#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"

Functions
STATIC VOID	SP805Unlock (VOID)

STATIC VOID	SP805Lock (VOID)

STATIC VOID EFIAPI	SP805InterruptHandler (IN HARDWARE_INTERRUPT_SOURCE Source, IN EFI_SYSTEM_CONTEXT SystemContext)

STATIC VOID	SP805Stop (VOID)

STATIC VOID	SP805Start (VOID)

STATIC VOID EFIAPI	ExitBootServicesEvent (IN EFI_EVENT Event, IN VOID *Context)

STATIC EFI_STATUS EFIAPI	SP805RegisterHandler (IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This, IN EFI_WATCHDOG_TIMER_NOTIFY NotifyFunction)

STATIC EFI_STATUS EFIAPI	SP805SetTimerPeriod (IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This, IN UINT64 TimerPeriod)

STATIC EFI_STATUS EFIAPI	SP805GetTimerPeriod (IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL This, OUT UINT64 TimerPeriod)

EFI_STATUS EFIAPI	SP805Initialize (IN EFI_HANDLE ImageHandle, IN EFI_SYSTEM_TABLE *SystemTable)

Variables
STATIC EFI_EVENT	mEfiExitBootServicesEvent

STATIC EFI_HARDWARE_INTERRUPT_PROTOCOL *	mInterrupt

STATIC EFI_WATCHDOG_TIMER_NOTIFY	mWatchdogNotify

STATIC UINT64	mTimerPeriod

STATIC EFI_WATCHDOG_TIMER_ARCH_PROTOCOL	mWatchdogTimer

Detailed Description

SPDX-License-Identifier: BSD-2-Clause-Patent

Definition in file SP805Watchdog.c.

Function Documentation

◆ ExitBootServicesEvent()

STATIC VOID EFIAPI ExitBootServicesEvent	(	IN EFI_EVENT	Event,
		IN VOID *	Context
	)

On exiting boot services we must make sure the SP805 Watchdog Timer is stopped.

Definition at line 132 of file SP805Watchdog.c.

◆ SP805GetTimerPeriod()

STATIC EFI_STATUS EFIAPI SP805GetTimerPeriod	(	IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *	This,
		OUT UINT64 *	TimerPeriod
	)

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.

Parameters

This	The EFI_TIMER_ARCH_PROTOCOL instance.
TimerPeriod	A pointer to the timer period to retrieve in 100 ns units. If 0 is returned, then the timer is currently disabled.

Return values

EFI_SUCCESS	The timer period was returned in TimerPeriod.
EFI_INVALID_PARAMETER	TimerPeriod is NULL.

Definition at line 292 of file SP805Watchdog.c.

◆ SP805Initialize()

EFI_STATUS EFIAPI SP805Initialize	(	IN EFI_HANDLE	ImageHandle,
		IN EFI_SYSTEM_TABLE *	SystemTable
	)

Initialize the state information for the Watchdog Timer Architectural Protocol.

Parameters

ImageHandle	of the loaded driver
SystemTable	Pointer to the System Table

Return values

EFI_SUCCESS	Protocol registered
EFI_OUT_OF_RESOURCES	Cannot allocate protocol data structure
EFI_DEVICE_ERROR	Hardware problems

Definition at line 356 of file SP805Watchdog.c.

◆ SP805InterruptHandler()

STATIC VOID EFIAPI SP805InterruptHandler	(	IN HARDWARE_INTERRUPT_SOURCE	Source,
		IN EFI_SYSTEM_CONTEXT	SystemContext
	)

Definition at line 69 of file SP805Watchdog.c.

◆ SP805Lock()

STATIC VOID SP805Lock ( VOID )

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.

Definition at line 56 of file SP805Watchdog.c.

◆ SP805RegisterHandler()

STATIC EFI_STATUS EFIAPI SP805RegisterHandler	(	IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *	This,
		IN EFI_WATCHDOG_TIMER_NOTIFY	NotifyFunction
	)

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.

Parameters

This	The EFI_TIMER_ARCH_PROTOCOL instance.
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.

Return values

EFI_SUCCESS	The watchdog timer handler was registered.
EFI_ALREADY_STARTED	NotifyFunction is not NULL, and a handler is already registered.
EFI_INVALID_PARAMETER	NotifyFunction is NULL, and a handler was not previously registered.

Definition at line 172 of file SP805Watchdog.c.

◆ SP805SetTimerPeriod()

STATIC EFI_STATUS EFIAPI SP805SetTimerPeriod	(	IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *	This,
		IN UINT64	TimerPeriod
	)

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.

Parameters

This	The EFI_TIMER_ARCH_PROTOCOL instance.
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.

Return values

EFI_SUCCESS	The timer period was changed.
EFI_UNSUPPORTED	The platform cannot change the period of the timer interrupt.
EFI_DEVICE_ERROR	The timer period could not be changed due to a device error.

Definition at line 220 of file SP805Watchdog.c.

◆ SP805Start()

STATIC VOID SP805Start ( VOID )

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.

Definition at line 115 of file SP805Watchdog.c.

◆ SP805Stop()

STATIC VOID SP805Stop ( VOID )

Stop the SP805 watchdog timer from counting down by disabling interrupts.

Definition at line 98 of file SP805Watchdog.c.

◆ SP805Unlock()

STATIC VOID SP805Unlock ( VOID )

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.

Definition at line 38 of file SP805Watchdog.c.

Variable Documentation

◆ mEfiExitBootServicesEvent

STATIC EFI_EVENT mEfiExitBootServicesEvent

Definition at line 24 of file SP805Watchdog.c.

◆ mInterrupt

STATIC EFI_HARDWARE_INTERRUPT_PROTOCOL* mInterrupt

Definition at line 25 of file SP805Watchdog.c.

◆ mTimerPeriod

STATIC UINT64 mTimerPeriod

Definition at line 27 of file SP805Watchdog.c.

◆ mWatchdogNotify

STATIC EFI_WATCHDOG_TIMER_NOTIFY mWatchdogNotify

Definition at line 26 of file SP805Watchdog.c.

◆ mWatchdogTimer

STATIC EFI_WATCHDOG_TIMER_ARCH_PROTOCOL mWatchdogTimer

Initial value:

= {
  SP805RegisterHandler,
  SP805SetTimerPeriod,
  SP805GetTimerPeriod
}

Interface structure for the Watchdog Architectural Protocol.

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.

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().

Parameters

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.
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.
GetTimerPeriod	Retrieves the period of the timer interrupt in 100 nS units.

Definition at line 337 of file SP805Watchdog.c.

Functions

Variables

Detailed Description

Function Documentation

◆ ExitBootServicesEvent()

◆ SP805GetTimerPeriod()

◆ SP805Initialize()

◆ SP805InterruptHandler()

◆ SP805Lock()

◆ SP805RegisterHandler()

◆ SP805SetTimerPeriod()

◆ SP805Start()

◆ SP805Stop()

◆ SP805Unlock()

Variable Documentation

◆ mEfiExitBootServicesEvent

◆ mInterrupt

◆ mTimerPeriod

◆ mWatchdogNotify

◆ mWatchdogTimer