MdeModulePkg/Universal/WatchdogTimerDxe/WatchdogTimer.c

   1 /** @file
   2   Implementation of Watchdog Timer Architectural Protocol using UEFI APIs.
   3
   4 Copyright (c) 2006 - 2010, 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   // Reset the platform
  79   //
  80   gRT->ResetSystem (EfiResetCold, EFI_TIMEOUT, 0, NULL);
  81 }
  82
  83
  84 /**
  85   Registers a handler that is to be invoked when the watchdog timer fires.
  86
  87   This function registers a handler that is to be invoked when the watchdog
  88   timer fires.  By default, the EFI_WATCHDOG_TIMER protocol will call the
  89   Runtime Service ResetSystem() when the watchdog timer fires.  If a
  90   NotifyFunction is registered, then the NotifyFunction will be called before
  91   the Runtime Service ResetSystem() is called.  If NotifyFunction is NULL, then
  92   the watchdog handler is unregistered.  If a watchdog handler is registered,
  93   then EFI_SUCCESS is returned.  If an attempt is made to register a handler
  94   when a handler is already registered, then EFI_ALREADY_STARTED is returned.
  95   If an attempt is made to uninstall a handler when a handler is not installed,
  96   then return EFI_INVALID_PARAMETER.
  97
  98   @param  This                  The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
  99   @param  NotifyFunction        The function to call when the watchdog timer fires.  If this
 100                                 is NULL, then the handler will be unregistered.
 101
 102   @retval EFI_SUCCESS           The watchdog timer handler was registered or unregistered.
 103   @retval EFI_ALREADY_STARTED   NotifyFunction is not NULL, and a handler is already registered.
 104   @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not previously registered.
 105
 106 **/
 107 EFI_STATUS
 108 EFIAPI
 109 WatchdogTimerDriverRegisterHandler (
 110   IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
 111   IN EFI_WATCHDOG_TIMER_NOTIFY         NotifyFunction
 112   )
 113 {
 114   //
 115   // If NotifyFunction is NULL, and a handler was not previously registered,
 116   // return EFI_INVALID_PARAMETER.
 117   //
 118   if (NotifyFunction == NULL && mWatchdogTimerNotifyFunction == NULL) {
 119     return EFI_INVALID_PARAMETER;
 120   }
 121   //
 122   // If NotifyFunction is not NULL, and a handler is already registered,
 123   // return EFI_ALREADY_STARTED.
 124   //
 125   if (NotifyFunction != NULL && mWatchdogTimerNotifyFunction != NULL) {
 126     return EFI_ALREADY_STARTED;
 127   }
 128
 129   mWatchdogTimerNotifyFunction = NotifyFunction;
 130
 131   return EFI_SUCCESS;
 132 }
 133
 134 /**
 135   Sets the amount of time in the future to fire the watchdog timer.
 136
 137   This function sets the amount of time to wait before firing the watchdog
 138   timer to TimerPeriod 100 ns units.  If TimerPeriod is 0, then the watchdog
 139   timer is disabled.
 140
 141   @param  This              The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
 142   @param  TimerPeriod       The amount of time in 100 ns units to wait before the watchdog
 143                             timer is fired.  If TimerPeriod is zero, then the watchdog
 144                             timer is disabled.
 145
 146   @retval EFI_SUCCESS       The watchdog timer has been programmed to fire in Time
 147                             100 ns units.
 148   @retval EFI_DEVICE_ERROR  A watchdog timer could not be programmed due to a device
 149                             error.
 150
 151 **/
 152 EFI_STATUS
 153 EFIAPI
 154 WatchdogTimerDriverSetTimerPeriod (
 155   IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
 156   IN UINT64                            TimerPeriod
 157   )
 158 {
 159   mWatchdogTimerPeriod = TimerPeriod;
 160
 161   return gBS->SetTimer (
 162                 mWatchdogTimerEvent,
 163                 (mWatchdogTimerPeriod == 0) ? TimerCancel : TimerRelative,
 164                 mWatchdogTimerPeriod
 165                 );
 166 }
 167
 168 /**
 169   Retrieves the amount of time in 100 ns units that the system will wait before firing the watchdog timer.
 170
 171   This function retrieves the amount of time the system will wait before firing
 172   the watchdog timer.  This period is returned in TimerPeriod, and EFI_SUCCESS
 173   is returned.  If TimerPeriod is NULL, then EFI_INVALID_PARAMETER is returned.
 174
 175   @param  This                    The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
 176   @param  TimerPeriod             A pointer to the amount of time in 100 ns units that the system
 177                                   will wait before the watchdog timer is fired.  If TimerPeriod of
 178                                   zero is returned, then the watchdog timer is disabled.
 179
 180   @retval EFI_SUCCESS             The amount of time that the system will wait before
 181                                   firing the watchdog timer was returned in TimerPeriod.
 182   @retval EFI_INVALID_PARAMETER   TimerPeriod is NULL.
 183
 184 **/
 185 EFI_STATUS
 186 EFIAPI
 187 WatchdogTimerDriverGetTimerPeriod (
 188   IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
 189   IN UINT64                            *TimerPeriod
 190   )
 191 {
 192   if (TimerPeriod == NULL) {
 193     return EFI_INVALID_PARAMETER;
 194   }
 195
 196   *TimerPeriod = mWatchdogTimerPeriod;
 197
 198   return EFI_SUCCESS;
 199 }
 200
 201 /**
 202   Entry point of the Watchdog Timer Architectural Protocol driver.
 203
 204   @param  ImageHandle   The image handle of this driver.
 205   @param  SystemTable   The pointer of EFI_SYSTEM_TABLE.
 206
 207   @retval EFI_SUCCESS   Watchdog Timer Architectural Protocol successfully installed.
 208
 209 **/
 210 EFI_STATUS
 211 EFIAPI
 212 WatchdogTimerDriverInitialize (
 213   IN EFI_HANDLE        ImageHandle,
 214   IN EFI_SYSTEM_TABLE  *SystemTable
 215   )
 216 {
 217   EFI_STATUS  Status;
 218
 219   //
 220   // Make sure the Watchdog Timer Architectural Protocol has not been installed in the system yet.
 221   //
 222   ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid);
 223
 224   //
 225   // Create the timer event to implement a simple watchdog timer
 226   //
 227   Status = gBS->CreateEvent (
 228                   EVT_TIMER | EVT_NOTIFY_SIGNAL,
 229                   TPL_NOTIFY,
 230                   WatchdogTimerDriverExpires,
 231                   NULL,
 232                   &mWatchdogTimerEvent
 233                   );
 234   ASSERT_EFI_ERROR (Status);
 235
 236   //
 237   // Install the Watchdog Timer Arch Protocol onto a new handle
 238   //
 239   Status = gBS->InstallMultipleProtocolInterfaces (
 240                   &mWatchdogTimerHandle,
 241                   &gEfiWatchdogTimerArchProtocolGuid,
 242                   &mWatchdogTimer,
 243                   NULL
 244                   );
 245   ASSERT_EFI_ERROR (Status);
 246
 247   return EFI_SUCCESS;
 248 }