MdePkg/Library/PeiSmbusLibSmbus2Ppi/PeiSmbusLib.c

   1 /** @file
   2 Implementation of SmBusLib class library for PEI phase.
   3
   4 Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
   5 SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 #include "InternalSmbusLib.h"
  10
  11 /**
  12   Gets Smbus PPIs.
  13
  14   This internal function retrieves Smbus PPI from PPI database.
  15
  16   @param  VOID
  17
  18   @return The pointer to Smbus PPI.
  19
  20 **/
  21 EFI_PEI_SMBUS2_PPI *
  22 InternalGetSmbusPpi (
  23   VOID
  24   )
  25 {
  26   EFI_STATUS            Status;
  27   EFI_PEI_SMBUS2_PPI     *SmbusPpi;
  28
  29   Status = PeiServicesLocatePpi (&gEfiPeiSmbus2PpiGuid, 0, NULL, (VOID **) &SmbusPpi);
  30   ASSERT_EFI_ERROR (Status);
  31   ASSERT (SmbusPpi != NULL);
  32
  33   return SmbusPpi;
  34 }
  35
  36 /**
  37   Executes an SMBus operation to an SMBus controller.
  38
  39   This function provides a standard way to execute Smbus script
  40   as defined in the SmBus Specification. The data can either be of
  41   the Length byte, word, or a block of data.
  42
  43   @param  SmbusOperation  Signifies which particular SMBus hardware protocol instance
  44                           that it will use to execute the SMBus transactions.
  45   @param  SmBusAddress    The address that encodes the SMBUS Slave Address,
  46                           SMBUS Command, SMBUS Data Length, and PEC.
  47   @param  Length          Signifies the number of bytes that this operation will
  48                           do. The maximum number of bytes can be revision specific
  49                           and operation specific.
  50   @param  Buffer          Contains the value of data to execute to the SMBus slave
  51                           device. Not all operations require this argument. The
  52                           length of this buffer is identified by Length.
  53   @param  Status          Return status for the executed command.
  54                           This is an optional parameter and may be NULL.
  55
  56   @return The actual number of bytes that are executed for this operation.
  57
  58 **/
  59 UINTN
  60 InternalSmBusExec (
  61   IN     EFI_SMBUS_OPERATION        SmbusOperation,
  62   IN     UINTN                      SmBusAddress,
  63   IN     UINTN                      Length,
  64   IN OUT VOID                       *Buffer,
  65      OUT RETURN_STATUS              *Status        OPTIONAL
  66   )
  67 {
  68   EFI_PEI_SMBUS2_PPI        *SmbusPpi;
  69   RETURN_STATUS             ReturnStatus;
  70   EFI_SMBUS_DEVICE_ADDRESS  SmbusDeviceAddress;
  71
  72   SmbusPpi    = InternalGetSmbusPpi ();
  73   SmbusDeviceAddress.SmbusDeviceAddress = SMBUS_LIB_SLAVE_ADDRESS (SmBusAddress);
  74
  75   ReturnStatus = SmbusPpi->Execute (
  76                              SmbusPpi,
  77                              SmbusDeviceAddress,
  78                              SMBUS_LIB_COMMAND (SmBusAddress),
  79                              SmbusOperation,
  80                              SMBUS_LIB_PEC (SmBusAddress),
  81                              &Length,
  82                              Buffer
  83                              );
  84   if (Status != NULL) {
  85     *Status = ReturnStatus;
  86   }
  87
  88   return Length;
  89 }