384 lines
12 KiB
C
384 lines
12 KiB
C
/** @file
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*
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* Copyright (c) 2013-2018, ARM Limited. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-2-Clause-Patent
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*
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**/
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#include <PiDxe.h>
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#include <Library/BaseLib.h>
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#include <Library/BaseMemoryLib.h>
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#include <Library/DebugLib.h>
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#include <Library/IoLib.h>
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#include <Library/PcdLib.h>
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#include <Library/UefiBootServicesTableLib.h>
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#include <Library/UefiRuntimeServicesTableLib.h>
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#include <Library/UefiLib.h>
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#include <Library/ArmGenericTimerCounterLib.h>
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#include <Protocol/HardwareInterrupt2.h>
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#include <Protocol/WatchdogTimer.h>
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#include "GenericWatchdog.h"
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/* The number of 100ns periods (the unit of time passed to these functions)
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in a second */
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#define TIME_UNITS_PER_SECOND 10000000
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// Tick frequency of the generic timer basis of the generic watchdog.
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STATIC UINTN mTimerFrequencyHz = 0;
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/* In cases where the compare register was set manually, information about
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how long the watchdog was asked to wait cannot be retrieved from hardware.
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It is therefore stored here. 0 means the timer is not running. */
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STATIC UINT64 mNumTimerTicks = 0;
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STATIC EFI_HARDWARE_INTERRUPT2_PROTOCOL *mInterruptProtocol;
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STATIC EFI_WATCHDOG_TIMER_NOTIFY mWatchdogNotify;
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STATIC
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VOID
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WatchdogWriteOffsetRegister (
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UINT32 Value
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)
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{
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MmioWrite32 (GENERIC_WDOG_OFFSET_REG, Value);
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}
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STATIC
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VOID
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WatchdogWriteCompareRegister (
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UINT64 Value
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)
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{
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MmioWrite32 (GENERIC_WDOG_COMPARE_VALUE_REG_LOW, Value & MAX_UINT32);
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MmioWrite32 (GENERIC_WDOG_COMPARE_VALUE_REG_HIGH, (Value >> 32) & MAX_UINT32);
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}
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STATIC
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VOID
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WatchdogEnable (
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VOID
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)
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{
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MmioWrite32 (GENERIC_WDOG_CONTROL_STATUS_REG, GENERIC_WDOG_ENABLED);
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}
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STATIC
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VOID
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WatchdogDisable (
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VOID
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)
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{
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MmioWrite32 (GENERIC_WDOG_CONTROL_STATUS_REG, GENERIC_WDOG_DISABLED);
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}
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/** On exiting boot services we must make sure the Watchdog Timer
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is stopped.
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**/
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STATIC
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VOID
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EFIAPI
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WatchdogExitBootServicesEvent (
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IN EFI_EVENT Event,
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IN VOID *Context
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)
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{
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WatchdogDisable ();
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mNumTimerTicks = 0;
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}
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/* This function is called when the watchdog's first signal (WS0) goes high.
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It uses the ResetSystem Runtime Service to reset the board.
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*/
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STATIC
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VOID
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EFIAPI
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WatchdogInterruptHandler (
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IN HARDWARE_INTERRUPT_SOURCE Source,
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IN EFI_SYSTEM_CONTEXT SystemContext
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)
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{
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STATIC CONST CHAR16 ResetString[] = L"The generic watchdog timer ran out.";
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UINT64 TimerPeriod;
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WatchdogDisable ();
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mInterruptProtocol->EndOfInterrupt (mInterruptProtocol, Source);
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//
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// The notify function should be called with the elapsed number of ticks
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// since the watchdog was armed, which should exceed the timer period.
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// We don't actually know the elapsed number of ticks, so let's return
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// the timer period plus 1.
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//
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if (mWatchdogNotify != NULL) {
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TimerPeriod = ((TIME_UNITS_PER_SECOND / mTimerFrequencyHz) * mNumTimerTicks);
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mWatchdogNotify (TimerPeriod + 1);
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}
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gRT->ResetSystem (
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EfiResetCold,
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EFI_TIMEOUT,
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StrSize (ResetString),
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(CHAR16 *)ResetString
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);
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// If we got here then the reset didn't work
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ASSERT (FALSE);
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}
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/**
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This function registers the handler NotifyFunction so it is called every time
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the watchdog timer expires. It also passes the amount of time since the last
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handler call to the NotifyFunction.
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If NotifyFunction is not NULL and a handler is not already registered,
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then the new handler is registered and EFI_SUCCESS is returned.
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If NotifyFunction is NULL, and a handler is already registered,
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then that handler is unregistered.
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If an attempt is made to register a handler when a handler is already
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registered, then EFI_ALREADY_STARTED is returned.
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If an attempt is made to unregister a handler when a handler is not
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registered, then EFI_INVALID_PARAMETER is returned.
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@param This The EFI_TIMER_ARCH_PROTOCOL instance.
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@param NotifyFunction The function to call when a timer interrupt fires.
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This function executes at TPL_HIGH_LEVEL. The DXE
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Core will register a handler for the timer interrupt,
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so it can know how much time has passed. This
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information is used to signal timer based events.
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NULL will unregister the handler.
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@retval EFI_UNSUPPORTED The code does not support NotifyFunction.
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**/
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STATIC
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EFI_STATUS
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EFIAPI
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WatchdogRegisterHandler (
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IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This,
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IN EFI_WATCHDOG_TIMER_NOTIFY NotifyFunction
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)
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{
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if ((mWatchdogNotify == NULL) && (NotifyFunction == NULL)) {
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return EFI_INVALID_PARAMETER;
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}
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if ((mWatchdogNotify != NULL) && (NotifyFunction != NULL)) {
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return EFI_ALREADY_STARTED;
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}
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mWatchdogNotify = NotifyFunction;
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return EFI_SUCCESS;
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}
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/**
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This function sets the amount of time to wait before firing the watchdog
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timer to TimerPeriod 100ns units. If TimerPeriod is 0, then the watchdog
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timer is disabled.
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@param This The EFI_WATCHDOG_TIMER_ARCH_PROTOCOL instance.
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@param TimerPeriod The amount of time in 100ns units to wait before
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the watchdog timer is fired. If TimerPeriod is zero,
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then the watchdog timer is disabled.
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@retval EFI_SUCCESS The watchdog timer has been programmed to fire
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in TimerPeriod 100ns units.
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**/
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STATIC
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EFI_STATUS
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EFIAPI
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WatchdogSetTimerPeriod (
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IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This,
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IN UINT64 TimerPeriod // In 100ns units
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)
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{
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UINTN SystemCount;
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// if TimerPeriod is 0, this is a request to stop the watchdog.
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if (TimerPeriod == 0) {
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mNumTimerTicks = 0;
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WatchdogDisable ();
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return EFI_SUCCESS;
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}
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// Work out how many timer ticks will equate to TimerPeriod
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mNumTimerTicks = (mTimerFrequencyHz * TimerPeriod) / TIME_UNITS_PER_SECOND;
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/* If the number of required ticks is greater than the max the watchdog's
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offset register (WOR) can hold, we need to manually compute and set
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the compare register (WCV) */
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if (mNumTimerTicks > MAX_UINT32) {
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/* We need to enable the watchdog *before* writing to the compare register,
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because enabling the watchdog causes an "explicit refresh", which
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clobbers the compare register (WCV). In order to make sure this doesn't
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trigger an interrupt, set the offset to max. */
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WatchdogWriteOffsetRegister (MAX_UINT32);
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WatchdogEnable ();
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SystemCount = ArmGenericTimerGetSystemCount ();
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WatchdogWriteCompareRegister (SystemCount + mNumTimerTicks);
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} else {
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WatchdogWriteOffsetRegister ((UINT32)mNumTimerTicks);
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WatchdogEnable ();
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}
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return EFI_SUCCESS;
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}
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/**
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This function retrieves the period of timer interrupts in 100ns units,
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returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod
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is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is
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returned, then the timer is currently disabled.
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@param This The EFI_TIMER_ARCH_PROTOCOL instance.
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@param TimerPeriod A pointer to the timer period to retrieve in
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100ns units. If 0 is returned, then the timer is
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currently disabled.
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@retval EFI_SUCCESS The timer period was returned in TimerPeriod.
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@retval EFI_INVALID_PARAMETER TimerPeriod is NULL.
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**/
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STATIC
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EFI_STATUS
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EFIAPI
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WatchdogGetTimerPeriod (
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IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This,
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OUT UINT64 *TimerPeriod
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)
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{
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if (TimerPeriod == NULL) {
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return EFI_INVALID_PARAMETER;
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}
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*TimerPeriod = ((TIME_UNITS_PER_SECOND / mTimerFrequencyHz) * mNumTimerTicks);
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return EFI_SUCCESS;
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}
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/**
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Interface structure for the Watchdog Architectural Protocol.
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@par Protocol Description:
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This protocol provides a service to set the amount of time to wait
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before firing the watchdog timer, and it also provides a service to
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register a handler that is invoked when the watchdog timer fires.
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@par When the watchdog timer fires, control will be passed to a handler
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if one has been registered. If no handler has been registered,
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or the registered handler returns, then the system will be
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reset by calling the Runtime Service ResetSystem().
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@param RegisterHandler
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Registers a handler that will be called each time the
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watchdogtimer interrupt fires. TimerPeriod defines the minimum
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time between timer interrupts, so TimerPeriod will also
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be the minimum time between calls to the registered
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handler.
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NOTE: If the watchdog resets the system in hardware, then
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this function will not have any chance of executing.
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@param SetTimerPeriod
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Sets the period of the timer interrupt in 100ns units.
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This function is optional, and may return EFI_UNSUPPORTED.
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If this function is supported, then the timer period will
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be rounded up to the nearest supported timer period.
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@param GetTimerPeriod
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Retrieves the period of the timer interrupt in 100ns units.
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**/
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STATIC EFI_WATCHDOG_TIMER_ARCH_PROTOCOL mWatchdogTimer = {
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WatchdogRegisterHandler,
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WatchdogSetTimerPeriod,
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WatchdogGetTimerPeriod
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};
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STATIC EFI_EVENT mEfiExitBootServicesEvent;
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EFI_STATUS
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EFIAPI
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GenericWatchdogEntry (
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IN EFI_HANDLE ImageHandle,
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IN EFI_SYSTEM_TABLE *SystemTable
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)
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{
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EFI_STATUS Status;
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EFI_HANDLE Handle;
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Status = gBS->LocateProtocol (
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&gHardwareInterrupt2ProtocolGuid,
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NULL,
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(VOID **)&mInterruptProtocol
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);
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ASSERT_EFI_ERROR (Status);
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/* Make sure the Watchdog Timer Architectural Protocol has not been installed
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in the system yet.
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This will avoid conflicts with the universal watchdog */
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ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid);
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mTimerFrequencyHz = ArmGenericTimerGetTimerFreq ();
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ASSERT (mTimerFrequencyHz != 0);
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// Install interrupt handler
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Status = mInterruptProtocol->RegisterInterruptSource (
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mInterruptProtocol,
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FixedPcdGet32 (PcdGenericWatchdogEl2IntrNum),
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WatchdogInterruptHandler
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);
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if (EFI_ERROR (Status)) {
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return Status;
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}
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Status = mInterruptProtocol->SetTriggerType (
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mInterruptProtocol,
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FixedPcdGet32 (PcdGenericWatchdogEl2IntrNum),
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EFI_HARDWARE_INTERRUPT2_TRIGGER_EDGE_RISING
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);
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if (EFI_ERROR (Status)) {
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goto UnregisterHandler;
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}
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// Install the Timer Architectural Protocol onto a new handle
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Handle = NULL;
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Status = gBS->InstallMultipleProtocolInterfaces (
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&Handle,
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&gEfiWatchdogTimerArchProtocolGuid,
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&mWatchdogTimer,
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NULL
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);
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if (EFI_ERROR (Status)) {
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goto UnregisterHandler;
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}
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// Register for an ExitBootServicesEvent
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Status = gBS->CreateEvent (
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EVT_SIGNAL_EXIT_BOOT_SERVICES,
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TPL_NOTIFY,
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WatchdogExitBootServicesEvent,
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NULL,
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&mEfiExitBootServicesEvent
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);
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ASSERT_EFI_ERROR (Status);
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mNumTimerTicks = 0;
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WatchdogDisable ();
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return EFI_SUCCESS;
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UnregisterHandler:
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// Unregister the handler
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mInterruptProtocol->RegisterInterruptSource (
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mInterruptProtocol,
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FixedPcdGet32 (PcdGenericWatchdogEl2IntrNum),
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NULL
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);
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return Status;
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}
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