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402 lines
12 KiB
C
402 lines
12 KiB
C
/** @file
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Timer Architectural Protocol as defined in the DXE CIS
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Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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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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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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// Pointer to the Legacy 8259 Protocol instance
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//
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EFI_LEGACY_8259_PROTOCOL *mLegacy8259;
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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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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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volatile UINT64 mTimerPeriod = 0;
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//
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// Worker Functions
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//
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/**
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Sets the counter value for Timer #0 in a legacy 8254 timer.
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@param Count The 16-bit counter value to program into Timer #0 of the legacy 8254 timer.
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**/
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VOID
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SetPitCount (
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IN UINT16 Count
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)
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{
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IoWrite8 (TIMER_CONTROL_PORT, 0x36);
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IoWrite8 (TIMER0_COUNT_PORT, (UINT8)(Count & 0xff));
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IoWrite8 (TIMER0_COUNT_PORT, (UINT8)((Count >> 8) & 0xff));
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}
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/**
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8254 Timer #0 Interrupt Handler.
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@param InterruptType The type of interrupt that occurred
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@param SystemContext A pointer to the system context when the interrupt occurred
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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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OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
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mLegacy8259->EndOfInterrupt (mLegacy8259, Efi8259Irq0);
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if (mTimerNotifyFunction != NULL) {
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//
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// @bug : This does not handle missed timer interrupts
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//
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mTimerNotifyFunction (mTimerPeriod);
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}
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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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//
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// Check for invalid parameters
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//
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if (NotifyFunction == NULL && mTimerNotifyFunction == NULL) {
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return EFI_INVALID_PARAMETER;
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}
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if (NotifyFunction != NULL && mTimerNotifyFunction != NULL) {
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return EFI_ALREADY_STARTED;
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}
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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 TimerCount;
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//
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// The basic clock is 1.19318 MHz or 0.119318 ticks per 100 ns.
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// TimerPeriod * 0.119318 = 8254 timer divisor. Using integer arithmetic
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// TimerCount = (TimerPeriod * 119318)/1000000.
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//
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// Round up to next highest integer. This guarantees that the timer is
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// equal to or slightly longer than the requested time.
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// TimerCount = ((TimerPeriod * 119318) + 500000)/1000000
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//
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// Note that a TimerCount of 0 is equivalent to a count of 65,536
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//
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// Since TimerCount is limited to 16 bits for IA32, TimerPeriod is limited
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// to 20 bits.
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//
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if (TimerPeriod == 0) {
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//
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// Disable timer interrupt for a TimerPeriod of 0
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//
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mLegacy8259->DisableIrq (mLegacy8259, Efi8259Irq0);
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} else {
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//
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// Convert TimerPeriod into 8254 counts
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//
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TimerCount = DivU64x32 (MultU64x32 (119318, (UINT32) TimerPeriod) + 500000, 1000000);
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//
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// Check for overflow
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//
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if (TimerCount >= 65536) {
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TimerCount = 0;
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TimerPeriod = MAX_TIMER_TICK_DURATION;
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}
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//
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// Program the 8254 timer with the new count value
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//
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SetPitCount ((UINT16) TimerCount);
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//
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// Enable timer interrupt
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//
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mLegacy8259->EnableIrq (mLegacy8259, Efi8259Irq0, FALSE);
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}
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//
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// Save the new timer period
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//
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mTimerPeriod = TimerPeriod;
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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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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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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_UNSUPPORTED 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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EFI_STATUS Status;
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UINT16 IRQMask;
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EFI_TPL OriginalTPL;
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//
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// If the timer interrupt is enabled, then the registered handler will be invoked.
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//
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Status = mLegacy8259->GetMask (mLegacy8259, NULL, NULL, &IRQMask, NULL);
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ASSERT_EFI_ERROR (Status);
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if ((IRQMask & 0x1) == 0) {
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//
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// Invoke the registered handler
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//
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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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// @bug : This does not handle missed timer interrupts
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//
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mTimerNotifyFunction (mTimerPeriod);
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}
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gBS->RestoreTPL (OriginalTPL);
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} else {
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return EFI_UNSUPPORTED;
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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 occurred 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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UINT32 TimerVector;
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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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//
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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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// Find the Legacy8259 protocol.
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//
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Status = gBS->LocateProtocol (&gEfiLegacy8259ProtocolGuid, NULL, (VOID **) &mLegacy8259);
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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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// Get the interrupt vector number corresponding to IRQ0 from the 8259 driver
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//
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TimerVector = 0;
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Status = mLegacy8259->GetVector (mLegacy8259, Efi8259Irq0, (UINT8 *) &TimerVector);
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ASSERT_EFI_ERROR (Status);
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//
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// Install interrupt handler for 8254 Timer #0 (ISA IRQ0)
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//
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Status = mCpu->RegisterInterruptHandler (mCpu, TimerVector, TimerInterruptHandler);
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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, &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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