MdePkg/Include/Protocol/WatchdogTimer.h

   1 /** @file
   2   Watchdog Timer Architectural Protocol as defined in PI Specification VOLUME 2 DXE
   3
   4   Used to provide system watchdog timer services
   5
   6   Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
   7   SPDX-License-Identifier: BSD-2-Clause-Patent
   8 **/
   9
  10 #ifndef __ARCH_PROTOCOL_WATCHDOG_TIMER_H__
  11 #define __ARCH_PROTOCOL_WATCHDOG_TIMER_H__
  12
  13 ///
  14 /// Global ID for the Watchdog Timer Architectural Protocol
  15 ///
  16 #define EFI_WATCHDOG_TIMER_ARCH_PROTOCOL_GUID \
  17   { 0x665E3FF5, 0x46CC, 0x11d4, {0x9A, 0x38, 0x00, 0x90, 0x27, 0x3F, 0xC1, 0x4D } }
  18
  19 ///
  20 /// Declare forward reference for the Timer Architectural Protocol
  21 ///
  22 typedef struct _EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  EFI_WATCHDOG_TIMER_ARCH_PROTOCOL;
  23
  24 /**
  25   A function of this type is called when the watchdog timer fires if a
  26   handler has been registered.
  27
  28   @param  Time             The time in 100 ns units that has passed since the watchdog
  29                            timer was armed. For the notify function to be called, this
  30                            must be greater than TimerPeriod.
  31
  32   @return None.
  33
  34 **/
  35 typedef
  36 VOID
  37 (EFIAPI *EFI_WATCHDOG_TIMER_NOTIFY)(
  38   IN UINT64  Time
  39   );
  40
  41 /**
  42   This function registers a handler that is to be invoked when the watchdog
  43   timer fires.  By default, the EFI_WATCHDOG_TIMER protocol will call the
  44   Runtime Service ResetSystem() when the watchdog timer fires.  If a
  45   NotifyFunction is registered, then the NotifyFunction will be called before
  46   the Runtime Service ResetSystem() is called.  If NotifyFunction is NULL, then
  47   the watchdog handler is unregistered.  If a watchdog handler is registered,
  48   then EFI_SUCCESS is returned.  If an attempt is made to register a handler
  49   when a handler is already registered, then EFI_ALREADY_STARTED is returned.
  50   If an attempt is made to uninstall a handler when a handler is not installed,
  51   then return EFI_INVALID_PARAMETER.
  52
  53   @param  This             The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
  54   @param  NotifyFunction   The function to call when the watchdog timer fires. If this
  55                            is NULL, then the handler will be unregistered.
  56
  57   @retval EFI_SUCCESS           The watchdog timer handler was registered or
  58                                 unregistered.
  59   @retval EFI_ALREADY_STARTED   NotifyFunction is not NULL, and a handler is already
  60                                 registered.
  61   @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not
  62                                 previously registered.
  63
  64 **/
  65 typedef
  66 EFI_STATUS
  67 (EFIAPI *EFI_WATCHDOG_TIMER_REGISTER_HANDLER)(
  68   IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
  69   IN EFI_WATCHDOG_TIMER_NOTIFY         NotifyFunction
  70   );
  71
  72 /**
  73   This function sets the amount of time to wait before firing the watchdog
  74   timer to TimerPeriod 100 nS units.  If TimerPeriod is 0, then the watchdog
  75   timer is disabled.
  76
  77   @param  This             The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
  78   @param  TimerPeriod      The amount of time in 100 nS units to wait before the watchdog
  79                            timer is fired. If TimerPeriod is zero, then the watchdog
  80                            timer is disabled.
  81
  82   @retval EFI_SUCCESS           The watchdog timer has been programmed to fire in Time
  83                                 100 nS units.
  84   @retval EFI_DEVICE_ERROR      A watchdog timer could not be programmed due to a device
  85                                 error.
  86
  87 **/
  88 typedef
  89 EFI_STATUS
  90 (EFIAPI *EFI_WATCHDOG_TIMER_SET_TIMER_PERIOD)(
  91   IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
  92   IN UINT64                            TimerPeriod
  93   );
  94
  95 /**
  96   This function retrieves the amount of time the system will wait before firing
  97   the watchdog timer.  This period is returned in TimerPeriod, and EFI_SUCCESS
  98   is returned.  If TimerPeriod is NULL, then EFI_INVALID_PARAMETER is returned.
  99
 100   @param  This             The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
 101   @param  TimerPeriod      A pointer to the amount of time in 100 nS units that the system
 102                            will wait before the watchdog timer is fired. If TimerPeriod of
 103                            zero is returned, then the watchdog timer is disabled.
 104
 105   @retval EFI_SUCCESS           The amount of time that the system will wait before
 106                                 firing the watchdog timer was returned in TimerPeriod.
 107   @retval EFI_INVALID_PARAMETER TimerPeriod is NULL.
 108
 109 **/
 110 typedef
 111 EFI_STATUS
 112 (EFIAPI *EFI_WATCHDOG_TIMER_GET_TIMER_PERIOD)(
 113   IN  EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  *This,
 114   OUT UINT64                            *TimerPeriod
 115   );
 116
 117
 118 ///
 119 /// This protocol provides the services required to implement the Boot Service
 120 /// SetWatchdogTimer().  It provides a service to set the amount of time to wait
 121 /// before firing the watchdog timer, and it also provides a service to register
 122 /// a handler that is invoked when the watchdog timer fires.  This protocol can
 123 /// implement the watchdog timer by using the event and timer Boot Services, or
 124 /// it can make use of custom hardware.  When the watchdog timer fires, control
 125 /// will be passed to a handler if one has been registered.  If no handler has
 126 /// been registered, or the registered handler returns, then the system will be
 127 /// reset by calling the Runtime Service ResetSystem().
 128 ///
 129 struct _EFI_WATCHDOG_TIMER_ARCH_PROTOCOL {
 130   EFI_WATCHDOG_TIMER_REGISTER_HANDLER  RegisterHandler;
 131   EFI_WATCHDOG_TIMER_SET_TIMER_PERIOD  SetTimerPeriod;
 132   EFI_WATCHDOG_TIMER_GET_TIMER_PERIOD  GetTimerPeriod;
 133 };
 134
 135 extern EFI_GUID gEfiWatchdogTimerArchProtocolGuid;
 136
 137 #endif
 138