MdeModulePkg/Universal/WatchdogTimerDxe/WatchdogTimer.c

   1 /** @file
   2   Implementation of Watchdog Timer Architectural Protocol using UEFI APIs.
   3
   4 Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
   5 SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 #include "WatchdogTimer.h"
  10
  11 //
  12 // Handle for the Watchdog Timer Architectural Protocol instance produced by this driver
  13 //
  14 EFI_HANDLE  mWatchdogTimerHandle = NULL;
  15
  16 //
  17 // The Watchdog Timer Architectural Protocol instance produced by this driver
  18 //
  19 EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  mWatchdogTimer = {
  20   WatchdogTimerDriverRegisterHandler,
  21   WatchdogTimerDriverSetTimerPeriod,
  22   WatchdogTimerDriverGetTimerPeriod
  23 };
  24
  25 //
  26 // The watchdog timer period in 100 ns units
  27 //
  28 UINT64  mWatchdogTimerPeriod = 0;
  29
  30 //
  31 // The notification function to call if the watchdig timer fires
  32 //
  33 EFI_WATCHDOG_TIMER_NOTIFY  mWatchdogTimerNotifyFunction = NULL;
  34
  35 //
  36 // The one-shot timer event that is armed when the watchdog timer is enabled
  37 //
  38 EFI_EVENT  mWatchdogTimerEvent;
  39
  40
  41 /**
  42   Notification function that is called if the watchdog timer is fired.
  43
  44   Notification function for the one-shot timer event that was signaled
  45   when the watchdog timer expired. If a handler has been registered with
  46   the Watchdog Timer Architectural Protocol, then that handler is called
  47   passing in the time period that has passed that cause the watchdog timer
  48   to fire.  Then, a call to the Runtime Service ResetSystem() is made to
  49   reset the platform.
  50
  51   @param  Timer     The one-shot timer event that was signaled when the
  52                     watchdog timer expired.
  53   @param  Context   The context that was registered when the event Timer was created.
  54
  55 **/
  56 VOID
  57 EFIAPI
  58 WatchdogTimerDriverExpires (
  59   IN EFI_EVENT    Timer,
  60   IN VOID         *Context
  61   )
  62 {
  63   REPORT_STATUS_CODE (EFI_ERROR_CODE | EFI_ERROR_MINOR, (EFI_COMPUTING_UNIT_HOST_PROCESSOR | EFI_CU_HP_EC_TIMER_EXPIRED));
  64
  65   //
  66   // If a notification function has been registered, then call it
  67   //
  68   if (mWatchdogTimerNotifyFunction != NULL) {
  69     mWatchdogTimerNotifyFunction (mWatchdogTimerPeriod);
  70   }
  71
  72   DEBUG ((EFI_D_ERROR, "Watchdog Timer resetting system\n"));
  73
  74   //
  75   // Reset the platform
  76   //
  77   gRT->ResetSystem (EfiResetCold, EFI_TIMEOUT, 0, NULL);
  78 }
  79
  80
  81 /**
  82   Registers a handler that is to be invoked when the watchdog timer fires.
  83
  84   This function registers a handler that is to be invoked when the watchdog
  85   timer fires.  By default, the EFI_WATCHDOG_TIMER protocol will call the
  86   Runtime Service ResetSystem() when the watchdog timer fires.  If a
  87   NotifyFunction is registered, then the NotifyFunction will be called before
  88   the Runtime Service ResetSystem() is called.  If NotifyFunction is NULL, then
  89   the watchdog handler is unregistered.  If a watchdog handler is registered,
  90   then EFI_SUCCESS is returned.  If an attempt is made to register a handler
  91   when a handler is already registered, then EFI_ALREADY_STARTED is returned.
  92   If an attempt is made to uninstall a handler when a handler is not installed,
  93   then return EFI_INVALID_PARAMETER.
  94
  95   @param  This                  The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
  96   @param  NotifyFunction        The function to call when the watchdog timer fires.  If this
  97                                 is NULL, then the handler will be unregistered.
  98
  99   @retval EFI_SUCCESS           The watchdog timer handler was registered or unregistered.
 100   @retval EFI_ALREADY_STARTED   NotifyFunction is not NULL, and a handler is already registered.
 101   @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not previously registered.
 102
 103 **/
 104 EFI_STATUS
 105 EFIAPI
 106 WatchdogTimerDriverRegisterHandler (
 107   IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
 108   IN EFI_WATCHDOG_TIMER_NOTIFY         NotifyFunction
 109   )
 110 {
 111   //
 112   // If NotifyFunction is NULL, and a handler was not previously registered,
 113   // return EFI_INVALID_PARAMETER.
 114   //
 115   if (NotifyFunction == NULL && mWatchdogTimerNotifyFunction == NULL) {
 116     return EFI_INVALID_PARAMETER;
 117   }
 118   //
 119   // If NotifyFunction is not NULL, and a handler is already registered,
 120   // return EFI_ALREADY_STARTED.
 121   //
 122   if (NotifyFunction != NULL && mWatchdogTimerNotifyFunction != NULL) {
 123     return EFI_ALREADY_STARTED;
 124   }
 125
 126   mWatchdogTimerNotifyFunction = NotifyFunction;
 127
 128   return EFI_SUCCESS;
 129 }
 130
 131 /**
 132   Sets the amount of time in the future to fire the watchdog timer.
 133
 134   This function sets the amount of time to wait before firing the watchdog
 135   timer to TimerPeriod 100 ns units.  If TimerPeriod is 0, then the watchdog
 136   timer is disabled.
 137
 138   @param  This              The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
 139   @param  TimerPeriod       The amount of time in 100 ns units to wait before the watchdog
 140                             timer is fired.  If TimerPeriod is zero, then the watchdog
 141                             timer is disabled.
 142
 143   @retval EFI_SUCCESS       The watchdog timer has been programmed to fire in Time
 144                             100 ns units.
 145   @retval EFI_DEVICE_ERROR  A watchdog timer could not be programmed due to a device
 146                             error.
 147
 148 **/
 149 EFI_STATUS
 150 EFIAPI
 151 WatchdogTimerDriverSetTimerPeriod (
 152   IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
 153   IN UINT64                            TimerPeriod
 154   )
 155 {
 156   mWatchdogTimerPeriod = TimerPeriod;
 157
 158   return gBS->SetTimer (
 159                 mWatchdogTimerEvent,
 160                 (mWatchdogTimerPeriod == 0) ? TimerCancel : TimerRelative,
 161                 mWatchdogTimerPeriod
 162                 );
 163 }
 164
 165 /**
 166   Retrieves the amount of time in 100 ns units that the system will wait before firing the watchdog timer.
 167
 168   This function retrieves the amount of time the system will wait before firing
 169   the watchdog timer.  This period is returned in TimerPeriod, and EFI_SUCCESS
 170   is returned.  If TimerPeriod is NULL, then EFI_INVALID_PARAMETER is returned.
 171
 172   @param  This                    The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
 173   @param  TimerPeriod             A pointer to the amount of time in 100 ns units that the system
 174                                   will wait before the watchdog timer is fired.  If TimerPeriod of
 175                                   zero is returned, then the watchdog timer is disabled.
 176
 177   @retval EFI_SUCCESS             The amount of time that the system will wait before
 178                                   firing the watchdog timer was returned in TimerPeriod.
 179   @retval EFI_INVALID_PARAMETER   TimerPeriod is NULL.
 180
 181 **/
 182 EFI_STATUS
 183 EFIAPI
 184 WatchdogTimerDriverGetTimerPeriod (
 185   IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
 186   IN UINT64                            *TimerPeriod
 187   )
 188 {
 189   if (TimerPeriod == NULL) {
 190     return EFI_INVALID_PARAMETER;
 191   }
 192
 193   *TimerPeriod = mWatchdogTimerPeriod;
 194
 195   return EFI_SUCCESS;
 196 }
 197
 198 /**
 199   Entry point of the Watchdog Timer Architectural Protocol driver.
 200
 201   @param  ImageHandle   The image handle of this driver.
 202   @param  SystemTable   The pointer of EFI_SYSTEM_TABLE.
 203
 204   @retval EFI_SUCCESS   Watchdog Timer Architectural Protocol successfully installed.
 205
 206 **/
 207 EFI_STATUS
 208 EFIAPI
 209 WatchdogTimerDriverInitialize (
 210   IN EFI_HANDLE        ImageHandle,
 211   IN EFI_SYSTEM_TABLE  *SystemTable
 212   )
 213 {
 214   EFI_STATUS  Status;
 215
 216   //
 217   // Make sure the Watchdog Timer Architectural Protocol has not been installed in the system yet.
 218   //
 219   ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid);
 220
 221   //
 222   // Create the timer event to implement a simple watchdog timer
 223   //
 224   Status = gBS->CreateEvent (
 225                   EVT_TIMER | EVT_NOTIFY_SIGNAL,
 226                   TPL_NOTIFY,
 227                   WatchdogTimerDriverExpires,
 228                   NULL,
 229                   &mWatchdogTimerEvent
 230                   );
 231   ASSERT_EFI_ERROR (Status);
 232
 233   //
 234   // Install the Watchdog Timer Arch Protocol onto a new handle
 235   //
 236   Status = gBS->InstallMultipleProtocolInterfaces (
 237                   &mWatchdogTimerHandle,
 238                   &gEfiWatchdogTimerArchProtocolGuid,
 239                   &mWatchdogTimer,
 240                   NULL
 241                   );
 242   ASSERT_EFI_ERROR (Status);
 243
 244   return EFI_SUCCESS;
 245 }