MdeModulePkg/Core/Dxe/Event/Timer.c

   1 /** @file
   2   Core Timer Services
   3
   4 Copyright (c) 2006 - 2008, Intel Corporation. <BR>
   5 All rights reserved. This program and the accompanying materials
   6 are licensed and made available under the terms and conditions of the BSD License
   7 which accompanies this distribution.  The full text of the license may be found at
   8 http://opensource.org/licenses/bsd-license.php
   9
  10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15
  16 #include "DxeMain.h"
  17
  18 //
  19 // Internal data
  20 //
  21
  22 LIST_ENTRY       mEfiTimerList = INITIALIZE_LIST_HEAD_VARIABLE (mEfiTimerList);
  23 EFI_LOCK         mEfiTimerLock = EFI_INITIALIZE_LOCK_VARIABLE (TPL_HIGH_LEVEL - 1);
  24 EFI_EVENT        mEfiCheckTimerEvent = NULL;
  25
  26 EFI_LOCK         mEfiSystemTimeLock = EFI_INITIALIZE_LOCK_VARIABLE (TPL_HIGH_LEVEL);
  27 UINT64           mEfiSystemTime = 0;
  28
  29 //
  30 // Timer functions
  31 //
  32 /**
  33   Inserts the timer event.
  34
  35   @param  Event                  Points to the internal structure of timer event
  36                                  to be installed
  37
  38 **/
  39 VOID
  40 CoreInsertEventTimer (
  41   IN IEVENT   *Event
  42   )
  43 {
  44   UINT64          TriggerTime;
  45   LIST_ENTRY      *Link;
  46   IEVENT          *Event2;
  47
  48   ASSERT_LOCKED (&mEfiTimerLock);
  49
  50   //
  51   // Get the timer's trigger time
  52   //
  53   TriggerTime = Event->u.Timer.TriggerTime;
  54
  55   //
  56   // Insert the timer into the timer database in assending sorted order
  57   //
  58   for (Link = mEfiTimerList.ForwardLink; Link != &mEfiTimerList; Link = Link->ForwardLink) {
  59     Event2 = CR (Link, IEVENT, u.Timer.Link, EVENT_SIGNATURE);
  60
  61     if (Event2->u.Timer.TriggerTime > TriggerTime) {
  62       break;
  63     }
  64   }
  65
  66   InsertTailList (Link, &Event->u.Timer.Link);
  67 }
  68
  69 /**
  70   Returns the current system time.
  71
  72   @return The current system time
  73
  74 **/
  75 UINT64
  76 CoreCurrentSystemTime (
  77   VOID
  78   )
  79 {
  80   UINT64          SystemTime;
  81
  82   CoreAcquireLock (&mEfiSystemTimeLock);
  83   SystemTime = mEfiSystemTime;
  84   CoreReleaseLock (&mEfiSystemTimeLock);
  85
  86   return SystemTime;
  87 }
  88
  89 /**
  90   Checks the sorted timer list against the current system time.
  91   Signals any expired event timer.
  92
  93   @param  CheckEvent             Not used
  94   @param  Context                Not used
  95
  96 **/
  97 VOID
  98 EFIAPI
  99 CoreCheckTimers (
 100   IN EFI_EVENT            CheckEvent,
 101   IN VOID                 *Context
 102   )
 103 {
 104   UINT64                  SystemTime;
 105   IEVENT                  *Event;
 106
 107   //
 108   // Check the timer database for expired timers
 109   //
 110   CoreAcquireLock (&mEfiTimerLock);
 111   SystemTime = CoreCurrentSystemTime ();
 112
 113   while (!IsListEmpty (&mEfiTimerList)) {
 114     Event = CR (mEfiTimerList.ForwardLink, IEVENT, u.Timer.Link, EVENT_SIGNATURE);
 115
 116     //
 117     // If this timer is not expired, then we're done
 118     //
 119     if (Event->u.Timer.TriggerTime > SystemTime) {
 120       break;
 121     }
 122
 123     //
 124     // Remove this timer from the timer queue
 125     //
 126
 127     RemoveEntryList (&Event->u.Timer.Link);
 128     Event->u.Timer.Link.ForwardLink = NULL;
 129
 130     //
 131     // Signal it
 132     //
 133     CoreSignalEvent (Event);
 134
 135     //
 136     // If this is a periodic timer, set it
 137     //
 138     if (Event->u.Timer.Period) {
 139       //
 140       // Compute the timers new trigger time
 141       //
 142       Event->u.Timer.TriggerTime = Event->u.Timer.TriggerTime + Event->u.Timer.Period;
 143
 144       //
 145       // If that's before now, then reset the timer to start from now
 146       //
 147       if (Event->u.Timer.TriggerTime <= SystemTime) {
 148         Event->u.Timer.TriggerTime = SystemTime;
 149         CoreSignalEvent (mEfiCheckTimerEvent);
 150       }
 151
 152       //
 153       // Add the timer
 154       //
 155       CoreInsertEventTimer (Event);
 156     }
 157   }
 158
 159   CoreReleaseLock (&mEfiTimerLock);
 160 }
 161
 162
 163 /**
 164   Initializes timer support.
 165
 166 **/
 167 VOID
 168 CoreInitializeTimer (
 169   VOID
 170   )
 171 {
 172   EFI_STATUS  Status;
 173
 174   Status = CoreCreateEvent (
 175              EVT_NOTIFY_SIGNAL,
 176              TPL_HIGH_LEVEL - 1,
 177              CoreCheckTimers,
 178              NULL,
 179              &mEfiCheckTimerEvent
 180              );
 181   ASSERT_EFI_ERROR (Status);
 182 }
 183
 184
 185 /**
 186   Called by the platform code to process a tick.
 187
 188   @param  Duration               The number of 100ns elasped since the last call
 189                                  to TimerTick
 190
 191 **/
 192 VOID
 193 EFIAPI
 194 CoreTimerTick (
 195   IN UINT64   Duration
 196   )
 197 {
 198   IEVENT          *Event;
 199
 200   //
 201   // Check runtiem flag in case there are ticks while exiting boot services
 202   //
 203   CoreAcquireLock (&mEfiSystemTimeLock);
 204
 205   //
 206   // Update the system time
 207   //
 208   mEfiSystemTime += Duration;
 209
 210   //
 211   // If the head of the list is expired, fire the timer event
 212   // to process it
 213   //
 214   if (!IsListEmpty (&mEfiTimerList)) {
 215     Event = CR (mEfiTimerList.ForwardLink, IEVENT, u.Timer.Link, EVENT_SIGNATURE);
 216
 217     if (Event->u.Timer.TriggerTime <= mEfiSystemTime) {
 218       CoreSignalEvent (mEfiCheckTimerEvent);
 219     }
 220   }
 221
 222   CoreReleaseLock (&mEfiSystemTimeLock);
 223 }
 224
 225
 226
 227 /**
 228   Sets the type of timer and the trigger time for a timer event.
 229
 230   @param  UserEvent              The timer event that is to be signaled at the
 231                                  specified time
 232   @param  Type                   The type of time that is specified in
 233                                  TriggerTime
 234   @param  TriggerTime            The number of 100ns units until the timer
 235                                  expires
 236
 237   @retval EFI_SUCCESS            The event has been set to be signaled at the
 238                                  requested time
 239   @retval EFI_INVALID_PARAMETER  Event or Type is not valid
 240
 241 **/
 242 EFI_STATUS
 243 EFIAPI
 244 CoreSetTimer (
 245   IN EFI_EVENT            UserEvent,
 246   IN EFI_TIMER_DELAY      Type,
 247   IN UINT64               TriggerTime
 248   )
 249 {
 250   IEVENT      *Event;
 251
 252   Event = UserEvent;
 253
 254   if (Event == NULL) {
 255     return EFI_INVALID_PARAMETER;
 256   }
 257
 258   if (Event->Signature != EVENT_SIGNATURE) {
 259     return EFI_INVALID_PARAMETER;
 260   }
 261
 262   if (Type < 0 || Type > TimerRelative  || !(Event->Type & EVT_TIMER)) {
 263     return EFI_INVALID_PARAMETER;
 264   }
 265
 266   CoreAcquireLock (&mEfiTimerLock);
 267
 268   //
 269   // If the timer is queued to the timer database, remove it
 270   //
 271   if (Event->u.Timer.Link.ForwardLink != NULL) {
 272     RemoveEntryList (&Event->u.Timer.Link);
 273     Event->u.Timer.Link.ForwardLink = NULL;
 274   }
 275
 276   Event->u.Timer.TriggerTime = 0;
 277   Event->u.Timer.Period = 0;
 278
 279   if (Type != TimerCancel) {
 280
 281     if (Type == TimerPeriodic) {
 282       Event->u.Timer.Period = TriggerTime;
 283     }
 284
 285     Event->u.Timer.TriggerTime = CoreCurrentSystemTime () + TriggerTime;
 286     CoreInsertEventTimer (Event);
 287
 288     if (TriggerTime == 0) {
 289       CoreSignalEvent (mEfiCheckTimerEvent);
 290     }
 291   }
 292
 293   CoreReleaseLock (&mEfiTimerLock);
 294
 295   return EFI_SUCCESS;
 296 }