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 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 #include "Event.h"
  18
  19 //
  20 // Internal data
  21 //
  22
  23 LIST_ENTRY       mEfiTimerList = INITIALIZE_LIST_HEAD_VARIABLE (mEfiTimerList);
  24 EFI_LOCK         mEfiTimerLock = EFI_INITIALIZE_LOCK_VARIABLE (TPL_HIGH_LEVEL - 1);
  25 EFI_EVENT        mEfiCheckTimerEvent = NULL;
  26
  27 EFI_LOCK         mEfiSystemTimeLock = EFI_INITIALIZE_LOCK_VARIABLE (TPL_HIGH_LEVEL);
  28 UINT64           mEfiSystemTime = 0;
  29
  30 //
  31 // Timer functions
  32 //
  33 /**
  34   Inserts the timer event.
  35
  36   @param  Event                  Points to the internal structure of timer event
  37                                  to be installed
  38
  39 **/
  40 VOID
  41 CoreInsertEventTimer (
  42   IN IEVENT   *Event
  43   )
  44 {
  45   UINT64          TriggerTime;
  46   LIST_ENTRY      *Link;
  47   IEVENT          *Event2;
  48
  49   ASSERT_LOCKED (&mEfiTimerLock);
  50
  51   //
  52   // Get the timer's trigger time
  53   //
  54   TriggerTime = Event->Timer.TriggerTime;
  55
  56   //
  57   // Insert the timer into the timer database in assending sorted order
  58   //
  59   for (Link = mEfiTimerList.ForwardLink; Link != &mEfiTimerList; Link = Link->ForwardLink) {
  60     Event2 = CR (Link, IEVENT, Timer.Link, EVENT_SIGNATURE);
  61
  62     if (Event2->Timer.TriggerTime > TriggerTime) {
  63       break;
  64     }
  65   }
  66
  67   InsertTailList (Link, &Event->Timer.Link);
  68 }
  69
  70 /**
  71   Returns the current system time.
  72
  73   @return The current system time
  74
  75 **/
  76 UINT64
  77 CoreCurrentSystemTime (
  78   VOID
  79   )
  80 {
  81   UINT64          SystemTime;
  82
  83   CoreAcquireLock (&mEfiSystemTimeLock);
  84   SystemTime = mEfiSystemTime;
  85   CoreReleaseLock (&mEfiSystemTimeLock);
  86
  87   return SystemTime;
  88 }
  89
  90 /**
  91   Checks the sorted timer list against the current system time.
  92   Signals any expired event timer.
  93
  94   @param  CheckEvent             Not used
  95   @param  Context                Not used
  96
  97 **/
  98 VOID
  99 EFIAPI
 100 CoreCheckTimers (
 101   IN EFI_EVENT            CheckEvent,
 102   IN VOID                 *Context
 103   )
 104 {
 105   UINT64                  SystemTime;
 106   IEVENT                  *Event;
 107
 108   //
 109   // Check the timer database for expired timers
 110   //
 111   CoreAcquireLock (&mEfiTimerLock);
 112   SystemTime = CoreCurrentSystemTime ();
 113
 114   while (!IsListEmpty (&mEfiTimerList)) {
 115     Event = CR (mEfiTimerList.ForwardLink, IEVENT, Timer.Link, EVENT_SIGNATURE);
 116
 117     //
 118     // If this timer is not expired, then we're done
 119     //
 120     if (Event->Timer.TriggerTime > SystemTime) {
 121       break;
 122     }
 123
 124     //
 125     // Remove this timer from the timer queue
 126     //
 127
 128     RemoveEntryList (&Event->Timer.Link);
 129     Event->Timer.Link.ForwardLink = NULL;
 130
 131     //
 132     // Signal it
 133     //
 134     CoreSignalEvent (Event);
 135
 136     //
 137     // If this is a periodic timer, set it
 138     //
 139     if (Event->Timer.Period != 0) {
 140       //
 141       // Compute the timers new trigger time
 142       //
 143       Event->Timer.TriggerTime = Event->Timer.TriggerTime + Event->Timer.Period;
 144
 145       //
 146       // If that's before now, then reset the timer to start from now
 147       //
 148       if (Event->Timer.TriggerTime <= SystemTime) {
 149         Event->Timer.TriggerTime = SystemTime;
 150         CoreSignalEvent (mEfiCheckTimerEvent);
 151       }
 152
 153       //
 154       // Add the timer
 155       //
 156       CoreInsertEventTimer (Event);
 157     }
 158   }
 159
 160   CoreReleaseLock (&mEfiTimerLock);
 161 }
 162
 163
 164 /**
 165   Initializes timer support.
 166
 167 **/
 168 VOID
 169 CoreInitializeTimer (
 170   VOID
 171   )
 172 {
 173   EFI_STATUS  Status;
 174
 175   Status = CoreCreateEventInternal (
 176              EVT_NOTIFY_SIGNAL,
 177              TPL_HIGH_LEVEL - 1,
 178              CoreCheckTimers,
 179              NULL,
 180              NULL,
 181              &mEfiCheckTimerEvent
 182              );
 183   ASSERT_EFI_ERROR (Status);
 184 }
 185
 186
 187 /**
 188   Called by the platform code to process a tick.
 189
 190   @param  Duration               The number of 100ns elapsed since the last call
 191                                  to TimerTick
 192
 193 **/
 194 VOID
 195 EFIAPI
 196 CoreTimerTick (
 197   IN UINT64   Duration
 198   )
 199 {
 200   IEVENT          *Event;
 201
 202   //
 203   // Check runtiem flag in case there are ticks while exiting boot services
 204   //
 205   CoreAcquireLock (&mEfiSystemTimeLock);
 206
 207   //
 208   // Update the system time
 209   //
 210   mEfiSystemTime += Duration;
 211
 212   //
 213   // If the head of the list is expired, fire the timer event
 214   // to process it
 215   //
 216   if (!IsListEmpty (&mEfiTimerList)) {
 217     Event = CR (mEfiTimerList.ForwardLink, IEVENT, Timer.Link, EVENT_SIGNATURE);
 218
 219     if (Event->Timer.TriggerTime <= mEfiSystemTime) {
 220       CoreSignalEvent (mEfiCheckTimerEvent);
 221     }
 222   }
 223
 224   CoreReleaseLock (&mEfiSystemTimeLock);
 225 }
 226
 227
 228
 229 /**
 230   Sets the type of timer and the trigger time for a timer event.
 231
 232   @param  UserEvent              The timer event that is to be signaled at the
 233                                  specified time
 234   @param  Type                   The type of time that is specified in
 235                                  TriggerTime
 236   @param  TriggerTime            The number of 100ns units until the timer
 237                                  expires
 238
 239   @retval EFI_SUCCESS            The event has been set to be signaled at the
 240                                  requested time
 241   @retval EFI_INVALID_PARAMETER  Event or Type is not valid
 242
 243 **/
 244 EFI_STATUS
 245 EFIAPI
 246 CoreSetTimer (
 247   IN EFI_EVENT            UserEvent,
 248   IN EFI_TIMER_DELAY      Type,
 249   IN UINT64               TriggerTime
 250   )
 251 {
 252   IEVENT      *Event;
 253
 254   Event = UserEvent;
 255
 256   if (Event == NULL) {
 257     return EFI_INVALID_PARAMETER;
 258   }
 259
 260   if (Event->Signature != EVENT_SIGNATURE) {
 261     return EFI_INVALID_PARAMETER;
 262   }
 263
 264   if ((UINT32)Type > TimerRelative  || (Event->Type & EVT_TIMER) == 0) {
 265     return EFI_INVALID_PARAMETER;
 266   }
 267
 268   CoreAcquireLock (&mEfiTimerLock);
 269
 270   //
 271   // If the timer is queued to the timer database, remove it
 272   //
 273   if (Event->Timer.Link.ForwardLink != NULL) {
 274     RemoveEntryList (&Event->Timer.Link);
 275     Event->Timer.Link.ForwardLink = NULL;
 276   }
 277
 278   Event->Timer.TriggerTime = 0;
 279   Event->Timer.Period = 0;
 280
 281   if (Type != TimerCancel) {
 282
 283     if (Type == TimerPeriodic) {
 284       if (TriggerTime == 0) {
 285         gTimer->GetTimerPeriod (gTimer, &TriggerTime);
 286       }
 287       Event->Timer.Period = TriggerTime;
 288     }
 289
 290     Event->Timer.TriggerTime = CoreCurrentSystemTime () + TriggerTime;
 291     CoreInsertEventTimer (Event);
 292
 293     if (TriggerTime == 0) {
 294       CoreSignalEvent (mEfiCheckTimerEvent);
 295     }
 296   }
 297
 298   CoreReleaseLock (&mEfiTimerLock);
 299
 300   return EFI_SUCCESS;
 301 }