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34d609402b
There is GetPerformanceCounterProperties() that relies on Device Tree to fetch timer frequency and removes the dependency from the PCDs, use that instead. Signed-off-by: Akshay Behl <cap2k4@rivosinc.com> Co-authored-by: Dhaval Sharma <dhaval@rivosinc.com>
374 lines
12 KiB
C
374 lines
12 KiB
C
/** @file
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RISC-V Timer Architectural Protocol
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Copyright (c) 2019, Hewlett Packard Enterprise Development LP. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include <Library/BaseLib.h>
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#include <Library/BaseRiscVSbiLib.h>
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#include <Library/UefiLib.h>
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#include <Library/TimerLib.h>
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#include "Timer.h"
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//
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// The handle onto which the Timer Architectural Protocol will be installed
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//
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STATIC EFI_HANDLE mTimerHandle = NULL;
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//
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// The Timer Architectural Protocol that this driver produces
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//
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EFI_TIMER_ARCH_PROTOCOL mTimer = {
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TimerDriverRegisterHandler,
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TimerDriverSetTimerPeriod,
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TimerDriverGetTimerPeriod,
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TimerDriverGenerateSoftInterrupt
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};
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//
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// Pointer to the CPU Architectural Protocol instance
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//
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EFI_CPU_ARCH_PROTOCOL *mCpu;
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//
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// The notification function to call on every timer interrupt.
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// A bug in the compiler prevents us from initializing this here.
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//
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STATIC EFI_TIMER_NOTIFY mTimerNotifyFunction;
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//
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// The current period of the timer interrupt
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//
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STATIC UINT64 mTimerPeriod = 0;
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STATIC UINT64 mLastPeriodStart = 0;
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//
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// Sstc support
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//
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STATIC BOOLEAN mSstcEnabled = FALSE;
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/**
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Program the timer.
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Program either using stimecmp (when Sstc extension is enabled) or using SBI
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TIME call.
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@param NextValue Core tick value the timer should expire.
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**/
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STATIC
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VOID
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RiscVProgramTimer (
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UINT64 NextValue
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)
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{
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if (mSstcEnabled) {
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RiscVSetSupervisorTimeCompareRegister (NextValue);
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} else {
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SbiSetTimer (NextValue);
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}
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}
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/**
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Check whether Sstc is enabled in PCD.
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**/
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STATIC
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BOOLEAN
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RiscVIsSstcEnabled (
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VOID
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)
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{
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return ((PcdGet64 (PcdRiscVFeatureOverride) & RISCV_CPU_FEATURE_SSTC_BITMASK) != 0);
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}
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/**
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Timer Interrupt Handler.
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@param InterruptType The type of interrupt that occured
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@param SystemContext A pointer to the system context when the interrupt occured
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**/
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VOID
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EFIAPI
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TimerInterruptHandler (
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IN EFI_EXCEPTION_TYPE InterruptType,
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IN EFI_SYSTEM_CONTEXT SystemContext
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)
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{
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EFI_TPL OriginalTPL;
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UINT64 PeriodStart;
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PeriodStart = RiscVReadTimer ();
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OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
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if (mTimerNotifyFunction != NULL) {
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//
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// For any number of reasons, the ticks could be coming
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// in slower than mTimerPeriod. For example, some code
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// is doing a *lot* of stuff inside an EFI_TPL_HIGH
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// critical section, and this should not cause the EFI
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// time to increment slower. So when we take an interrupt,
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// account for the actual time passed.
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//
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mTimerNotifyFunction (
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DivU64x32 (
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EFI_TIMER_PERIOD_SECONDS (PeriodStart - mLastPeriodStart),
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GetPerformanceCounterProperties (NULL, NULL)
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)
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);
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}
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if (mTimerPeriod == 0) {
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RiscVDisableTimerInterrupt ();
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gBS->RestoreTPL (OriginalTPL);
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return;
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}
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mLastPeriodStart = PeriodStart;
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PeriodStart += DivU64x32 (
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MultU64x32 (
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mTimerPeriod,
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GetPerformanceCounterProperties (NULL, NULL)
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),
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1000000u
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); // convert to tick
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RiscVProgramTimer (PeriodStart);
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RiscVEnableTimerInterrupt (); // enable SMode timer int
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gBS->RestoreTPL (OriginalTPL);
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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 timer interrupt fires. It also passes the amount of time since the last
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handler call to the NotifyFunction. If NotifyFunction is NULL, then the
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handler is unregistered. If the handler is registered, then EFI_SUCCESS is
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returned. If the CPU does not support registering a timer interrupt handler,
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then EFI_UNSUPPORTED is returned. If an attempt is made to register a handler
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when a handler is already 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 registered,
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then EFI_INVALID_PARAMETER is returned. If an error occurs attempting to
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register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
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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 timer handler was registered.
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@retval EFI_UNSUPPORTED The platform does not support timer interrupts.
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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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@retval EFI_DEVICE_ERROR The timer handler could not be registered.
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**/
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EFI_STATUS
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EFIAPI
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TimerDriverRegisterHandler (
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IN EFI_TIMER_ARCH_PROTOCOL *This,
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IN EFI_TIMER_NOTIFY NotifyFunction
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)
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{
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DEBUG ((DEBUG_INFO, "TimerDriverRegisterHandler(0x%lx) called\n", NotifyFunction));
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mTimerNotifyFunction = 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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EFI_STATUS
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EFIAPI
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TimerDriverSetTimerPeriod (
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IN EFI_TIMER_ARCH_PROTOCOL *This,
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IN UINT64 TimerPeriod
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)
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{
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UINT64 PeriodStart;
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DEBUG ((DEBUG_INFO, "TimerDriverSetTimerPeriod(0x%lx)\n", TimerPeriod));
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if (TimerPeriod == 0) {
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mTimerPeriod = 0;
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RiscVDisableTimerInterrupt (); // Disable SMode timer int
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return EFI_SUCCESS;
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}
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mTimerPeriod = TimerPeriod / 10; // convert unit from 100ns to 1us
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mLastPeriodStart = RiscVReadTimer ();
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PeriodStart = mLastPeriodStart;
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PeriodStart += DivU64x32 (
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MultU64x32 (
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mTimerPeriod,
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GetPerformanceCounterProperties (NULL, NULL)
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),
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1000000u
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); // convert to tick
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RiscVProgramTimer (PeriodStart);
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mCpu->EnableInterrupt (mCpu);
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RiscVEnableTimerInterrupt (); // enable SMode timer int
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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 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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EFI_STATUS
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EFIAPI
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TimerDriverGetTimerPeriod (
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IN EFI_TIMER_ARCH_PROTOCOL *This,
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OUT UINT64 *TimerPeriod
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)
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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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This function generates a soft timer interrupt. If the platform does not support soft
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timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
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If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
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service, then a soft timer interrupt will be generated. If the timer interrupt is
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enabled when this service is called, then the registered handler will be invoked. The
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registered handler should not be able to distinguish a hardware-generated timer
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interrupt from a software-generated timer interrupt.
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@param This The EFI_TIMER_ARCH_PROTOCOL instance.
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@retval EFI_SUCCESS The soft timer interrupt was generated.
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@retval EFI_UNSUPPORTEDT The platform does not support the generation of soft timer interrupts.
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**/
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EFI_STATUS
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EFIAPI
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TimerDriverGenerateSoftInterrupt (
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IN EFI_TIMER_ARCH_PROTOCOL *This
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)
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{
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return EFI_SUCCESS;
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}
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/**
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Initialize the Timer Architectural Protocol driver
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@param ImageHandle ImageHandle of the loaded driver
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@param SystemTable Pointer to the System Table
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@retval EFI_SUCCESS Timer Architectural Protocol created
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@retval EFI_OUT_OF_RESOURCES Not enough resources available to initialize driver.
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@retval EFI_DEVICE_ERROR A device error occured attempting to initialize the driver.
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**/
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EFI_STATUS
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EFIAPI
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TimerDriverInitialize (
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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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//
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// Initialize the pointer to our notify function.
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//
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mTimerNotifyFunction = NULL;
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if (RiscVIsSstcEnabled ()) {
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mSstcEnabled = TRUE;
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DEBUG ((DEBUG_INFO, "TimerDriverInitialize: Timer interrupt is via Sstc extension\n"));
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}
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//
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// Make sure the Timer Architectural Protocol is not already installed in the system
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//
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ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);
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//
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// Find the CPU architectural protocol.
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//
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Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **)&mCpu);
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ASSERT_EFI_ERROR (Status);
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//
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// Force the timer to be disabled
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//
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Status = TimerDriverSetTimerPeriod (&mTimer, 0);
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ASSERT_EFI_ERROR (Status);
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//
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// Install interrupt handler for RISC-V Timer.
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//
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Status = mCpu->RegisterInterruptHandler (
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mCpu,
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EXCEPT_RISCV_IRQ_TIMER_FROM_SMODE,
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TimerInterruptHandler
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);
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ASSERT_EFI_ERROR (Status);
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//
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// Force the timer to be enabled at its default period
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//
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Status = TimerDriverSetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
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ASSERT_EFI_ERROR (Status);
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//
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// Install the Timer Architectural Protocol onto a new handle
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//
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Status = gBS->InstallMultipleProtocolInterfaces (
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&mTimerHandle,
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&gEfiTimerArchProtocolGuid,
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&mTimer,
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NULL
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);
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ASSERT_EFI_ERROR (Status);
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return Status;
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}
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