1 /** @file 2 Timer Architectural Protocol as defined in the DXE CIS 3 4 Copyright (c) 2005 - 2016, Intel Corporation. All rights reserved.<BR> 5 This program and the accompanying materials 6 are licensed and made available under the terms and conditions of the BSD License 7 which accompanies this distribution. The full text of the license may be found at 8 http://opensource.org/licenses/bsd-license.php 9 10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 12 13 **/ 14 15 #include "Timer.h" 16 17 // 18 // The handle onto which the Timer Architectural Protocol will be installed 19 // 20 EFI_HANDLE mTimerHandle = NULL; 21 22 // 23 // The Timer Architectural Protocol that this driver produces 24 // 25 EFI_TIMER_ARCH_PROTOCOL mTimer = { 26 TimerDriverRegisterHandler, 27 TimerDriverSetTimerPeriod, 28 TimerDriverGetTimerPeriod, 29 TimerDriverGenerateSoftInterrupt 30 }; 31 32 // 33 // Pointer to the CPU Architectural Protocol instance 34 // 35 EFI_CPU_ARCH_PROTOCOL *mCpu; 36 37 // 38 // Pointer to the Legacy 8259 Protocol instance 39 // 40 EFI_LEGACY_8259_PROTOCOL *mLegacy8259; 41 42 // 43 // The notification function to call on every timer interrupt. 44 // A bug in the compiler prevents us from initializing this here. 45 // 46 EFI_TIMER_NOTIFY mTimerNotifyFunction; 47 48 // 49 // The current period of the timer interrupt 50 // 51 volatile UINT64 mTimerPeriod = 0; 52 53 // 54 // Worker Functions 55 // 56 /** 57 Sets the counter value for Timer #0 in a legacy 8254 timer. 58 59 @param Count The 16-bit counter value to program into Timer #0 of the legacy 8254 timer. 60 **/ 61 VOID 62 SetPitCount ( 63 IN UINT16 Count 64 ) 65 { 66 IoWrite8 (TIMER_CONTROL_PORT, 0x36); 67 IoWrite8 (TIMER0_COUNT_PORT, (UINT8)(Count & 0xff)); 68 IoWrite8 (TIMER0_COUNT_PORT, (UINT8)((Count >> 8) & 0xff)); 69 } 70 71 /** 72 8254 Timer #0 Interrupt Handler. 73 74 @param InterruptType The type of interrupt that occured 75 @param SystemContext A pointer to the system context when the interrupt occured 76 **/ 77 VOID 78 EFIAPI 79 TimerInterruptHandler ( 80 IN EFI_EXCEPTION_TYPE InterruptType, 81 IN EFI_SYSTEM_CONTEXT SystemContext 82 ) 83 { 84 EFI_TPL OriginalTPL; 85 86 OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL); 87 88 mLegacy8259->EndOfInterrupt (mLegacy8259, Efi8259Irq0); 89 90 if (mTimerNotifyFunction != NULL) { 91 // 92 // @bug : This does not handle missed timer interrupts 93 // 94 mTimerNotifyFunction (mTimerPeriod); 95 } 96 97 gBS->RestoreTPL (OriginalTPL); 98 } 99 100 /** 101 102 This function registers the handler NotifyFunction so it is called every time 103 the timer interrupt fires. It also passes the amount of time since the last 104 handler call to the NotifyFunction. If NotifyFunction is NULL, then the 105 handler is unregistered. If the handler is registered, then EFI_SUCCESS is 106 returned. If the CPU does not support registering a timer interrupt handler, 107 then EFI_UNSUPPORTED is returned. If an attempt is made to register a handler 108 when a handler is already registered, then EFI_ALREADY_STARTED is returned. 109 If an attempt is made to unregister a handler when a handler is not registered, 110 then EFI_INVALID_PARAMETER is returned. If an error occurs attempting to 111 register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR 112 is returned. 113 114 115 @param This The EFI_TIMER_ARCH_PROTOCOL instance. 116 @param NotifyFunction The function to call when a timer interrupt fires. This 117 function executes at TPL_HIGH_LEVEL. The DXE Core will 118 register a handler for the timer interrupt, so it can know 119 how much time has passed. This information is used to 120 signal timer based events. NULL will unregister the handler. 121 122 @retval EFI_SUCCESS The timer handler was registered. 123 @retval EFI_UNSUPPORTED The platform does not support timer interrupts. 124 @retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already 125 registered. 126 @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not 127 previously registered. 128 @retval EFI_DEVICE_ERROR The timer handler could not be registered. 129 130 **/ 131 EFI_STATUS 132 EFIAPI 133 TimerDriverRegisterHandler ( 134 IN EFI_TIMER_ARCH_PROTOCOL *This, 135 IN EFI_TIMER_NOTIFY NotifyFunction 136 ) 137 { 138 // 139 // Check for invalid parameters 140 // 141 if (NotifyFunction == NULL && mTimerNotifyFunction == NULL) { 142 return EFI_INVALID_PARAMETER; 143 } 144 145 if (NotifyFunction != NULL && mTimerNotifyFunction != NULL) { 146 return EFI_ALREADY_STARTED; 147 } 148 149 mTimerNotifyFunction = NotifyFunction; 150 151 return EFI_SUCCESS; 152 } 153 154 /** 155 156 This function adjusts the period of timer interrupts to the value specified 157 by TimerPeriod. If the timer period is updated, then the selected timer 158 period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If 159 the timer hardware is not programmable, then EFI_UNSUPPORTED is returned. 160 If an error occurs while attempting to update the timer period, then the 161 timer hardware will be put back in its state prior to this call, and 162 EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt 163 is disabled. This is not the same as disabling the CPU's interrupts. 164 Instead, it must either turn off the timer hardware, or it must adjust the 165 interrupt controller so that a CPU interrupt is not generated when the timer 166 interrupt fires. 167 168 169 @param This The EFI_TIMER_ARCH_PROTOCOL instance. 170 @param TimerPeriod The rate to program the timer interrupt in 100 nS units. If 171 the timer hardware is not programmable, then EFI_UNSUPPORTED is 172 returned. If the timer is programmable, then the timer period 173 will be rounded up to the nearest timer period that is supported 174 by the timer hardware. If TimerPeriod is set to 0, then the 175 timer interrupts will be disabled. 176 177 @retval EFI_SUCCESS The timer period was changed. 178 @retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt. 179 @retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error. 180 181 **/ 182 EFI_STATUS 183 EFIAPI 184 TimerDriverSetTimerPeriod ( 185 IN EFI_TIMER_ARCH_PROTOCOL *This, 186 IN UINT64 TimerPeriod 187 ) 188 { 189 UINT64 TimerCount; 190 191 // 192 // The basic clock is 1.19318 MHz or 0.119318 ticks per 100 ns. 193 // TimerPeriod * 0.119318 = 8254 timer divisor. Using integer arithmetic 194 // TimerCount = (TimerPeriod * 119318)/1000000. 195 // 196 // Round up to next highest integer. This guarantees that the timer is 197 // equal to or slightly longer than the requested time. 198 // TimerCount = ((TimerPeriod * 119318) + 500000)/1000000 199 // 200 // Note that a TimerCount of 0 is equivalent to a count of 65,536 201 // 202 // Since TimerCount is limited to 16 bits for IA32, TimerPeriod is limited 203 // to 20 bits. 204 // 205 if (TimerPeriod == 0) { 206 // 207 // Disable timer interrupt for a TimerPeriod of 0 208 // 209 mLegacy8259->DisableIrq (mLegacy8259, Efi8259Irq0); 210 } else { 211 212 // 213 // Convert TimerPeriod into 8254 counts 214 // 215 TimerCount = DivU64x32 (MultU64x32 (119318, (UINT32) TimerPeriod) + 500000, 1000000); 216 217 // 218 // Check for overflow 219 // 220 if (TimerCount >= 65536) { 221 TimerCount = 0; 222 TimerPeriod = MAX_TIMER_TICK_DURATION; 223 } 224 // 225 // Program the 8254 timer with the new count value 226 // 227 SetPitCount ((UINT16) TimerCount); 228 229 // 230 // Enable timer interrupt 231 // 232 mLegacy8259->EnableIrq (mLegacy8259, Efi8259Irq0, FALSE); 233 } 234 // 235 // Save the new timer period 236 // 237 mTimerPeriod = TimerPeriod; 238 239 return EFI_SUCCESS; 240 } 241 242 /** 243 244 This function retrieves the period of timer interrupts in 100 ns units, 245 returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod 246 is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is 247 returned, then the timer is currently disabled. 248 249 250 @param This The EFI_TIMER_ARCH_PROTOCOL instance. 251 @param TimerPeriod A pointer to the timer period to retrieve in 100 ns units. If 252 0 is returned, then the timer is currently disabled. 253 254 @retval EFI_SUCCESS The timer period was returned in TimerPeriod. 255 @retval EFI_INVALID_PARAMETER TimerPeriod is NULL. 256 257 **/ 258 EFI_STATUS 259 EFIAPI 260 TimerDriverGetTimerPeriod ( 261 IN EFI_TIMER_ARCH_PROTOCOL *This, 262 OUT UINT64 *TimerPeriod 263 ) 264 { 265 if (TimerPeriod == NULL) { 266 return EFI_INVALID_PARAMETER; 267 } 268 269 *TimerPeriod = mTimerPeriod; 270 271 return EFI_SUCCESS; 272 } 273 274 /** 275 276 This function generates a soft timer interrupt. If the platform does not support soft 277 timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned. 278 If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler() 279 service, then a soft timer interrupt will be generated. If the timer interrupt is 280 enabled when this service is called, then the registered handler will be invoked. The 281 registered handler should not be able to distinguish a hardware-generated timer 282 interrupt from a software-generated timer interrupt. 283 284 285 @param This The EFI_TIMER_ARCH_PROTOCOL instance. 286 287 @retval EFI_SUCCESS The soft timer interrupt was generated. 288 @retval EFI_UNSUPPORTED The platform does not support the generation of soft timer interrupts. 289 290 **/ 291 EFI_STATUS 292 EFIAPI 293 TimerDriverGenerateSoftInterrupt ( 294 IN EFI_TIMER_ARCH_PROTOCOL *This 295 ) 296 { 297 EFI_STATUS Status; 298 UINT16 IRQMask; 299 EFI_TPL OriginalTPL; 300 301 // 302 // If the timer interrupt is enabled, then the registered handler will be invoked. 303 // 304 Status = mLegacy8259->GetMask (mLegacy8259, NULL, NULL, &IRQMask, NULL); 305 ASSERT_EFI_ERROR (Status); 306 if ((IRQMask & 0x1) == 0) { 307 // 308 // Invoke the registered handler 309 // 310 OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL); 311 312 if (mTimerNotifyFunction != NULL) { 313 // 314 // @bug : This does not handle missed timer interrupts 315 // 316 mTimerNotifyFunction (mTimerPeriod); 317 } 318 319 gBS->RestoreTPL (OriginalTPL); 320 } else { 321 return EFI_UNSUPPORTED; 322 } 323 324 return EFI_SUCCESS; 325 } 326 327 /** 328 Initialize the Timer Architectural Protocol driver 329 330 @param ImageHandle ImageHandle of the loaded driver 331 @param SystemTable Pointer to the System Table 332 333 @retval EFI_SUCCESS Timer Architectural Protocol created 334 @retval EFI_OUT_OF_RESOURCES Not enough resources available to initialize driver. 335 @retval EFI_DEVICE_ERROR A device error occured attempting to initialize the driver. 336 337 **/ 338 EFI_STATUS 339 EFIAPI 340 TimerDriverInitialize ( 341 IN EFI_HANDLE ImageHandle, 342 IN EFI_SYSTEM_TABLE *SystemTable 343 ) 344 { 345 EFI_STATUS Status; 346 UINT32 TimerVector; 347 348 // 349 // Initialize the pointer to our notify function. 350 // 351 mTimerNotifyFunction = NULL; 352 353 // 354 // Make sure the Timer Architectural Protocol is not already installed in the system 355 // 356 ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid); 357 358 // 359 // Find the CPU architectural protocol. 360 // 361 Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **) &mCpu); 362 ASSERT_EFI_ERROR (Status); 363 364 // 365 // Find the Legacy8259 protocol. 366 // 367 Status = gBS->LocateProtocol (&gEfiLegacy8259ProtocolGuid, NULL, (VOID **) &mLegacy8259); 368 ASSERT_EFI_ERROR (Status); 369 370 // 371 // Force the timer to be disabled 372 // 373 Status = TimerDriverSetTimerPeriod (&mTimer, 0); 374 ASSERT_EFI_ERROR (Status); 375 376 // 377 // Get the interrupt vector number corresponding to IRQ0 from the 8259 driver 378 // 379 TimerVector = 0; 380 Status = mLegacy8259->GetVector (mLegacy8259, Efi8259Irq0, (UINT8 *) &TimerVector); 381 ASSERT_EFI_ERROR (Status); 382 383 // 384 // Install interrupt handler for 8254 Timer #0 (ISA IRQ0) 385 // 386 Status = mCpu->RegisterInterruptHandler (mCpu, TimerVector, TimerInterruptHandler); 387 ASSERT_EFI_ERROR (Status); 388 389 // 390 // Force the timer to be enabled at its default period 391 // 392 Status = TimerDriverSetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION); 393 ASSERT_EFI_ERROR (Status); 394 395 // 396 // Install the Timer Architectural Protocol onto a new handle 397 // 398 Status = gBS->InstallMultipleProtocolInterfaces ( 399 &mTimerHandle, 400 &gEfiTimerArchProtocolGuid, &mTimer, 401 NULL 402 ); 403 ASSERT_EFI_ERROR (Status); 404 405 return Status; 406 } 407 408
