DuetPkg/8254TimerDxe/Timer.c

   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.c
  16
  17 Abstract:
  18
  19   Timer Architectural Protocol as defined in the DXE CIS
  20
  21 --*/
  22
  23 #include "Timer.h"
  24
  25 //
  26 // The handle onto which the Timer Architectural Protocol will be installed
  27 //
  28 EFI_HANDLE                mTimerHandle = NULL;
  29
  30 //
  31 // The Timer Architectural Protocol that this driver produces
  32 //
  33 EFI_TIMER_ARCH_PROTOCOL   mTimer = {
  34   TimerDriverRegisterHandler,
  35   TimerDriverSetTimerPeriod,
  36   TimerDriverGetTimerPeriod,
  37   TimerDriverGenerateSoftInterrupt
  38 };
  39
  40 //
  41 // Pointer to the CPU Architectural Protocol instance
  42 //
  43 EFI_CPU_ARCH_PROTOCOL     *mCpu;
  44
  45 //
  46 // Pointer to the CPU I/O Protocol instance
  47 //
  48 EFI_CPU_IO_PROTOCOL       *mCpuIo;
  49
  50 //
  51 // Pointer to the Legacy 8259 Protocol instance
  52 //
  53 EFI_LEGACY_8259_PROTOCOL  *mLegacy8259;
  54
  55 //
  56 // The notification function to call on every timer interrupt.
  57 // A bug in the compiler prevents us from initializing this here.
  58 //
  59 volatile EFI_TIMER_NOTIFY mTimerNotifyFunction;
  60
  61 //
  62 // The current period of the timer interrupt
  63 //
  64 volatile UINT64           mTimerPeriod = 0;
  65
  66 //
  67 // Worker Functions
  68 //
  69 VOID
  70 SetPitCount (
  71   IN UINT16  Count
  72   )
  73 /*++
  74
  75 Routine Description:
  76
  77   Sets the counter value for Timer #0 in a legacy 8254 timer.
  78
  79 Arguments:
  80
  81   Count - The 16-bit counter value to program into Timer #0 of the legacy 8254 timer.
  82
  83 Returns:
  84
  85   None
  86
  87 --*/
  88 {
  89   UINT8 Data;
  90
  91   Data = 0x36;
  92   mCpuIo->Io.Write (mCpuIo, EfiCpuIoWidthUint8, TIMER_CONTROL_PORT, 1, &Data);
  93   mCpuIo->Io.Write (mCpuIo, EfiCpuIoWidthFifoUint8, TIMER0_COUNT_PORT, 2, &Count);
  94 }
  95
  96 VOID
  97 EFIAPI
  98 TimerInterruptHandler (
  99   IN EFI_EXCEPTION_TYPE   InterruptType,
 100   IN EFI_SYSTEM_CONTEXT   SystemContext
 101   )
 102 /*++
 103
 104 Routine Description:
 105
 106   8254 Timer #0 Interrupt Handler
 107
 108 Arguments:
 109
 110   InterruptType - The type of interrupt that occured
 111
 112   SystemContext - A pointer to the system context when the interrupt occured
 113
 114 Returns:
 115
 116   None
 117
 118 --*/
 119 {
 120   EFI_TPL OriginalTPL;
 121
 122   OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
 123
 124   mLegacy8259->EndOfInterrupt (mLegacy8259, Efi8259Irq0);
 125
 126   if (mTimerNotifyFunction) {
 127     //
 128     // BUGBUG : This does not handle missed timer interrupts
 129     //
 130     mTimerNotifyFunction (mTimerPeriod);
 131   }
 132
 133   gBS->RestoreTPL (OriginalTPL);
 134 }
 135
 136 EFI_STATUS
 137 EFIAPI
 138 TimerDriverRegisterHandler (
 139   IN EFI_TIMER_ARCH_PROTOCOL  *This,
 140   IN EFI_TIMER_NOTIFY         NotifyFunction
 141   )
 142 /*++
 143
 144 Routine Description:
 145
 146   This function registers the handler NotifyFunction so it is called every time
 147   the timer interrupt fires.  It also passes the amount of time since the last
 148   handler call to the NotifyFunction.  If NotifyFunction is NULL, then the
 149   handler is unregistered.  If the handler is registered, then EFI_SUCCESS is
 150   returned.  If the CPU does not support registering a timer interrupt handler,
 151   then EFI_UNSUPPORTED is returned.  If an attempt is made to register a handler
 152   when a handler is already registered, then EFI_ALREADY_STARTED is returned.
 153   If an attempt is made to unregister a handler when a handler is not registered,
 154   then EFI_INVALID_PARAMETER is returned.  If an error occurs attempting to
 155   register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
 156   is returned.
 157
 158 Arguments:
 159
 160   This           - The EFI_TIMER_ARCH_PROTOCOL instance.
 161
 162   NotifyFunction - The function to call when a timer interrupt fires.  This
 163                    function executes at TPL_HIGH_LEVEL.  The DXE Core will
 164                    register a handler for the timer interrupt, so it can know
 165                    how much time has passed.  This information is used to
 166                    signal timer based events.  NULL will unregister the handler.
 167
 168 Returns:
 169
 170   EFI_SUCCESS           - The timer handler was registered.
 171
 172   EFI_UNSUPPORTED       - The platform does not support timer interrupts.
 173
 174   EFI_ALREADY_STARTED   - NotifyFunction is not NULL, and a handler is already
 175                           registered.
 176
 177   EFI_INVALID_PARAMETER - NotifyFunction is NULL, and a handler was not
 178                           previously registered.
 179
 180   EFI_DEVICE_ERROR      - The timer handler could not be registered.
 181
 182 --*/
 183 {
 184   //
 185   // Check for invalid parameters
 186   //
 187   if (NotifyFunction == NULL && mTimerNotifyFunction == NULL) {
 188     return EFI_INVALID_PARAMETER;
 189   }
 190
 191   if (NotifyFunction != NULL && mTimerNotifyFunction != NULL) {
 192     return EFI_ALREADY_STARTED;
 193   }
 194
 195   mTimerNotifyFunction = NotifyFunction;
 196
 197   return EFI_SUCCESS;
 198 }
 199
 200 EFI_STATUS
 201 EFIAPI
 202 TimerDriverSetTimerPeriod (
 203   IN EFI_TIMER_ARCH_PROTOCOL  *This,
 204   IN UINT64                   TimerPeriod
 205   )
 206 /*++
 207
 208 Routine Description:
 209
 210   This function adjusts the period of timer interrupts to the value specified
 211   by TimerPeriod.  If the timer period is updated, then the selected timer
 212   period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned.  If
 213   the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
 214   If an error occurs while attempting to update the timer period, then the
 215   timer hardware will be put back in its state prior to this call, and
 216   EFI_DEVICE_ERROR is returned.  If TimerPeriod is 0, then the timer interrupt
 217   is disabled.  This is not the same as disabling the CPU's interrupts.
 218   Instead, it must either turn off the timer hardware, or it must adjust the
 219   interrupt controller so that a CPU interrupt is not generated when the timer
 220   interrupt fires.
 221
 222 Arguments:
 223
 224   This        - The EFI_TIMER_ARCH_PROTOCOL instance.
 225
 226   TimerPeriod - The rate to program the timer interrupt in 100 nS units.  If
 227                 the timer hardware is not programmable, then EFI_UNSUPPORTED is
 228                 returned.  If the timer is programmable, then the timer period
 229                 will be rounded up to the nearest timer period that is supported
 230                 by the timer hardware.  If TimerPeriod is set to 0, then the
 231                 timer interrupts will be disabled.
 232
 233 Returns:
 234
 235   EFI_SUCCESS      - The timer period was changed.
 236
 237   EFI_UNSUPPORTED  - The platform cannot change the period of the timer interrupt.
 238
 239   EFI_DEVICE_ERROR - The timer period could not be changed due to a device error.
 240
 241 --*/
 242 {
 243   UINT64  TimerCount;
 244
 245   //
 246   //  The basic clock is 1.19318 MHz or 0.119318 ticks per 100 ns.
 247   //  TimerPeriod * 0.119318 = 8254 timer divisor. Using integer arithmetic
 248   //  TimerCount = (TimerPeriod * 119318)/1000000.
 249   //
 250   //  Round up to next highest integer. This guarantees that the timer is
 251   //  equal to or slightly longer than the requested time.
 252   //  TimerCount = ((TimerPeriod * 119318) + 500000)/1000000
 253   //
 254   // Note that a TimerCount of 0 is equivalent to a count of 65,536
 255   //
 256   // Since TimerCount is limited to 16 bits for IA32, TimerPeriod is limited
 257   // to 20 bits.
 258   //
 259   if (TimerPeriod == 0) {
 260     //
 261     // Disable timer interrupt for a TimerPeriod of 0
 262     //
 263     mLegacy8259->DisableIrq (mLegacy8259, Efi8259Irq0);
 264   } else {
 265     //
 266     // Convert TimerPeriod into 8254 counts
 267     //
 268     TimerCount = DivU64x32 (MultU64x32 (119318, (UINT32) TimerPeriod) + 500000, 1000000);
 269
 270     //
 271     // Check for overflow
 272     //
 273     if (TimerCount >= 65536) {
 274       TimerCount = 0;
 275       if (TimerPeriod >= DEFAULT_TIMER_TICK_DURATION) {
 276         TimerPeriod = DEFAULT_TIMER_TICK_DURATION;
 277       }
 278     }
 279     //
 280     // Program the 8254 timer with the new count value
 281     //
 282     SetPitCount ((UINT16) TimerCount);
 283
 284     //
 285     // Enable timer interrupt
 286     //
 287     mLegacy8259->EnableIrq (mLegacy8259, Efi8259Irq0, FALSE);
 288   }
 289   //
 290   // Save the new timer period
 291   //
 292   mTimerPeriod = TimerPeriod;
 293
 294   return EFI_SUCCESS;
 295 }
 296
 297 EFI_STATUS
 298 EFIAPI
 299 TimerDriverGetTimerPeriod (
 300   IN EFI_TIMER_ARCH_PROTOCOL   *This,
 301   OUT UINT64                   *TimerPeriod
 302   )
 303 /*++
 304
 305 Routine Description:
 306
 307   This function retrieves the period of timer interrupts in 100 ns units,
 308   returns that value in TimerPeriod, and returns EFI_SUCCESS.  If TimerPeriod
 309   is NULL, then EFI_INVALID_PARAMETER is returned.  If a TimerPeriod of 0 is
 310   returned, then the timer is currently disabled.
 311
 312 Arguments:
 313
 314   This        - The EFI_TIMER_ARCH_PROTOCOL instance.
 315
 316   TimerPeriod - A pointer to the timer period to retrieve in 100 ns units.  If
 317                 0 is returned, then the timer is currently disabled.
 318
 319 Returns:
 320
 321   EFI_SUCCESS           - The timer period was returned in TimerPeriod.
 322
 323   EFI_INVALID_PARAMETER - TimerPeriod is NULL.
 324
 325 --*/
 326 {
 327   if (TimerPeriod == NULL) {
 328     return EFI_INVALID_PARAMETER;
 329   }
 330
 331   *TimerPeriod = mTimerPeriod;
 332
 333   return EFI_SUCCESS;
 334 }
 335
 336 EFI_STATUS
 337 EFIAPI
 338 TimerDriverGenerateSoftInterrupt (
 339   IN EFI_TIMER_ARCH_PROTOCOL  *This
 340   )
 341 /*++
 342
 343 Routine Description:
 344
 345   This function generates a soft timer interrupt. If the platform does not support soft
 346   timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
 347   If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
 348   service, then a soft timer interrupt will be generated. If the timer interrupt is
 349   enabled when this service is called, then the registered handler will be invoked. The
 350   registered handler should not be able to distinguish a hardware-generated timer
 351   interrupt from a software-generated timer interrupt.
 352
 353 Arguments:
 354
 355   This  -  The EFI_TIMER_ARCH_PROTOCOL instance.
 356
 357 Returns:
 358
 359   EFI_SUCCESS       - The soft timer interrupt was generated.
 360
 361   EFI_UNSUPPORTEDT  - The platform does not support the generation of soft timer interrupts.
 362
 363 --*/
 364 {
 365   EFI_STATUS  Status;
 366   UINT16      IRQMask;
 367   EFI_TPL     OriginalTPL;
 368
 369   //
 370   // If the timer interrupt is enabled, then the registered handler will be invoked.
 371   //
 372   Status = mLegacy8259->GetMask (mLegacy8259, NULL, NULL, &IRQMask, NULL);
 373   ASSERT_EFI_ERROR (Status);
 374   if ((IRQMask & 0x1) == 0) {
 375     //
 376     // Invoke the registered handler
 377     //
 378     OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
 379
 380     if (mTimerNotifyFunction) {
 381       //
 382       // BUGBUG : This does not handle missed timer interrupts
 383       //
 384       mTimerNotifyFunction (mTimerPeriod);
 385     }
 386
 387     gBS->RestoreTPL (OriginalTPL);
 388   } else {
 389     return EFI_UNSUPPORTED;
 390   }
 391
 392   return EFI_SUCCESS;
 393 }
 394
 395 EFI_STATUS
 396 EFIAPI
 397 TimerDriverInitialize (
 398   IN EFI_HANDLE        ImageHandle,
 399   IN EFI_SYSTEM_TABLE  *SystemTable
 400   )
 401 /*++
 402
 403 Routine Description:
 404
 405   Initialize the Timer Architectural Protocol driver
 406
 407 Arguments:
 408
 409   ImageHandle - ImageHandle of the loaded driver
 410
 411   SystemTable - Pointer to the System Table
 412
 413 Returns:
 414
 415   EFI_SUCCESS           - Timer Architectural Protocol created
 416
 417   EFI_OUT_OF_RESOURCES  - Not enough resources available to initialize driver.
 418
 419   EFI_DEVICE_ERROR      - A device error occured attempting to initialize the driver.
 420
 421 --*/
 422 {
 423   EFI_STATUS  Status;
 424   UINT32      TimerVector;
 425
 426   //
 427   // Initialize the pointer to our notify function.
 428   //
 429   mTimerNotifyFunction = NULL;
 430
 431   //
 432   // Make sure the Timer Architectural Protocol is not already installed in the system
 433   //
 434   ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);
 435
 436   //
 437   // Find the CPU I/O Protocol.
 438   //
 439   Status = gBS->LocateProtocol (&gEfiCpuIoProtocolGuid, NULL, (VOID **) &mCpuIo);
 440   ASSERT_EFI_ERROR (Status);
 441
 442   //
 443   // Find the CPU architectural protocol.
 444   //
 445   Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **) &mCpu);
 446   ASSERT_EFI_ERROR (Status);
 447
 448   //
 449   // Find the Legacy8259 protocol.
 450   //
 451   Status = gBS->LocateProtocol (&gEfiLegacy8259ProtocolGuid, NULL, (VOID **) &mLegacy8259);
 452   ASSERT_EFI_ERROR (Status);
 453
 454   //
 455   // Force the timer to be disabled
 456   //
 457   Status = TimerDriverSetTimerPeriod (&mTimer, 0);
 458   ASSERT_EFI_ERROR (Status);
 459
 460   //
 461   // Get the interrupt vector number corresponding to IRQ0 from the 8259 driver
 462   //
 463   TimerVector = 0;
 464   Status      = mLegacy8259->GetVector (mLegacy8259, Efi8259Irq0, (UINT8 *) &TimerVector);
 465   ASSERT_EFI_ERROR (Status);
 466
 467   //
 468   // Install interrupt handler for 8254 Timer #0 (ISA IRQ0)
 469   //
 470   Status = mCpu->RegisterInterruptHandler (mCpu, TimerVector, TimerInterruptHandler);
 471   ASSERT_EFI_ERROR (Status);
 472
 473   //
 474   // Force the timer to be enabled at its default period
 475   //
 476   Status = TimerDriverSetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
 477   ASSERT_EFI_ERROR (Status);
 478
 479   //
 480   // Install the Timer Architectural Protocol onto a new handle
 481   //
 482   Status = gBS->InstallMultipleProtocolInterfaces (
 483                   &mTimerHandle,
 484                   &gEfiTimerArchProtocolGuid,
 485                   &mTimer,
 486                   NULL
 487                   );
 488   ASSERT_EFI_ERROR (Status);
 489
 490   return Status;
 491 }