Vlv2TbltDevicePkg/Library/I2CLibPei/I2CDelayPei.c

   1 /** @file
   2   MicroSecondDelay implementation of ACPI Timer.
   3
   4   Copyright (c) 2007 - 2015, Intel Corporation. All rights reserved.<BR>
   5
   6   This program and the accompanying materials are licensed and made available under
   7   the terms and conditions of the BSD License that accompanies this distribution.
   8   The full text of the license may be found at
   9   http://opensource.org/licenses/bsd-license.php.
  10
  11   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13
  14 --*/
  15
  16 #include "PiPei.h"
  17 #include "I2CAccess.h"
  18 #include "I2CDelayPei.h"
  19 #include <Library/DebugLib.h>
  20 #include <Library/PeiServicesTablePointerLib.h>
  21 #include <Ppi/Stall.h>
  22
  23 /**
  24   Stalls the CPU for at least the given number of microseconds.
  25   Stalls the CPU for the number of microseconds specified by MicroSeconds.
  26
  27   @param  MicroSeconds  The minimum number of microseconds to delay.
  28
  29   @return EFI_STATUS
  30
  31 **/
  32 EFI_STATUS
  33 EFIAPI
  34 MicroSecondDelay (
  35   IN      UINTN                     MicroSeconds
  36   )
  37 {
  38
  39   EFI_PEI_STALL_PPI              *StallPpi;
  40   EFI_STATUS                     Status;
  41   CONST EFI_PEI_SERVICES         **PeiServices;
  42
  43   PeiServices = GetPeiServicesTablePointer();
  44
  45
  46   Status = (**PeiServices).LocatePpi (PeiServices, &gEfiPeiStallPpiGuid, 0, NULL, &StallPpi);
  47   ASSERT(!EFI_ERROR(Status));
  48
  49   StallPpi->Stall (PeiServices, StallPpi, MicroSeconds);
  50
  51   return EFI_SUCCESS;
  52 }