MdePkg/Include/Protocol/Timer.h

   1 /** @file
   2   Timer Architectural Protocol as defined in PI Specification VOLUME 2 DXE
   3
   4   This code is used to provide the timer tick for the DXE core.
   5
   6   Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
   7   SPDX-License-Identifier: BSD-2-Clause-Patent
   8
   9 **/
  10
  11 #ifndef __ARCH_PROTOCOL_TIMER_H__
  12 #define __ARCH_PROTOCOL_TIMER_H__
  13
  14 ///
  15 /// Global ID for the Timer Architectural Protocol
  16 ///
  17 #define EFI_TIMER_ARCH_PROTOCOL_GUID \
  18   { 0x26baccb3, 0x6f42, 0x11d4, {0xbc, 0xe7, 0x0, 0x80, 0xc7, 0x3c, 0x88, 0x81 } }
  19
  20 ///
  21 /// Declare forward reference for the Timer Architectural Protocol
  22 ///
  23 typedef struct _EFI_TIMER_ARCH_PROTOCOL   EFI_TIMER_ARCH_PROTOCOL;
  24
  25 /**
  26   This function of this type is called when a timer interrupt fires.  This
  27   function executes at TPL_HIGH_LEVEL.  The DXE Core will register a function
  28   of this type to be called for the timer interrupt, so it can know how much
  29   time has passed.  This information is used to signal timer based events.
  30
  31   @param  Time   Time since the last timer interrupt in 100 ns units. This will
  32                  typically be TimerPeriod, but if a timer interrupt is missed, and the
  33                  EFI_TIMER_ARCH_PROTOCOL driver can detect missed interrupts, then Time
  34                  will contain the actual amount of time since the last interrupt.
  35
  36   None.
  37
  38 **/
  39 typedef
  40 VOID
  41 (EFIAPI *EFI_TIMER_NOTIFY)(
  42   IN UINT64  Time
  43   );
  44
  45 /**
  46   This function registers the handler NotifyFunction so it is called every time
  47   the timer interrupt fires.  It also passes the amount of time since the last
  48   handler call to the NotifyFunction.  If NotifyFunction is NULL, then the
  49   handler is unregistered.  If the handler is registered, then EFI_SUCCESS is
  50   returned.  If the CPU does not support registering a timer interrupt handler,
  51   then EFI_UNSUPPORTED is returned.  If an attempt is made to register a handler
  52   when a handler is already registered, then EFI_ALREADY_STARTED is returned.
  53   If an attempt is made to unregister a handler when a handler is not registered,
  54   then EFI_INVALID_PARAMETER is returned.  If an error occurs attempting to
  55   register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
  56   is returned.
  57
  58   @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
  59   @param  NotifyFunction   The function to call when a timer interrupt fires. This
  60                            function executes at TPL_HIGH_LEVEL. The DXE Core will
  61                            register a handler for the timer interrupt, so it can know
  62                            how much time has passed. This information is used to
  63                            signal timer based events. NULL will unregister the handler.
  64
  65   @retval EFI_SUCCESS           The timer handler was registered.
  66   @retval EFI_UNSUPPORTED       The platform does not support timer interrupts.
  67   @retval EFI_ALREADY_STARTED   NotifyFunction is not NULL, and a handler is already
  68                                 registered.
  69   @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not
  70                                 previously registered.
  71   @retval EFI_DEVICE_ERROR      The timer handler could not be registered.
  72
  73 **/
  74 typedef
  75 EFI_STATUS
  76 (EFIAPI *EFI_TIMER_REGISTER_HANDLER)(
  77   IN EFI_TIMER_ARCH_PROTOCOL    *This,
  78   IN EFI_TIMER_NOTIFY           NotifyFunction
  79 );
  80
  81 /**
  82   This function adjusts the period of timer interrupts to the value specified
  83   by TimerPeriod.  If the timer period is updated, then the selected timer
  84   period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
  85   the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
  86   If an error occurs while attempting to update the timer period, then the
  87   timer hardware will be put back in its state prior to this call, and
  88   EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
  89   is disabled.  This is not the same as disabling the CPU's interrupts.
  90   Instead, it must either turn off the timer hardware, or it must adjust the
  91   interrupt controller so that a CPU interrupt is not generated when the timer
  92   interrupt fires.
  93
  94   @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
  95   @param  TimerPeriod      The rate to program the timer interrupt in 100 nS units. If
  96                            the timer hardware is not programmable, then EFI_UNSUPPORTED is
  97                            returned. If the timer is programmable, then the timer period
  98                            will be rounded up to the nearest timer period that is supported
  99                            by the timer hardware. If TimerPeriod is set to 0, then the
 100                            timer interrupts will be disabled.
 101
 102   @retval EFI_SUCCESS           The timer period was changed.
 103   @retval EFI_UNSUPPORTED       The platform cannot change the period of the timer interrupt.
 104   @retval EFI_DEVICE_ERROR      The timer period could not be changed due to a device error.
 105
 106 **/
 107 typedef
 108 EFI_STATUS
 109 (EFIAPI *EFI_TIMER_SET_TIMER_PERIOD)(
 110   IN EFI_TIMER_ARCH_PROTOCOL    *This,
 111   IN UINT64                     TimerPeriod
 112   );
 113
 114 /**
 115   This function retrieves the period of timer interrupts in 100 ns units,
 116   returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
 117   is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
 118   returned, then the timer is currently disabled.
 119
 120   @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
 121   @param  TimerPeriod      A pointer to the timer period to retrieve in 100 ns units. If
 122                            0 is returned, then the timer is currently disabled.
 123
 124   @retval EFI_SUCCESS           The timer period was returned in TimerPeriod.
 125   @retval EFI_INVALID_PARAMETER TimerPeriod is NULL.
 126
 127 **/
 128 typedef
 129 EFI_STATUS
 130 (EFIAPI *EFI_TIMER_GET_TIMER_PERIOD)(
 131   IN EFI_TIMER_ARCH_PROTOCOL      *This,
 132   OUT UINT64                      *TimerPeriod
 133   );
 134
 135 /**
 136   This function generates a soft timer interrupt. If the platform does not support soft
 137   timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
 138   If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
 139   service, then a soft timer interrupt will be generated. If the timer interrupt is
 140   enabled when this service is called, then the registered handler will be invoked. The
 141   registered handler should not be able to distinguish a hardware-generated timer
 142   interrupt from a software-generated timer interrupt.
 143
 144   @param  This                  The EFI_TIMER_ARCH_PROTOCOL instance.
 145
 146   @retval EFI_SUCCESS           The soft timer interrupt was generated.
 147   @retval EFI_UNSUPPORTED       The platform does not support the generation of soft timer interrupts.
 148
 149 **/
 150 typedef
 151 EFI_STATUS
 152 (EFIAPI *EFI_TIMER_GENERATE_SOFT_INTERRUPT)(
 153   IN EFI_TIMER_ARCH_PROTOCOL    *This
 154   );
 155
 156
 157 ///
 158 /// This protocol provides the services to initialize a periodic timer
 159 /// interrupt, and to register a handler that is called each time the timer
 160 /// interrupt fires.  It may also provide a service to adjust the rate of the
 161 /// periodic timer interrupt.  When a timer interrupt occurs, the handler is
 162 /// passed the amount of time that has passed since the previous timer
 163 /// interrupt.
 164 ///
 165 struct _EFI_TIMER_ARCH_PROTOCOL {
 166   EFI_TIMER_REGISTER_HANDLER          RegisterHandler;
 167   EFI_TIMER_SET_TIMER_PERIOD          SetTimerPeriod;
 168   EFI_TIMER_GET_TIMER_PERIOD          GetTimerPeriod;
 169   EFI_TIMER_GENERATE_SOFT_INTERRUPT   GenerateSoftInterrupt;
 170 };
 171
 172 extern EFI_GUID gEfiTimerArchProtocolGuid;
 173
 174 #endif