 344    @param  Enabled               Enable or disable the wakeup alarm.
 345    @param  Time                  If Enable is TRUE, the time to set the wakeup alarm for.
 346
 347    @retval EFI_SUCCESS           If Enable is TRUE, then the wakeup alarm was enabled. If
 348    Enable is FALSE, then the wakeup alarm was disabled.
 349    @retval EFI_INVALID_PARAMETER A time field is out of range.
 350    @retval EFI_DEVICE_ERROR      The wakeup time could not be set due to a hardware error.
 351    @retval EFI_UNSUPPORTED       A wakeup timer is not supported on this platform.
 352
 353 **/
 354 EFI_STATUS
 355 EFIAPI
 356 LibSetWakeupTime (
 357   IN  BOOLEAN   Enabled,
 358   OUT EFI_TIME  *Time
 359   )
 360 {
 361   return EFI_UNSUPPORTED;
 362 }
 363
 364 /**
 365    This is the declaration of an EFI image entry point. This can be the entry point to an application
 366    written to this specification, an EFI boot service driver, or an EFI runtime driver.
 367
 368    @param  ImageHandle           Handle that identifies the loaded image.
 369    @param  SystemTable           System Table for this image.
 370
 371    @retval EFI_SUCCESS           The operation completed successfully.
 372
 373 **/
 374 EFI_STATUS
 375 EFIAPI
 376 LibRtcInitialize (
 377   IN EFI_HANDLE        ImageHandle,
 378   IN EFI_SYSTEM_TABLE  *SystemTable
 379   )
 380 {
 381   return EFI_SUCCESS;
 382 }
 383
 384 /**
 385    Fixup internal data so that EFI can be call in virtual mode.
 386    Call the passed in Child Notify event and convert any pointers in
 387    lib to virtual mode.
 388
 389    @param[in]    Event   The Event that is being processed
 390    @param[in]    Context Event Context
 391 **/
 392 VOID
 393 EFIAPI
 394 LibRtcVirtualNotifyEvent (
 395   IN EFI_EVENT  Event,
 396   IN VOID       *Context
 397   )
 398 {
 399   return;
 400 }