path: root/MdePkg/Include/Protocol/Pcd.h

/** @file
  Platform Configuration Database (PCD) Protocol

  Copyright (c) 2006 - 2008, 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.             

**/

#ifndef __PCD_H__
#define __PCD_H__

#include <PiDxe.h>

extern EFI_GUID gPcdProtocolGuid;

#define PCD_PROTOCOL_GUID \
  { 0x11b34006, 0xd85b, 0x4d0a, { 0xa2, 0x90, 0xd5, 0xa5, 0x71, 0x31, 0xe, 0xf7 } }

#define PCD_INVALID_TOKEN_NUMBER ((UINTN) 0)


/**
  Sets the SKU value for subsequent calls to set or get PCD token values.

  SetSku() sets the SKU Id to be used for subsequent calls to set or get PCD values. 
  SetSku() is normally called only once by the system.

  For each item (token), the database can hold a single value that applies to all SKUs, 
  or multiple values, where each value is associated with a specific SKU Id. Items with multiple, 
  SKU-specific values are called SKU enabled. 
  
  The SKU Id of zero is reserved as a default. The valid SkuId range is 1 to 255.  
  For tokens that are not SKU enabled, the system ignores any set SKU Id and works with the 
  single value for that token. For SKU-enabled tokens, the system will use the SKU Id set by the 
  last call to SetSku(). If no SKU Id is set or the currently set SKU Id isn't valid for the specified token, 
  the system uses the default SKU Id. If the system attempts to use the default SKU Id and no value has been 
  set for that Id, the results are unpredictable.

  @param[in]  SkuId The SKU value that will be used when the PCD service will retrieve and 
                    set values associated with a PCD token.

  @retval VOID

**/
typedef 
VOID
(EFIAPI *PCD_PROTOCOL_SET_SKU)(
  IN  UINTN                  SkuId
  );



/**
  Retrieves an 8-bit value for a given PCD token.

  Retrieves the current byte-sized value for a PCD token number.  
  If the TokenNumber is invalid, the results are unpredictable.
  
  @param[in]  TokenNumber The PCD token number. 

  @return The UINT8 value.
  
**/
typedef
UINT8
(EFIAPI *PCD_PROTOCOL_GET8)(
  IN UINTN             TokenNumber
  );



/**
  Retrieves an 16-bit value for a given PCD token.

  Retrieves the current 16-bits value for a PCD token number.  
  If the TokenNumber is invalid, the results are unpredictable.
  
  @param[in]  TokenNumber The PCD token number. 

  @return The UINT16 value.
  
**/
typedef
UINT16
(EFIAPI *PCD_PROTOCOL_GET16)(
  IN UINTN             TokenNumber
  );



/**
  Retrieves an 32-bit value for a given PCD token.

  Retrieves the current 32-bits value for a PCD token number.  
  If the TokenNumber is invalid, the results are unpredictable.
  
  @param[in]  TokenNumber The PCD token number. 

  @return The UINT32 value.
  
**/
typedef
UINT32
(EFIAPI *PCD_PROTOCOL_GET32)(
  IN UINTN             TokenNumber
  );



/**
  Retrieves an 64-bit value for a given PCD token.

  Retrieves the current 64-bits value for a PCD token number.  
  If the TokenNumber is invalid, the results are unpredictable.
  
  @param[in]  TokenNumber The PCD token number. 

  @return The UINT64 value.
  
**/
typedef
UINT64
(EFIAPI *PCD_PROTOCOL_GET64)(
  IN UINTN             TokenNumber
  );



/**
  Retrieves a pointer to a value for a given PCD token.

  Retrieves the current pointer to the buffer for a PCD token number.  
  Do not make any assumptions about the alignment of the pointer that 
  is returned by this function call.  If the TokenNumber is invalid, 
  the results are unpredictable.

  @param[in]  TokenNumber The PCD token number. 

  @return The pointer to the buffer to be retrived.
  
**/
typedef
VOID *
(EFIAPI *PCD_PROTOCOL_GET_POINTER)(
  IN UINTN             TokenNumber
  );



/**
  Retrieves a Boolean value for a given PCD token.

  Retrieves the current boolean value for a PCD token number.  
  Do not make any assumptions about the alignment of the pointer that 
  is returned by this function call.  If the TokenNumber is invalid, 
  the results are unpredictable.

  @param[in]  TokenNumber The PCD token number. 

  @return The Boolean value.
  
**/
typedef
BOOLEAN
(EFIAPI *PCD_PROTOCOL_GET_BOOLEAN)(
  IN UINTN             TokenNumber
  );



/**
  Retrieves the size of the value for a given PCD token.

  Retrieves the current size of a particular PCD token.  
  If the TokenNumber is invalid, the results are unpredictable.

  @param[in]  TokenNumber The PCD token number. 

  @return The size of the value for the PCD token.
  
**/
typedef
UINTN
(EFIAPI *PCD_PROTOCOL_GET_SIZE)(
  IN UINTN             TokenNumber
  );



/**
  Retrieves an 8-bit value for a given PCD token.

  Retrieves the 8-bit value of a particular PCD token.  
  If the TokenNumber is invalid or the token space
  specified by Guid does not exist, the results are 
  unpredictable.

  @param[in]  Guid        The token space for the token number.
  @param[in]  TokenNumber The PCD token number. 

  @return The size 8-bit value for the PCD token.
  
**/
typedef
UINT8
(EFIAPI *PCD_PROTOCOL_GET_EX_8)(
  IN CONST EFI_GUID    *Guid,
  IN UINTN             TokenNumber
  );



/**
  Retrieves an 16-bit value for a given PCD token.

  Retrieves the 16-bit value of a particular PCD token.  
  If the TokenNumber is invalid or the token space
  specified by Guid does not exist, the results are 
  unpredictable.

  @param[in]  Guid        The token space for the token number.
  @param[in]  TokenNumber The PCD token number. 

  @return The size 16-bit value for the PCD token.
  
**/
typedef
UINT16
(EFIAPI *PCD_PROTOCOL_GET_EX_16)(
  IN CONST EFI_GUID    *Guid,
  IN UINTN             TokenNumber
  );



/**
  Retrieves an 32-bit value for a given PCD token.

  Retrieves the 32-bit value of a particular PCD token.  
  If the TokenNumber is invalid or the token space
  specified by Guid does not exist, the results are 
  unpredictable.

  @param[in]  Guid        The token space for the token number.
  @param[in]  TokenNumber The PCD token number. 

  @return The size 32-bit value for the PCD token.
  
**/
typedef
UINT32
(EFIAPI *PCD_PROTOCOL_GET_EX_32)(
  IN CONST EFI_GUID    *Guid,
  IN UINTN             TokenNumber
  );



/**
  Retrieves an 64-bit value for a given PCD token.

  Retrieves the 64-bit value of a particular PCD token.  
  If the TokenNumber is invalid or the token space
  specified by Guid does not exist, the results are 
  unpredictable.

  @param[in]  Guid        The token space for the token number.
  @param[in]  TokenNumber The PCD token number. 

  @return The size 64-bit value for the PCD token.
  
**/
typedef
UINT64
(EFIAPI *PCD_PROTOCOL_GET_EX_64)(
  IN CONST EFI_GUID    *Guid,
  IN UINTN             TokenNumber
  );



/**
  Retrieves a pointer to a value for a given PCD token.

  Retrieves the current pointer to the buffer for a PCD token number.  
  Do not make any assumptions about the alignment of the pointer that 
  is returned by this function call.  If the TokenNumber is invalid, 
  the results are unpredictable.

  @param[in]  Guid        The token space for the token number.
  @param[in]  TokenNumber The PCD token number. 

  @return The pointer to the buffer to be retrived.
  
**/
typedef
VOID *
(EFIAPI *PCD_PROTOCOL_GET_EX_POINTER)(
  IN CONST EFI_GUID    *Guid,
  IN UINTN             TokenNumber
  );



/**
  Retrieves an Boolean value for a given PCD token.

  Retrieves the Boolean value of a particular PCD token.  
  If the TokenNumber is invalid or the token space
  specified by Guid does not exist, the results are 
  unpredictable.

  @param[in]  Guid        The token space for the token number.
  @param[in]  TokenNumber The PCD token number. 

  @return The size Boolean value for the PCD token.
  
**/
typedef
BOOLEAN
(EFIAPI *PCD_PROTOCOL_GET_EX_BOOLEAN)(
  IN CONST EFI_GUID    *Guid,
  IN UINTN             TokenNumber
  );



/**
  Retrieves the size of the value for a given PCD token.

  Retrieves the current size of a particular PCD token.  
  If the TokenNumber is invalid, the results are unpredictable.

  @param[in]  Guid        The token space for the token number.
  @param[in]  TokenNumber The PCD token number. 

  @return The size of the value for the PCD token.
  
**/
typedef
UINTN
(EFIAPI *PCD_PROTOCOL_GET_EX_SIZE)(
  IN CONST EFI_GUID    *Guid,
  IN UINTN             TokenNumber
  );



/**
  Sets an 8-bit value for a given PCD token.

  When the PCD service sets a value, it will check to ensure that the 
  size of the value being set is compatible with the Token's existing definition.  
  If it is not, an error will be returned.

  @param[in]  TokenNumber The PCD token number. 
  @param[in]  Value       The value to set for the PCD token.

  @retval EFI_SUCCESS  Procedure returned successfully.
  @retval EFI_INVALID_PARAMETER The PCD service determined that the size of the data 
                                  being set was incompatible with a call to this function.  
                                  Use GetSize() to retrieve the size of the target data.
  @retval EFI_NOT_FOUND The PCD service could not find the requested token number.
  
**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_SET8)(
  IN UINTN             TokenNumber,
  IN UINT8             Value
  );



/**
  Sets an 16-bit value for a given PCD token.

  When the PCD service sets a value, it will check to ensure that the 
  size of the value being set is compatible with the Token's existing definition.  
  If it is not, an error will be returned.

  @param[in]  TokenNumber The PCD token number. 
  @param[in]  Value       The value to set for the PCD token.

  @retval EFI_SUCCESS  Procedure returned successfully.
  @retval EFI_INVALID_PARAMETER The PCD service determined that the size of the data 
                                  being set was incompatible with a call to this function.  
                                  Use GetSize() to retrieve the size of the target data.
  @retval EFI_NOT_FOUND The PCD service could not find the requested token number.
  
**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_SET16)(
  IN UINTN              TokenNumber,
  IN UINT16             Value
  );



/**
  Sets an 32-bit value for a given PCD token.

  When the PCD service sets a value, it will check to ensure that the 
  size of the value being set is compatible with the Token's existing definition.  
  If it is not, an error will be returned.

  @param[in]  TokenNumber The PCD token number. 
  @param[in]  Value       The value to set for the PCD token.

  @retval EFI_SUCCESS  Procedure returned successfully.
  @retval EFI_INVALID_PARAMETER The PCD service determined that the size of the data 
                                  being set was incompatible with a call to this function.  
                                  Use GetSize() to retrieve the size of the target data.
  @retval EFI_NOT_FOUND The PCD service could not find the requested token number.
  
**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_SET32)(
  IN UINTN              TokenNumber,
  IN UINT32             Value
  );



/**
  Sets an 64-bit value for a given PCD token.

  When the PCD service sets a value, it will check to ensure that the 
  size of the value being set is compatible with the Token's existing definition.  
  If it is not, an error will be returned.

  @param[in]  TokenNumber The PCD token number. 
  @param[in]  Value       The value to set for the PCD token.

  @retval EFI_SUCCESS  Procedure returned successfully.
  @retval EFI_INVALID_PARAMETER The PCD service determined that the size of the data 
                                  being set was incompatible with a call to this function.  
                                  Use GetSize() to retrieve the size of the target data.
  @retval EFI_NOT_FOUND The PCD service could not find the requested token number.
  
**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_SET64)(
  IN UINTN             TokenNumber,
  IN UINT64            Value
  );



/**
  Sets a value of a specified size for a given PCD token.

  When the PCD service sets a value, it will check to ensure that the 
  size of the value being set is compatible with the Token's existing definition.  
  If it is not, an error will be returned.

  @param[in]      TokenNumber  The PCD token number. 
  @param[in, out] SizeOfBuffer A pointer to the length of the value being set for the PCD token.  
                               On input, if the SizeOfValue is greater than the maximum size supported 
                               for this TokenNumber then the output value of SizeOfValue will reflect 
                               the maximum size supported for this TokenNumber.
  @param[in]      Buffer       The buffer to set for the PCD token.

  @retval EFI_SUCCESS  Procedure returned successfully.
  @retval EFI_INVALID_PARAMETER The PCD service determined that the size of the data 
                                  being set was incompatible with a call to this function.  
                                  Use GetSize() to retrieve the size of the target data.
  @retval EFI_NOT_FOUND The PCD service could not find the requested token number.
  
**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_SET_POINTER)(
  IN      UINTN             TokenNumber,
  IN OUT  UINTN             *SizeOfBuffer,
  IN      VOID              *Buffer
  );



/**
  Sets an Boolean value for a given PCD token.

  When the PCD service sets a value, it will check to ensure that the 
  size of the value being set is compatible with the Token's existing definition.  
  If it is not, an error will be returned.

  @param[in]  TokenNumber The PCD token number. 
  @param[in]  Value       The value to set for the PCD token.

  @retval EFI_SUCCESS  Procedure returned successfully.
  @retval EFI_INVALID_PARAMETER The PCD service determined that the size of the data 
                                  being set was incompatible with a call to this function.  
                                  Use GetSize() to retrieve the size of the target data.
  @retval EFI_NOT_FOUND The PCD service could not find the requested token number.
  
**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_SET_BOOLEAN)(
  IN UINTN             TokenNumber,
  IN BOOLEAN           Value
  );



/**
  Sets an 8-bit value for a given PCD token.

  When the PCD service sets a value, it will check to ensure that the 
  size of the value being set is compatible with the Token's existing definition.  
  If it is not, an error will be returned.

  @param[in]  Guid        The 128-bit unique value that designates the namespace from which to extract the value.
  @param[in]  TokenNumber The PCD token number. 
  @param[in]  Value       The value to set for the PCD token.

  @retval EFI_SUCCESS  Procedure returned successfully.
  @retval EFI_INVALID_PARAMETER The PCD service determined that the size of the data 
                                  being set was incompatible with a call to this function.  
                                  Use GetSize() to retrieve the size of the target data.
  @retval EFI_NOT_FOUND The PCD service could not find the requested token number.
  
**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_SET_EX_8)(
  IN CONST EFI_GUID    *Guid,
  IN UINTN             TokenNumber,
  IN UINT8             Value
  );



/**
  Sets an 16-bit value for a given PCD token.

  When the PCD service sets a value, it will check to ensure that the 
  size of the value being set is compatible with the Token's existing definition.  
  If it is not, an error will be returned.

  @param[in]  Guid        The 128-bit unique value that designates the namespace from which to extract the value.
  @param[in]  TokenNumber The PCD token number. 
  @param[in]  Value       The value to set for the PCD token.

  @retval EFI_SUCCESS  Procedure returned successfully.
  @retval EFI_INVALID_PARAMETER The PCD service determined that the size of the data 
                                  being set was incompatible with a call to this function.  
                                  Use GetSize() to retrieve the size of the target data.
  @retval EFI_NOT_FOUND The PCD service could not find the requested token number.
  
**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_SET_EX_16)(
  IN CONST EFI_GUID    *Guid,
  IN UINTN             TokenNumber,
  IN UINT16            Value
  );



/**
  Sets an 32-bit value for a given PCD token.

  When the PCD service sets a value, it will check to ensure that the 
  size of the value being set is compatible with the Token's existing definition.  
  If it is not, an error will be returned.

  @param[in]  Guid        The 128-bit unique value that designates the namespace from which to extract the value.
  @param[in]  TokenNumber The PCD token number. 
  @param[in]  Value       The value to set for the PCD token.

  @retval EFI_SUCCESS  Procedure returned successfully.
  @retval EFI_INVALID_PARAMETER The PCD service determined that the size of the data 
                                  being set was incompatible with a call to this function.  
                                  Use GetSize() to retrieve the size of the target data.
  @retval EFI_NOT_FOUND The PCD service could not find the requested token number.
  
**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_SET_EX_32)(
  IN CONST EFI_GUID     *Guid,
  IN UINTN              TokenNumber,
  IN UINT32             Value
  );



/**
  Sets an 64-bit value for a given PCD token.

  When the PCD service sets a value, it will check to ensure that the 
  size of the value being set is compatible with the Token's existing definition.  
  If it is not, an error will be returned.

  @param[in]  Guid        The 128-bit unique value that designates the namespace from which to extract the value.
  @param[in]  TokenNumber The PCD token number. 
  @param[in]  Value       The value to set for the PCD token.

  @retval EFI_SUCCESS  Procedure returned successfully.
  @retval EFI_INVALID_PARAMETER The PCD service determined that the size of the data 
                                  being set was incompatible with a call to this function.  
                                  Use GetSize() to retrieve the size of the target data.
  @retval EFI_NOT_FOUND The PCD service could not find the requested token number.
  
**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_SET_EX_64)(
  IN CONST EFI_GUID    *Guid,
  IN UINTN             TokenNumber,
  IN UINT64            Value
  );



/**
  Sets a value of a specified size for a given PCD token.

  When the PCD service sets a value, it will check to ensure that the 
  size of the value being set is compatible with the Token's existing definition.  
  If it is not, an error will be returned.

  @param[in]  Guid            The 128-bit unique value that designates the namespace from which to extract the value.
  @param[in]  TokenNumber     The PCD token number. 
  @param[in, out] SizeOfBuffer A pointer to the length of the value being set for the PCD token.  
                              On input, if the SizeOfValue is greater than the maximum size supported 
                              for this TokenNumber then the output value of SizeOfValue will reflect 
                              the maximum size supported for this TokenNumber.
  @param[in]  Buffer          The buffer to set for the PCD token.

  @retval EFI_SUCCESS  Procedure returned successfully.
  @retval EFI_INVALID_PARAMETER The PCD service determined that the size of the data 
                                  being set was incompatible with a call to this function.  
                                  Use GetSize() to retrieve the size of the target data.
  @retval EFI_NOT_FOUND The PCD service could not find the requested token number.
  
**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_SET_EX_POINTER)(
  IN      CONST EFI_GUID    *Guid,
  IN      UINTN             TokenNumber,
  IN OUT  UINTN             *SizeOfBuffer,
  IN      VOID              *Buffer
  );



/**
  Sets an Boolean value for a given PCD token.

  When the PCD service sets a value, it will check to ensure that the 
  size of the value being set is compatible with the Token's existing definition.  
  If it is not, an error will be returned.

  @param[in]  Guid        The 128-bit unique value that designates the namespace from which to extract the value.
  @param[in]  TokenNumber The PCD token number. 
  @param[in]  Value       The value to set for the PCD token.

  @retval EFI_SUCCESS  Procedure returned successfully.
  @retval EFI_INVALID_PARAMETER The PCD service determined that the size of the data 
                                  being set was incompatible with a call to this function.  
                                  Use GetSize() to retrieve the size of the target data.
  @retval EFI_NOT_FOUND The PCD service could not find the requested token number.
  
**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_SET_EX_BOOLEAN)(
  IN CONST EFI_GUID    *Guid,
  IN UINTN             TokenNumber,
  IN BOOLEAN           Value
  );
  


/**
  Callback on SET function prototype definition.

  This notification function serves two purposes. 
  Firstly, it notifies the module which did the registration that the value 
  of this PCD token has been set. Secondly, it provides a mechanism for the 
  module which did the registration to intercept the set operation and override 
  the value been set if necessary. After the invocation of the callback function, 
  TokenData will be used by PCD service DXE driver to modify the internal data in 
  PCD database.

  @param[in]  CallBackGuid    The PCD token GUID being set.
  @param[in]  CallBackToken   The PCD token number being set.
  @param[in, out] TokenData   A pointer to the token data being set.
  @param[in]  TokenDataSize   The size, in bytes, of the data being set.

  @retval VOID

**/
typedef
VOID
(EFIAPI *PCD_PROTOCOL_CALLBACK)(
  IN      CONST EFI_GUID   *CallBackGuid, OPTIONAL
  IN      UINTN            CallBackToken,
  IN  OUT VOID             *TokenData,
  IN      UINTN            TokenDataSize
  );



/**
  Specifies a function to be called anytime the value of a designated token is changed.

  @param[in]  TokenNumber       The PCD token number. 
  @param[in]  Guid              The 128-bit unique value that designates the namespace from which to extract the value.
  @param[in]  CallBackFunction  The function prototype called when the value associated with the CallBackToken is set.  

  @retval EFI_SUCCESS   The PCD service has successfully established a call event 
                        for the CallBackToken requested.
  @retval EFI_NOT_FOUND The PCD service could not find the referenced token number.

**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_CALLBACK_ONSET)(
  IN  CONST EFI_GUID          *Guid, OPTIONAL
  IN  UINTN                   TokenNumber,
  IN  PCD_PROTOCOL_CALLBACK   CallBackFunction
  );



/**
  Cancels a previously set callback function for a particular PCD token number.

  @param[in]  TokenNumber      The PCD token number. 
  @param[in]  Guid             The 128-bit unique value that designates the namespace from which to extract the value.
  @param[in]  CallBackFunction The function prototype called when the value associated with the CallBackToken is set.  

  @retval EFI_SUCCESS   The PCD service has successfully established a call event 
                        for the CallBackToken requested.
  @retval EFI_NOT_FOUND The PCD service could not find the referenced token number.

**/
typedef
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_CANCEL_CALLBACK)(
  IN  CONST EFI_GUID          *Guid, OPTIONAL
  IN  UINTN                   TokenNumber,
  IN  PCD_PROTOCOL_CALLBACK   CallBackFunction
  );



/**
  Retrieves the next valid PCD token for a given namespace.

  @param[in]      Guid    The 128-bit unique value that designates the namespace from which to extract the value.
  @param[in,out]  TokenNumber 
                          A pointer to the PCD token number to use to find the subsequent token number.  
                          If the input token namespace or token number does not exist on the platform, 
                          an error is returned and the value of *TokenNumber is undefined. To retrieve the "first" token, 
                          have the pointer reference a TokenNumber value of 0. If the input token number is 0 and 
                          there is no valid token number for this token namespace,  *TokenNumber will be assigned to 
                          0 and the function return EFI_SUCCESS. If the token number is the last valid token number, 
                          *TokenNumber will be assigned to 0 and the function return EFI_SUCCESS.

  @retval EFI_SUCCESS   The PCD service retrieved the next valid token number. Or the input token number 
                        is already the last valid token number in the PCD database. 
                        In the later case, *TokenNumber is updated with the value of 0.
  @retval EFI_NOT_FOUND If this input token number and token namespace does not exist on the platform.

**/
typedef 
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_GET_NEXT_TOKEN)(
  IN      CONST EFI_GUID      *Guid, OPTIONAL
  IN OUT  UINTN               *TokenNumber
  );



/**
  Retrieves the next valid PCD token namespace for a given namespace.

  @param[in, out]  Guid An indirect pointer to EFI_GUID.  On input it designates 
                        a known token namespace from which the search will start. On output, 
                        it designates the next valid token namespace on the platform. If the input 
                        token namespace does not exist on the platform, an error is returned and 
                        the value of *Guid is undefined. If *Guid is NULL, then the GUID of the 
                        first token space of the current platform is assigned to *Guid the function 
                        return EFI_SUCCESS. If  *Guid is NULL  and there is no namespace exist in 
                        the platform other than the default (NULL) tokennamespace, *Guid is unchanged 
                        and the function return EFI_SUCCESS. If this input token namespace is the last 
                        namespace on the platform, *Guid will be assigned to NULL and the function return 
                        EFI_SUCCESS. 

  @retval EFI_SUCCESS  The PCD service retrieved the next valid token space Guid. 
                        Or the input token space Guid is already the last valid token space Guid 
                        in the PCD database. In the later case, *Guid is updated with the value of NULL.
  @retval EFI_NOT_FOUND If the input token namespace does not exist on the platform.

**/
typedef 
EFI_STATUS
(EFIAPI *PCD_PROTOCOL_GET_NEXT_TOKENSPACE)(
  IN  OUT    CONST EFI_GUID      **Guid
  );

//
// Interface structure for the PCD Protocol
//
/**
  @par Protocol Description:
  This service abstracts the ability to set/get Platform Configuration Database (PCD).

  @param SetSku
  Sets the SKU value for subsequent calls to set or get PCD token values.
  
  @param Get8
  Retrieves an 8-bit value for a given PCD token.

  @param Get16
  Retrieves an 16-bit value for a given PCD token.

  @param Get32
  Retrieves an 32-bit value for a given PCD token.

  @param Get64
  Retrieves an 64-bit value for a given PCD token.

  @param GetPtr
  Retrieves a pointer to a value for a given PCD token.

  @param GetBool
  Retrieves an Boolean value for a given PCD token.

  @param GetSize
  Retrieves the size of the value for a given PCD token.

  @param Get8Ex
  Retrieves an 8-bit value for a given PCD token and token space.

  @param Get16Ex
  Retrieves an 16-bit value for a given PCD token and token space.

  @param Get32Ex
  Retrieves an 32-bit value for a given PCD token and token space.

  @param Get64Ex
  Retrieves an 64-bit value for a given PCD token and token space.

  @param GetPtrEx
  Retrieves a pointer to a value for a given PCD token and token space.

  @param GetBoolEx
  Retrieves an Boolean value for a given PCD token and token space.

  @param GetSizeEx
  Retrieves the size of the value for a given PCD token and token space.

  @param Set8
  Sets an 8-bit value for a given PCD token.

  @param Set16
  Sets an 16-bit value for a given PCD token.

  @param Set32
  Sets an 32-bit value for a given PCD token.

  @param Set64
  Sets an 64-bit value for a given PCD token.

  @param SetPtr
  Sets the buffer of a specified size for a given PCD token.

  @param SetBool
  Sets an Boolean value for a given PCD token.

  @param Set8Ex
  Sets an 8-bit value for a given PCD token and token space.

  @param Set16Ex
  Sets an 16-bit value for a given PCD token and token space.

  @param Set32Ex
  Sets an 32-bit value for a given PCD token and token space.

  @param Set64Ex
  Sets an 64-bit value for a given PCD token and token space.

  @param SetPtrEx
  Sets the buffer of a specified size for a given PCD token and token space.

  @param SetBoolEx
  Sets an Boolean value for a given PCD token and token space.
  
  @param CallbackOnSet
  Specifies a function to be called anytime the value of a designated token is changed.
  
  @param CancelCallback
  Cancels a previously set callback function for a particular PCD token number.
  
  @param GetNextToken
  Retrieves the next valid PCD token for a given namespace.
  
  @param GetNextTokenSpace
  Retrieves the next valid PCD token namespace for a given namespace.
 
**/
typedef struct {
  PCD_PROTOCOL_SET_SKU              SetSku;

  PCD_PROTOCOL_GET8                 Get8;
  PCD_PROTOCOL_GET16                Get16;
  PCD_PROTOCOL_GET32                Get32;
  PCD_PROTOCOL_GET64                Get64;
  PCD_PROTOCOL_GET_POINTER          GetPtr;
  PCD_PROTOCOL_GET_BOOLEAN          GetBool;
  PCD_PROTOCOL_GET_SIZE             GetSize;

  PCD_PROTOCOL_GET_EX_8             Get8Ex;
  PCD_PROTOCOL_GET_EX_16            Get16Ex;
  PCD_PROTOCOL_GET_EX_32            Get32Ex;
  PCD_PROTOCOL_GET_EX_64            Get64Ex;
  PCD_PROTOCOL_GET_EX_POINTER       GetPtrEx;
  PCD_PROTOCOL_GET_EX_BOOLEAN       GetBoolEx;
  PCD_PROTOCOL_GET_EX_SIZE          GetSizeEx;

  PCD_PROTOCOL_SET8                 Set8;
  PCD_PROTOCOL_SET16                Set16;
  PCD_PROTOCOL_SET32                Set32;
  PCD_PROTOCOL_SET64                Set64;
  PCD_PROTOCOL_SET_POINTER          SetPtr;
  PCD_PROTOCOL_SET_BOOLEAN          SetBool;

  PCD_PROTOCOL_SET_EX_8             Set8Ex;
  PCD_PROTOCOL_SET_EX_16            Set16Ex;
  PCD_PROTOCOL_SET_EX_32            Set32Ex;
  PCD_PROTOCOL_SET_EX_64            Set64Ex;
  PCD_PROTOCOL_SET_EX_POINTER       SetPtrEx;
  PCD_PROTOCOL_SET_EX_BOOLEAN       SetBoolEx;

  PCD_PROTOCOL_CALLBACK_ONSET       CallbackOnSet;
  PCD_PROTOCOL_CANCEL_CALLBACK      CancelCallback;
  PCD_PROTOCOL_GET_NEXT_TOKEN       GetNextToken;
  PCD_PROTOCOL_GET_NEXT_TOKENSPACE  GetNextTokenSpace;
} PCD_PROTOCOL;

#endif