/*++

Copyright (c) 2004, 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:

    Stall.c

Abstract:

    Tiano Miscellaneous Services Stall service implementation

--*/

//
// Include statements
//

#include "Tiano.h"
#include "DxeCore.h"

EFI_BOOTSERVICE
EFI_STATUS
EFIAPI
CoreStall (
  IN UINTN            Microseconds
  )
/*++

Routine Description:

  Introduces a fine-grained stall.

Arguments:

  Microseconds      The number of microseconds to stall execution

Returns:

  EFI_SUCCESS            - Execution was stalled for at least the requested amount
                           of microseconds.

  EFI_NOT_AVAILABLE_YET  - gMetronome is not available yet

--*/
{
  UINT32  Counter;
  UINTN   Remainder;

  if (gMetronome == NULL) {
    return EFI_NOT_AVAILABLE_YET;
  }
  
  //
  // Calculate the number of ticks by dividing the number of microseconds by
  // the TickPeriod.
  // Calcullation is based on 100ns unit.
  //
  Counter = (UINT32) DivU64x32 ((Microseconds * 10), (UINTN) 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;
}