mirror of https://github.com/acidanthera/audk.git
67 lines
1.9 KiB
C
67 lines
1.9 KiB
C
/** @file
|
|
Base Library CPU functions for Itanium
|
|
|
|
Copyright (c) 2006 - 2009, 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 <Library/PalLib.h>
|
|
#include <Library/BaseLib.h>
|
|
|
|
/**
|
|
Places the CPU in a sleep state until an interrupt is received.
|
|
|
|
Places the CPU in a sleep state until an interrupt is received. If interrupts
|
|
are disabled prior to calling this function, then the CPU will be placed in a
|
|
sleep state indefinitely.
|
|
|
|
**/
|
|
VOID
|
|
EFIAPI
|
|
CpuSleep (
|
|
VOID
|
|
)
|
|
{
|
|
UINT64 Tpr;
|
|
|
|
//
|
|
// It is the TPR register that controls if external interrupt would bring processor in LIGHT HALT low-power state
|
|
// back to normal state. PAL_HALT_LIGHT does not depend on PSR setting.
|
|
// So here if interrupts are disabled (via PSR.i), TRP.mmi needs to be set to prevent processor being interrupted by external interrupts.
|
|
// If interrupts are enabled, then just use current TRP setting.
|
|
//
|
|
if (GetInterruptState ()) {
|
|
//
|
|
// If interrupts are enabled, then call PAL_HALT_LIGHT with the current TPR setting.
|
|
//
|
|
PalCall (PAL_HALT_LIGHT, 0, 0, 0);
|
|
} else {
|
|
//
|
|
// If interrupts are disabled on entry, then mask all interrupts in TPR before calling PAL_HALT_LIGHT.
|
|
//
|
|
|
|
//
|
|
// Save TPR
|
|
//
|
|
Tpr = AsmReadTpr();
|
|
//
|
|
// Set TPR.mmi to mask all external interrupts
|
|
//
|
|
AsmWriteTpr (BIT16 | Tpr);
|
|
|
|
PalCall (PAL_HALT_LIGHT, 0, 0, 0);
|
|
|
|
//
|
|
// Restore TPR
|
|
//
|
|
AsmWriteTpr (Tpr);
|
|
}
|
|
}
|