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/*++
Copyright (c) 2006, Intel Corporation
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
Module Name:
timer.c
Abstract:
EFI Event support
Revision History
--*/
#include <DxeMain.h>
//
// Internal prototypes
//
STATIC
UINT64
CoreCurrentSystemTime (
VOID
);
STATIC
VOID
EFIAPI
CoreCheckTimers (
IN EFI_EVENT Event,
IN VOID *Context
);
STATIC
VOID
CoreInsertEventTimer (
IN IEVENT *Event
);
//
// Internal data
//
static LIST_ENTRY mEfiTimerList = INITIALIZE_LIST_HEAD_VARIABLE (mEfiTimerList);
static EFI_LOCK mEfiTimerLock = EFI_INITIALIZE_LOCK_VARIABLE (EFI_TPL_HIGH_LEVEL - 1);
static EFI_EVENT mEfiCheckTimerEvent;
static EFI_LOCK mEfiSystemTimeLock = EFI_INITIALIZE_LOCK_VARIABLE (EFI_TPL_HIGH_LEVEL);
static UINT64 mEfiSystemTime = 0;
//
// Timer functions
//
VOID
CoreInitializeTimer (
VOID
)
/*++
Routine Description:
Initializes timer support
Arguments:
None
Returns:
None
--*/
{
EFI_STATUS Status;
Status = CoreCreateEvent (
EFI_EVENT_NOTIFY_SIGNAL,
EFI_TPL_HIGH_LEVEL - 1,
CoreCheckTimers,
NULL,
&mEfiCheckTimerEvent
);
ASSERT_EFI_ERROR (Status);
}
STATIC
UINT64
CoreCurrentSystemTime (
VOID
)
/*++
Routine Description:
Returns the current system time
Arguments:
None
Returns:
Returns the current system time
--*/
{
UINT64 SystemTime;
CoreAcquireLock (&mEfiSystemTimeLock);
SystemTime = mEfiSystemTime;
CoreReleaseLock (&mEfiSystemTimeLock);
return SystemTime;
}
VOID
EFIAPI
CoreTimerTick (
IN UINT64 Duration
)
/*++
Routine Description:
Called by the platform code to process a tick.
Arguments:
Duration - The number of 100ns elasped since the last call to TimerTick
Returns:
None
--*/
{
IEVENT *Event;
//
// Check runtiem flag in case there are ticks while exiting boot services
//
CoreAcquireLock (&mEfiSystemTimeLock);
//
// Update the system time
//
mEfiSystemTime += Duration;
//
// If the head of the list is expired, fire the timer event
// to process it
//
if (!IsListEmpty (&mEfiTimerList)) {
Event = CR (mEfiTimerList.ForwardLink, IEVENT, u.Timer.Link, EVENT_SIGNATURE);
if (Event->u.Timer.TriggerTime <= mEfiSystemTime) {
CoreSignalEvent (mEfiCheckTimerEvent);
}
}
CoreReleaseLock (&mEfiSystemTimeLock);
}
STATIC
VOID
EFIAPI
CoreCheckTimers (
IN EFI_EVENT CheckEvent,
IN VOID *Context
)
/*++
Routine Description:
Checks the sorted timer list against the current system time.
Signals any expired event timer.
Arguments:
CheckEvent - Not used
Context - Not used
Returns:
None
--*/
{
UINT64 SystemTime;
IEVENT *Event;
//
// Check the timer database for expired timers
//
CoreAcquireLock (&mEfiTimerLock);
SystemTime = CoreCurrentSystemTime ();
while (!IsListEmpty (&mEfiTimerList)) {
Event = CR (mEfiTimerList.ForwardLink, IEVENT, u.Timer.Link, EVENT_SIGNATURE);
//
// If this timer is not expired, then we're done
//
if (Event->u.Timer.TriggerTime > SystemTime) {
break;
}
//
// Remove this timer from the timer queue
//
RemoveEntryList (&Event->u.Timer.Link);
Event->u.Timer.Link.ForwardLink = NULL;
//
// Signal it
//
CoreSignalEvent (Event);
//
// If this is a periodic timer, set it
//
if (Event->u.Timer.Period) {
//
// Compute the timers new trigger time
//
Event->u.Timer.TriggerTime = Event->u.Timer.TriggerTime + Event->u.Timer.Period;
//
// If that's before now, then reset the timer to start from now
//
if (Event->u.Timer.TriggerTime <= SystemTime) {
Event->u.Timer.TriggerTime = SystemTime;
CoreSignalEvent (mEfiCheckTimerEvent);
}
//
// Add the timer
//
CoreInsertEventTimer (Event);
}
}
CoreReleaseLock (&mEfiTimerLock);
}
STATIC
VOID
CoreInsertEventTimer (
IN IEVENT *Event
)
/*++
Routine Description:
Inserts the timer event
Arguments:
Event - Points to the internal structure of timer event to be installed
Returns:
None
--*/
{
UINT64 TriggerTime;
LIST_ENTRY *Link;
IEVENT *Event2;
ASSERT_LOCKED (&mEfiTimerLock);
//
// Get the timer's trigger time
//
TriggerTime = Event->u.Timer.TriggerTime;
//
// Insert the timer into the timer database in assending sorted order
//
for (Link = mEfiTimerList.ForwardLink; Link != &mEfiTimerList; Link = Link->ForwardLink) {
Event2 = CR (Link, IEVENT, u.Timer.Link, EVENT_SIGNATURE);
if (Event2->u.Timer.TriggerTime > TriggerTime) {
break;
}
}
InsertTailList (Link, &Event->u.Timer.Link);
}
EFI_STATUS
EFIAPI
CoreSetTimer (
IN EFI_EVENT UserEvent,
IN EFI_TIMER_DELAY Type,
IN UINT64 TriggerTime
)
/*++
Routine Description:
Sets the type of timer and the trigger time for a timer event.
Arguments:
UserEvent - The timer event that is to be signaled at the specified time
Type - The type of time that is specified in TriggerTime
TriggerTime - The number of 100ns units until the timer expires
Returns:
EFI_SUCCESS - The event has been set to be signaled at the requested time
EFI_INVALID_PARAMETER - Event or Type is not valid
--*/
{
IEVENT *Event;
Event = UserEvent;
if (Event == NULL) {
return EFI_INVALID_PARAMETER;
}
if (Event->Signature != EVENT_SIGNATURE) {
return EFI_INVALID_PARAMETER;
}
if (Type < 0 || Type > TimerRelative || !(Event->Type & EFI_EVENT_TIMER)) {
return EFI_INVALID_PARAMETER;
}
CoreAcquireLock (&mEfiTimerLock);
//
// If the timer is queued to the timer database, remove it
//
if (Event->u.Timer.Link.ForwardLink != NULL) {
RemoveEntryList (&Event->u.Timer.Link);
Event->u.Timer.Link.ForwardLink = NULL;
}
Event->u.Timer.TriggerTime = 0;
Event->u.Timer.Period = 0;
if (Type != TimerCancel) {
if (Type == TimerPeriodic) {
Event->u.Timer.Period = TriggerTime;
}
Event->u.Timer.TriggerTime = CoreCurrentSystemTime () + TriggerTime;
CoreInsertEventTimer (Event);
if (TriggerTime == 0) {
CoreSignalEvent (mEfiCheckTimerEvent);
}
}
CoreReleaseLock (&mEfiTimerLock);
return EFI_SUCCESS;
}
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