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      1 /*++
      2 
      3 Copyright (c) 2004 - 2006, Intel Corporation. All rights reserved.<BR>
      4 This program and the accompanying materials
      5 are licensed and made available under the terms and conditions of the BSD License
      6 which accompanies this distribution.  The full text of the license may be found at
      7 http://opensource.org/licenses/bsd-license.php
      8 
      9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
     10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
     11 
     12 
     13 Module Name:
     14 
     15   PeiSmbusLib.c
     16 
     17 Abstract:
     18 
     19   PEI Smbus Lib internal functions
     20 
     21 --*/
     22 
     23 #include "PeiSmbusLibInternal.h"
     24 
     25 /**
     26   Gets Smbus PPIs.
     27 
     28   This internal function retrieves Smbus PPI from PPI database.
     29 
     30   @param  PeiServices   An indirect pointer to the EFI_PEI_SERVICES published by the PEI Foundation.
     31 
     32   @return The pointer to Smbus PPI.
     33 
     34 **/
     35 EFI_PEI_SMBUS_PPI *
     36 InternalGetSmbusPpi (
     37   EFI_PEI_SERVICES      **PeiServices
     38   )
     39 {
     40   EFI_STATUS            Status;
     41   EFI_PEI_SMBUS_PPI     *SmbusPpi;
     42 
     43   Status = (*PeiServices)->LocatePpi (PeiServices, &gEfiPeiSmbusPpiGuid, 0, NULL, (VOID **) &SmbusPpi);
     44   ASSERT_EFI_ERROR (Status);
     45   ASSERT (SmbusPpi != NULL);
     46 
     47   return SmbusPpi;
     48 }
     49 
     50 /**
     51   Executes an SMBus operation to an SMBus controller.
     52 
     53   This function provides a standard way to execute Smbus script
     54   as defined in the SmBus Specification. The data can either be of
     55   the Length byte, word, or a block of data.
     56 
     57   @param  SmbusOperation  Signifies which particular SMBus hardware protocol instance that it will use to
     58                           execute the SMBus transactions.
     59   @param  SmBusAddress    Address that encodes the SMBUS Slave Address,
     60                           SMBUS Command, SMBUS Data Length, and PEC.
     61   @param  Length          Signifies the number of bytes that this operation will do. The maximum number of
     62                           bytes can be revision specific and operation specific.
     63   @param  Buffer          Contains the value of data to execute to the SMBus slave device. Not all operations
     64                           require this argument. The length of this buffer is identified by Length.
     65   @param  Status          Return status for the executed command.
     66                           This is an optional parameter and may be NULL.
     67 
     68   @return The actual number of bytes that are executed for this operation..
     69 
     70 **/
     71 UINTN
     72 InternalSmBusExec (
     73   IN     EFI_SMBUS_OPERATION        SmbusOperation,
     74   IN     UINTN                      SmBusAddress,
     75   IN     UINTN                      Length,
     76   IN OUT VOID                       *Buffer,
     77      OUT RETURN_STATUS              *Status        OPTIONAL
     78   )
     79 {
     80   EFI_PEI_SMBUS_PPI         *SmbusPpi;
     81   EFI_PEI_SERVICES          **PeiServices;
     82   RETURN_STATUS             ReturnStatus;
     83   EFI_SMBUS_DEVICE_ADDRESS  SmbusDeviceAddress;
     84 
     85   PeiServices = GetPeiServicesTablePointer ();
     86   SmbusPpi    = InternalGetSmbusPpi (PeiServices);
     87   SmbusDeviceAddress.SmbusDeviceAddress = SMBUS_LIB_SLAVE_ADDRESS (SmBusAddress);
     88 
     89   ReturnStatus = SmbusPpi->Execute (
     90                              PeiServices,
     91                              SmbusPpi,
     92                              SmbusDeviceAddress,
     93                              SMBUS_LIB_COMMAND (SmBusAddress),
     94                              SmbusOperation,
     95                              SMBUS_LIB_PEC (SmBusAddress),
     96                              &Length,
     97                              Buffer
     98                              );
     99   if (Status != NULL) {
    100     *Status = ReturnStatus;
    101   }
    102 
    103   return Length;
    104 }
    105