MdePkg/Include/Ppi/Stall.h

/** @file
  This file declares Stall PPI.

  This ppi abstracts the blocking stall service to other agents.

  Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

  @par Revision Reference:
  This PPI is introduced in PI Version 1.0.

**/

#ifndef __STALL_PPI_H__
#define __STALL_PPI_H__

#define EFI_PEI_STALL_PPI_GUID \
  { 0x1f4c6f90, 0xb06b, 0x48d8, {0xa2, 0x01, 0xba, 0xe5, 0xf1, 0xcd, 0x7d, 0x56 } }

typedef struct _EFI_PEI_STALL_PPI EFI_PEI_STALL_PPI;

/**
  The Stall() function provides a blocking stall for at least the number
  of microseconds stipulated in the final argument of the API.

  @param  PeiServices    An indirect pointer to the PEI Services Table
                         published by the PEI Foundation.
  @param  This           Pointer to the local data for the interface.
  @param  Microseconds   Number of microseconds for which to stall.

  @retval EFI_SUCCESS    The service provided at least the required delay.

**/
typedef
EFI_STATUS
(EFIAPI *EFI_PEI_STALL)(
  IN CONST EFI_PEI_SERVICES     **PeiServices,
  IN CONST EFI_PEI_STALL_PPI    *This,
  IN UINTN                      Microseconds
  );

///
/// This service provides a simple, blocking stall with platform-specific resolution.
///
struct _EFI_PEI_STALL_PPI {
  ///
  /// The resolution in microseconds of the stall services.
  ///
  UINTN            Resolution;

  EFI_PEI_STALL    Stall;
};

extern EFI_GUID  gEfiPeiStallPpiGuid;

#endif