mirror of https://github.com/acidanthera/audk.git
432 lines
14 KiB
C
432 lines
14 KiB
C
/** @file
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*
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* Copyright (c) 2011-2013, ARM Limited. All rights reserved.
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* Copyright (c) 2018, Linaro 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/UefiBootServicesTableLib.h>
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#include <Library/UefiRuntimeServicesTableLib.h>
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#include <Protocol/HardwareInterrupt.h>
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#include <Protocol/WatchdogTimer.h>
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#include "SP805Watchdog.h"
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STATIC EFI_EVENT mEfiExitBootServicesEvent;
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STATIC EFI_HARDWARE_INTERRUPT_PROTOCOL *mInterrupt;
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STATIC EFI_WATCHDOG_TIMER_NOTIFY mWatchdogNotify;
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STATIC UINT32 mTimerPeriod;
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/**
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Make sure the SP805 registers are unlocked for writing.
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Note: The SP805 Watchdog Timer supports locking of its registers,
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i.e. it inhibits all writes to avoid rogue software accidentally
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corrupting their contents.
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**/
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STATIC
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VOID
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SP805Unlock (
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VOID
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)
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{
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if (MmioRead32 (SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_LOCKED) {
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MmioWrite32 (SP805_WDOG_LOCK_REG, SP805_WDOG_SPECIAL_UNLOCK_CODE);
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}
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}
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/**
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Make sure the SP805 registers are locked and can not be overwritten.
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Note: The SP805 Watchdog Timer supports locking of its registers,
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i.e. it inhibits all writes to avoid rogue software accidentally
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corrupting their contents.
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**/
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STATIC
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VOID
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SP805Lock (
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VOID
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)
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{
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if (MmioRead32 (SP805_WDOG_LOCK_REG) == SP805_WDOG_LOCK_IS_UNLOCKED) {
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// To lock it, just write in any number (except the special unlock code).
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MmioWrite32 (SP805_WDOG_LOCK_REG, SP805_WDOG_LOCK_IS_LOCKED);
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}
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}
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STATIC
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VOID
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EFIAPI
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SP805InterruptHandler (
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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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SP805Unlock ();
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MmioWrite32 (SP805_WDOG_INT_CLR_REG, 0); // write of any value clears the irq
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SP805Lock ();
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mInterrupt->EndOfInterrupt (mInterrupt, 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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mWatchdogNotify (mTimerPeriod + 1);
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}
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gRT->ResetSystem (EfiResetCold, EFI_TIMEOUT, 0, NULL);
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}
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/**
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Stop the SP805 watchdog timer from counting down by disabling interrupts.
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**/
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STATIC
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VOID
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SP805Stop (
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VOID
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)
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{
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// Disable interrupts
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if ((MmioRead32 (SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) != 0) {
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MmioAnd32 (SP805_WDOG_CONTROL_REG, ~SP805_WDOG_CTRL_INTEN);
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}
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}
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/**
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Starts the SP805 counting down by enabling interrupts.
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The count down will start from the value stored in the Load register,
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not from the value where it was previously stopped.
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**/
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STATIC
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VOID
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SP805Start (
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VOID
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)
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{
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// Enable interrupts
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if ((MmioRead32 (SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_INTEN) == 0) {
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MmioOr32 (SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_INTEN);
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}
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}
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/**
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On exiting boot services we must make sure the SP805 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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ExitBootServicesEvent (
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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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SP805Unlock ();
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SP805Stop ();
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SP805Lock ();
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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 registered,
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then EFI_ALREADY_STARTED is returned.
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If an attempt is made to unregister a handler when a handler is not registered,
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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. This
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function executes at TPL_HIGH_LEVEL. The DXE Core will
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register a handler for the timer interrupt, so it can know
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how much time has passed. This information is used to
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signal timer based events. NULL will unregister the handler.
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@retval EFI_SUCCESS The watchdog timer handler was registered.
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@retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already
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registered.
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@retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not
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previously registered.
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**/
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STATIC
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EFI_STATUS
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EFIAPI
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SP805RegisterHandler (
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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 adjusts the period of timer interrupts to the value specified
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by TimerPeriod. If the timer period is updated, then the selected timer
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period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If
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the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
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If an error occurs while attempting to update the timer period, then the
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timer hardware will be put back in its state prior to this call, and
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EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt
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is disabled. This is not the same as disabling the CPU's interrupts.
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Instead, it must either turn off the timer hardware, or it must adjust the
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interrupt controller so that a CPU interrupt is not generated when the timer
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interrupt fires.
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@param This The EFI_TIMER_ARCH_PROTOCOL instance.
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@param TimerPeriod The rate to program the timer interrupt in 100 nS units. If
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the timer hardware is not programmable, then EFI_UNSUPPORTED is
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returned. If the timer is programmable, then the timer period
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will be rounded up to the nearest timer period that is supported
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by the timer hardware. If TimerPeriod is set to 0, then the
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timer interrupts will be disabled.
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@retval EFI_SUCCESS The timer period was changed.
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@retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt.
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@retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error.
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**/
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STATIC
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EFI_STATUS
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EFIAPI
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SP805SetTimerPeriod (
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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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EFI_STATUS Status;
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UINT64 Ticks64bit;
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SP805Unlock ();
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Status = EFI_SUCCESS;
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if (TimerPeriod == 0) {
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// This is a watchdog stop request
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SP805Stop ();
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} else {
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// Calculate the Watchdog ticks required for a delay of (TimerTicks * 100) nanoseconds
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// The SP805 will count down to zero and generate an interrupt.
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//
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// WatchdogTicks = ((TimerPeriod * 100 * SP805_CLOCK_FREQUENCY) / 1GHz);
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//
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// i.e.:
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//
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// WatchdogTicks = (TimerPeriod * SP805_CLOCK_FREQUENCY) / 10 MHz ;
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Ticks64bit = MultU64x32 (TimerPeriod, PcdGet32 (PcdSP805WatchdogClockFrequencyInHz));
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Ticks64bit = DivU64x32 (Ticks64bit, 10 * 1000 * 1000);
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// The registers in the SP805 are only 32 bits
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if (Ticks64bit > MAX_UINT32) {
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// We could load the watchdog with the maximum supported value but
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// if a smaller value was requested, this could have the watchdog
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// triggering before it was intended.
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// Better generate an error to let the caller know.
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Status = EFI_DEVICE_ERROR;
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goto EXIT;
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}
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// Update the watchdog with a 32-bit value.
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MmioWrite32 (SP805_WDOG_LOAD_REG, (UINT32)Ticks64bit);
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// Start the watchdog
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SP805Start ();
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}
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mTimerPeriod = TimerPeriod;
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EXIT:
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// Ensure the watchdog is locked before exiting.
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SP805Lock ();
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ASSERT_EFI_ERROR (Status);
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return Status;
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}
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/**
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This function retrieves the period of timer interrupts in 100 ns 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 100 ns units. If
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0 is returned, then the timer is 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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SP805GetTimerPeriod (
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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 = mTimerPeriod;
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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 100 nS 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 100 nS units.
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**/
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STATIC EFI_WATCHDOG_TIMER_ARCH_PROTOCOL mWatchdogTimer = {
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SP805RegisterHandler,
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SP805SetTimerPeriod,
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SP805GetTimerPeriod
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};
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/**
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Initialize the state information for the Watchdog Timer Architectural Protocol.
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@param ImageHandle of the loaded driver
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@param SystemTable Pointer to the System Table
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@retval EFI_SUCCESS Protocol registered
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@retval EFI_OUT_OF_RESOURCES Cannot allocate protocol data structure
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@retval EFI_DEVICE_ERROR Hardware problems
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**/
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EFI_STATUS
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EFIAPI
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SP805Initialize (
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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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// Find the interrupt controller protocol. ASSERT if not found.
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Status = gBS->LocateProtocol (&gHardwareInterruptProtocolGuid, NULL,
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(VOID **)&mInterrupt);
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ASSERT_EFI_ERROR (Status);
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// Unlock access to the SP805 registers
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SP805Unlock ();
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// Stop the watchdog from triggering unexpectedly
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SP805Stop ();
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// Set the watchdog to reset the board when triggered
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// This is a last resort in case the interrupt handler fails
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if ((MmioRead32 (SP805_WDOG_CONTROL_REG) & SP805_WDOG_CTRL_RESEN) == 0) {
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MmioOr32 (SP805_WDOG_CONTROL_REG, SP805_WDOG_CTRL_RESEN);
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}
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// Clear any pending interrupts
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MmioWrite32 (SP805_WDOG_INT_CLR_REG, 0); // write of any value clears the irq
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// Prohibit any rogue access to SP805 registers
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SP805Lock ();
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if (PcdGet32 (PcdSP805WatchdogInterrupt) > 0) {
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Status = mInterrupt->RegisterInterruptSource (mInterrupt,
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PcdGet32 (PcdSP805WatchdogInterrupt),
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SP805InterruptHandler);
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if (EFI_ERROR (Status)) {
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DEBUG ((DEBUG_ERROR, "%a: failed to register watchdog interrupt - %r\n",
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__FUNCTION__, Status));
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return Status;
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}
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} else {
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DEBUG ((DEBUG_WARN, "%a: no interrupt specified, running in RESET mode only\n",
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__FUNCTION__));
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}
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//
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// Make sure the Watchdog Timer Architectural Protocol has not been installed in the system yet.
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// This will avoid conflicts with the universal watchdog
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//
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ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiWatchdogTimerArchProtocolGuid);
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// Register for an ExitBootServicesEvent
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Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_NOTIFY,
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ExitBootServicesEvent, NULL, &mEfiExitBootServicesEvent);
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if (EFI_ERROR (Status)) {
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Status = EFI_OUT_OF_RESOURCES;
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goto EXIT;
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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, &mWatchdogTimer,
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NULL
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);
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if (EFI_ERROR (Status)) {
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Status = EFI_OUT_OF_RESOURCES;
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goto EXIT;
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}
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EXIT:
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ASSERT_EFI_ERROR (Status);
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return Status;
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}
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