OvmfPkg/Library/XenRealTimeClockLib/XenRealTimeClockLib.c

   1 /** @file
   2   Implement EFI RealTimeClock runtime services via Xen shared info page
   3
   4   Copyright (c) 2015, Linaro Ltd. All rights reserved.<BR>
   5
   6   SPDX-License-Identifier: BSD-2-Clause-Patent
   7
   8 **/
   9
  10 #include <Uefi.h>
  11 #include <PiDxe.h>
  12 #include <Library/BaseLib.h>
  13 #include <Library/DebugLib.h>
  14
  15 /**
  16   Converts Epoch seconds (elapsed since 1970 JANUARY 01, 00:00:00 UTC) to EFI_TIME
  17  **/
  18 STATIC
  19 VOID
  20 EpochToEfiTime (
  21   IN  UINTN     EpochSeconds,
  22   OUT EFI_TIME  *Time
  23   )
  24 {
  25   UINTN         a;
  26   UINTN         b;
  27   UINTN         c;
  28   UINTN         d;
  29   UINTN         g;
  30   UINTN         j;
  31   UINTN         m;
  32   UINTN         y;
  33   UINTN         da;
  34   UINTN         db;
  35   UINTN         dc;
  36   UINTN         dg;
  37   UINTN         hh;
  38   UINTN         mm;
  39   UINTN         ss;
  40   UINTN         J;
  41
  42   J  = (EpochSeconds / 86400) + 2440588;
  43   j  = J + 32044;
  44   g  = j / 146097;
  45   dg = j % 146097;
  46   c  = (((dg / 36524) + 1) * 3) / 4;
  47   dc = dg - (c * 36524);
  48   b  = dc / 1461;
  49   db = dc % 1461;
  50   a  = (((db / 365) + 1) * 3) / 4;
  51   da = db - (a * 365);
  52   y  = (g * 400) + (c * 100) + (b * 4) + a;
  53   m  = (((da * 5) + 308) / 153) - 2;
  54   d  = da - (((m + 4) * 153) / 5) + 122;
  55
  56   Time->Year  = (UINT16)(y - 4800 + ((m + 2) / 12));
  57   Time->Month = ((m + 2) % 12) + 1;
  58   Time->Day   = (UINT8)(d + 1);
  59
  60   ss = EpochSeconds % 60;
  61   a  = (EpochSeconds - ss) / 60;
  62   mm = a % 60;
  63   b = (a - mm) / 60;
  64   hh = b % 24;
  65
  66   Time->Hour        = (UINT8)hh;
  67   Time->Minute      = (UINT8)mm;
  68   Time->Second      = (UINT8)ss;
  69   Time->Nanosecond  = 0;
  70
  71 }
  72
  73 /**
  74   Returns the current time and date information, and the time-keeping capabilities
  75   of the hardware platform.
  76
  77   @param  Time                  A pointer to storage to receive a snapshot of the current time.
  78   @param  Capabilities          An optional pointer to a buffer to receive the real time clock
  79                                 device's capabilities.
  80
  81   @retval EFI_SUCCESS           The operation completed successfully.
  82   @retval EFI_INVALID_PARAMETER Time is NULL.
  83   @retval EFI_DEVICE_ERROR      The time could not be retrieved due to hardware error.
  84
  85 **/
  86 EFI_STATUS
  87 EFIAPI
  88 LibGetTime (
  89   OUT EFI_TIME                *Time,
  90   OUT  EFI_TIME_CAPABILITIES  *Capabilities
  91   )
  92 {
  93   ASSERT (Time != NULL);
  94
  95   //
  96   // For now, there is nothing that we can do besides returning a bogus time,
  97   // as Xen's timekeeping uses a shared info page which cannot be shared
  98   // between UEFI and the OS
  99   //
 100   EpochToEfiTime(1421770011, Time);
 101
 102   return EFI_SUCCESS;
 103 }
 104
 105 /**
 106   Sets the current local time and date information.
 107
 108   @param  Time                  A pointer to the current time.
 109
 110   @retval EFI_SUCCESS           The operation completed successfully.
 111   @retval EFI_INVALID_PARAMETER A time field is out of range.
 112   @retval EFI_DEVICE_ERROR      The time could not be set due due to hardware error.
 113
 114 **/
 115 EFI_STATUS
 116 EFIAPI
 117 LibSetTime (
 118   IN EFI_TIME                *Time
 119   )
 120 {
 121   return EFI_DEVICE_ERROR;
 122 }
 123
 124
 125 /**
 126   Returns the current wakeup alarm clock setting.
 127
 128   @param  Enabled               Indicates if the alarm is currently enabled or disabled.
 129   @param  Pending               Indicates if the alarm signal is pending and requires acknowledgement.
 130   @param  Time                  The current alarm setting.
 131
 132   @retval EFI_SUCCESS           The alarm settings were returned.
 133   @retval EFI_INVALID_PARAMETER Any parameter is NULL.
 134   @retval EFI_DEVICE_ERROR      The wakeup time could not be retrieved due to a hardware error.
 135   @retval EFI_UNSUPPORTED       A wakeup timer is not supported on this platform.
 136
 137 **/
 138 EFI_STATUS
 139 EFIAPI
 140 LibGetWakeupTime (
 141   OUT BOOLEAN     *Enabled,
 142   OUT BOOLEAN     *Pending,
 143   OUT EFI_TIME    *Time
 144   )
 145 {
 146   return EFI_UNSUPPORTED;
 147 }
 148
 149 /**
 150   Sets the system wakeup alarm clock time.
 151
 152   @param  Enabled               Enable or disable the wakeup alarm.
 153   @param  Time                  If Enable is TRUE, the time to set the wakeup alarm for.
 154
 155   @retval EFI_SUCCESS           If Enable is TRUE, then the wakeup alarm was enabled. If
 156                                 Enable is FALSE, then the wakeup alarm was disabled.
 157   @retval EFI_INVALID_PARAMETER A time field is out of range.
 158   @retval EFI_DEVICE_ERROR      The wakeup time could not be set due to a hardware error.
 159   @retval EFI_UNSUPPORTED       A wakeup timer is not supported on this platform.
 160
 161 **/
 162 EFI_STATUS
 163 EFIAPI
 164 LibSetWakeupTime (
 165   IN BOOLEAN      Enabled,
 166   OUT EFI_TIME    *Time
 167   )
 168 {
 169   return EFI_UNSUPPORTED;
 170 }
 171
 172 /**
 173   This is the declaration of an EFI image entry point. This can be the entry point to an application
 174   written to this specification, an EFI boot service driver, or an EFI runtime driver.
 175
 176   @param  ImageHandle           Handle that identifies the loaded image.
 177   @param  SystemTable           System Table for this image.
 178
 179   @retval EFI_SUCCESS           The operation completed successfully.
 180
 181 **/
 182 EFI_STATUS
 183 EFIAPI
 184 LibRtcInitialize (
 185   IN EFI_HANDLE                            ImageHandle,
 186   IN EFI_SYSTEM_TABLE                      *SystemTable
 187   )
 188 {
 189   return EFI_SUCCESS;
 190 }