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 - 2008, Intel Corporation. All rights reserved.<BR>
   7   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 **/
  16
  17 #ifndef __ARCH_PROTOCOL_TIMER_H__
  18 #define __ARCH_PROTOCOL_TIMER_H__
  19
  20 ///
  21 /// Global ID for the Timer Architectural Protocol
  22 ///
  23 #define EFI_TIMER_ARCH_PROTOCOL_GUID \
  24   { 0x26baccb3, 0x6f42, 0x11d4, {0xbc, 0xe7, 0x0, 0x80, 0xc7, 0x3c, 0x88, 0x81 } }
  25
  26 ///
  27 /// Declare forward reference for the Timer Architectural Protocol
  28 ///
  29 typedef struct _EFI_TIMER_ARCH_PROTOCOL   EFI_TIMER_ARCH_PROTOCOL;
  30
  31 /**
  32   This function of this type is called when a timer interrupt fires.  This
  33   function executes at TPL_HIGH_LEVEL.  The DXE Core will register a funtion
  34   of this type to be called for the timer interrupt, so it can know how much
  35   time has passed.  This information is used to signal timer based events.
  36
  37   @param  Time   Time since the last timer interrupt in 100 ns units. This will
  38                  typically be TimerPeriod, but if a timer interrupt is missed, and the
  39                  EFI_TIMER_ARCH_PROTOCOL driver can detect missed interrupts, then Time
  40                  will contain the actual amount of time since the last interrupt.
  41
  42   None.
  43
  44 **/
  45 typedef
  46 VOID
  47 (EFIAPI *EFI_TIMER_NOTIFY)(
  48   IN UINT64  Time
  49   );
  50
  51 /**
  52   This function registers the handler NotifyFunction so it is called every time
  53   the timer interrupt fires.  It also passes the amount of time since the last
  54   handler call to the NotifyFunction.  If NotifyFunction is NULL, then the
  55   handler is unregistered.  If the handler is registered, then EFI_SUCCESS is
  56   returned.  If the CPU does not support registering a timer interrupt handler,
  57   then EFI_UNSUPPORTED is returned.  If an attempt is made to register a handler
  58   when a handler is already registered, then EFI_ALREADY_STARTED is returned.
  59   If an attempt is made to unregister a handler when a handler is not registered,
  60   then EFI_INVALID_PARAMETER is returned.  If an error occurs attempting to
  61   register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
  62   is returned.
  63
  64   @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
  65   @param  NotifyFunction   The function to call when a timer interrupt fires. This
  66                            function executes at TPL_HIGH_LEVEL. The DXE Core will
  67                            register a handler for the timer interrupt, so it can know
  68                            how much time has passed. This information is used to
  69                            signal timer based events. NULL will unregister the handler.
  70
  71   @retval EFI_SUCCESS           The timer handler was registered.
  72   @retval EFI_UNSUPPORTED       The platform does not support timer interrupts.
  73   @retval EFI_ALREADY_STARTED   NotifyFunction is not NULL, and a handler is already
  74                                 registered.
  75   @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not
  76                                 previously registered.
  77   @retval EFI_DEVICE_ERROR      The timer handler could not be registered.
  78
  79 **/
  80 typedef
  81 EFI_STATUS
  82 (EFIAPI *EFI_TIMER_REGISTER_HANDLER)(
  83   IN EFI_TIMER_ARCH_PROTOCOL    *This,
  84   IN EFI_TIMER_NOTIFY           NotifyFunction
  85 );
  86
  87 /**
  88   This function adjusts the period of timer interrupts to the value specified
  89   by TimerPeriod.  If the timer period is updated, then the selected timer
  90   period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
  91   the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
  92   If an error occurs while attempting to update the timer period, then the
  93   timer hardware will be put back in its state prior to this call, and
  94   EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
  95   is disabled.  This is not the same as disabling the CPU's interrupts.
  96   Instead, it must either turn off the timer hardware, or it must adjust the
  97   interrupt controller so that a CPU interrupt is not generated when the timer
  98   interrupt fires.
  99
 100   @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
 101   @param  TimerPeriod      The rate to program the timer interrupt in 100 nS units. If
 102                            the timer hardware is not programmable, then EFI_UNSUPPORTED is
 103                            returned. If the timer is programmable, then the timer period
 104                            will be rounded up to the nearest timer period that is supported
 105                            by the timer hardware. If TimerPeriod is set to 0, then the
 106                            timer interrupts will be disabled.
 107
 108   @retval EFI_SUCCESS           The timer period was changed.
 109   @retval EFI_UNSUPPORTED       The platform cannot change the period of the timer interrupt.
 110   @retval EFI_DEVICE_ERROR      The timer period could not be changed due to a device error.
 111
 112 **/
 113 typedef
 114 EFI_STATUS
 115 (EFIAPI *EFI_TIMER_SET_TIMER_PERIOD)(
 116   IN EFI_TIMER_ARCH_PROTOCOL    *This,
 117   IN UINT64                     TimerPeriod
 118   );
 119
 120 /**
 121   This function retrieves the period of timer interrupts in 100 ns units,
 122   returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
 123   is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
 124   returned, then the timer is currently disabled.
 125
 126   @param  This             The EFI_TIMER_ARCH_PROTOCOL instance.
 127   @param  TimerPeriod      A pointer to the timer period to retrieve in 100 ns units. If
 128                            0 is returned, then the timer is currently disabled.
 129
 130   @retval EFI_SUCCESS           The timer period was returned in TimerPeriod.
 131   @retval EFI_INVALID_PARAMETER TimerPeriod is NULL.
 132
 133 **/
 134 typedef
 135 EFI_STATUS
 136 (EFIAPI *EFI_TIMER_GET_TIMER_PERIOD)(
 137   IN EFI_TIMER_ARCH_PROTOCOL      *This,
 138   OUT UINT64                      *TimerPeriod
 139   );
 140
 141 /**
 142   This function generates a soft timer interrupt. If the platform does not support soft
 143   timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
 144   If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
 145   service, then a soft timer interrupt will be generated. If the timer interrupt is
 146   enabled when this service is called, then the registered handler will be invoked. The
 147   registered handler should not be able to distinguish a hardware-generated timer
 148   interrupt from a software-generated timer interrupt.
 149
 150   @param  This                  The EFI_TIMER_ARCH_PROTOCOL instance.
 151
 152   @retval EFI_SUCCESS           The soft timer interrupt was generated.
 153   @retval EFI_UNSUPPORTEDT      The platform does not support the generation of soft timer interrupts.
 154
 155 **/
 156 typedef
 157 EFI_STATUS
 158 (EFIAPI *EFI_TIMER_GENERATE_SOFT_INTERRUPT)(
 159   IN EFI_TIMER_ARCH_PROTOCOL    *This
 160   );
 161
 162
 163 ///
 164 /// This protocol provides the services to initialize a periodic timer
 165 /// interrupt, and to register a handler that is called each time the timer
 166 /// interrupt fires.  It may also provide a service to adjust the rate of the
 167 /// periodic timer interrupt.  When a timer interrupt occurs, the handler is
 168 /// passed the amount of time that has passed since the previous timer
 169 /// interrupt.
 170 ///
 171 struct _EFI_TIMER_ARCH_PROTOCOL {
 172   EFI_TIMER_REGISTER_HANDLER          RegisterHandler;
 173   EFI_TIMER_SET_TIMER_PERIOD          SetTimerPeriod;
 174   EFI_TIMER_GET_TIMER_PERIOD          GetTimerPeriod;
 175   EFI_TIMER_GENERATE_SOFT_INTERRUPT   GenerateSoftInterrupt;
 176 };
 177
 178 extern EFI_GUID gEfiTimerArchProtocolGuid;
 179
 180 #endif