MdePkg/Include/Protocol/Timer.h

   1 /** @file
   2   Timer Architectural Protocol as defined in the DXE CIS
   3
   4   This code is used to provide the timer tick for the DXE core.
   5
   6   Copyright (c) 2006, Intel Corporation
   7   All rights reserved. This program and the accompanying materials
   8   are licensed and made available under the terms and conditions of the BSD License
   9   which accompanies this distribution.  The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15   @par Revision Reference:
  16   Version 0.91B.
  17
  18 **/
  19
  20 #ifndef __ARCH_PROTOCOL_TIMER_H__
  21 #define __ARCH_PROTOCOL_TIMER_H__
  22
  23 //
  24 // Global ID for the Timer Architectural Protocol
  25 //
  26 #define EFI_TIMER_ARCH_PROTOCOL_GUID \
  27   { 0x26baccb3, 0x6f42, 0x11d4, {0xbc, 0xe7, 0x0, 0x80, 0xc7, 0x3c, 0x88, 0x81 } }
  28
  29 //
  30 // Declare forward reference for the Timer Architectural Protocol
  31 //
  32 typedef struct _EFI_TIMER_ARCH_PROTOCOL   EFI_TIMER_ARCH_PROTOCOL;
  33
  34 /**
  35   This function of this type is called when a timer interrupt fires.  This
  36   function executes at TPL_HIGH_LEVEL.  The DXE Core will register a funtion
  37   of tyis type to be called for the timer interrupt, so it can know how much
  38   time has passed.  This information is used to signal timer based events.
  39
  40   @param  Time             Time since the last timer interrupt in 100 ns units. This will
  41                            typically be TimerPeriod, but if a timer interrupt is missed, and the
  42                            EFI_TIMER_ARCH_PROTOCOL driver can detect missed interrupts, then Time
  43                            will contain the actual amount of time since the last interrupt.
  44
  45   None.
  46
  47 **/
  48 typedef
  49 VOID
  50 (EFIAPI *EFI_TIMER_NOTIFY) (
  51   IN UINT64  Time
  52   );
  53
  54 /**
  55   This function registers the handler NotifyFunction so it is called every time
  56   the timer interrupt fires.  It also passes the amount of time since the last
  57   handler call to the NotifyFunction.  If NotifyFunction is NULL, then the
  58   handler is unregistered.  If the handler is registered, then EFI_SUCCESS is
  59   returned.  If the CPU does not support registering a timer interrupt handler,
  60   then EFI_UNSUPPORTED is returned.  If an attempt is made to register a handler
  61   when a handler is already registered, then EFI_ALREADY_STARTED is returned.
  62   If an attempt is made to unregister a handler when a handler is not registered,
  63   then EFI_INVALID_PARAMETER is returned.  If an error occurs attempting to
  64   register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
  65   is returned.
  66
  67   @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
  68   @param  NotifyFunction   The function to call when a timer interrupt fires. This
  69                            function executes at TPL_HIGH_LEVEL. The DXE Core will
  70                            register a handler for the timer interrupt, so it can know
  71                            how much time has passed. This information is used to
  72                            signal timer based events. NULL will unregister the handler.
  73
  74   @retval EFI_SUCCESS           The timer handler was registered.
  75   @retval EFI_UNSUPPORTED       The platform does not support timer interrupts.
  76   @retval EFI_ALREADY_STARTED   NotifyFunction is not NULL, and a handler is already
  77                                 registered.
  78   @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not
  79                                 previously registered.
  80   @retval EFI_DEVICE_ERROR      The timer handler could not be registered.
  81
  82 **/
  83 typedef
  84 EFI_STATUS
  85 (EFIAPI *EFI_TIMER_REGISTER_HANDLER) (
  86   IN EFI_TIMER_ARCH_PROTOCOL    *This,
  87   IN EFI_TIMER_NOTIFY           NotifyFunction
  88 );
  89
  90 /**
  91   This function adjusts the period of timer interrupts to the value specified
  92   by TimerPeriod.  If the timer period is updated, then the selected timer
  93   period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
  94   the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
  95   If an error occurs while attempting to update the timer period, then the
  96   timer hardware will be put back in its state prior to this call, and
  97   EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
  98   is disabled.  This is not the same as disabling the CPU's interrupts.
  99   Instead, it must either turn off the timer hardware, or it must adjust the
 100   interrupt controller so that a CPU interrupt is not generated when the timer
 101   interrupt fires.
 102
 103   @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
 104   @param  TimerPeriod      The rate to program the timer interrupt in 100 nS units. If
 105                            the timer hardware is not programmable, then EFI_UNSUPPORTED is
 106                            returned. If the timer is programmable, then the timer period
 107                            will be rounded up to the nearest timer period that is supported
 108                            by the timer hardware. If TimerPeriod is set to 0, then the
 109                            timer interrupts will be disabled.
 110
 111   @retval EFI_SUCCESS           The timer period was changed.
 112   @retval EFI_UNSUPPORTED       The platform cannot change the period of the timer interrupt.
 113   @retval EFI_DEVICE_ERROR      The timer period could not be changed due to a device error.
 114
 115 **/
 116 typedef
 117 EFI_STATUS
 118 (EFIAPI *EFI_TIMER_SET_TIMER_PERIOD) (
 119   IN EFI_TIMER_ARCH_PROTOCOL    *This,
 120   IN UINT64                     TimerPeriod
 121   );
 122
 123 /**
 124   This function retrieves the period of timer interrupts in 100 ns units,
 125   returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
 126   is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
 127   returned, then the timer is currently disabled.
 128
 129   @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
 130   @param  TimerPeriod      A pointer to the timer period to retrieve in 100 ns units. If
 131                            0 is returned, then the timer is currently disabled.
 132
 133   @retval EFI_SUCCESS           The timer period was returned in TimerPeriod.
 134   @retval EFI_INVALID_PARAMETER TimerPeriod is NULL.
 135
 136 **/
 137 typedef
 138 EFI_STATUS
 139 (EFIAPI *EFI_TIMER_GET_TIMER_PERIOD) (
 140   IN EFI_TIMER_ARCH_PROTOCOL      *This,
 141   OUT UINT64                      *TimerPeriod
 142   );
 143
 144 /**
 145   This function generates a soft timer interrupt. If the platform does not support soft
 146   timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
 147   If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
 148   service, then a soft timer interrupt will be generated. If the timer interrupt is
 149   enabled when this service is called, then the registered handler will be invoked. The
 150   registered handler should not be able to distinguish a hardware-generated timer
 151   interrupt from a software-generated timer interrupt.
 152
 153   @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
 154
 155   @retval EFI_SUCCESS           The soft timer interrupt was generated.
 156   @retval EFI_UNSUPPORTEDT      The platform does not support the generation of soft timer interrupts.
 157
 158 **/
 159 typedef
 160 EFI_STATUS
 161 (EFIAPI *EFI_TIMER_GENERATE_SOFT_INTERRUPT) (
 162   IN EFI_TIMER_ARCH_PROTOCOL    *This
 163   );
 164
 165
 166 /**
 167   Interface stucture for the Timer Architectural Protocol.
 168
 169   @par Protocol Description:
 170   This protocol provides the services to initialize a periodic timer
 171   interrupt, and to register a handler that is called each time the timer
 172   interrupt fires.  It may also provide a service to adjust the rate of the
 173   periodic timer interrupt.  When a timer interrupt occurs, the handler is
 174   passed the amount of time that has passed since the previous timer
 175   interrupt.
 176
 177   @param RegisterHandler
 178   Registers a handler that will be called each time the
 179   timer interrupt fires.  TimerPeriod defines the minimum
 180   time between timer interrupts, so TimerPeriod will also
 181   be the minimum time between calls to the registered
 182   handler.
 183
 184   @param SetTimerPeriod
 185   Sets the period of the timer interrupt in 100 nS units.
 186   This function is optional, and may return EFI_UNSUPPORTED.
 187   If this function is supported, then the timer period will
 188   be rounded up to the nearest supported timer period.
 189
 190   @param GetTimerPeriod
 191   Retrieves the period of the timer interrupt in 100 nS units.
 192
 193   @param GenerateSoftInterrupt
 194   Generates a soft timer interrupt that simulates the firing of
 195   the timer interrupt. This service can be used to invoke the
 196   registered handler if the timer interrupt has been masked for
 197   a period of time.
 198
 199 **/
 200 struct _EFI_TIMER_ARCH_PROTOCOL {
 201   EFI_TIMER_REGISTER_HANDLER          RegisterHandler;
 202   EFI_TIMER_SET_TIMER_PERIOD          SetTimerPeriod;
 203   EFI_TIMER_GET_TIMER_PERIOD          GetTimerPeriod;
 204   EFI_TIMER_GENERATE_SOFT_INTERRUPT   GenerateSoftInterrupt;
 205 };
 206
 207 extern EFI_GUID gEfiTimerArchProtocolGuid;
 208
 209 #endif