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
  53 VOID
  54 EFIAPI
  55 TimerCallback (UINT64 DeltaMs)
  56 {
  57   EFI_TPL           OriginalTPL;
  58   EFI_TIMER_NOTIFY  CallbackFunction;
  59
  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
  79 EFI_STATUS
  80 EFIAPI
  81 EmuTimerDriverRegisterHandler (
  82   IN EFI_TIMER_ARCH_PROTOCOL           *This,
  83   IN EFI_TIMER_NOTIFY                  NotifyFunction
  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   mTimerNotifyFunction = NotifyFunction;
 146
 147   return EFI_SUCCESS;
 148 }
 149
 150 EFI_STATUS
 151 EFIAPI
 152 EmuTimerDriverSetTimerPeriod (
 153   IN EFI_TIMER_ARCH_PROTOCOL  *This,
 154   IN UINT64                   TimerPeriod
 155   )
 156 /*++
 157
 158 Routine Description:
 159
 160   This function adjusts the period of timer interrupts to the value specified
 161   by TimerPeriod.  If the timer period is updated, then the selected timer
 162   period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
 163   the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
 164   If an error occurs while attempting to update the timer period, then the
 165   timer hardware will be put back in its state prior to this call, and
 166   EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
 167   is disabled.  This is not the same as disabling the CPU's interrupts.
 168   Instead, it must either turn off the timer hardware, or it must adjust the
 169   interrupt controller so that a CPU interrupt is not generated when the timer
 170   interrupt fires.
 171
 172 Arguments:
 173
 174   This        - The EFI_TIMER_ARCH_PROTOCOL instance.
 175
 176   TimerPeriod - The rate to program the timer interrupt in 100 nS units.  If
 177                 the timer hardware is not programmable, then EFI_UNSUPPORTED is
 178                 returned.  If the timer is programmable, then the timer period
 179                 will be rounded up to the nearest timer period that is supported
 180                 by the timer hardware.  If TimerPeriod is set to 0, then the
 181                 timer interrupts will be disabled.
 182
 183 Returns:
 184
 185   EFI_SUCCESS      - The timer period was changed.
 186
 187   EFI_UNSUPPORTED  - The platform cannot change the period of the timer interrupt.
 188
 189   EFI_DEVICE_ERROR - The timer period could not be changed due to a device error.
 190
 191 **/
 192 {
 193
 194   //
 195   // If TimerPeriod is 0, then the timer thread should be canceled
 196   // If the TimerPeriod is valid, then create and/or adjust the period of the timer thread
 197   //
 198   if (TimerPeriod == 0
 199       || ((TimerPeriod > TIMER_MINIMUM_VALUE)
 200     && (TimerPeriod < TIMER_MAXIMUM_VALUE))) {
 201     mTimerPeriodMs = DivU64x32 (TimerPeriod + 5000, 10000);
 202
 203     gEmuThunk->SetTimer (mTimerPeriodMs, TimerCallback);
 204   }
 205
 206   return EFI_SUCCESS;
 207 }
 208
 209 EFI_STATUS
 210 EFIAPI
 211 EmuTimerDriverGetTimerPeriod (
 212   IN EFI_TIMER_ARCH_PROTOCOL            *This,
 213   OUT UINT64                            *TimerPeriod
 214   )
 215 /*++
 216
 217 Routine Description:
 218
 219   This function retrieves the period of timer interrupts in 100 ns units,
 220   returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
 221   is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
 222   returned, then the timer is currently disabled.
 223
 224 Arguments:
 225
 226   This        - The EFI_TIMER_ARCH_PROTOCOL instance.
 227
 228   TimerPeriod - A pointer to the timer period to retrieve in 100 ns units.  If
 229                 0 is returned, then the timer is currently disabled.
 230
 231 Returns:
 232
 233   EFI_SUCCESS           - The timer period was returned in TimerPeriod.
 234
 235   EFI_INVALID_PARAMETER - TimerPeriod is NULL.
 236
 237 **/
 238 {
 239   if (TimerPeriod == NULL) {
 240     return EFI_INVALID_PARAMETER;
 241   }
 242
 243   *TimerPeriod = MultU64x32 (mTimerPeriodMs, 10000);
 244
 245   return EFI_SUCCESS;
 246 }
 247
 248 EFI_STATUS
 249 EFIAPI
 250 EmuTimerDriverGenerateSoftInterrupt (
 251   IN EFI_TIMER_ARCH_PROTOCOL  *This
 252   )
 253 /*++
 254
 255 Routine Description:
 256
 257   This function generates a soft timer interrupt. If the platform does not support soft
 258   timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
 259   If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
 260   service, then a soft timer interrupt will be generated. If the timer interrupt is
 261   enabled when this service is called, then the registered handler will be invoked. The
 262   registered handler should not be able to distinguish a hardware-generated timer
 263   interrupt from a software-generated timer interrupt.
 264
 265 Arguments:
 266
 267   This  -  The EFI_TIMER_ARCH_PROTOCOL instance.
 268
 269 Returns:
 270
 271   EFI_SUCCESS       - The soft timer interrupt was generated.
 272
 273   EFI_UNSUPPORTED   - The platform does not support the generation of soft timer interrupts.
 274
 275 **/
 276 {
 277   return EFI_UNSUPPORTED;
 278 }
 279
 280 EFI_STATUS
 281 EFIAPI
 282 EmuTimerDriverInitialize (
 283   IN EFI_HANDLE        ImageHandle,
 284   IN EFI_SYSTEM_TABLE  *SystemTable
 285   )
 286 /*++
 287
 288 Routine Description:
 289
 290   Initialize the Timer Architectural Protocol driver
 291
 292 Arguments:
 293
 294   ImageHandle - ImageHandle of the loaded driver
 295
 296   SystemTable - Pointer to the System Table
 297
 298 Returns:
 299
 300   EFI_SUCCESS           - Timer Architectural Protocol created
 301
 302   EFI_OUT_OF_RESOURCES  - Not enough resources available to initialize driver.
 303
 304   EFI_DEVICE_ERROR      - A device error occured attempting to initialize the driver.
 305
 306 **/
 307 {
 308   EFI_STATUS  Status;
 309   EFI_HANDLE  Handle;
 310
 311   //
 312   // Make sure the Timer Architectural Protocol is not already installed in the system
 313   //
 314   ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);
 315
 316   //
 317   // Get the CPU Architectural Protocol instance
 318   //
 319   Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (void *)&mCpu);
 320   ASSERT_EFI_ERROR (Status);
 321
 322   //
 323   // Start the timer thread at the default timer period
 324   //
 325   Status = mTimer.SetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
 326   if (EFI_ERROR (Status)) {
 327     return Status;
 328   }
 329
 330   //
 331   // Install the Timer Architectural Protocol onto a new handle
 332   //
 333   Handle = NULL;
 334   Status = gBS->InstallProtocolInterface (
 335                   &Handle,
 336                   &gEfiTimerArchProtocolGuid,
 337                   EFI_NATIVE_INTERFACE,
 338                   &mTimer
 339                   );
 340   if (EFI_ERROR (Status)) {
 341     return Status;
 342   }
 343
 344
 345   return EFI_SUCCESS;
 346 }