MdeModulePkg/Core/Dxe/Event/Timer.c

   1 /** @file
   2   Core Timer Services
   3
   4 Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
   5 SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 #include "DxeMain.h"
  10 #include "Event.h"
  11
  12 //
  13 // Internal data
  14 //
  15
  16 LIST_ENTRY  mEfiTimerList       = INITIALIZE_LIST_HEAD_VARIABLE (mEfiTimerList);
  17 EFI_LOCK    mEfiTimerLock       = EFI_INITIALIZE_LOCK_VARIABLE (TPL_HIGH_LEVEL - 1);
  18 EFI_EVENT   mEfiCheckTimerEvent = NULL;
  19
  20 EFI_LOCK  mEfiSystemTimeLock = EFI_INITIALIZE_LOCK_VARIABLE (TPL_HIGH_LEVEL);
  21 UINT64    mEfiSystemTime     = 0;
  22
  23 //
  24 // Timer functions
  25 //
  26
  27 /**
  28   Inserts the timer event.
  29
  30   @param  Event                  Points to the internal structure of timer event
  31                                  to be installed
  32
  33 **/
  34 VOID
  35 CoreInsertEventTimer (
  36   IN IEVENT  *Event
  37   )
  38 {
  39   UINT64      TriggerTime;
  40   LIST_ENTRY  *Link;
  41   IEVENT      *Event2;
  42
  43   ASSERT_LOCKED (&mEfiTimerLock);
  44
  45   //
  46   // Get the timer's trigger time
  47   //
  48   TriggerTime = Event->Timer.TriggerTime;
  49
  50   //
  51   // Insert the timer into the timer database in assending sorted order
  52   //
  53   for (Link = mEfiTimerList.ForwardLink; Link != &mEfiTimerList; Link = Link->ForwardLink) {
  54     Event2 = CR (Link, IEVENT, Timer.Link, EVENT_SIGNATURE);
  55
  56     if (Event2->Timer.TriggerTime > TriggerTime) {
  57       break;
  58     }
  59   }
  60
  61   InsertTailList (Link, &Event->Timer.Link);
  62 }
  63
  64 /**
  65   Returns the current system time.
  66
  67   @return The current system time
  68
  69 **/
  70 UINT64
  71 CoreCurrentSystemTime (
  72   VOID
  73   )
  74 {
  75   UINT64  SystemTime;
  76
  77   CoreAcquireLock (&mEfiSystemTimeLock);
  78   SystemTime = mEfiSystemTime;
  79   CoreReleaseLock (&mEfiSystemTimeLock);
  80
  81   return SystemTime;
  82 }
  83
  84 /**
  85   Checks the sorted timer list against the current system time.
  86   Signals any expired event timer.
  87
  88   @param  CheckEvent             Not used
  89   @param  Context                Not used
  90
  91 **/
  92 VOID
  93 EFIAPI
  94 CoreCheckTimers (
  95   IN EFI_EVENT  CheckEvent,
  96   IN VOID       *Context
  97   )
  98 {
  99   UINT64  SystemTime;
 100   IEVENT  *Event;
 101
 102   //
 103   // Check the timer database for expired timers
 104   //
 105   CoreAcquireLock (&mEfiTimerLock);
 106   SystemTime = CoreCurrentSystemTime ();
 107
 108   while (!IsListEmpty (&mEfiTimerList)) {
 109     Event = CR (mEfiTimerList.ForwardLink, IEVENT, Timer.Link, EVENT_SIGNATURE);
 110
 111     //
 112     // If this timer is not expired, then we're done
 113     //
 114     if (Event->Timer.TriggerTime > SystemTime) {
 115       break;
 116     }
 117
 118     //
 119     // Remove this timer from the timer queue
 120     //
 121
 122     RemoveEntryList (&Event->Timer.Link);
 123     Event->Timer.Link.ForwardLink = NULL;
 124
 125     //
 126     // Signal it
 127     //
 128     CoreSignalEvent (Event);
 129
 130     //
 131     // If this is a periodic timer, set it
 132     //
 133     if (Event->Timer.Period != 0) {
 134       //
 135       // Compute the timers new trigger time
 136       //
 137       Event->Timer.TriggerTime = Event->Timer.TriggerTime + Event->Timer.Period;
 138
 139       //
 140       // If that's before now, then reset the timer to start from now
 141       //
 142       if (Event->Timer.TriggerTime <= SystemTime) {
 143         Event->Timer.TriggerTime = SystemTime;
 144         CoreSignalEvent (mEfiCheckTimerEvent);
 145       }
 146
 147       //
 148       // Add the timer
 149       //
 150       CoreInsertEventTimer (Event);
 151     }
 152   }
 153
 154   CoreReleaseLock (&mEfiTimerLock);
 155 }
 156
 157 /**
 158   Initializes timer support.
 159
 160 **/
 161 VOID
 162 CoreInitializeTimer (
 163   VOID
 164   )
 165 {
 166   EFI_STATUS  Status;
 167
 168   Status = CoreCreateEventInternal (
 169              EVT_NOTIFY_SIGNAL,
 170              TPL_HIGH_LEVEL - 1,
 171              CoreCheckTimers,
 172              NULL,
 173              NULL,
 174              &mEfiCheckTimerEvent
 175              );
 176   ASSERT_EFI_ERROR (Status);
 177 }
 178
 179 /**
 180   Called by the platform code to process a tick.
 181
 182   @param  Duration               The number of 100ns elapsed since the last call
 183                                  to TimerTick
 184
 185 **/
 186 VOID
 187 EFIAPI
 188 CoreTimerTick (
 189   IN UINT64  Duration
 190   )
 191 {
 192   IEVENT  *Event;
 193
 194   //
 195   // Check runtiem flag in case there are ticks while exiting boot services
 196   //
 197   CoreAcquireLock (&mEfiSystemTimeLock);
 198
 199   //
 200   // Update the system time
 201   //
 202   mEfiSystemTime += Duration;
 203
 204   //
 205   // If the head of the list is expired, fire the timer event
 206   // to process it
 207   //
 208   if (!IsListEmpty (&mEfiTimerList)) {
 209     Event = CR (mEfiTimerList.ForwardLink, IEVENT, Timer.Link, EVENT_SIGNATURE);
 210
 211     if (Event->Timer.TriggerTime <= mEfiSystemTime) {
 212       CoreSignalEvent (mEfiCheckTimerEvent);
 213     }
 214   }
 215
 216   CoreReleaseLock (&mEfiSystemTimeLock);
 217 }
 218
 219 /**
 220   Sets the type of timer and the trigger time for a timer event.
 221
 222   @param  UserEvent              The timer event that is to be signaled at the
 223                                  specified time
 224   @param  Type                   The type of time that is specified in
 225                                  TriggerTime
 226   @param  TriggerTime            The number of 100ns units until the timer
 227                                  expires
 228
 229   @retval EFI_SUCCESS            The event has been set to be signaled at the
 230                                  requested time
 231   @retval EFI_INVALID_PARAMETER  Event or Type is not valid
 232
 233 **/
 234 EFI_STATUS
 235 EFIAPI
 236 CoreSetTimer (
 237   IN EFI_EVENT        UserEvent,
 238   IN EFI_TIMER_DELAY  Type,
 239   IN UINT64           TriggerTime
 240   )
 241 {
 242   IEVENT  *Event;
 243
 244   Event = UserEvent;
 245
 246   if (Event == NULL) {
 247     return EFI_INVALID_PARAMETER;
 248   }
 249
 250   if (Event->Signature != EVENT_SIGNATURE) {
 251     return EFI_INVALID_PARAMETER;
 252   }
 253
 254   if (((UINT32)Type > TimerRelative) || ((Event->Type & EVT_TIMER) == 0)) {
 255     return EFI_INVALID_PARAMETER;
 256   }
 257
 258   CoreAcquireLock (&mEfiTimerLock);
 259
 260   //
 261   // If the timer is queued to the timer database, remove it
 262   //
 263   if (Event->Timer.Link.ForwardLink != NULL) {
 264     RemoveEntryList (&Event->Timer.Link);
 265     Event->Timer.Link.ForwardLink = NULL;
 266   }
 267
 268   Event->Timer.TriggerTime = 0;
 269   Event->Timer.Period      = 0;
 270
 271   if (Type != TimerCancel) {
 272     if (Type == TimerPeriodic) {
 273       if (TriggerTime == 0) {
 274         gTimer->GetTimerPeriod (gTimer, &TriggerTime);
 275       }
 276
 277       Event->Timer.Period = TriggerTime;
 278     }
 279
 280     Event->Timer.TriggerTime = CoreCurrentSystemTime () + TriggerTime;
 281     CoreInsertEventTimer (Event);
 282
 283     if (TriggerTime == 0) {
 284       CoreSignalEvent (mEfiCheckTimerEvent);
 285     }
 286   }
 287
 288   CoreReleaseLock (&mEfiTimerLock);
 289
 290   return EFI_SUCCESS;
 291 }