878ddf1fc3
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@3 6f19259b-4bc3-4df7-8a09-765794883524
199 lines
3.5 KiB
C
199 lines
3.5 KiB
C
/*++
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Copyright (c) 2006, Intel Corporation
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All rights reserved. This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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Module Name:
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tpl.c
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Abstract:
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Task priority function
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--*/
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#include <DxeMain.h>
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STATIC
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VOID
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CoreSetInterruptState (
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IN BOOLEAN Enable
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)
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/*++
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Routine Description:
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Set Interrupt State
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Arguments:
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Enable - The state of enable or disable interrupt
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Returns:
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None
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--*/
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{
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if (gCpu != NULL) {
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if (Enable) {
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gCpu->EnableInterrupt(gCpu);
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} else {
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gCpu->DisableInterrupt(gCpu);
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}
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}
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}
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//
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// Return the highest set bit
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//
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UINTN
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CoreHighestSetBit (
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IN UINTN Number
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)
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/*++
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Routine Description:
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Return the highest set bit
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Arguments:
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Number - The value to check
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Returns:
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Bit position of the highest set bit
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--*/
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{
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UINTN msb;
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msb = 31;
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while ((msb > 0) && ((Number & (UINTN)(1 << msb)) == 0)) {
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msb--;
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}
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return msb;
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}
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EFI_TPL
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EFIAPI
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CoreRaiseTpl (
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IN EFI_TPL NewTpl
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)
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/*++
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Routine Description:
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Raise the task priority level to the new level.
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High level is implemented by disabling processor interrupts.
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Arguments:
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NewTpl - New task priority level
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Returns:
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The previous task priority level
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--*/
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{
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EFI_TPL OldTpl;
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OldTpl = gEfiCurrentTpl;
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ASSERT (OldTpl <= NewTpl);
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ASSERT (VALID_TPL (NewTpl));
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//
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// If raising to high level, disable interrupts
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//
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if (NewTpl >= EFI_TPL_HIGH_LEVEL && OldTpl < EFI_TPL_HIGH_LEVEL) {
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CoreSetInterruptState (FALSE);
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}
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//
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// Set the new value
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//
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gEfiCurrentTpl = NewTpl;
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return OldTpl;
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}
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VOID
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EFIAPI
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CoreRestoreTpl (
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IN EFI_TPL NewTpl
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)
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/*++
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Routine Description:
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Lowers the task priority to the previous value. If the new
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priority unmasks events at a higher priority, they are dispatched.
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Arguments:
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NewTpl - New, lower, task priority
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Returns:
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None
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--*/
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{
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EFI_TPL OldTpl;
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OldTpl = gEfiCurrentTpl;
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ASSERT (NewTpl <= OldTpl);
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ASSERT (VALID_TPL (NewTpl));
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//
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// If lowering below HIGH_LEVEL, make sure
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// interrupts are enabled
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//
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if (OldTpl >= EFI_TPL_HIGH_LEVEL && NewTpl < EFI_TPL_HIGH_LEVEL) {
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gEfiCurrentTpl = EFI_TPL_HIGH_LEVEL;
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}
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//
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// Dispatch any pending events
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//
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while ((-2 << NewTpl) & gEventPending) {
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gEfiCurrentTpl = CoreHighestSetBit (gEventPending);
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if (gEfiCurrentTpl < EFI_TPL_HIGH_LEVEL) {
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CoreSetInterruptState (TRUE);
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}
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CoreDispatchEventNotifies (gEfiCurrentTpl);
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}
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//
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// Set the new value
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//
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gEfiCurrentTpl = NewTpl;
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//
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// If lowering below HIGH_LEVEL, make sure
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// interrupts are enabled
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//
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if (gEfiCurrentTpl < EFI_TPL_HIGH_LEVEL) {
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CoreSetInterruptState (TRUE);
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}
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}
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