/**@file
Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
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:
NT Emulation Timer Architectural Protocol Driver as defined in DXE CIS
This Timer module uses an NT Thread to simulate the timer-tick driven
timer service. In the future, the Thread creation should possibly be
abstracted by the CPU architectural protocol
**/
#include "Timer.h"
//
// Pointer to the CPU Architectural Protocol instance
//
EFI_CPU_ARCH_PROTOCOL *mCpu;
//
// The Timer Architectural Protocol that this driver produces
//
EFI_TIMER_ARCH_PROTOCOL mTimer = {
WinNtTimerDriverRegisterHandler,
WinNtTimerDriverSetTimerPeriod,
WinNtTimerDriverGetTimerPeriod,
WinNtTimerDriverGenerateSoftInterrupt
};
//
// Define a global that we can use to shut down the NT timer thread when
// the timer is canceled.
//
BOOLEAN mCancelTimerThread = FALSE;
//
// The notification function to call on every timer interrupt
//
EFI_TIMER_NOTIFY mTimerNotifyFunction = NULL;
//
// The current period of the timer interrupt
//
UINT64 mTimerPeriod;
//
// The thread handle for this driver
//
HANDLE mNtMainThreadHandle;
//
// The timer value from the last timer interrupt
//
UINT32 mNtLastTick;
//
// Critical section used to update varibles shared between the main thread and
// the timer interrupt thread.
//
CRITICAL_SECTION mNtCriticalSection;
//
// Worker Functions
//
UINT mMMTimerThreadID = 0;
VOID
CALLBACK
MMTimerThread (
UINT wTimerID,
UINT msg,
DWORD dwUser,
DWORD dw1,
DWORD dw2
)
/*++
Routine Description:
TODO: Add function description
Arguments:
wTimerID - TODO: add argument description
msg - TODO: add argument description
dwUser - TODO: add argument description
dw1 - TODO: add argument description
dw2 - TODO: add argument description
Returns:
TODO: add return values
--*/
{
EFI_TPL OriginalTPL;
UINT32 CurrentTick;
UINT32 Delta;
EFI_TIMER_NOTIFY CallbackFunction;
BOOLEAN InterruptState;
if (!mCancelTimerThread) {
//
// Suspend the main thread until we are done.
// Enter the critical section before suspending
// and leave the critical section after resuming
// to avoid deadlock between main and timer thread.
//
gWinNt->EnterCriticalSection (&mNtCriticalSection);
gWinNt->SuspendThread (mNtMainThreadHandle);
//
// If the timer thread is being canceled, then bail immediately.
// We check again here because there's a small window of time from when
// this thread was kicked off and when we suspended the main thread above.
//
if (mCancelTimerThread) {
gWinNt->ResumeThread (mNtMainThreadHandle);
gWinNt->LeaveCriticalSection (&mNtCriticalSection);
gWinNt->timeKillEvent (wTimerID);
mMMTimerThreadID = 0;
return ;
}
mCpu->GetInterruptState (mCpu, &InterruptState);
while (!InterruptState) {
//
// Resume the main thread
//
gWinNt->ResumeThread (mNtMainThreadHandle);
gWinNt->LeaveCriticalSection (&mNtCriticalSection);
//
// Wait for interrupts to be enabled.
//
mCpu->GetInterruptState (mCpu, &InterruptState);
while (!InterruptState) {
gWinNt->Sleep (1);
mCpu->GetInterruptState (mCpu, &InterruptState);
}
//
// Suspend the main thread until we are done
//
gWinNt->EnterCriticalSection (&mNtCriticalSection);
gWinNt->SuspendThread (mNtMainThreadHandle);
mCpu->GetInterruptState (mCpu, &InterruptState);
}
//
// Get the current system tick
//
CurrentTick = gWinNt->GetTickCount ();
Delta = CurrentTick - mNtLastTick;
mNtLastTick = CurrentTick;
//
// If delay was more then 1 second, ignore it (probably debugging case)
//
if (Delta < 1000) {
OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
//
// Inform the firmware of an "timer interrupt". The time
// expired since the last call is 10,000 times the number
// of ms. (or 100ns units)
//
CallbackFunction = mTimerNotifyFunction;
//
// Only invoke the callback function if a Non-NULL handler has been
// registered. Assume all other handlers are legal.
//
if (CallbackFunction != NULL) {
CallbackFunction ((UINT64) (Delta * 10000));
}
gBS->RestoreTPL (OriginalTPL);
}
//
// Resume the main thread
//
gWinNt->ResumeThread (mNtMainThreadHandle);
gWinNt->LeaveCriticalSection (&mNtCriticalSection);
} else {
gWinNt->timeKillEvent (wTimerID);
mMMTimerThreadID = 0;
}
}
UINT
CreateNtTimer (
VOID
)
/*++
Routine Description:
It is used to emulate a platform
timer-driver interrupt handler.
Returns:
Timer ID
--*/
// TODO: function comment is missing 'Arguments:'
{
UINT32 SleepCount;
//
// Set our thread priority higher than the "main" thread.
//
gWinNt->SetThreadPriority (
gWinNt->GetCurrentThread (),
THREAD_PRIORITY_HIGHEST
);
//
// Calc the appropriate interval
//
gWinNt->EnterCriticalSection (&mNtCriticalSection);
SleepCount = (UINT32) (mTimerPeriod + 5000) / 10000;
gWinNt->LeaveCriticalSection (&mNtCriticalSection);
return gWinNt->timeSetEvent (
SleepCount,
0,
MMTimerThread,
(DWORD_PTR) NULL,
TIME_PERIODIC | TIME_KILL_SYNCHRONOUS | TIME_CALLBACK_FUNCTION
);
}
EFI_STATUS
EFIAPI
WinNtTimerDriverRegisterHandler (
IN EFI_TIMER_ARCH_PROTOCOL *This,
IN EFI_TIMER_NOTIFY NotifyFunction
)
/*++
Routine Description:
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.
Arguments:
This - The EFI_TIMER_ARCH_PROTOCOL instance.
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.
Returns:
EFI_SUCCESS - The timer handler was registered.
EFI_UNSUPPORTED - The platform does not support timer interrupts.
EFI_ALREADY_STARTED - NotifyFunction is not NULL, and a handler is already
registered.
EFI_INVALID_PARAMETER - NotifyFunction is NULL, and a handler was not
previously registered.
EFI_DEVICE_ERROR - The timer handler could not be registered.
--*/
{
//
// Check for invalid parameters
//
if (NotifyFunction == NULL && mTimerNotifyFunction == NULL) {
return EFI_INVALID_PARAMETER;
}
if (NotifyFunction != NULL && mTimerNotifyFunction != NULL) {
return EFI_ALREADY_STARTED;
}
//
// Use Critical Section to update the notification function that is
// used from the timer interrupt thread.
//
gWinNt->EnterCriticalSection (&mNtCriticalSection);
mTimerNotifyFunction = NotifyFunction;
gWinNt->LeaveCriticalSection (&mNtCriticalSection);
return EFI_SUCCESS;
}
EFI_STATUS
EFIAPI
WinNtTimerDriverSetTimerPeriod (
IN EFI_TIMER_ARCH_PROTOCOL *This,
IN UINT64 TimerPeriod
)
/*++
Routine Description:
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.
Arguments:
This - The EFI_TIMER_ARCH_PROTOCOL instance.
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.
Returns:
EFI_SUCCESS - The timer period was changed.
EFI_UNSUPPORTED - The platform cannot change the period of the timer interrupt.
EFI_DEVICE_ERROR - The timer period could not be changed due to a device error.
--*/
{
//
// If TimerPeriod is 0, then the timer thread should be canceled
//
if (TimerPeriod == 0) {
//
// Cancel the timer thread
//
gWinNt->EnterCriticalSection (&mNtCriticalSection);
mCancelTimerThread = TRUE;
gWinNt->LeaveCriticalSection (&mNtCriticalSection);
//
// Wait for the timer thread to exit
//
if (mMMTimerThreadID) {
gWinNt->timeKillEvent (mMMTimerThreadID);
}
mMMTimerThreadID = 0;
//
// Update the timer period
//
gWinNt->EnterCriticalSection (&mNtCriticalSection);
mTimerPeriod = TimerPeriod;
gWinNt->LeaveCriticalSection (&mNtCriticalSection);
//
// NULL out the thread handle so it will be re-created if the timer is enabled again
//
} else if ((TimerPeriod > TIMER_MINIMUM_VALUE) && (TimerPeriod < TIMER_MAXIMUM_VALUE)) {
//
// If the TimerPeriod is valid, then create and/or adjust the period of the timer thread
//
gWinNt->EnterCriticalSection (&mNtCriticalSection);
mTimerPeriod = TimerPeriod;
mCancelTimerThread = FALSE;
gWinNt->LeaveCriticalSection (&mNtCriticalSection);
//
// Get the starting tick location if we are just starting the timer thread
//
mNtLastTick = gWinNt->GetTickCount ();
if (mMMTimerThreadID) {
gWinNt->timeKillEvent (mMMTimerThreadID);
}
mMMTimerThreadID = 0;
mMMTimerThreadID = CreateNtTimer ();
}
return EFI_SUCCESS;
}
EFI_STATUS
EFIAPI
WinNtTimerDriverGetTimerPeriod (
IN EFI_TIMER_ARCH_PROTOCOL *This,
OUT UINT64 *TimerPeriod
)
/*++
Routine Description:
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.
Arguments:
This - The EFI_TIMER_ARCH_PROTOCOL instance.
TimerPeriod - A pointer to the timer period to retrieve in 100 ns units. If
0 is returned, then the timer is currently disabled.
Returns:
EFI_SUCCESS - The timer period was returned in TimerPeriod.
EFI_INVALID_PARAMETER - TimerPeriod is NULL.
--*/
{
if (TimerPeriod == NULL) {
return EFI_INVALID_PARAMETER;
}
*TimerPeriod = mTimerPeriod;
return EFI_SUCCESS;
}
EFI_STATUS
EFIAPI
WinNtTimerDriverGenerateSoftInterrupt (
IN EFI_TIMER_ARCH_PROTOCOL *This
)
/*++
Routine Description:
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.
Arguments:
This - The EFI_TIMER_ARCH_PROTOCOL instance.
Returns:
EFI_SUCCESS - The soft timer interrupt was generated.
EFI_UNSUPPORTEDT - The platform does not support the generation of soft timer interrupts.
--*/
{
return EFI_UNSUPPORTED;
}
EFI_STATUS
EFIAPI
WinNtTimerDriverInitialize (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
/*++
Routine Description:
Initialize the Timer Architectural Protocol driver
Arguments:
ImageHandle - ImageHandle of the loaded driver
SystemTable - Pointer to the System Table
Returns:
EFI_SUCCESS - Timer Architectural Protocol created
EFI_OUT_OF_RESOURCES - Not enough resources available to initialize driver.
EFI_DEVICE_ERROR - A device error occured attempting to initialize the driver.
--*/
{
EFI_STATUS Status;
UINTN Result;
EFI_HANDLE Handle;
EFI_HANDLE hSourceProcessHandle;
EFI_HANDLE hSourceHandle;
EFI_HANDLE hTargetProcessHandle;
//
// Make sure the Timer Architectural Protocol is not already installed in the system
//
ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);
//
// Get the CPU Architectural Protocol instance
//
Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID**)&mCpu);
ASSERT_EFI_ERROR (Status);
//
// Get our handle so the timer tick thread can suspend
//
hSourceProcessHandle = gWinNt->GetCurrentProcess ();
hSourceHandle = gWinNt->GetCurrentThread ();
hTargetProcessHandle = gWinNt->GetCurrentProcess ();
Result = gWinNt->DuplicateHandle (
hSourceProcessHandle,
hSourceHandle,
hTargetProcessHandle,
&mNtMainThreadHandle,
0,
FALSE,
DUPLICATE_SAME_ACCESS
);
if (Result == 0) {
return EFI_DEVICE_ERROR;
}
//
// Initialize Critical Section used to update variables shared between the main
// thread and the timer interrupt thread.
//
gWinNt->InitializeCriticalSection (&mNtCriticalSection);
//
// Start the timer thread at the default timer period
//
Status = mTimer.SetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
if (EFI_ERROR (Status)) {
gWinNt->DeleteCriticalSection (&mNtCriticalSection);
return Status;
}
//
// Install the Timer Architectural Protocol onto a new handle
//
Handle = NULL;
Status = gBS->InstallProtocolInterface (
&Handle,
&gEfiTimerArchProtocolGuid,
EFI_NATIVE_INTERFACE,
&mTimer
);
if (EFI_ERROR (Status)) {
//
// Cancel the timer
//
mTimer.SetTimerPeriod (&mTimer, 0);
gWinNt->DeleteCriticalSection (&mNtCriticalSection);
return Status;
}
return EFI_SUCCESS;
}