3 * Copyright (c) 2011, ARM Limited. All rights reserved.
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
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.
18 #include <Library/BaseLib.h>
19 #include <Library/DebugLib.h>
20 #include <Library/BaseMemoryLib.h>
21 #include <Library/UefiBootServicesTableLib.h>
22 #include <Library/UefiRuntimeServicesTableLib.h>
23 #include <Library/UefiLib.h>
24 #include <Library/IoLib.h>
26 #include <Protocol/WatchdogTimer.h>
27 #include <ArmPlatform.h>
28 #include <Drivers/SP805Watchdog.h>
31 Interface structure for the Watchdog Architectural Protocol.
33 @par Protocol Description:
34 This protocol provides a service to set the amount of time to wait
35 before firing the watchdog timer, and it also provides a service to
36 register a handler that is invoked when the watchdog timer fires.
38 @par When the watchdog timer fires, control will be passed to a handler
39 if one has been registered. If no handler has been registered,
40 or the registered handler returns, then the system will be
41 reset by calling the Runtime Service ResetSystem().
43 @param RegisterHandler
44 Registers a handler that will be called each time the
45 watchdogtimer interrupt fires. TimerPeriod defines the minimum
46 time between timer interrupts, so TimerPeriod will also
47 be the minimum time between calls to the registered
49 NOTE: If the watchdog resets the system in hardware, then
50 this function will not have any chance of executing.
53 Sets the period of the timer interrupt in 100 nS units.
54 This function is optional, and may return EFI_UNSUPPORTED.
55 If this function is supported, then the timer period will
56 be rounded up to the nearest supported timer period.
59 Retrieves the period of the timer interrupt in 100 nS units.
62 EFI_WATCHDOG_TIMER_ARCH_PROTOCOL gWatchdogTimer
= {
63 (EFI_WATCHDOG_TIMER_REGISTER_HANDLER
) SP805RegisterHandler
,
64 (EFI_WATCHDOG_TIMER_SET_TIMER_PERIOD
) SP805SetTimerPeriod
,
65 (EFI_WATCHDOG_TIMER_GET_TIMER_PERIOD
) SP805GetTimerPeriod
68 EFI_EVENT EfiExitBootServicesEvent
= (EFI_EVENT
)NULL
;
70 BOOLEAN mSP805Initialized
= FALSE
;
77 // Check if this is a PrimeCell Peripheral
78 if( ( MmioRead8( SP805_WDOG_PCELL_ID0
) != 0x0D )
79 || ( MmioRead8( SP805_WDOG_PCELL_ID1
) != 0xF0 )
80 || ( MmioRead8( SP805_WDOG_PCELL_ID2
) != 0x05 )
81 || ( MmioRead8( SP805_WDOG_PCELL_ID3
) != 0xB1 ) ) {
85 // Check if this PrimeCell Peripheral is the SP805 Watchdog Timer
86 if( ( MmioRead8( SP805_WDOG_PERIPH_ID0
) != 0x05 )
87 || ( MmioRead8( SP805_WDOG_PERIPH_ID1
) != 0x18 )
88 || (( MmioRead8( SP805_WDOG_PERIPH_ID2
) & 0x0000000F) != 0x04 )
89 || ( MmioRead8( SP805_WDOG_PERIPH_ID3
) != 0x00 ) ) {
97 Make sure the SP805 registers are unlocked for writing.
99 Note: The SP805 Watchdog Timer supports locking of its registers,
100 i.e. it inhibits all writes to avoid rogue software accidentally
101 corrupting their contents.
109 if( MmioRead32(SP805_WDOG_LOCK_REG
) == SP805_WDOG_LOCK_IS_LOCKED
) {
110 MmioWrite32(SP805_WDOG_LOCK_REG
, SP805_WDOG_SPECIAL_UNLOCK_CODE
);
115 Make sure the SP805 registers are locked and can not be overwritten.
117 Note: The SP805 Watchdog Timer supports locking of its registers,
118 i.e. it inhibits all writes to avoid rogue software accidentally
119 corrupting their contents.
127 if( MmioRead32(SP805_WDOG_LOCK_REG
) == SP805_WDOG_LOCK_IS_UNLOCKED
) {
128 // To lock it, just write in any number (except the special unlock code).
129 MmioWrite32(SP805_WDOG_LOCK_REG
, SP805_WDOG_LOCK_IS_LOCKED
);
134 Stop the SP805 watchdog timer from counting down by disabling interrupts.
142 // Disable interrupts
143 if ( (MmioRead32(SP805_WDOG_CONTROL_REG
) & SP805_WDOG_CTRL_INTEN
) != 0 ) {
144 MmioAnd32(SP805_WDOG_CONTROL_REG
, ~SP805_WDOG_CTRL_INTEN
);
149 Starts the SP805 counting down by enabling interrupts.
150 The count down will start from the value stored in the Load register,
151 not from the value where it was previously stopped.
160 if ( (MmioRead32(SP805_WDOG_CONTROL_REG
) & SP805_WDOG_CTRL_INTEN
) == 0 ) {
161 MmioOr32(SP805_WDOG_CONTROL_REG
, SP805_WDOG_CTRL_INTEN
);
166 On exiting boot services we must make sure the SP805 Watchdog Timer
171 ExitBootServicesEvent (
182 This function registers the handler NotifyFunction so it is called every time
183 the watchdog timer expires. It also passes the amount of time since the last
184 handler call to the NotifyFunction.
185 If NotifyFunction is not NULL and a handler is not already registered,
186 then the new handler is registered and EFI_SUCCESS is returned.
187 If NotifyFunction is NULL, and a handler is already registered,
188 then that handler is unregistered.
189 If an attempt is made to register a handler when a handler is already registered,
190 then EFI_ALREADY_STARTED is returned.
191 If an attempt is made to unregister a handler when a handler is not registered,
192 then EFI_INVALID_PARAMETER is returned.
194 @param This The EFI_TIMER_ARCH_PROTOCOL instance.
195 @param NotifyFunction The function to call when a timer interrupt fires. This
196 function executes at TPL_HIGH_LEVEL. The DXE Core will
197 register a handler for the timer interrupt, so it can know
198 how much time has passed. This information is used to
199 signal timer based events. NULL will unregister the handler.
201 @retval EFI_SUCCESS The watchdog timer handler was registered.
202 @retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already
204 @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not
205 previously registered.
210 SP805RegisterHandler (
211 IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL
*This
,
212 IN EFI_WATCHDOG_TIMER_NOTIFY NotifyFunction
215 // ERROR: This function is not supported.
216 // The hardware watchdog will reset the board
217 return EFI_INVALID_PARAMETER
;
222 This function adjusts the period of timer interrupts to the value specified
223 by TimerPeriod. If the timer period is updated, then the selected timer
224 period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If
225 the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
226 If an error occurs while attempting to update the timer period, then the
227 timer hardware will be put back in its state prior to this call, and
228 EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt
229 is disabled. This is not the same as disabling the CPU's interrupts.
230 Instead, it must either turn off the timer hardware, or it must adjust the
231 interrupt controller so that a CPU interrupt is not generated when the timer
234 @param This The EFI_TIMER_ARCH_PROTOCOL instance.
235 @param TimerPeriod The rate to program the timer interrupt in 100 nS units. If
236 the timer hardware is not programmable, then EFI_UNSUPPORTED is
237 returned. If the timer is programmable, then the timer period
238 will be rounded up to the nearest timer period that is supported
239 by the timer hardware. If TimerPeriod is set to 0, then the
240 timer interrupts will be disabled.
243 @retval EFI_SUCCESS The timer period was changed.
244 @retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt.
245 @retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error.
250 SP805SetTimerPeriod (
251 IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL
*This
,
252 IN UINT64 TimerPeriod
// In 100ns units
255 EFI_STATUS Status
= EFI_SUCCESS
;
258 // Initialize the hardware if not already done
259 if( !mSP805Initialized
) {
260 Status
= SP805Initialize();
261 if (EFI_ERROR(Status
)) {
268 if( TimerPeriod
== 0 ) {
269 // This is a watchdog stop request
273 // Calculate the Watchdog ticks required for a delay of (TimerTicks * 100) nanoseconds
274 // The SP805 will count down to ZERO once, generate an interrupt and
275 // then it will again reload the initial value and start again.
276 // On the second time when it reaches ZERO, it will actually reset the board.
277 // Therefore, we need to load half the required delay.
279 // WatchdogTicks = ((TimerPeriod * 100 * SP805_CLOCK_FREQUENCY) / 1GHz) / 2 ;
283 // WatchdogTicks = (TimerPeriod * SP805_CLOCK_FREQUENCY) / 20 MHz ;
285 Ticks64bit
= DivU64x32( MultU64x32( TimerPeriod
, SP805_CLOCK_FREQUENCY
), 20000000 );
287 // The registers in the SP805 are only 32 bits
288 if( Ticks64bit
> SP805_MAX_TICKS
) {
289 // We could load the watchdog with the maximum supported value but
290 // if a smaller value was requested, this could have the watchdog
291 // triggering before it was intended.
292 // Better generate an error to let the caller know.
293 Status
= EFI_DEVICE_ERROR
;
297 // Update the watchdog with a 32-bit value.
298 MmioWrite32(SP805_WDOG_LOAD_REG
, (UINT32
)Ticks64bit
);
300 // Start the watchdog
305 // Ensure the watchdog is locked before exiting.
311 This function retrieves the period of timer interrupts in 100 ns units,
312 returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod
313 is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is
314 returned, then the timer is currently disabled.
316 @param This The EFI_TIMER_ARCH_PROTOCOL instance.
317 @param TimerPeriod A pointer to the timer period to retrieve in 100 ns units. If
318 0 is returned, then the timer is currently disabled.
321 @retval EFI_SUCCESS The timer period was returned in TimerPeriod.
322 @retval EFI_INVALID_PARAMETER TimerPeriod is NULL.
327 SP805GetTimerPeriod (
328 IN CONST EFI_WATCHDOG_TIMER_ARCH_PROTOCOL
*This
,
329 OUT UINT64
*TimerPeriod
332 EFI_STATUS Status
= EFI_SUCCESS
;
335 if (TimerPeriod
== NULL
) {
336 return EFI_INVALID_PARAMETER
;
339 // Initialize the hardware if not already done
340 if( !mSP805Initialized
) {
341 Status
= SP805Initialize();
342 if (EFI_ERROR(Status
)) {
347 // Check if the watchdog is stopped
348 if ( (MmioRead32(SP805_WDOG_CONTROL_REG
) & SP805_WDOG_CTRL_INTEN
) == 0 ) {
349 // It is stopped, so return zero.
352 // Convert the Watchdog ticks into TimerPeriod
353 // Ensure 64bit arithmetic throughout because the Watchdog ticks may already
354 // be at the maximum 32 bit value and we still need to multiply that by 600.
355 ReturnValue
= MultU64x32( MmioRead32(SP805_WDOG_LOAD_REG
), 600 );
358 *TimerPeriod
= ReturnValue
;
365 Initialize the state information for the Watchdog Timer Architectural Protocol.
367 @param ImageHandle of the loaded driver
368 @param SystemTable Pointer to the System Table
370 @retval EFI_SUCCESS Protocol registered
371 @retval EFI_OUT_OF_RESOURCES Cannot allocate protocol data structure
372 @retval EFI_DEVICE_ERROR Hardware problems
382 // Check if the SP805 hardware watchdog module exists on board
383 Status
= SP805Identify();
384 if (EFI_ERROR( Status
)) {
385 Status
= EFI_DEVICE_ERROR
;
389 // Unlock access to the SP805 registers
392 // Stop the watchdog from triggering unexpectedly
395 // Set the watchdog to reset the board when triggered
396 if ( (MmioRead32(SP805_WDOG_CONTROL_REG
) & SP805_WDOG_CTRL_RESEN
) == 0 ) {
397 MmioOr32(SP805_WDOG_CONTROL_REG
, SP805_WDOG_CTRL_RESEN
);
400 // Prohibit any rogue access to SP805 registers
403 mSP805Initialized
= TRUE
;
411 SP805InstallProtocol (
412 IN EFI_HANDLE ImageHandle
,
413 IN EFI_SYSTEM_TABLE
*SystemTable
420 // Make sure the Watchdog Timer Architectural Protocol has not been installed in the system yet.
421 // This will avoid conflicts with the universal watchdog
423 ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL
, &gEfiWatchdogTimerArchProtocolGuid
);
425 // Register for an ExitBootServicesEvent
426 Status
= gBS
->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES
, TPL_NOTIFY
, ExitBootServicesEvent
, NULL
, &EfiExitBootServicesEvent
);
427 if (EFI_ERROR(Status
)) {
428 Status
= EFI_OUT_OF_RESOURCES
;
432 // Install the Timer Architectural Protocol onto a new handle
434 Status
= gBS
->InstallMultipleProtocolInterfaces(
436 &gEfiWatchdogTimerArchProtocolGuid
, &gWatchdogTimer
,
439 if (EFI_ERROR(Status
)) {
440 Status
= EFI_OUT_OF_RESOURCES
;
445 if(EFI_ERROR(Status
)) {
446 // The watchdog failed to initialize