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 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 #include "WatchdogTimer.h"
  16
  17 //
  18 // Handle for the Watchdog Timer Architectural Protocol instance produced by this driver
  19 //
  20 EFI_HANDLE  mWatchdogTimerHandle = NULL;
  21
  22 //
  23 // The Watchdog Timer Architectural Protocol instance produced by this driver
  24 //
  25 EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  mWatchdogTimer = {
  26   WatchdogTimerDriverRegisterHandler,
  27   WatchdogTimerDriverSetTimerPeriod,
  28   WatchdogTimerDriverGetTimerPeriod
  29 };
  30
  31 //
  32 // The watchdog timer period in 100 ns units
  33 //
  34 UINT64  mWatchdogTimerPeriod = 0;
  35
  36 //
  37 // The notification function to call if the watchdig timer fires
  38 //
  39 EFI_WATCHDOG_TIMER_NOTIFY  mWatchdogTimerNotifyFunction = NULL;
  40
  41 //
  42 // The one-shot timer event that is armed when the watchdog timer is enabled
  43 //
  44 EFI_EVENT  mWatchdogTimerEvent;
  45
  46
  47 /**
  48   Notification function that is called if the watchdog timer is fired.
  49
  50   Notification function for the one-shot timer event that was signaled
  51   when the watchdog timer expired. If a handler has been registered with
  52   the Watchdog Timer Architectural Protocol, then that handler is called
  53   passing in the time period that has passed that cause the watchdog timer
  54   to fire.  Then, a call to the Runtime Service ResetSystem() is made to
  55   reset the platform.
  56
  57   @param  Timer     The one-shot timer event that was signaled when the
  58                     watchdog timer expired.
  59   @param  Context   The context that was registered when the event Timer was created.
  60
  61 **/
  62 VOID
  63 EFIAPI
  64 WatchdogTimerDriverExpires (
  65   IN EFI_EVENT    Timer,
  66   IN VOID         *Context
  67   )
  68 {
  69   REPORT_STATUS_CODE (EFI_ERROR_CODE | EFI_ERROR_MINOR, (EFI_COMPUTING_UNIT_HOST_PROCESSOR | EFI_CU_HP_EC_TIMER_EXPIRED));
  70
  71   //
  72   // If a notification function has been registered, then call it
  73   //
  74   if (mWatchdogTimerNotifyFunction != NULL) {
  75     mWatchdogTimerNotifyFunction (mWatchdogTimerPeriod);
  76   }
  77
  78   DEBUG ((EFI_D_ERROR, "Watchdog Timer resetting system\n"));
  79
  80   //
  81   // Reset the platform
  82   //
  83   gRT->ResetSystem (EfiResetCold, EFI_TIMEOUT, 0, NULL);
  84 }
  85
  86
  87 /**
  88   Registers a handler that is to be invoked when the watchdog timer fires.
  89
  90   This function registers a handler that is to be invoked when the watchdog
  91   timer fires.  By default, the EFI_WATCHDOG_TIMER protocol will call the
  92   Runtime Service ResetSystem() when the watchdog timer fires.  If a
  93   NotifyFunction is registered, then the NotifyFunction will be called before
  94   the Runtime Service ResetSystem() is called.  If NotifyFunction is NULL, then
  95   the watchdog handler is unregistered.  If a watchdog handler is registered,
  96   then EFI_SUCCESS is returned.  If an attempt is made to register a handler
  97   when a handler is already registered, then EFI_ALREADY_STARTED is returned.
  98   If an attempt is made to uninstall a handler when a handler is not installed,
  99   then return EFI_INVALID_PARAMETER.
 100
 101   @param  This                  The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
 102   @param  NotifyFunction        The function to call when the watchdog timer fires.  If this
 103                                 is NULL, then the handler will be unregistered.
 104
 105   @retval EFI_SUCCESS           The watchdog timer handler was registered or unregistered.
 106   @retval EFI_ALREADY_STARTED   NotifyFunction is not NULL, and a handler is already registered.
 107   @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not previously registered.
 108
 109 **/
 110 EFI_STATUS
 111 EFIAPI
 112 WatchdogTimerDriverRegisterHandler (
 113   IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
 114   IN EFI_WATCHDOG_TIMER_NOTIFY         NotifyFunction
 115   )
 116 {
 117   //
 118   // If NotifyFunction is NULL, and a handler was not previously registered,
 119   // return EFI_INVALID_PARAMETER.
 120   //
 121   if (NotifyFunction == NULL && mWatchdogTimerNotifyFunction == NULL) {
 122     return EFI_INVALID_PARAMETER;
 123   }
 124   //
 125   // If NotifyFunction is not NULL, and a handler is already registered,
 126   // return EFI_ALREADY_STARTED.
 127   //
 128   if (NotifyFunction != NULL && mWatchdogTimerNotifyFunction != NULL) {
 129     return EFI_ALREADY_STARTED;
 130   }
 131
 132   mWatchdogTimerNotifyFunction = NotifyFunction;
 133
 134   return EFI_SUCCESS;
 135 }
 136
 137 /**
 138   Sets the amount of time in the future to fire the watchdog timer.
 139
 140   This function sets the amount of time to wait before firing the watchdog
 141   timer to TimerPeriod 100 ns units.  If TimerPeriod is 0, then the watchdog
 142   timer is disabled.
 143
 144   @param  This              The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
 145   @param  TimerPeriod       The amount of time in 100 ns units to wait before the watchdog
 146                             timer is fired.  If TimerPeriod is zero, then the watchdog
 147                             timer is disabled.
 148
 149   @retval EFI_SUCCESS       The watchdog timer has been programmed to fire in Time
 150                             100 ns units.
 151   @retval EFI_DEVICE_ERROR  A watchdog timer could not be programmed due to a device
 152                             error.
 153
 154 **/
 155 EFI_STATUS
 156 EFIAPI
 157 WatchdogTimerDriverSetTimerPeriod (
 158   IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
 159   IN UINT64                            TimerPeriod
 160   )
 161 {
 162   mWatchdogTimerPeriod = TimerPeriod;
 163
 164   return gBS->SetTimer (
 165                 mWatchdogTimerEvent,
 166                 (mWatchdogTimerPeriod == 0) ? TimerCancel : TimerRelative,
 167                 mWatchdogTimerPeriod
 168                 );
 169 }
 170
 171 /**
 172   Retrieves the amount of time in 100 ns units that the system will wait before firing the watchdog timer.
 173
 174   This function retrieves the amount of time the system will wait before firing
 175   the watchdog timer.  This period is returned in TimerPeriod, and EFI_SUCCESS
 176   is returned.  If TimerPeriod is NULL, then EFI_INVALID_PARAMETER is returned.
 177
 178   @param  This                    The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
 179   @param  TimerPeriod             A pointer to the amount of time in 100 ns units that the system
 180                                   will wait before the watchdog timer is fired.  If TimerPeriod of
 181                                   zero is returned, then the watchdog timer is disabled.
 182
 183   @retval EFI_SUCCESS             The amount of time that the system will wait before
 184                                   firing the watchdog timer was returned in TimerPeriod.
 185   @retval EFI_INVALID_PARAMETER   TimerPeriod is NULL.
 186
 187 **/
 188 EFI_STATUS
 189 EFIAPI
 190 WatchdogTimerDriverGetTimerPeriod (
 191   IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
 192   IN UINT64                            *TimerPeriod
 193   )
 194 {
 195   if (TimerPeriod == NULL) {
 196     return EFI_INVALID_PARAMETER;
 197   }
 198
 199   *TimerPeriod = mWatchdogTimerPeriod;
 200
 201   return EFI_SUCCESS;
 202 }
 203
 204 /**
 205   Entry point of the Watchdog Timer Architectural Protocol driver.
 206
 207   @param  ImageHandle   The image handle of this driver.
 208   @param  SystemTable   The pointer of EFI_SYSTEM_TABLE.
 209
 210   @retval EFI_SUCCESS   Watchdog Timer Architectural Protocol successfully installed.
 211
 212 **/
 213 EFI_STATUS
 214 EFIAPI
 215 WatchdogTimerDriverInitialize (
 216   IN EFI_HANDLE        ImageHandle,
 217   IN EFI_SYSTEM_TABLE  *SystemTable
 218   )
 219 {
 220   EFI_STATUS  Status;
 221
 222   //
 223   // Make sure the Watchdog Timer Architectural Protocol has not been installed in the system yet.
 224   //
 225   ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid);
 226
 227   //
 228   // Create the timer event to implement a simple watchdog timer
 229   //
 230   Status = gBS->CreateEvent (
 231                   EVT_TIMER | EVT_NOTIFY_SIGNAL,
 232                   TPL_NOTIFY,
 233                   WatchdogTimerDriverExpires,
 234                   NULL,
 235                   &mWatchdogTimerEvent
 236                   );
 237   ASSERT_EFI_ERROR (Status);
 238
 239   //
 240   // Install the Watchdog Timer Arch Protocol onto a new handle
 241   //
 242   Status = gBS->InstallMultipleProtocolInterfaces (
 243                   &mWatchdogTimerHandle,
 244                   &gEfiWatchdogTimerArchProtocolGuid,
 245                   &mWatchdogTimer,
 246                   NULL
 247                   );
 248   ASSERT_EFI_ERROR (Status);
 249
 250   return EFI_SUCCESS;
 251 }