mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
synced 2024-12-17 15:18:06 +01:00
88 lines
2.4 KiB
C
88 lines
2.4 KiB
C
/** @file
|
|
UEFI Miscellaneous boot Services Stall service implementation
|
|
|
|
Copyright (c) 2006 - 2011, 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.
|
|
|
|
**/
|
|
|
|
//
|
|
// Include statements
|
|
//
|
|
|
|
#include "DxeMain.h"
|
|
|
|
/**
|
|
Internal worker function to call the Metronome Architectural Protocol for
|
|
the number of ticks specified by the UINT64 Counter value. WaitForTick()
|
|
service of the Metronome Architectural Protocol uses a UINT32 for the number
|
|
of ticks to wait, so this function loops when Counter is larger than 0xffffffff.
|
|
|
|
@param Counter Number of ticks to wait.
|
|
|
|
**/
|
|
VOID
|
|
CoreInternalWaitForTick (
|
|
IN UINT64 Counter
|
|
)
|
|
{
|
|
while ((Counter & 0xffffffff00000000ULL) != 0) {
|
|
gMetronome->WaitForTick (gMetronome, 0xffffffff);
|
|
Counter -= 0xffffffff;
|
|
}
|
|
gMetronome->WaitForTick (gMetronome, (UINT32)Counter);
|
|
}
|
|
|
|
/**
|
|
Introduces a fine-grained stall.
|
|
|
|
@param Microseconds The number of microseconds to stall execution.
|
|
|
|
@retval EFI_SUCCESS Execution was stalled for at least the requested
|
|
amount of microseconds.
|
|
@retval EFI_NOT_AVAILABLE_YET gMetronome is not available yet
|
|
|
|
**/
|
|
EFI_STATUS
|
|
EFIAPI
|
|
CoreStall (
|
|
IN UINTN Microseconds
|
|
)
|
|
{
|
|
UINT32 Counter;
|
|
UINT32 Remainder;
|
|
|
|
if (gMetronome == NULL) {
|
|
return EFI_NOT_AVAILABLE_YET;
|
|
}
|
|
|
|
//
|
|
// Calculate the number of ticks by dividing the number of microseconds by
|
|
// the TickPeriod.
|
|
// Calculation is based on 100ns unit.
|
|
//
|
|
Counter = (UINT32) DivU64x32Remainder (
|
|
Microseconds * 10,
|
|
gMetronome->TickPeriod,
|
|
&Remainder
|
|
);
|
|
|
|
//
|
|
// Call WaitForTick for Counter + 1 ticks to try to guarantee Counter tick
|
|
// periods, thus attempting to ensure Microseconds of stall time.
|
|
//
|
|
if (Remainder != 0) {
|
|
Counter++;
|
|
}
|
|
|
|
gMetronome->WaitForTick (gMetronome, Counter);
|
|
|
|
return EFI_SUCCESS;
|
|
}
|