PcAtChipsetPkg/8254TimerDxe/Timer.h

   1 /*++
   2
   3 Copyright (c) 2005 - 2006, Intel Corporation
   4 All rights reserved. This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12
  13 Module Name:
  14
  15  Timer.h
  16
  17 Abstract:
  18
  19   Private data structures
  20
  21 --*/
  22
  23 #ifndef _TIMER_H_
  24 #define _TIMER_H_
  25
  26 #include <PiDxe.h>
  27
  28 #include <Protocol/Cpu.h>
  29 #include <Protocol/Legacy8259.h>
  30 #include <Protocol/Timer.h>
  31
  32 #include <Library/UefiBootServicesTableLib.h>
  33 #include <Library/BaseLib.h>
  34 #include <Library/DebugLib.h>
  35 #include <Library/IoLib.h>
  36
  37 //
  38 // The PCAT 8253/8254 has an input clock at 1.193182 MHz and Timer 0 is
  39 // initialized as a 16 bit free running counter that generates an interrupt(IRQ0)
  40 // each time the counter rolls over.
  41 //
  42 //   65536 counts
  43 // ---------------- * 1,000,000 uS/S = 54925.4 uS = 549254 * 100 ns
  44 //   1,193,182 Hz
  45 //
  46 // The default timer tick duration is set to 10 ms = 100000 100 ns units
  47 //
  48 #define DEFAULT_TIMER_TICK_DURATION 100000
  49 #define TIMER_CONTROL_PORT          0x43
  50 #define TIMER0_COUNT_PORT           0x40
  51
  52 //
  53 // Function Prototypes
  54 //
  55 EFI_STATUS
  56 EFIAPI
  57 TimerDriverInitialize (
  58   IN EFI_HANDLE        ImageHandle,
  59   IN EFI_SYSTEM_TABLE  *SystemTable
  60   )
  61 /*++
  62
  63 Routine Description:
  64
  65   Initialize the Timer Architectural Protocol driver
  66
  67 Arguments:
  68
  69   ImageHandle - ImageHandle of the loaded driver
  70
  71   SystemTable - Pointer to the System Table
  72
  73 Returns:
  74
  75   EFI_SUCCESS           - Timer Architectural Protocol created
  76
  77   EFI_OUT_OF_RESOURCES  - Not enough resources available to initialize driver.
  78
  79   EFI_DEVICE_ERROR      - A device error occured attempting to initialize the driver.
  80
  81 --*/
  82 ;
  83
  84 EFI_STATUS
  85 EFIAPI
  86 TimerDriverRegisterHandler (
  87   IN EFI_TIMER_ARCH_PROTOCOL  *This,
  88   IN EFI_TIMER_NOTIFY         NotifyFunction
  89   )
  90 /*++
  91
  92 Routine Description:
  93
  94   This function registers the handler NotifyFunction so it is called every time
  95   the timer interrupt fires.  It also passes the amount of time since the last
  96   handler call to the NotifyFunction.  If NotifyFunction is NULL, then the
  97   handler is unregistered.  If the handler is registered, then EFI_SUCCESS is
  98   returned.  If the CPU does not support registering a timer interrupt handler,
  99   then EFI_UNSUPPORTED is returned.  If an attempt is made to register a handler
 100   when a handler is already registered, then EFI_ALREADY_STARTED is returned.
 101   If an attempt is made to unregister a handler when a handler is not registered,
 102   then EFI_INVALID_PARAMETER is returned.  If an error occurs attempting to
 103   register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
 104   is returned.
 105
 106 Arguments:
 107
 108   This           - The EFI_TIMER_ARCH_PROTOCOL instance.
 109
 110   NotifyFunction - The function to call when a timer interrupt fires.  This
 111                    function executes at TPL_HIGH_LEVEL.  The DXE Core will
 112                    register a handler for the timer interrupt, so it can know
 113                    how much time has passed.  This information is used to
 114                    signal timer based events.  NULL will unregister the handler.
 115
 116 Returns:
 117
 118   EFI_SUCCESS           - The timer handler was registered.
 119
 120   EFI_UNSUPPORTED       - The platform does not support timer interrupts.
 121
 122   EFI_ALREADY_STARTED   - NotifyFunction is not NULL, and a handler is already
 123                           registered.
 124
 125   EFI_INVALID_PARAMETER - NotifyFunction is NULL, and a handler was not
 126                           previously registered.
 127
 128   EFI_DEVICE_ERROR      - The timer handler could not be registered.
 129
 130 --*/
 131 ;
 132
 133 EFI_STATUS
 134 EFIAPI
 135 TimerDriverSetTimerPeriod (
 136   IN EFI_TIMER_ARCH_PROTOCOL  *This,
 137   IN UINT64                   TimerPeriod
 138   )
 139 /*++
 140
 141 Routine Description:
 142
 143   This function adjusts the period of timer interrupts to the value specified
 144   by TimerPeriod.  If the timer period is updated, then the selected timer
 145   period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
 146   the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
 147   If an error occurs while attempting to update the timer period, then the
 148   timer hardware will be put back in its state prior to this call, and
 149   EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
 150   is disabled.  This is not the same as disabling the CPU's interrupts.
 151   Instead, it must either turn off the timer hardware, or it must adjust the
 152   interrupt controller so that a CPU interrupt is not generated when the timer
 153   interrupt fires.
 154
 155 Arguments:
 156
 157   This        - The EFI_TIMER_ARCH_PROTOCOL instance.
 158
 159   TimerPeriod - The rate to program the timer interrupt in 100 nS units.  If
 160                 the timer hardware is not programmable, then EFI_UNSUPPORTED is
 161                 returned.  If the timer is programmable, then the timer period
 162                 will be rounded up to the nearest timer period that is supported
 163                 by the timer hardware.  If TimerPeriod is set to 0, then the
 164                 timer interrupts will be disabled.
 165
 166 Returns:
 167
 168   EFI_SUCCESS      - The timer period was changed.
 169
 170   EFI_UNSUPPORTED  - The platform cannot change the period of the timer interrupt.
 171
 172   EFI_DEVICE_ERROR - The timer period could not be changed due to a device error.
 173
 174 --*/
 175 ;
 176
 177 EFI_STATUS
 178 EFIAPI
 179 TimerDriverGetTimerPeriod (
 180   IN EFI_TIMER_ARCH_PROTOCOL   *This,
 181   OUT UINT64                   *TimerPeriod
 182   )
 183 /*++
 184
 185 Routine Description:
 186
 187   This function retrieves the period of timer interrupts in 100 ns units,
 188   returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
 189   is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
 190   returned, then the timer is currently disabled.
 191
 192 Arguments:
 193
 194   This        - The EFI_TIMER_ARCH_PROTOCOL instance.
 195
 196   TimerPeriod - A pointer to the timer period to retrieve in 100 ns units.  If
 197                 0 is returned, then the timer is currently disabled.
 198
 199 Returns:
 200
 201   EFI_SUCCESS           - The timer period was returned in TimerPeriod.
 202
 203   EFI_INVALID_PARAMETER - TimerPeriod is NULL.
 204
 205 --*/
 206 ;
 207
 208 EFI_STATUS
 209 EFIAPI
 210 TimerDriverGenerateSoftInterrupt (
 211   IN EFI_TIMER_ARCH_PROTOCOL  *This
 212   )
 213 /*++
 214
 215 Routine Description:
 216
 217   This function generates a soft timer interrupt. If the platform does not support soft
 218   timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
 219   If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
 220   service, then a soft timer interrupt will be generated. If the timer interrupt is
 221   enabled when this service is called, then the registered handler will be invoked. The
 222   registered handler should not be able to distinguish a hardware-generated timer
 223   interrupt from a software-generated timer interrupt.
 224
 225 Arguments:
 226
 227   This  -  The EFI_TIMER_ARCH_PROTOCOL instance.
 228
 229 Returns:
 230
 231   EFI_SUCCESS       - The soft timer interrupt was generated.
 232
 233   EFI_UNSUPPORTEDT  - The platform does not support the generation of soft timer interrupts.
 234
 235 --*/
 236 ;
 237
 238 #endif