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 This program and the accompanying materials
  11 are licensed and made available under the terms and conditions of the BSD License
  12 which accompanies this distribution.  The full text of the license may be found at
  13 http://opensource.org/licenses/bsd-license.php
  14
  15 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  16 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  17
  18
  19 **/
  20
  21 #include "PiDxe.h"
  22 #include <Protocol/Timer.h>
  23 #include <Protocol/Cpu.h>
  24 #include "Timer.h"
  25 #include <Library/BaseLib.h>
  26 #include <Library/DebugLib.h>
  27 #include <Library/UefiLib.h>
  28 #include <Library/UefiDriverEntryPoint.h>
  29 #include <Library/MemoryAllocationLib.h>
  30 #include <Library/UefiBootServicesTableLib.h>
  31 #include <Library/EmuThunkLib.h>
  32
  33 //
  34 // Pointer to the CPU Architectural Protocol instance
  35 //
  36 EFI_CPU_ARCH_PROTOCOL   *mCpu;
  37
  38 //
  39 // The Timer Architectural Protocol that this driver produces
  40 //
  41 EFI_TIMER_ARCH_PROTOCOL mTimer = {
  42   EmuTimerDriverRegisterHandler,
  43   EmuTimerDriverSetTimerPeriod,
  44   EmuTimerDriverGetTimerPeriod,
  45   EmuTimerDriverGenerateSoftInterrupt
  46 };
  47
  48 //
  49 // The notification function to call on every timer interrupt
  50 //
  51 EFI_TIMER_NOTIFY        mTimerNotifyFunction = NULL;
  52
  53 //
  54 // The current period of the timer interrupt
  55 //
  56 UINT64                  mTimerPeriodMs;
  57
  58
  59 VOID
  60 EFIAPI
  61 TimerCallback (UINT64 DeltaMs)
  62 {
  63   EFI_TPL           OriginalTPL;
  64   EFI_TIMER_NOTIFY  CallbackFunction;
  65
  66
  67   OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
  68
  69   if (OriginalTPL < TPL_HIGH_LEVEL) {
  70     CallbackFunction = mTimerNotifyFunction;
  71
  72     //
  73     // Only invoke the callback function if a Non-NULL handler has been
  74     // registered. Assume all other handlers are legal.
  75     //
  76     if (CallbackFunction != NULL) {
  77       CallbackFunction (MultU64x32 (DeltaMs, 10000));
  78     }
  79   }
  80
  81   gBS->RestoreTPL (OriginalTPL);
  82
  83 }
  84
  85 EFI_STATUS
  86 EFIAPI
  87 EmuTimerDriverRegisterHandler (
  88   IN EFI_TIMER_ARCH_PROTOCOL           *This,
  89   IN EFI_TIMER_NOTIFY                  NotifyFunction
  90   )
  91 /*++
  92
  93 Routine Description:
  94
  95   This function registers the handler NotifyFunction so it is called every time
  96   the timer interrupt fires.  It also passes the amount of time since the last
  97   handler call to the NotifyFunction.  If NotifyFunction is NULL, then the
  98   handler is unregistered.  If the handler is registered, then EFI_SUCCESS is
  99   returned.  If the CPU does not support registering a timer interrupt handler,
 100   then EFI_UNSUPPORTED is returned.  If an attempt is made to register a handler
 101   when a handler is already registered, then EFI_ALREADY_STARTED is returned.
 102   If an attempt is made to unregister a handler when a handler is not registered,
 103   then EFI_INVALID_PARAMETER is returned.  If an error occurs attempting to
 104   register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
 105   is returned.
 106
 107 Arguments:
 108
 109   This           - The EFI_TIMER_ARCH_PROTOCOL instance.
 110
 111   NotifyFunction - The function to call when a timer interrupt fires.  This
 112                    function executes at TPL_HIGH_LEVEL.  The DXE Core will
 113                    register a handler for the timer interrupt, so it can know
 114                    how much time has passed.  This information is used to
 115                    signal timer based events.  NULL will unregister the handler.
 116
 117 Returns:
 118
 119   EFI_SUCCESS           - The timer handler was registered.
 120
 121   EFI_UNSUPPORTED       - The platform does not support timer interrupts.
 122
 123   EFI_ALREADY_STARTED   - NotifyFunction is not NULL, and a handler is already
 124                           registered.
 125
 126   EFI_INVALID_PARAMETER - NotifyFunction is NULL, and a handler was not
 127                           previously registered.
 128
 129   EFI_DEVICE_ERROR      - The timer handler could not be registered.
 130
 131 **/
 132 {
 133   //
 134   // Check for invalid parameters
 135   //
 136   if (NotifyFunction == NULL && mTimerNotifyFunction == NULL) {
 137     return EFI_INVALID_PARAMETER;
 138   }
 139
 140   if (NotifyFunction != NULL && mTimerNotifyFunction != NULL) {
 141     return EFI_ALREADY_STARTED;
 142   }
 143
 144   if (NotifyFunction == NULL) {
 145     /* Disable timer.  */
 146     gEmuThunk->SetTimer (0, TimerCallback);
 147   } else if (mTimerNotifyFunction == NULL) {
 148     /* Enable Timer.  */
 149     gEmuThunk->SetTimer (mTimerPeriodMs, TimerCallback);
 150   }
 151   mTimerNotifyFunction = NotifyFunction;
 152
 153   return EFI_SUCCESS;
 154 }
 155
 156 EFI_STATUS
 157 EFIAPI
 158 EmuTimerDriverSetTimerPeriod (
 159   IN EFI_TIMER_ARCH_PROTOCOL  *This,
 160   IN UINT64                   TimerPeriod
 161   )
 162 /*++
 163
 164 Routine Description:
 165
 166   This function adjusts the period of timer interrupts to the value specified
 167   by TimerPeriod.  If the timer period is updated, then the selected timer
 168   period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
 169   the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
 170   If an error occurs while attempting to update the timer period, then the
 171   timer hardware will be put back in its state prior to this call, and
 172   EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
 173   is disabled.  This is not the same as disabling the CPU's interrupts.
 174   Instead, it must either turn off the timer hardware, or it must adjust the
 175   interrupt controller so that a CPU interrupt is not generated when the timer
 176   interrupt fires.
 177
 178 Arguments:
 179
 180   This        - The EFI_TIMER_ARCH_PROTOCOL instance.
 181
 182   TimerPeriod - The rate to program the timer interrupt in 100 nS units.  If
 183                 the timer hardware is not programmable, then EFI_UNSUPPORTED is
 184                 returned.  If the timer is programmable, then the timer period
 185                 will be rounded up to the nearest timer period that is supported
 186                 by the timer hardware.  If TimerPeriod is set to 0, then the
 187                 timer interrupts will be disabled.
 188
 189 Returns:
 190
 191   EFI_SUCCESS      - The timer period was changed.
 192
 193   EFI_UNSUPPORTED  - The platform cannot change the period of the timer interrupt.
 194
 195   EFI_DEVICE_ERROR - The timer period could not be changed due to a device error.
 196
 197 **/
 198 {
 199
 200   //
 201   // If TimerPeriod is 0, then the timer thread should be canceled
 202   // If the TimerPeriod is valid, then create and/or adjust the period of the timer thread
 203   //
 204   if (TimerPeriod == 0
 205       || ((TimerPeriod > TIMER_MINIMUM_VALUE)
 206     && (TimerPeriod < TIMER_MAXIMUM_VALUE))) {
 207     mTimerPeriodMs = DivU64x32 (TimerPeriod + 5000, 10000);
 208
 209     gEmuThunk->SetTimer (mTimerPeriodMs, TimerCallback);
 210   }
 211
 212   return EFI_SUCCESS;
 213 }
 214
 215 EFI_STATUS
 216 EFIAPI
 217 EmuTimerDriverGetTimerPeriod (
 218   IN EFI_TIMER_ARCH_PROTOCOL            *This,
 219   OUT UINT64                            *TimerPeriod
 220   )
 221 /*++
 222
 223 Routine Description:
 224
 225   This function retrieves the period of timer interrupts in 100 ns units,
 226   returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
 227   is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
 228   returned, then the timer is currently disabled.
 229
 230 Arguments:
 231
 232   This        - The EFI_TIMER_ARCH_PROTOCOL instance.
 233
 234   TimerPeriod - A pointer to the timer period to retrieve in 100 ns units.  If
 235                 0 is returned, then the timer is currently disabled.
 236
 237 Returns:
 238
 239   EFI_SUCCESS           - The timer period was returned in TimerPeriod.
 240
 241   EFI_INVALID_PARAMETER - TimerPeriod is NULL.
 242
 243 **/
 244 {
 245   if (TimerPeriod == NULL) {
 246     return EFI_INVALID_PARAMETER;
 247   }
 248
 249   *TimerPeriod = MultU64x32 (mTimerPeriodMs, 10000);
 250
 251   return EFI_SUCCESS;
 252 }
 253
 254 EFI_STATUS
 255 EFIAPI
 256 EmuTimerDriverGenerateSoftInterrupt (
 257   IN EFI_TIMER_ARCH_PROTOCOL  *This
 258   )
 259 /*++
 260
 261 Routine Description:
 262
 263   This function generates a soft timer interrupt. If the platform does not support soft
 264   timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
 265   If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
 266   service, then a soft timer interrupt will be generated. If the timer interrupt is
 267   enabled when this service is called, then the registered handler will be invoked. The
 268   registered handler should not be able to distinguish a hardware-generated timer
 269   interrupt from a software-generated timer interrupt.
 270
 271 Arguments:
 272
 273   This  -  The EFI_TIMER_ARCH_PROTOCOL instance.
 274
 275 Returns:
 276
 277   EFI_SUCCESS       - The soft timer interrupt was generated.
 278
 279   EFI_UNSUPPORTED   - The platform does not support the generation of soft timer interrupts.
 280
 281 **/
 282 {
 283   return EFI_UNSUPPORTED;
 284 }
 285
 286 EFI_STATUS
 287 EFIAPI
 288 EmuTimerDriverInitialize (
 289   IN EFI_HANDLE        ImageHandle,
 290   IN EFI_SYSTEM_TABLE  *SystemTable
 291   )
 292 /*++
 293
 294 Routine Description:
 295
 296   Initialize the Timer Architectural Protocol driver
 297
 298 Arguments:
 299
 300   ImageHandle - ImageHandle of the loaded driver
 301
 302   SystemTable - Pointer to the System Table
 303
 304 Returns:
 305
 306   EFI_SUCCESS           - Timer Architectural Protocol created
 307
 308   EFI_OUT_OF_RESOURCES  - Not enough resources available to initialize driver.
 309
 310   EFI_DEVICE_ERROR      - A device error occured attempting to initialize the driver.
 311
 312 **/
 313 {
 314   EFI_STATUS  Status;
 315   EFI_HANDLE  Handle;
 316
 317   //
 318   // Make sure the Timer Architectural Protocol is not already installed in the system
 319   //
 320   ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);
 321
 322   //
 323   // Get the CPU Architectural Protocol instance
 324   //
 325   Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (void *)&mCpu);
 326   ASSERT_EFI_ERROR (Status);
 327
 328   //
 329   // Start the timer thread at the default timer period
 330   //
 331   Status = mTimer.SetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
 332   if (EFI_ERROR (Status)) {
 333     return Status;
 334   }
 335
 336   //
 337   // Install the Timer Architectural Protocol onto a new handle
 338   //
 339   Handle = NULL;
 340   Status = gBS->InstallProtocolInterface (
 341                   &Handle,
 342                   &gEfiTimerArchProtocolGuid,
 343                   EFI_NATIVE_INTERFACE,
 344                   &mTimer
 345                   );
 346   if (EFI_ERROR (Status)) {
 347     return Status;
 348   }
 349
 350
 351   return EFI_SUCCESS;
 352 }