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- /** @file
- RISC-V Timer Architectural Protocol for U5 series platform.
- Copyright (c) 2019, Hewlett Packard Enterprise Development LP. All rights reserved.<BR>
- SPDX-License-Identifier: BSD-2-Clause-Patent
- **/
- #include "Timer.h"
- #include <Library/RiscVEdk2SbiLib.h>
- #include <sbi/riscv_asm.h>
- #include <sbi/riscv_encoding.h>
- #include <sbi/riscv_io.h>
- #include <sbi/riscv_atomic.h>
- #include <U5Clint.h>
- BOOLEAN TimerHandlerReentry = FALSE;
- //
- // The handle onto which the Timer Architectural Protocol will be installed
- //
- STATIC EFI_HANDLE mTimerHandle = NULL;
- //
- // The Timer Architectural Protocol that this driver produces
- //
- EFI_TIMER_ARCH_PROTOCOL mTimer = {
- TimerDriverRegisterHandler,
- TimerDriverSetTimerPeriod,
- TimerDriverGetTimerPeriod,
- TimerDriverGenerateSoftInterrupt
- };
- //
- // Pointer to the CPU Architectural Protocol instance
- //
- EFI_CPU_ARCH_PROTOCOL *mCpu;
- //
- // The notification function to call on every timer interrupt.
- // A bug in the compiler prevents us from initializing this here.
- //
- STATIC EFI_TIMER_NOTIFY mTimerNotifyFunction;
- //
- // The current period of the timer interrupt
- //
- STATIC UINT64 mTimerPeriod = 0;
- /**
- U5 Series Timer Interrupt Handler.
- @param InterruptType The type of interrupt that occured
- @param SystemContext A pointer to the system context when the interrupt occured
- **/
- VOID
- EFIAPI
- TimerInterruptHandler (
- IN EFI_EXCEPTION_TYPE InterruptType,
- IN EFI_SYSTEM_CONTEXT SystemContext
- )
- {
- EFI_TPL OriginalTPL;
- UINT64 RiscvTimer;
- if (TimerHandlerReentry) {
- //
- // MMode timer occurred when processing
- // SMode timer handler.
- //
- RiscvTimer = RiscVReadMachineTimerInterface();
- SbiSetTimer (RiscvTimer += mTimerPeriod);
- csr_clear(CSR_SIP, MIP_STIP);
- return;
- }
- TimerHandlerReentry = TRUE;
- OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
- csr_clear(CSR_SIE, MIP_STIP); // Disable SMode timer int
- csr_clear(CSR_SIP, MIP_STIP);
- if (mTimerPeriod == 0) {
- gBS->RestoreTPL (OriginalTPL);
- csr_clear(CSR_SIE, MIP_STIP); // Disable SMode timer int
- return;
- }
- if (mTimerNotifyFunction != NULL) {
- mTimerNotifyFunction (mTimerPeriod);
- }
- RiscvTimer = RiscVReadMachineTimerInterface();
- SbiSetTimer (RiscvTimer += mTimerPeriod);
- gBS->RestoreTPL (OriginalTPL);
- csr_set(CSR_SIE, MIP_STIP); // enable SMode timer int
- TimerHandlerReentry = FALSE;
- }
- /**
- This function registers the handler NotifyFunction so it is called every time
- the timer interrupt fires. It also passes the amount of time since the last
- handler call to the NotifyFunction. If NotifyFunction is NULL, then the
- handler is unregistered. If the handler is registered, then EFI_SUCCESS is
- returned. If the CPU does not support registering a timer interrupt handler,
- then EFI_UNSUPPORTED is returned. 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. If an error occurs attempting to
- register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
- is returned.
- @param This The EFI_TIMER_ARCH_PROTOCOL instance.
- @param NotifyFunction The function to call when a timer interrupt fires. This
- function executes at TPL_HIGH_LEVEL. The DXE Core will
- register a handler for the timer interrupt, so it can know
- how much time has passed. This information is used to
- signal timer based events. NULL will unregister the handler.
- @retval EFI_SUCCESS The timer handler was registered.
- @retval EFI_UNSUPPORTED The platform does not support timer interrupts.
- @retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already
- registered.
- @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not
- previously registered.
- @retval EFI_DEVICE_ERROR The timer handler could not be registered.
- **/
- EFI_STATUS
- EFIAPI
- TimerDriverRegisterHandler (
- IN EFI_TIMER_ARCH_PROTOCOL *This,
- IN EFI_TIMER_NOTIFY NotifyFunction
- )
- {
- DEBUG ((DEBUG_INFO, "TimerDriverRegisterHandler(0x%lx) called\n", NotifyFunction));
- mTimerNotifyFunction = NotifyFunction;
- return EFI_SUCCESS;
- }
- /**
- This function adjusts the period of timer interrupts to the value specified
- by TimerPeriod. If the timer period is updated, then the selected timer
- period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If
- the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
- If an error occurs while attempting to update the timer period, then the
- timer hardware will be put back in its state prior to this call, and
- EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt
- is disabled. This is not the same as disabling the CPU's interrupts.
- Instead, it must either turn off the timer hardware, or it must adjust the
- interrupt controller so that a CPU interrupt is not generated when the timer
- interrupt fires.
- @param This The EFI_TIMER_ARCH_PROTOCOL instance.
- @param TimerPeriod The rate to program the timer interrupt in 100 nS units. If
- the timer hardware is not programmable, then EFI_UNSUPPORTED is
- returned. If the timer is programmable, then the timer period
- will be rounded up to the nearest timer period that is supported
- by the timer hardware. If TimerPeriod is set to 0, then the
- timer interrupts will be disabled.
- @retval EFI_SUCCESS The timer period was changed.
- @retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt.
- @retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error.
- **/
- EFI_STATUS
- EFIAPI
- TimerDriverSetTimerPeriod (
- IN EFI_TIMER_ARCH_PROTOCOL *This,
- IN UINT64 TimerPeriod
- )
- {
- UINT64 RiscvTimer;
- DEBUG ((DEBUG_INFO, "TimerDriverSetTimerPeriod(0x%lx)\n", TimerPeriod));
- if (TimerPeriod == 0) {
- mTimerPeriod = 0;
- csr_clear(CSR_SIE, MIP_STIP); // disable timer int
- return EFI_SUCCESS;
- }
- mTimerPeriod = TimerPeriod; // convert unit from 100ns to 1us
- RiscvTimer = RiscVReadMachineTimerInterface();
- SbiSetTimer(RiscvTimer + mTimerPeriod / 10);
- mCpu->EnableInterrupt(mCpu);
- csr_set(CSR_SIE, MIP_STIP); // enable timer int
- return EFI_SUCCESS;
- }
- /**
- This function retrieves the period of timer interrupts in 100 ns units,
- returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod
- is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is
- returned, then the timer is currently disabled.
- @param This The EFI_TIMER_ARCH_PROTOCOL instance.
- @param TimerPeriod A pointer to the timer period to retrieve in 100 ns units. If
- 0 is returned, then the timer is currently disabled.
- @retval EFI_SUCCESS The timer period was returned in TimerPeriod.
- @retval EFI_INVALID_PARAMETER TimerPeriod is NULL.
- **/
- EFI_STATUS
- EFIAPI
- TimerDriverGetTimerPeriod (
- IN EFI_TIMER_ARCH_PROTOCOL *This,
- OUT UINT64 *TimerPeriod
- )
- {
- *TimerPeriod = mTimerPeriod;
- return EFI_SUCCESS;
- }
- /**
- This function generates a soft timer interrupt. If the platform does not support soft
- timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
- If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
- service, then a soft timer interrupt will be generated. If the timer interrupt is
- enabled when this service is called, then the registered handler will be invoked. The
- registered handler should not be able to distinguish a hardware-generated timer
- interrupt from a software-generated timer interrupt.
- @param This The EFI_TIMER_ARCH_PROTOCOL instance.
- @retval EFI_SUCCESS The soft timer interrupt was generated.
- @retval EFI_UNSUPPORTEDT The platform does not support the generation of soft timer interrupts.
- **/
- EFI_STATUS
- EFIAPI
- TimerDriverGenerateSoftInterrupt (
- IN EFI_TIMER_ARCH_PROTOCOL *This
- )
- {
- return EFI_SUCCESS;
- }
- /**
- Initialize the Timer Architectural Protocol driver
- @param ImageHandle ImageHandle of the loaded driver
- @param SystemTable Pointer to the System Table
- @retval EFI_SUCCESS Timer Architectural Protocol created
- @retval EFI_OUT_OF_RESOURCES Not enough resources available to initialize driver.
- @retval EFI_DEVICE_ERROR A device error occured attempting to initialize the driver.
- **/
- EFI_STATUS
- EFIAPI
- TimerDriverInitialize (
- IN EFI_HANDLE ImageHandle,
- IN EFI_SYSTEM_TABLE *SystemTable
- )
- {
- EFI_STATUS Status;
- //
- // Initialize the pointer to our notify function.
- //
- mTimerNotifyFunction = NULL;
- //
- // Make sure the Timer Architectural Protocol is not already installed in the system
- //
- ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);
- //
- // Find the CPU architectural protocol.
- //
- Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **) &mCpu);
- ASSERT_EFI_ERROR (Status);
- //
- // Force the timer to be disabled
- //
- Status = TimerDriverSetTimerPeriod (&mTimer, 0);
- ASSERT_EFI_ERROR (Status);
- //
- // Install interrupt handler for RISC-V Timer.
- //
- Status = mCpu->RegisterInterruptHandler (mCpu, EXCEPT_RISCV_TIMER_INT, TimerInterruptHandler);
- ASSERT_EFI_ERROR (Status);
- //
- // Force the timer to be enabled at its default period
- //
- Status = TimerDriverSetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
- ASSERT_EFI_ERROR (Status);
- //
- // Install the Timer Architectural Protocol onto a new handle
- //
- Status = gBS->InstallMultipleProtocolInterfaces (
- &mTimerHandle,
- &gEfiTimerArchProtocolGuid, &mTimer,
- NULL
- );
- ASSERT_EFI_ERROR (Status);
- return Status;
- }
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