EmulatorPkg/TimerDxe/Timer.c

   1 /*++ @file
   2   Emu Emulation Timer Architectural Protocol Driver as defined in DXE CIS
   3
   4   This Timer module uses an Emu Thread to simulate the timer-tick driven
   5   timer service.  In the future, the Thread creation should possibly be
   6   abstracted by the CPU architectural protocol
   7
   8 Copyright (c) 2004 - 2016, Intel Corporation. All rights reserved.<BR>
   9 Portions copyright (c) 2010 - 2011, Apple Inc. All rights reserved.
  10 SPDX-License-Identifier: BSD-2-Clause-Patent
  11
  12
  13 **/
  14
  15 #include "PiDxe.h"
  16 #include <Protocol/Timer.h>
  17 #include <Protocol/Cpu.h>
  18 #include "Timer.h"
  19 #include <Library/BaseLib.h>
  20 #include <Library/DebugLib.h>
  21 #include <Library/UefiLib.h>
  22 #include <Library/UefiDriverEntryPoint.h>
  23 #include <Library/MemoryAllocationLib.h>
  24 #include <Library/UefiBootServicesTableLib.h>
  25 #include <Library/EmuThunkLib.h>
  26
  27 //
  28 // Pointer to the CPU Architectural Protocol instance
  29 //
  30 EFI_CPU_ARCH_PROTOCOL  *mCpu;
  31
  32 //
  33 // The Timer Architectural Protocol that this driver produces
  34 //
  35 EFI_TIMER_ARCH_PROTOCOL  mTimer = {
  36   EmuTimerDriverRegisterHandler,
  37   EmuTimerDriverSetTimerPeriod,
  38   EmuTimerDriverGetTimerPeriod,
  39   EmuTimerDriverGenerateSoftInterrupt
  40 };
  41
  42 //
  43 // The notification function to call on every timer interrupt
  44 //
  45 EFI_TIMER_NOTIFY  mTimerNotifyFunction = NULL;
  46
  47 //
  48 // The current period of the timer interrupt
  49 //
  50 UINT64  mTimerPeriodMs;
  51
  52 VOID
  53 EFIAPI
  54 TimerCallback (
  55   UINT64  DeltaMs
  56   )
  57 {
  58   EFI_TPL           OriginalTPL;
  59   EFI_TIMER_NOTIFY  CallbackFunction;
  60
  61   OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
  62
  63   if (OriginalTPL < TPL_HIGH_LEVEL) {
  64     CallbackFunction = mTimerNotifyFunction;
  65
  66     //
  67     // Only invoke the callback function if a Non-NULL handler has been
  68     // registered. Assume all other handlers are legal.
  69     //
  70     if (CallbackFunction != NULL) {
  71       CallbackFunction (MultU64x32 (DeltaMs, 10000));
  72     }
  73   }
  74
  75   gBS->RestoreTPL (OriginalTPL);
  76 }
  77
  78 EFI_STATUS
  79 EFIAPI
  80 EmuTimerDriverRegisterHandler (
  81   IN EFI_TIMER_ARCH_PROTOCOL  *This,
  82   IN EFI_TIMER_NOTIFY         NotifyFunction
  83   )
  84
  85 /*++
  86
  87 Routine Description:
  88
  89   This function registers the handler NotifyFunction so it is called every time
  90   the timer interrupt fires.  It also passes the amount of time since the last
  91   handler call to the NotifyFunction.  If NotifyFunction is NULL, then the
  92   handler is unregistered.  If the handler is registered, then EFI_SUCCESS is
  93   returned.  If the CPU does not support registering a timer interrupt handler,
  94   then EFI_UNSUPPORTED is returned.  If an attempt is made to register a handler
  95   when a handler is already registered, then EFI_ALREADY_STARTED is returned.
  96   If an attempt is made to unregister a handler when a handler is not registered,
  97   then EFI_INVALID_PARAMETER is returned.  If an error occurs attempting to
  98   register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
  99   is returned.
 100
 101 Arguments:
 102
 103   This           - The EFI_TIMER_ARCH_PROTOCOL instance.
 104
 105   NotifyFunction - The function to call when a timer interrupt fires.  This
 106                    function executes at TPL_HIGH_LEVEL.  The DXE Core will
 107                    register a handler for the timer interrupt, so it can know
 108                    how much time has passed.  This information is used to
 109                    signal timer based events.  NULL will unregister the handler.
 110
 111 Returns:
 112
 113   EFI_SUCCESS           - The timer handler was registered.
 114
 115   EFI_UNSUPPORTED       - The platform does not support timer interrupts.
 116
 117   EFI_ALREADY_STARTED   - NotifyFunction is not NULL, and a handler is already
 118                           registered.
 119
 120   EFI_INVALID_PARAMETER - NotifyFunction is NULL, and a handler was not
 121                           previously registered.
 122
 123   EFI_DEVICE_ERROR      - The timer handler could not be registered.
 124
 125 **/
 126 {
 127   //
 128   // Check for invalid parameters
 129   //
 130   if ((NotifyFunction == NULL) && (mTimerNotifyFunction == NULL)) {
 131     return EFI_INVALID_PARAMETER;
 132   }
 133
 134   if ((NotifyFunction != NULL) && (mTimerNotifyFunction != NULL)) {
 135     return EFI_ALREADY_STARTED;
 136   }
 137
 138   if (NotifyFunction == NULL) {
 139     /* Disable timer.  */
 140     gEmuThunk->SetTimer (0, TimerCallback);
 141   } else if (mTimerNotifyFunction == NULL) {
 142     /* Enable Timer.  */
 143     gEmuThunk->SetTimer (mTimerPeriodMs, TimerCallback);
 144   }
 145
 146   mTimerNotifyFunction = NotifyFunction;
 147
 148   return EFI_SUCCESS;
 149 }
 150
 151 EFI_STATUS
 152 EFIAPI
 153 EmuTimerDriverSetTimerPeriod (
 154   IN EFI_TIMER_ARCH_PROTOCOL  *This,
 155   IN UINT64                   TimerPeriod
 156   )
 157
 158 /*++
 159
 160 Routine Description:
 161
 162   This function adjusts the period of timer interrupts to the value specified
 163   by TimerPeriod.  If the timer period is updated, then the selected timer
 164   period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
 165   the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
 166   If an error occurs while attempting to update the timer period, then the
 167   timer hardware will be put back in its state prior to this call, and
 168   EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
 169   is disabled.  This is not the same as disabling the CPU's interrupts.
 170   Instead, it must either turn off the timer hardware, or it must adjust the
 171   interrupt controller so that a CPU interrupt is not generated when the timer
 172   interrupt fires.
 173
 174 Arguments:
 175
 176   This        - The EFI_TIMER_ARCH_PROTOCOL instance.
 177
 178   TimerPeriod - The rate to program the timer interrupt in 100 nS units.  If
 179                 the timer hardware is not programmable, then EFI_UNSUPPORTED is
 180                 returned.  If the timer is programmable, then the timer period
 181                 will be rounded up to the nearest timer period that is supported
 182                 by the timer hardware.  If TimerPeriod is set to 0, then the
 183                 timer interrupts will be disabled.
 184
 185 Returns:
 186
 187   EFI_SUCCESS      - The timer period was changed.
 188
 189   EFI_UNSUPPORTED  - The platform cannot change the period of the timer interrupt.
 190
 191   EFI_DEVICE_ERROR - The timer period could not be changed due to a device error.
 192
 193 **/
 194 {
 195   //
 196   // If TimerPeriod is 0, then the timer thread should be canceled
 197   // If the TimerPeriod is valid, then create and/or adjust the period of the timer thread
 198   //
 199   if (  (TimerPeriod == 0)
 200      || (  (TimerPeriod > TIMER_MINIMUM_VALUE)
 201         && (TimerPeriod < TIMER_MAXIMUM_VALUE)))
 202   {
 203     mTimerPeriodMs = DivU64x32 (TimerPeriod + 5000, 10000);
 204
 205     gEmuThunk->SetTimer (mTimerPeriodMs, TimerCallback);
 206   }
 207
 208   return EFI_SUCCESS;
 209 }
 210
 211 EFI_STATUS
 212 EFIAPI
 213 EmuTimerDriverGetTimerPeriod (
 214   IN EFI_TIMER_ARCH_PROTOCOL  *This,
 215   OUT UINT64                  *TimerPeriod
 216   )
 217
 218 /*++
 219
 220 Routine Description:
 221
 222   This function retrieves the period of timer interrupts in 100 ns units,
 223   returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
 224   is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
 225   returned, then the timer is currently disabled.
 226
 227 Arguments:
 228
 229   This        - The EFI_TIMER_ARCH_PROTOCOL instance.
 230
 231   TimerPeriod - A pointer to the timer period to retrieve in 100 ns units.  If
 232                 0 is returned, then the timer is currently disabled.
 233
 234 Returns:
 235
 236   EFI_SUCCESS           - The timer period was returned in TimerPeriod.
 237
 238   EFI_INVALID_PARAMETER - TimerPeriod is NULL.
 239
 240 **/
 241 {
 242   if (TimerPeriod == NULL) {
 243     return EFI_INVALID_PARAMETER;
 244   }
 245
 246   *TimerPeriod = MultU64x32 (mTimerPeriodMs, 10000);
 247
 248   return EFI_SUCCESS;
 249 }
 250
 251 EFI_STATUS
 252 EFIAPI
 253 EmuTimerDriverGenerateSoftInterrupt (
 254   IN EFI_TIMER_ARCH_PROTOCOL  *This
 255   )
 256
 257 /*++
 258
 259 Routine Description:
 260
 261   This function generates a soft timer interrupt. If the platform does not support soft
 262   timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
 263   If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
 264   service, then a soft timer interrupt will be generated. If the timer interrupt is
 265   enabled when this service is called, then the registered handler will be invoked. The
 266   registered handler should not be able to distinguish a hardware-generated timer
 267   interrupt from a software-generated timer interrupt.
 268
 269 Arguments:
 270
 271   This  -  The EFI_TIMER_ARCH_PROTOCOL instance.
 272
 273 Returns:
 274
 275   EFI_SUCCESS       - The soft timer interrupt was generated.
 276
 277   EFI_UNSUPPORTED   - The platform does not support the generation of soft timer interrupts.
 278
 279 **/
 280 {
 281   return EFI_UNSUPPORTED;
 282 }
 283
 284 EFI_STATUS
 285 EFIAPI
 286 EmuTimerDriverInitialize (
 287   IN EFI_HANDLE        ImageHandle,
 288   IN EFI_SYSTEM_TABLE  *SystemTable
 289   )
 290
 291 /*++
 292
 293 Routine Description:
 294
 295   Initialize the Timer Architectural Protocol driver
 296
 297 Arguments:
 298
 299   ImageHandle - ImageHandle of the loaded driver
 300
 301   SystemTable - Pointer to the System Table
 302
 303 Returns:
 304
 305   EFI_SUCCESS           - Timer Architectural Protocol created
 306
 307   EFI_OUT_OF_RESOURCES  - Not enough resources available to initialize driver.
 308
 309   EFI_DEVICE_ERROR      - A device error occurred attempting to initialize the driver.
 310
 311 **/
 312 {
 313   EFI_STATUS  Status;
 314   EFI_HANDLE  Handle;
 315
 316   //
 317   // Make sure the Timer Architectural Protocol is not already installed in the system
 318   //
 319   ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);
 320
 321   //
 322   // Get the CPU Architectural Protocol instance
 323   //
 324   Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (void *)&mCpu);
 325   ASSERT_EFI_ERROR (Status);
 326
 327   //
 328   // Start the timer thread at the default timer period
 329   //
 330   Status = mTimer.SetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
 331   if (EFI_ERROR (Status)) {
 332     return Status;
 333   }
 334
 335   //
 336   // Install the Timer Architectural Protocol onto a new handle
 337   //
 338   Handle = NULL;
 339   Status = gBS->InstallProtocolInterface (
 340                   &Handle,
 341                   &gEfiTimerArchProtocolGuid,
 342                   EFI_NATIVE_INTERFACE,
 343                   &mTimer
 344                   );
 345   if (EFI_ERROR (Status)) {
 346     return Status;
 347   }
 348
 349   return EFI_SUCCESS;
 350 }