1 /** @file 2 Timer Architecture Protocol driver of the ARM flavor 3 4 Copyright (c) 2011-2013 ARM Ltd. All rights reserved.<BR> 5 6 This program and the accompanying materials 7 are licensed and made available under the terms and conditions of the BSD License 8 which accompanies this distribution. The full text of the license may be found at 9 http://opensource.org/licenses/bsd-license.php 10 11 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 12 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 13 14 **/ 15 16 17 #include <PiDxe.h> 18 19 #include <Library/ArmLib.h> 20 #include <Library/BaseLib.h> 21 #include <Library/DebugLib.h> 22 #include <Library/BaseMemoryLib.h> 23 #include <Library/UefiBootServicesTableLib.h> 24 #include <Library/UefiLib.h> 25 #include <Library/PcdLib.h> 26 #include <Library/IoLib.h> 27 #include <Library/ArmGenericTimerCounterLib.h> 28 #include <Library/ArmArchTimer.h> 29 30 #include <Protocol/Timer.h> 31 #include <Protocol/HardwareInterrupt.h> 32 33 // The notification function to call on every timer interrupt. 34 EFI_TIMER_NOTIFY mTimerNotifyFunction = (EFI_TIMER_NOTIFY)NULL; 35 EFI_EVENT EfiExitBootServicesEvent = (EFI_EVENT)NULL; 36 37 // The current period of the timer interrupt 38 UINT64 mTimerPeriod = 0; 39 // The latest Timer Tick calculated for mTimerPeriod 40 UINT64 mTimerTicks = 0; 41 // Number of elapsed period since the last Timer interrupt 42 UINT64 mElapsedPeriod = 1; 43 44 // Cached copy of the Hardware Interrupt protocol instance 45 EFI_HARDWARE_INTERRUPT_PROTOCOL *gInterrupt = NULL; 46 47 /** 48 This function registers the handler NotifyFunction so it is called every time 49 the timer interrupt fires. It also passes the amount of time since the last 50 handler call to the NotifyFunction. If NotifyFunction is NULL, then the 51 handler is unregistered. If the handler is registered, then EFI_SUCCESS is 52 returned. If the CPU does not support registering a timer interrupt handler, 53 then EFI_UNSUPPORTED is returned. If an attempt is made to register a handler 54 when a handler is already registered, then EFI_ALREADY_STARTED is returned. 55 If an attempt is made to unregister a handler when a handler is not registered, 56 then EFI_INVALID_PARAMETER is returned. If an error occurs attempting to 57 register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR 58 is returned. 59 60 @param This The EFI_TIMER_ARCH_PROTOCOL instance. 61 @param NotifyFunction The function to call when a timer interrupt fires. This 62 function executes at TPL_HIGH_LEVEL. The DXE Core will 63 register a handler for the timer interrupt, so it can know 64 how much time has passed. This information is used to 65 signal timer based events. NULL will unregister the handler. 66 @retval EFI_SUCCESS The timer handler was registered. 67 @retval EFI_UNSUPPORTED The platform does not support timer interrupts. 68 @retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already 69 registered. 70 @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not 71 previously registered. 72 @retval EFI_DEVICE_ERROR The timer handler could not be registered. 73 74 **/ 75 EFI_STATUS 76 EFIAPI 77 TimerDriverRegisterHandler ( 78 IN EFI_TIMER_ARCH_PROTOCOL *This, 79 IN EFI_TIMER_NOTIFY NotifyFunction 80 ) 81 { 82 if ((NotifyFunction == NULL) && (mTimerNotifyFunction == NULL)) { 83 return EFI_INVALID_PARAMETER; 84 } 85 86 if ((NotifyFunction != NULL) && (mTimerNotifyFunction != NULL)) { 87 return EFI_ALREADY_STARTED; 88 } 89 90 mTimerNotifyFunction = NotifyFunction; 91 92 return EFI_SUCCESS; 93 } 94 95 /** 96 Disable the timer 97 **/ 98 VOID 99 EFIAPI 100 ExitBootServicesEvent ( 101 IN EFI_EVENT Event, 102 IN VOID *Context 103 ) 104 { 105 ArmGenericTimerDisableTimer (); 106 } 107 108 /** 109 110 This function adjusts the period of timer interrupts to the value specified 111 by TimerPeriod. If the timer period is updated, then the selected timer 112 period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If 113 the timer hardware is not programmable, then EFI_UNSUPPORTED is returned. 114 If an error occurs while attempting to update the timer period, then the 115 timer hardware will be put back in its state prior to this call, and 116 EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt 117 is disabled. This is not the same as disabling the CPU's interrupts. 118 Instead, it must either turn off the timer hardware, or it must adjust the 119 interrupt controller so that a CPU interrupt is not generated when the timer 120 interrupt fires. 121 122 @param This The EFI_TIMER_ARCH_PROTOCOL instance. 123 @param TimerPeriod The rate to program the timer interrupt in 100 nS units. If 124 the timer hardware is not programmable, then EFI_UNSUPPORTED is 125 returned. If the timer is programmable, then the timer period 126 will be rounded up to the nearest timer period that is supported 127 by the timer hardware. If TimerPeriod is set to 0, then the 128 timer interrupts will be disabled. 129 130 131 @retval EFI_SUCCESS The timer period was changed. 132 @retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt. 133 @retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error. 134 135 **/ 136 EFI_STATUS 137 EFIAPI 138 TimerDriverSetTimerPeriod ( 139 IN EFI_TIMER_ARCH_PROTOCOL *This, 140 IN UINT64 TimerPeriod 141 ) 142 { 143 UINT64 CounterValue; 144 UINT64 TimerTicks; 145 EFI_TPL OriginalTPL; 146 147 // Always disable the timer 148 ArmGenericTimerDisableTimer (); 149 150 if (TimerPeriod != 0) { 151 // mTimerTicks = TimerPeriod in 1ms unit x Frequency.10^-3 152 // = TimerPeriod.10^-4 x Frequency.10^-3 153 // = (TimerPeriod x Frequency) x 10^-7 154 TimerTicks = MultU64x32 (TimerPeriod, ArmGenericTimerGetTimerFreq ()); 155 TimerTicks = DivU64x32 (TimerTicks, 10000000U); 156 157 // Raise TPL to update the mTimerTicks and mTimerPeriod to ensure these values 158 // are coherent in the interrupt handler 159 OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL); 160 161 mTimerTicks = TimerTicks; 162 mTimerPeriod = TimerPeriod; 163 mElapsedPeriod = 1; 164 165 gBS->RestoreTPL (OriginalTPL); 166 167 // Get value of the current timer 168 CounterValue = ArmGenericTimerGetSystemCount (); 169 // Set the interrupt in Current Time + mTimerTick 170 ArmGenericTimerSetCompareVal (CounterValue + mTimerTicks); 171 172 // Enable the timer 173 ArmGenericTimerEnableTimer (); 174 } else { 175 // Save the new timer period 176 mTimerPeriod = TimerPeriod; 177 // Reset the elapsed period 178 mElapsedPeriod = 1; 179 } 180 181 return EFI_SUCCESS; 182 } 183 184 /** 185 This function retrieves the period of timer interrupts in 100 ns units, 186 returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod 187 is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is 188 returned, then the timer is currently disabled. 189 190 @param This The EFI_TIMER_ARCH_PROTOCOL instance. 191 @param TimerPeriod A pointer to the timer period to retrieve in 100 ns units. If 192 0 is returned, then the timer is currently disabled. 193 194 195 @retval EFI_SUCCESS The timer period was returned in TimerPeriod. 196 @retval EFI_INVALID_PARAMETER TimerPeriod is NULL. 197 198 **/ 199 EFI_STATUS 200 EFIAPI 201 TimerDriverGetTimerPeriod ( 202 IN EFI_TIMER_ARCH_PROTOCOL *This, 203 OUT UINT64 *TimerPeriod 204 ) 205 { 206 if (TimerPeriod == NULL) { 207 return EFI_INVALID_PARAMETER; 208 } 209 210 *TimerPeriod = mTimerPeriod; 211 return EFI_SUCCESS; 212 } 213 214 /** 215 This function generates a soft timer interrupt. If the platform does not support soft 216 timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned. 217 If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler() 218 service, then a soft timer interrupt will be generated. If the timer interrupt is 219 enabled when this service is called, then the registered handler will be invoked. The 220 registered handler should not be able to distinguish a hardware-generated timer 221 interrupt from a software-generated timer interrupt. 222 223 @param This The EFI_TIMER_ARCH_PROTOCOL instance. 224 225 @retval EFI_SUCCESS The soft timer interrupt was generated. 226 @retval EFI_UNSUPPORTED The platform does not support the generation of soft timer interrupts. 227 228 **/ 229 EFI_STATUS 230 EFIAPI 231 TimerDriverGenerateSoftInterrupt ( 232 IN EFI_TIMER_ARCH_PROTOCOL *This 233 ) 234 { 235 return EFI_UNSUPPORTED; 236 } 237 238 /** 239 Interface structure for the Timer Architectural Protocol. 240 241 @par Protocol Description: 242 This protocol provides the services to initialize a periodic timer 243 interrupt, and to register a handler that is called each time the timer 244 interrupt fires. It may also provide a service to adjust the rate of the 245 periodic timer interrupt. When a timer interrupt occurs, the handler is 246 passed the amount of time that has passed since the previous timer 247 interrupt. 248 249 @param RegisterHandler 250 Registers a handler that will be called each time the 251 timer interrupt fires. TimerPeriod defines the minimum 252 time between timer interrupts, so TimerPeriod will also 253 be the minimum time between calls to the registered 254 handler. 255 256 @param SetTimerPeriod 257 Sets the period of the timer interrupt in 100 nS units. 258 This function is optional, and may return EFI_UNSUPPORTED. 259 If this function is supported, then the timer period will 260 be rounded up to the nearest supported timer period. 261 262 263 @param GetTimerPeriod 264 Retrieves the period of the timer interrupt in 100 nS units. 265 266 @param GenerateSoftInterrupt 267 Generates a soft timer interrupt that simulates the firing of 268 the timer interrupt. This service can be used to invoke the registered handler if the timer interrupt has been masked for 269 a period of time. 270 271 **/ 272 EFI_TIMER_ARCH_PROTOCOL gTimer = { 273 TimerDriverRegisterHandler, 274 TimerDriverSetTimerPeriod, 275 TimerDriverGetTimerPeriod, 276 TimerDriverGenerateSoftInterrupt 277 }; 278 279 /** 280 281 C Interrupt Handler called in the interrupt context when Source interrupt is active. 282 283 284 @param Source Source of the interrupt. Hardware routing off a specific platform defines 285 what source means. 286 287 @param SystemContext Pointer to system register context. Mostly used by debuggers and will 288 update the system context after the return from the interrupt if 289 modified. Don't change these values unless you know what you are doing 290 291 **/ 292 VOID 293 EFIAPI 294 TimerInterruptHandler ( 295 IN HARDWARE_INTERRUPT_SOURCE Source, 296 IN EFI_SYSTEM_CONTEXT SystemContext 297 ) 298 { 299 EFI_TPL OriginalTPL; 300 UINT64 CurrentValue; 301 UINT64 CompareValue; 302 303 // 304 // DXE core uses this callback for the EFI timer tick. The DXE core uses locks 305 // that raise to TPL_HIGH and then restore back to current level. Thus we need 306 // to make sure TPL level is set to TPL_HIGH while we are handling the timer tick. 307 // 308 OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL); 309 310 // Check if the timer interrupt is active 311 if ((ArmGenericTimerGetTimerCtrlReg () ) & ARM_ARCH_TIMER_ISTATUS) { 312 313 // Signal end of interrupt early to help avoid losing subsequent ticks from long duration handlers 314 gInterrupt->EndOfInterrupt (gInterrupt, Source); 315 316 if (mTimerNotifyFunction) { 317 mTimerNotifyFunction (mTimerPeriod * mElapsedPeriod); 318 } 319 320 // 321 // Reload the Timer 322 // 323 324 // Get current counter value 325 CurrentValue = ArmGenericTimerGetSystemCount (); 326 // Get the counter value to compare with 327 CompareValue = ArmGenericTimerGetCompareVal (); 328 329 // This loop is needed in case we missed interrupts (eg: case when the interrupt handling 330 // has taken longer than mTickPeriod). 331 // Note: Physical Counter is counting up 332 mElapsedPeriod = 0; 333 do { 334 CompareValue += mTimerTicks; 335 mElapsedPeriod++; 336 } while (CompareValue < CurrentValue); 337 338 // Set next compare value 339 ArmGenericTimerSetCompareVal (CompareValue); 340 ArmGenericTimerEnableTimer (); 341 } 342 343 // Enable timer interrupts 344 gInterrupt->EnableInterruptSource (gInterrupt, Source); 345 346 gBS->RestoreTPL (OriginalTPL); 347 } 348 349 350 /** 351 Initialize the state information for the Timer Architectural Protocol and 352 the Timer Debug support protocol that allows the debugger to break into a 353 running program. 354 355 @param ImageHandle of the loaded driver 356 @param SystemTable Pointer to the System Table 357 358 @retval EFI_SUCCESS Protocol registered 359 @retval EFI_OUT_OF_RESOURCES Cannot allocate protocol data structure 360 @retval EFI_DEVICE_ERROR Hardware problems 361 362 **/ 363 EFI_STATUS 364 EFIAPI 365 TimerInitialize ( 366 IN EFI_HANDLE ImageHandle, 367 IN EFI_SYSTEM_TABLE *SystemTable 368 ) 369 { 370 EFI_HANDLE Handle = NULL; 371 EFI_STATUS Status; 372 UINTN TimerCtrlReg; 373 UINT32 TimerHypIntrNum; 374 375 if (ArmIsArchTimerImplemented () == 0) { 376 DEBUG ((EFI_D_ERROR, "ARM Architectural Timer is not available in the CPU, hence cann't use this Driver \n")); 377 ASSERT (0); 378 } 379 380 // Find the interrupt controller protocol. ASSERT if not found. 381 Status = gBS->LocateProtocol (&gHardwareInterruptProtocolGuid, NULL, (VOID **)&gInterrupt); 382 ASSERT_EFI_ERROR (Status); 383 384 // Disable the timer 385 TimerCtrlReg = ArmGenericTimerGetTimerCtrlReg (); 386 TimerCtrlReg |= ARM_ARCH_TIMER_IMASK; 387 TimerCtrlReg &= ~ARM_ARCH_TIMER_ENABLE; 388 ArmGenericTimerSetTimerCtrlReg (TimerCtrlReg); 389 Status = TimerDriverSetTimerPeriod (&gTimer, 0); 390 ASSERT_EFI_ERROR (Status); 391 392 // Install secure and Non-secure interrupt handlers 393 // Note: Because it is not possible to determine the security state of the 394 // CPU dynamically, we just install interrupt handler for both sec and non-sec 395 // timer PPI 396 Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerVirtIntrNum), TimerInterruptHandler); 397 ASSERT_EFI_ERROR (Status); 398 399 // 400 // The hypervisor timer interrupt may be omitted by implementations that 401 // execute under virtualization. 402 // 403 TimerHypIntrNum = PcdGet32 (PcdArmArchTimerHypIntrNum); 404 if (TimerHypIntrNum != 0) { 405 Status = gInterrupt->RegisterInterruptSource (gInterrupt, TimerHypIntrNum, TimerInterruptHandler); 406 ASSERT_EFI_ERROR (Status); 407 } 408 409 Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerSecIntrNum), TimerInterruptHandler); 410 ASSERT_EFI_ERROR (Status); 411 412 Status = gInterrupt->RegisterInterruptSource (gInterrupt, PcdGet32 (PcdArmArchTimerIntrNum), TimerInterruptHandler); 413 ASSERT_EFI_ERROR (Status); 414 415 // Set up default timer 416 Status = TimerDriverSetTimerPeriod (&gTimer, FixedPcdGet32(PcdTimerPeriod)); // TIMER_DEFAULT_PERIOD 417 ASSERT_EFI_ERROR (Status); 418 419 // Install the Timer Architectural Protocol onto a new handle 420 Status = gBS->InstallMultipleProtocolInterfaces( 421 &Handle, 422 &gEfiTimerArchProtocolGuid, &gTimer, 423 NULL 424 ); 425 ASSERT_EFI_ERROR(Status); 426 427 // Everything is ready, unmask and enable timer interrupts 428 TimerCtrlReg = ARM_ARCH_TIMER_ENABLE; 429 ArmGenericTimerSetTimerCtrlReg (TimerCtrlReg); 430 431 // Register for an ExitBootServicesEvent 432 Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_NOTIFY, ExitBootServicesEvent, NULL, &EfiExitBootServicesEvent); 433 ASSERT_EFI_ERROR (Status); 434 435 return Status; 436 } 437