audk/MdePkg/Include/Protocol/CpuIo2.h

/** @file
  This files describes the CPU I/O 2 Protocol.
  
  This protocol provides an I/O abstraction for a system processor. This protocol
  is used by a PCI root bridge I/O driver to perform memory-mapped I/O and I/O transactions.
  The I/O or memory primitives can be used by the consumer of the protocol to materialize
  bus-specific configuration cycles, such as the transitional configuration address and data
  ports for PCI. Only drivers that require direct access to the entire system should use this 
  protocol. 
  
  Note: This is a boot-services only protocol and it may not be used by runtime drivers after
  ExitBootServices(). It is different from the Framework CPU I/O Protocol, which is a runtime
  protocol and can be used by runtime drivers after ExitBootServices().

  Copyright (c) 2007 - 2009, 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.

  @par Revision Reference:
  This Protocol is defined in UEFI Platform Initialization Specification 1.2 
  Volume 5: Standards

**/

#ifndef __CPU_IO2_H__
#define __CPU_IO2_H__


#define EFI_CPU_IO2_PROTOCOL_GUID \
  { \
    0xad61f191, 0xae5f, 0x4c0e, {0xb9, 0xfa, 0xe8, 0x69, 0xd2, 0x88, 0xc6, 0x4f} \
  }

typedef struct _EFI_CPU_IO2_PROTOCOL EFI_CPU_IO2_PROTOCOL;


///
/// Enumeration that defines the width of the I/O operation.
///
typedef enum {
  EfiCpuIoWidthUint8,
  EfiCpuIoWidthUint16,
  EfiCpuIoWidthUint32,
  EfiCpuIoWidthUint64,
  EfiCpuIoWidthFifoUint8,
  EfiCpuIoWidthFifoUint16,
  EfiCpuIoWidthFifoUint32,
  EfiCpuIoWidthFifoUint64,
  EfiCpuIoWidthFillUint8,
  EfiCpuIoWidthFillUint16,
  EfiCpuIoWidthFillUint32,
  EfiCpuIoWidthFillUint64,
  EfiCpuIoWidthMaximum
} EFI_CPU_IO_PROTOCOL_WIDTH;


/**
  Enables a driver to access registers in the PI CPU I/O space. 

  The Io.Read() and Io.Write() functions enable a driver to access PCI controller registers in 
  the PI CPU I/O space. 

  The I/O operations are carried out exactly as requested. The caller is responsible for satisfying any 
  alignment and I/O width restrictions that a PI System on a platform might require. For example on 
  some platforms, width requests of EfiCpuIoWidthUint64 do not work. Misaligned buffers, on 
  the other hand, will be handled by the driver.
  
  If Width is EfiCpuIoWidthUint8, EfiCpuIoWidthUint16, EfiCpuIoWidthUint32, 
  or EfiCpuIoWidthUint64, then both Address and Buffer are incremented for each of the 
  Count operations that is performed.
  
  If Width is EfiCpuIoWidthFifoUint8, EfiCpuIoWidthFifoUint16, 
  EfiCpuIoWidthFifoUint32, or EfiCpuIoWidthFifoUint64, then only Buffer is 
  incremented for each of the Count operations that is performed. The read or write operation is 
  performed Count times on the same Address.
  
  If Width is EfiCpuIoWidthFillUint8, EfiCpuIoWidthFillUint16, 
  EfiCpuIoWidthFillUint32, or EfiCpuIoWidthFillUint64, then only Address is 
  incremented for each of the Count operations that is performed. The read or write operation is 
  performed Count times from the first element of Buffer.

  @param[in]       This         A pointer to the EFI_CPU_IO2_PROTOCOL instance.
  @param[in]       Width        Signifies the width of the I/O or Memory operation.
  @param[in]       Address      The base address of the I/O operation. The caller is responsible
                                for aligning the Address if required. 
  @param[in]       Count        The number of I/O operations to perform. The number of bytes moved
                                is Width size * Count, starting at Address.
  @param[in, out]  Buffer       For read operations, the destination buffer to store the results.
                                For write operations, the source buffer from which to write data.

  @retval EFI_SUCCESS           The data was read from or written to the EFI system.
  @retval EFI_INVALID_PARAMETER Width is invalid for this EFI system. Or Buffer is NULL.
  @retval EFI_UNSUPPORTED       The Buffer is not aligned for the given Width.
                                Or,The address range specified by Address, Width, and Count is not valid for this EFI system.

**/
typedef
EFI_STATUS
(EFIAPI *EFI_CPU_IO_PROTOCOL_IO_MEM)(
  IN     EFI_CPU_IO2_PROTOCOL              *This,
  IN     EFI_CPU_IO_PROTOCOL_WIDTH         Width,
  IN     UINT64                            Address,
  IN     UINTN                             Count,
  IN OUT VOID                              *Buffer
  );


///
/// Service for read and write accesses.
///
typedef struct {
  ///
  /// This service provides the various modalities of memory and I/O read.
  ///
  EFI_CPU_IO_PROTOCOL_IO_MEM  Read;
  ///
  /// This service provides the various modalities of memory and I/O write.
  ///
  EFI_CPU_IO_PROTOCOL_IO_MEM  Write;
} EFI_CPU_IO_PROTOCOL_ACCESS;


///
/// Provides the basic memory and I/O interfaces that are used to abstract
/// accesses to devices in a system.
///
struct _EFI_CPU_IO2_PROTOCOL {
  ///
  /// Enables a driver to access memory-mapped registers in the EFI system memory space.
  ///
  EFI_CPU_IO_PROTOCOL_ACCESS  Mem;
  ///
  /// Enables a driver to access registers in the EFI CPU I/O space.
  ///
  EFI_CPU_IO_PROTOCOL_ACCESS  Io;
};

extern EFI_GUID gEfiCpuIo2ProtocolGuid;

#endif