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- /** @file
- *
- * Copyright (c) 2011-2013, ARM Limited. All rights reserved.
- * Copyright (c) 2018, Linaro Limited. All rights reserved.
- *
- * SPDX-License-Identifier: BSD-2-Clause-Patent
- *
- **/
- #include <PiDxe.h>
- #include <Library/BaseLib.h>
- #include <Library/BaseMemoryLib.h>
- #include <Library/DebugLib.h>
- #include <Library/IoLib.h>
- #include <Library/UefiBootServicesTableLib.h>
- #include <Library/UefiRuntimeServicesTableLib.h>
- #include <Protocol/HardwareInterrupt.h>
- #include <Protocol/WatchdogTimer.h>
- #include "SP805Watchdog.h"
- STATIC EFI_EVENT mEfiExitBootServicesEvent;
- STATIC EFI_HARDWARE_INTERRUPT_PROTOCOL *mInterrupt;
- STATIC EFI_WATCHDOG_TIMER_NOTIFY mWatchdogNotify;
- STATIC UINT32 mTimerPeriod;
- /**
- Make sure the SP805 registers are unlocked for writing.
- Note: The SP805 Watchdog Timer supports locking of its registers,
- i.e. it inhibits all writes to avoid rogue software accidentally
- corrupting their contents.
- **/
- STATIC
- VOID
- SP805Unlock (
- VOID
- )
- {
- if (MmioRead32 (SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_LOCKED) {
- MmioWrite32 (SP805_WDOG_LOCK_REG, SP805_WDOG_SPECIAL_UNLOCK_CODE);
- }
- }
- /**
- Make sure the SP805 registers are locked and can not be overwritten.
- Note: The SP805 Watchdog Timer supports locking of its registers,
- i.e. it inhibits all writes to avoid rogue software accidentally
- corrupting their contents.
- **/
- STATIC
- VOID
- SP805Lock (
- VOID
- )
- {
- if (MmioRead32 (SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_UNLOCKED) {
- // To lock it, just write in any number (except the special unlock code).
- MmioWrite32 (SP805_WDOG_LOCK_REG, SP805_WDOG_LOCK_IS_LOCKED);
- }
- }
- STATIC
- VOID
- EFIAPI
- SP805InterruptHandler (
- IN HARDWARE_INTERRUPT_SOURCE Source,
- IN EFI_SYSTEM_CONTEXT SystemContext
- )
- {
- SP805Unlock ();
- MmioWrite32 (SP805_WDOG_INT_CLR_REG, 0); // write of any value clears the irq
- SP805Lock ();
- mInterrupt->EndOfInterrupt (mInterrupt, Source);
- //
- // The notify function should be called with the elapsed number of ticks
- // since the watchdog was armed, which should exceed the timer period.
- // We don't actually know the elapsed number of ticks, so let's return
- // the timer period plus 1.
- //
- if (mWatchdogNotify != NULL) {
- mWatchdogNotify (mTimerPeriod + 1);
- }
- gRT->ResetSystem (EfiResetCold, EFI_TIMEOUT, 0, NULL);
- }
- /**
- Stop the SP805 watchdog timer from counting down by disabling interrupts.
- **/
- STATIC
- VOID
- SP805Stop (
- VOID
- )
- {
- // Disable interrupts
- if ((MmioRead32 (SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) != 0) {
- MmioAnd32 (SP805_WDOG_CONTROL_REG, ~SP805_WDOG_CTRL_INTEN);
- }
- }
- /**
- Starts the SP805 counting down by enabling interrupts.
- The count down will start from the value stored in the Load register,
- not from the value where it was previously stopped.
- **/
- STATIC
- VOID
- SP805Start (
- VOID
- )
- {
- // Enable interrupts
- if ((MmioRead32 (SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) == 0) {
- MmioOr32 (SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_INTEN);
- }
- }
- /**
- On exiting boot services we must make sure the SP805 Watchdog Timer
- is stopped.
- **/
- STATIC
- VOID
- EFIAPI
- ExitBootServicesEvent (
- IN EFI_EVENT Event,
- IN VOID *Context
- )
- {
- SP805Unlock ();
- SP805Stop ();
- SP805Lock ();
- }
- /**
- This function registers the handler NotifyFunction so it is called every time
- the watchdog timer expires. It also passes the amount of time since the last
- handler call to the NotifyFunction.
- If NotifyFunction is not NULL and a handler is not already registered,
- then the new handler is registered and EFI_SUCCESS is returned.
- If NotifyFunction is NULL, and a handler is already registered,
- then that handler is unregistered.
- If an attempt is made to register a handler when a handler is already registered,
- then EFI_ALREADY_STARTED is returned.
- If an attempt is made to unregister a handler when a handler is not registered,
- then EFI_INVALID_PARAMETER is returned.
- @param This The EFI_TIMER_ARCH_PROTOCOL instance.
- @param NotifyFunction The function to call when a timer interrupt fires. This
- function executes at TPL_HIGH_LEVEL. The DXE Core will
- register a handler for the timer interrupt, so it can know
- how much time has passed. This information is used to
- signal timer based events. NULL will unregister the handler.
- @retval EFI_SUCCESS The watchdog timer handler was registered.
- @retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already
- registered.
- @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not
- previously registered.
- **/
- STATIC
- EFI_STATUS
- EFIAPI
- SP805RegisterHandler (
- IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This,
- IN EFI_WATCHDOG_TIMER_NOTIFY NotifyFunction
- )
- {
- if (mWatchdogNotify == NULL && NotifyFunction == NULL) {
- return EFI_INVALID_PARAMETER;
- }
- if (mWatchdogNotify != NULL && NotifyFunction != NULL) {
- return EFI_ALREADY_STARTED;
- }
- mWatchdogNotify = NotifyFunction;
- return EFI_SUCCESS;
- }
- /**
- This function adjusts the period of timer interrupts to the value specified
- by TimerPeriod. If the timer period is updated, then the selected timer
- period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If
- the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
- If an error occurs while attempting to update the timer period, then the
- timer hardware will be put back in its state prior to this call, and
- EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt
- is disabled. This is not the same as disabling the CPU's interrupts.
- Instead, it must either turn off the timer hardware, or it must adjust the
- interrupt controller so that a CPU interrupt is not generated when the timer
- interrupt fires.
- @param This The EFI_TIMER_ARCH_PROTOCOL instance.
- @param TimerPeriod The rate to program the timer interrupt in 100 nS units. If
- the timer hardware is not programmable, then EFI_UNSUPPORTED is
- returned. If the timer is programmable, then the timer period
- will be rounded up to the nearest timer period that is supported
- by the timer hardware. If TimerPeriod is set to 0, then the
- timer interrupts will be disabled.
- @retval EFI_SUCCESS The timer period was changed.
- @retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt.
- @retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error.
- **/
- STATIC
- EFI_STATUS
- EFIAPI
- SP805SetTimerPeriod (
- IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This,
- IN UINT64 TimerPeriod // In 100ns units
- )
- {
- EFI_STATUS Status;
- UINT64 Ticks64bit;
- SP805Unlock ();
- Status = EFI_SUCCESS;
- if (TimerPeriod == 0) {
- // This is a watchdog stop request
- SP805Stop ();
- } else {
- // Calculate the Watchdog ticks required for a delay of (TimerTicks * 100) nanoseconds
- // The SP805 will count down to zero and generate an interrupt.
- //
- // WatchdogTicks = ((TimerPeriod * 100 * SP805_CLOCK_FREQUENCY) / 1GHz);
- //
- // i.e.:
- //
- // WatchdogTicks = (TimerPeriod * SP805_CLOCK_FREQUENCY) / 10 MHz ;
- Ticks64bit = MultU64x32 (TimerPeriod, PcdGet32 (PcdSP805WatchdogClockFrequencyInHz));
- Ticks64bit = DivU64x32 (Ticks64bit, 10 * 1000 * 1000);
- // The registers in the SP805 are only 32 bits
- if (Ticks64bit > MAX_UINT32) {
- // We could load the watchdog with the maximum supported value but
- // if a smaller value was requested, this could have the watchdog
- // triggering before it was intended.
- // Better generate an error to let the caller know.
- Status = EFI_DEVICE_ERROR;
- goto EXIT;
- }
- // Update the watchdog with a 32-bit value.
- MmioWrite32 (SP805_WDOG_LOAD_REG, (UINT32)Ticks64bit);
- // Start the watchdog
- SP805Start ();
- }
- mTimerPeriod = TimerPeriod;
- EXIT:
- // Ensure the watchdog is locked before exiting.
- SP805Lock ();
- ASSERT_EFI_ERROR (Status);
- return Status;
- }
- /**
- This function retrieves the period of timer interrupts in 100 ns units,
- returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod
- is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is
- returned, then the timer is currently disabled.
- @param This The EFI_TIMER_ARCH_PROTOCOL instance.
- @param TimerPeriod A pointer to the timer period to retrieve in 100 ns units. If
- 0 is returned, then the timer is currently disabled.
- @retval EFI_SUCCESS The timer period was returned in TimerPeriod.
- @retval EFI_INVALID_PARAMETER TimerPeriod is NULL.
- **/
- STATIC
- EFI_STATUS
- EFIAPI
- SP805GetTimerPeriod (
- IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This,
- OUT UINT64 *TimerPeriod
- )
- {
- if (TimerPeriod == NULL) {
- return EFI_INVALID_PARAMETER;
- }
- *TimerPeriod = mTimerPeriod;
- return EFI_SUCCESS;
- }
- /**
- Interface structure for the Watchdog Architectural Protocol.
- @par Protocol Description:
- This protocol provides a service to set the amount of time to wait
- before firing the watchdog timer, and it also provides a service to
- register a handler that is invoked when the watchdog timer fires.
- @par When the watchdog timer fires, control will be passed to a handler
- if one has been registered. If no handler has been registered,
- or the registered handler returns, then the system will be
- reset by calling the Runtime Service ResetSystem().
- @param RegisterHandler
- Registers a handler that will be called each time the
- watchdogtimer interrupt fires. TimerPeriod defines the minimum
- time between timer interrupts, so TimerPeriod will also
- be the minimum time between calls to the registered
- handler.
- NOTE: If the watchdog resets the system in hardware, then
- this function will not have any chance of executing.
- @param SetTimerPeriod
- Sets the period of the timer interrupt in 100 nS units.
- This function is optional, and may return EFI_UNSUPPORTED.
- If this function is supported, then the timer period will
- be rounded up to the nearest supported timer period.
- @param GetTimerPeriod
- Retrieves the period of the timer interrupt in 100 nS units.
- **/
- STATIC EFI_WATCHDOG_TIMER_ARCH_PROTOCOL mWatchdogTimer = {
- SP805RegisterHandler,
- SP805SetTimerPeriod,
- SP805GetTimerPeriod
- };
- /**
- Initialize the state information for the Watchdog Timer Architectural Protocol.
- @param ImageHandle of the loaded driver
- @param SystemTable Pointer to the System Table
- @retval EFI_SUCCESS Protocol registered
- @retval EFI_OUT_OF_RESOURCES Cannot allocate protocol data structure
- @retval EFI_DEVICE_ERROR Hardware problems
- **/
- EFI_STATUS
- EFIAPI
- SP805Initialize (
- IN EFI_HANDLE ImageHandle,
- IN EFI_SYSTEM_TABLE *SystemTable
- )
- {
- EFI_STATUS Status;
- EFI_HANDLE Handle;
- // Find the interrupt controller protocol. ASSERT if not found.
- Status = gBS->LocateProtocol (&gHardwareInterruptProtocolGuid, NULL,
- (VOID **)&mInterrupt);
- ASSERT_EFI_ERROR (Status);
- // Unlock access to the SP805 registers
- SP805Unlock ();
- // Stop the watchdog from triggering unexpectedly
- SP805Stop ();
- // Set the watchdog to reset the board when triggered
- // This is a last resort in case the interrupt handler fails
- if ((MmioRead32 (SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_RESEN) == 0) {
- MmioOr32 (SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_RESEN);
- }
- // Clear any pending interrupts
- MmioWrite32 (SP805_WDOG_INT_CLR_REG, 0); // write of any value clears the irq
- // Prohibit any rogue access to SP805 registers
- SP805Lock ();
- if (PcdGet32 (PcdSP805WatchdogInterrupt) > 0) {
- Status = mInterrupt->RegisterInterruptSource (mInterrupt,
- PcdGet32 (PcdSP805WatchdogInterrupt),
- SP805InterruptHandler);
- if (EFI_ERROR (Status)) {
- DEBUG ((DEBUG_ERROR, "%a: failed to register watchdog interrupt - %r\n",
- __FUNCTION__, Status));
- return Status;
- }
- } else {
- DEBUG ((DEBUG_WARN, "%a: no interrupt specified, running in RESET mode only\n",
- __FUNCTION__));
- }
- //
- // Make sure the Watchdog Timer Architectural Protocol has not been installed in the system yet.
- // This will avoid conflicts with the universal watchdog
- //
- ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid);
- // Register for an ExitBootServicesEvent
- Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_NOTIFY,
- ExitBootServicesEvent, NULL, &mEfiExitBootServicesEvent);
- if (EFI_ERROR (Status)) {
- Status = EFI_OUT_OF_RESOURCES;
- goto EXIT;
- }
- // Install the Timer Architectural Protocol onto a new handle
- Handle = NULL;
- Status = gBS->InstallMultipleProtocolInterfaces (
- &Handle,
- &gEfiWatchdogTimerArchProtocolGuid, &mWatchdogTimer,
- NULL
- );
- if (EFI_ERROR (Status)) {
- Status = EFI_OUT_OF_RESOURCES;
- goto EXIT;
- }
- EXIT:
- ASSERT_EFI_ERROR (Status);
- return Status;
- }
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