1/** @file 2* 3* Copyright (c) 2011-2013, ARM Limited. All rights reserved. 4* 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 16#include <PiDxe.h> 17 18#include <Library/BaseLib.h> 19#include <Library/BaseMemoryLib.h> 20#include <Library/DebugLib.h> 21#include <Library/IoLib.h> 22#include <Library/PcdLib.h> 23#include <Library/UefiBootServicesTableLib.h> 24#include <Library/UefiRuntimeServicesTableLib.h> 25#include <Library/UefiLib.h> 26 27#include <Protocol/WatchdogTimer.h> 28#include <Drivers/SP805Watchdog.h> 29 30EFI_EVENT EfiExitBootServicesEvent = (EFI_EVENT)NULL; 31 32/** 33 Make sure the SP805 registers are unlocked for writing. 34 35 Note: The SP805 Watchdog Timer supports locking of its registers, 36 i.e. it inhibits all writes to avoid rogue software accidentally 37 corrupting their contents. 38**/ 39STATIC 40VOID 41SP805Unlock ( 42 VOID 43 ) 44{ 45 if( MmioRead32(SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_LOCKED ) { 46 MmioWrite32(SP805_WDOG_LOCK_REG, SP805_WDOG_SPECIAL_UNLOCK_CODE); 47 } 48} 49 50/** 51 Make sure the SP805 registers are locked and can not be overwritten. 52 53 Note: The SP805 Watchdog Timer supports locking of its registers, 54 i.e. it inhibits all writes to avoid rogue software accidentally 55 corrupting their contents. 56**/ 57STATIC 58VOID 59SP805Lock ( 60 VOID 61 ) 62{ 63 if( MmioRead32(SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_UNLOCKED ) { 64 // To lock it, just write in any number (except the special unlock code). 65 MmioWrite32(SP805_WDOG_LOCK_REG, SP805_WDOG_LOCK_IS_LOCKED); 66 } 67} 68 69/** 70 Stop the SP805 watchdog timer from counting down by disabling interrupts. 71**/ 72STATIC 73VOID 74SP805Stop ( 75 VOID 76 ) 77{ 78 // Disable interrupts 79 if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) != 0 ) { 80 MmioAnd32(SP805_WDOG_CONTROL_REG, ~SP805_WDOG_CTRL_INTEN); 81 } 82} 83 84/** 85 Starts the SP805 counting down by enabling interrupts. 86 The count down will start from the value stored in the Load register, 87 not from the value where it was previously stopped. 88**/ 89STATIC 90VOID 91SP805Start ( 92 VOID 93 ) 94{ 95 // Enable interrupts 96 if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) == 0 ) { 97 MmioOr32(SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_INTEN); 98 } 99} 100 101/** 102 On exiting boot services we must make sure the SP805 Watchdog Timer 103 is stopped. 104**/ 105VOID 106EFIAPI 107ExitBootServicesEvent ( 108 IN EFI_EVENT Event, 109 IN VOID *Context 110 ) 111{ 112 SP805Unlock(); 113 SP805Stop(); 114 SP805Lock(); 115} 116 117/** 118 This function registers the handler NotifyFunction so it is called every time 119 the watchdog timer expires. It also passes the amount of time since the last 120 handler call to the NotifyFunction. 121 If NotifyFunction is not NULL and a handler is not already registered, 122 then the new handler is registered and EFI_SUCCESS is returned. 123 If NotifyFunction is NULL, and a handler is already registered, 124 then that handler is unregistered. 125 If an attempt is made to register a handler when a handler is already registered, 126 then EFI_ALREADY_STARTED is returned. 127 If an attempt is made to unregister a handler when a handler is not registered, 128 then EFI_INVALID_PARAMETER is returned. 129 130 @param This The EFI_TIMER_ARCH_PROTOCOL instance. 131 @param NotifyFunction The function to call when a timer interrupt fires. This 132 function executes at TPL_HIGH_LEVEL. The DXE Core will 133 register a handler for the timer interrupt, so it can know 134 how much time has passed. This information is used to 135 signal timer based events. NULL will unregister the handler. 136 137 @retval EFI_SUCCESS The watchdog timer handler was registered. 138 @retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already 139 registered. 140 @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not 141 previously registered. 142 143**/ 144EFI_STATUS 145EFIAPI 146SP805RegisterHandler ( 147 IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This, 148 IN EFI_WATCHDOG_TIMER_NOTIFY NotifyFunction 149 ) 150{ 151 // ERROR: This function is not supported. 152 // The hardware watchdog will reset the board 153 return EFI_INVALID_PARAMETER; 154} 155 156/** 157 158 This function adjusts the period of timer interrupts to the value specified 159 by TimerPeriod. If the timer period is updated, then the selected timer 160 period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If 161 the timer hardware is not programmable, then EFI_UNSUPPORTED is returned. 162 If an error occurs while attempting to update the timer period, then the 163 timer hardware will be put back in its state prior to this call, and 164 EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt 165 is disabled. This is not the same as disabling the CPU's interrupts. 166 Instead, it must either turn off the timer hardware, or it must adjust the 167 interrupt controller so that a CPU interrupt is not generated when the timer 168 interrupt fires. 169 170 @param This The EFI_TIMER_ARCH_PROTOCOL instance. 171 @param TimerPeriod The rate to program the timer interrupt in 100 nS units. If 172 the timer hardware is not programmable, then EFI_UNSUPPORTED is 173 returned. If the timer is programmable, then the timer period 174 will be rounded up to the nearest timer period that is supported 175 by the timer hardware. If TimerPeriod is set to 0, then the 176 timer interrupts will be disabled. 177 178 179 @retval EFI_SUCCESS The timer period was changed. 180 @retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt. 181 @retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error. 182 183**/ 184EFI_STATUS 185EFIAPI 186SP805SetTimerPeriod ( 187 IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This, 188 IN UINT64 TimerPeriod // In 100ns units 189 ) 190{ 191 EFI_STATUS Status = EFI_SUCCESS; 192 UINT64 Ticks64bit; 193 194 SP805Unlock(); 195 196 if( TimerPeriod == 0 ) { 197 // This is a watchdog stop request 198 SP805Stop(); 199 goto EXIT; 200 } else { 201 // Calculate the Watchdog ticks required for a delay of (TimerTicks * 100) nanoseconds 202 // The SP805 will count down to ZERO once, generate an interrupt and 203 // then it will again reload the initial value and start again. 204 // On the second time when it reaches ZERO, it will actually reset the board. 205 // Therefore, we need to load half the required delay. 206 // 207 // WatchdogTicks = ((TimerPeriod * 100 * SP805_CLOCK_FREQUENCY) / 1GHz) / 2 ; 208 // 209 // i.e.: 210 // 211 // WatchdogTicks = (TimerPeriod * SP805_CLOCK_FREQUENCY) / 20 MHz ; 212 213 Ticks64bit = DivU64x32(MultU64x32(TimerPeriod, (UINTN)PcdGet32(PcdSP805WatchdogClockFrequencyInHz)), 20000000); 214 215 // The registers in the SP805 are only 32 bits 216 if(Ticks64bit > (UINT64)0xFFFFFFFF) { 217 // We could load the watchdog with the maximum supported value but 218 // if a smaller value was requested, this could have the watchdog 219 // triggering before it was intended. 220 // Better generate an error to let the caller know. 221 Status = EFI_DEVICE_ERROR; 222 goto EXIT; 223 } 224 225 // Update the watchdog with a 32-bit value. 226 MmioWrite32(SP805_WDOG_LOAD_REG, (UINT32)Ticks64bit); 227 228 // Start the watchdog 229 SP805Start(); 230 } 231 232 EXIT: 233 // Ensure the watchdog is locked before exiting. 234 SP805Lock(); 235 return Status; 236} 237 238/** 239 This function retrieves the period of timer interrupts in 100 ns units, 240 returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod 241 is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is 242 returned, then the timer is currently disabled. 243 244 @param This The EFI_TIMER_ARCH_PROTOCOL instance. 245 @param TimerPeriod A pointer to the timer period to retrieve in 100 ns units. If 246 0 is returned, then the timer is currently disabled. 247 248 249 @retval EFI_SUCCESS The timer period was returned in TimerPeriod. 250 @retval EFI_INVALID_PARAMETER TimerPeriod is NULL. 251 252**/ 253EFI_STATUS 254EFIAPI 255SP805GetTimerPeriod ( 256 IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This, 257 OUT UINT64 *TimerPeriod 258 ) 259{ 260 EFI_STATUS Status = EFI_SUCCESS; 261 UINT64 ReturnValue; 262 263 if (TimerPeriod == NULL) { 264 return EFI_INVALID_PARAMETER; 265 } 266 267 // Check if the watchdog is stopped 268 if ( (MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) == 0 ) { 269 // It is stopped, so return zero. 270 ReturnValue = 0; 271 } else { 272 // Convert the Watchdog ticks into TimerPeriod 273 // Ensure 64bit arithmetic throughout because the Watchdog ticks may already 274 // be at the maximum 32 bit value and we still need to multiply that by 600. 275 ReturnValue = MultU64x32( MmioRead32(SP805_WDOG_LOAD_REG), 600 ); 276 } 277 278 *TimerPeriod = ReturnValue; 279 280 return Status; 281} 282 283/** 284 Interface structure for the Watchdog Architectural Protocol. 285 286 @par Protocol Description: 287 This protocol provides a service to set the amount of time to wait 288 before firing the watchdog timer, and it also provides a service to 289 register a handler that is invoked when the watchdog timer fires. 290 291 @par When the watchdog timer fires, control will be passed to a handler 292 if one has been registered. If no handler has been registered, 293 or the registered handler returns, then the system will be 294 reset by calling the Runtime Service ResetSystem(). 295 296 @param RegisterHandler 297 Registers a handler that will be called each time the 298 watchdogtimer interrupt fires. TimerPeriod defines the minimum 299 time between timer interrupts, so TimerPeriod will also 300 be the minimum time between calls to the registered 301 handler. 302 NOTE: If the watchdog resets the system in hardware, then 303 this function will not have any chance of executing. 304 305 @param SetTimerPeriod 306 Sets the period of the timer interrupt in 100 nS units. 307 This function is optional, and may return EFI_UNSUPPORTED. 308 If this function is supported, then the timer period will 309 be rounded up to the nearest supported timer period. 310 311 @param GetTimerPeriod 312 Retrieves the period of the timer interrupt in 100 nS units. 313 314**/ 315EFI_WATCHDOG_TIMER_ARCH_PROTOCOL gWatchdogTimer = { 316 (EFI_WATCHDOG_TIMER_REGISTER_HANDLER) SP805RegisterHandler, 317 (EFI_WATCHDOG_TIMER_SET_TIMER_PERIOD) SP805SetTimerPeriod, 318 (EFI_WATCHDOG_TIMER_GET_TIMER_PERIOD) SP805GetTimerPeriod 319}; 320 321/** 322 Initialize the state information for the Watchdog Timer Architectural Protocol. 323 324 @param ImageHandle of the loaded driver 325 @param SystemTable Pointer to the System Table 326 327 @retval EFI_SUCCESS Protocol registered 328 @retval EFI_OUT_OF_RESOURCES Cannot allocate protocol data structure 329 @retval EFI_DEVICE_ERROR Hardware problems 330 331**/ 332EFI_STATUS 333EFIAPI 334SP805Initialize ( 335 IN EFI_HANDLE ImageHandle, 336 IN EFI_SYSTEM_TABLE *SystemTable 337 ) 338{ 339 EFI_STATUS Status; 340 EFI_HANDLE Handle; 341 342 // Unlock access to the SP805 registers 343 SP805Unlock (); 344 345 // Stop the watchdog from triggering unexpectedly 346 SP805Stop (); 347 348 // Set the watchdog to reset the board when triggered 349 if ((MmioRead32(SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_RESEN) == 0) { 350 MmioOr32 (SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_RESEN); 351 } 352 353 // Prohibit any rogue access to SP805 registers 354 SP805Lock(); 355 356 // 357 // Make sure the Watchdog Timer Architectural Protocol has not been installed in the system yet. 358 // This will avoid conflicts with the universal watchdog 359 // 360 ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid); 361 362 // Register for an ExitBootServicesEvent 363 Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_NOTIFY, ExitBootServicesEvent, NULL, &EfiExitBootServicesEvent); 364 if (EFI_ERROR(Status)) { 365 Status = EFI_OUT_OF_RESOURCES; 366 goto EXIT; 367 } 368 369 // Install the Timer Architectural Protocol onto a new handle 370 Handle = NULL; 371 Status = gBS->InstallMultipleProtocolInterfaces( 372 &Handle, 373 &gEfiWatchdogTimerArchProtocolGuid, &gWatchdogTimer, 374 NULL 375 ); 376 if (EFI_ERROR(Status)) { 377 Status = EFI_OUT_OF_RESOURCES; 378 goto EXIT; 379 } 380 381EXIT: 382 if(EFI_ERROR(Status)) { 383 // The watchdog failed to initialize 384 ASSERT(FALSE); 385 } 386 return Status; 387} 388