[PATCH v4 25/29] ArmVirtualizationPkg: implement dummy RealTimeClockLib for Xen

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

This implements a dummy RealTimeClockLib for Xen, as there is no
guest interface to access the time kept by Xen that can be shared
between UEFI and the OS.

Contributed-under: TianoCore Contribution Agreement 1.0
Acked-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-By: Olivier Martin <olivier.martin@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 ArmPlatformPkg/ArmVirtualizationPkg/Library/XenRealTimeClockLib/XenRealTimeClockLib.c   | 196 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ArmPlatformPkg/ArmVirtualizationPkg/Library/XenRealTimeClockLib/XenRealTimeClockLib.inf |  38 +++++++++++++++++
 2 files changed, 234 insertions(+)

diff --git a/ArmPlatformPkg/ArmVirtualizationPkg/Library/XenRealTimeClockLib/XenRealTimeClockLib.c b/ArmPlatformPkg/ArmVirtualizationPkg/Library/XenRealTimeClockLib/XenRealTimeClockLib.c
new file mode 100644
index 000000000000..70204ac22a92
--- /dev/null
+++ b/ArmPlatformPkg/ArmVirtualizationPkg/Library/XenRealTimeClockLib/XenRealTimeClockLib.c
@@ -0,0 +1,196 @@
+/** @file
+  Implement EFI RealTimeClock runtime services via Xen shared info page
+
+  Copyright (c) 2015, Linaro Ltd. All rights reserved.<BR>
+
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Uefi.h>
+#include <PiDxe.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+
+/**
+  Converts Epoch seconds (elapsed since 1970 JANUARY 01, 00:00:00 UTC) to EFI_TIME
+ **/
+STATIC
+VOID
+EpochToEfiTime (
+  IN  UINTN     EpochSeconds,
+  OUT EFI_TIME  *Time
+  )
+{
+  UINTN         a;
+  UINTN         b;
+  UINTN         c;
+  UINTN         d;
+  UINTN         g;
+  UINTN         j;
+  UINTN         m;
+  UINTN         y;
+  UINTN         da;
+  UINTN         db;
+  UINTN         dc;
+  UINTN         dg;
+  UINTN         hh;
+  UINTN         mm;
+  UINTN         ss;
+  UINTN         J;
+
+  J  = (EpochSeconds / 86400) + 2440588;
+  j  = J + 32044;
+  g  = j / 146097;
+  dg = j % 146097;
+  c  = (((dg / 36524) + 1) * 3) / 4;
+  dc = dg - (c * 36524);
+  b  = dc / 1461;
+  db = dc % 1461;
+  a  = (((db / 365) + 1) * 3) / 4;
+  da = db - (a * 365);
+  y  = (g * 400) + (c * 100) + (b * 4) + a;
+  m  = (((da * 5) + 308) / 153) - 2;
+  d  = da - (((m + 4) * 153) / 5) + 122;
+
+  Time->Year  = y - 4800 + ((m + 2) / 12);
+  Time->Month = ((m + 2) % 12) + 1;
+  Time->Day   = d + 1;
+
+  ss = EpochSeconds % 60;
+  a  = (EpochSeconds - ss) / 60;
+  mm = a % 60;
+  b = (a - mm) / 60;
+  hh = b % 24;
+
+  Time->Hour        = hh;
+  Time->Minute      = mm;
+  Time->Second      = ss;
+  Time->Nanosecond  = 0;
+
+}
+
+/**
+  Returns the current time and date information, and the time-keeping capabilities
+  of the hardware platform.
+
+  @param  Time                  A pointer to storage to receive a snapshot of the current time.
+  @param  Capabilities          An optional pointer to a buffer to receive the real time clock
+                                device's capabilities.
+
+  @retval EFI_SUCCESS           The operation completed successfully.
+  @retval EFI_INVALID_PARAMETER Time is NULL.
+  @retval EFI_DEVICE_ERROR      The time could not be retrieved due to hardware error.
+
+**/
+EFI_STATUS
+EFIAPI
+LibGetTime (
+  OUT EFI_TIME                *Time,
+  OUT  EFI_TIME_CAPABILITIES  *Capabilities
+  )
+{
+  ASSERT (Time != NULL);
+
+  //
+  // For now, there is nothing that we can do besides returning a bogus time,
+  // as Xen's timekeeping uses a shared info page which cannot be shared
+  // between UEFI and the OS
+  //
+  EpochToEfiTime(1421770011, Time);
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Sets the current local time and date information.
+
+  @param  Time                  A pointer to the current time.
+
+  @retval EFI_SUCCESS           The operation completed successfully.
+  @retval EFI_INVALID_PARAMETER A time field is out of range.
+  @retval EFI_DEVICE_ERROR      The time could not be set due due to hardware error.
+
+**/
+EFI_STATUS
+EFIAPI
+LibSetTime (
+  IN EFI_TIME                *Time
+  )
+{
+  return EFI_DEVICE_ERROR;
+}
+
+
+/**
+  Returns the current wakeup alarm clock setting.
+
+  @param  Enabled               Indicates if the alarm is currently enabled or disabled.
+  @param  Pending               Indicates if the alarm signal is pending and requires acknowledgement.
+  @param  Time                  The current alarm setting.
+
+  @retval EFI_SUCCESS           The alarm settings were returned.
+  @retval EFI_INVALID_PARAMETER Any parameter is NULL.
+  @retval EFI_DEVICE_ERROR      The wakeup time could not be retrieved due to a hardware error.
+  @retval EFI_UNSUPPORTED       A wakeup timer is not supported on this platform.
+
+**/
+EFI_STATUS
+EFIAPI
+LibGetWakeupTime (
+  OUT BOOLEAN     *Enabled,
+  OUT BOOLEAN     *Pending,
+  OUT EFI_TIME    *Time
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Sets the system wakeup alarm clock time.
+
+  @param  Enabled               Enable or disable the wakeup alarm.
+  @param  Time                  If Enable is TRUE, the time to set the wakeup alarm for.
+
+  @retval EFI_SUCCESS           If Enable is TRUE, then the wakeup alarm was enabled. If
+                                Enable is FALSE, then the wakeup alarm was disabled.
+  @retval EFI_INVALID_PARAMETER A time field is out of range.
+  @retval EFI_DEVICE_ERROR      The wakeup time could not be set due to a hardware error.
+  @retval EFI_UNSUPPORTED       A wakeup timer is not supported on this platform.
+
+**/
+EFI_STATUS
+EFIAPI
+LibSetWakeupTime (
+  IN BOOLEAN      Enabled,
+  OUT EFI_TIME    *Time
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  This is the declaration of an EFI image entry point. This can be the entry point to an application
+  written to this specification, an EFI boot service driver, or an EFI runtime driver.
+
+  @param  ImageHandle           Handle that identifies the loaded image.
+  @param  SystemTable           System Table for this image.
+
+  @retval EFI_SUCCESS           The operation completed successfully.
+
+**/
+EFI_STATUS
+EFIAPI
+LibRtcInitialize (
+  IN EFI_HANDLE                            ImageHandle,
+  IN EFI_SYSTEM_TABLE                      *SystemTable
+  )
+{
+  return EFI_SUCCESS;
+}
diff --git a/ArmPlatformPkg/ArmVirtualizationPkg/Library/XenRealTimeClockLib/XenRealTimeClockLib.inf b/ArmPlatformPkg/ArmVirtualizationPkg/Library/XenRealTimeClockLib/XenRealTimeClockLib.inf
new file mode 100644
index 000000000000..aafbfda6b491
--- /dev/null
+++ b/ArmPlatformPkg/ArmVirtualizationPkg/Library/XenRealTimeClockLib/XenRealTimeClockLib.inf
@@ -0,0 +1,38 @@
+#/** @file
+#
+# Copyright (c) 2015, L Ltd. All rights reserved.<BR>
+#
+#  This program and the accompanying materials
+#  are licensed and made available under the terms and conditions of the BSD License
+#  which accompanies this distribution. The full text of the license may be found at
+#  http://opensource.org/licenses/bsd-license.php
+#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+#
+#
+#**/
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = XenRealTimeClockLib
+  FILE_GUID                      = EC2557E8-7005-430B-9F6F-9BA109698248
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = RealTimeClockLib|DXE_CORE DXE_DRIVER UEFI_DRIVER DXE_RUNTIME_DRIVER UEFI_APPLICATION
+
+[Sources.common]
+  XenRealTimeClockLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+  EmbeddedPkg/EmbeddedPkg.dec
+
+[LibraryClasses]
+  UefiLib
+  DebugLib
+  DxeServicesTableLib
+  UefiRuntimeLib
+
+[Guids]
+  gEfiEventVirtualAddressChangeGuid
-- 
1.8.3.2