source: vbox/trunk/src/VBox/Devices/EFI/Firmware/MdePkg/Library/PeiSmbusLibSmbus2Ppi/PeiSmbusLib.c@ 107675

/** @file
Implementation of SmBusLib class library for PEI phase.

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

**/

#include "InternalSmbusLib.h"

/**
  Gets Smbus PPIs.

  This internal function retrieves Smbus PPI from PPI database.

  @param  VOID

  @return The pointer to Smbus PPI.

**/
EFI_PEI_SMBUS2_PPI *
InternalGetSmbusPpi (
  VOID
  )
{
  EFI_STATUS          Status;
  EFI_PEI_SMBUS2_PPI  *SmbusPpi;

  Status = PeiServicesLocatePpi (&gEfiPeiSmbus2PpiGuid, 0, NULL, (VOID **)&SmbusPpi);
  ASSERT_EFI_ERROR (Status);
  ASSERT (SmbusPpi != NULL);

  return SmbusPpi;
}

/**
  Executes an SMBus operation to an SMBus controller.

  This function provides a standard way to execute Smbus script
  as defined in the SmBus Specification. The data can either be of
  the Length byte, word, or a block of data.

  @param  SmbusOperation  Signifies which particular SMBus hardware protocol instance
                          that it will use to execute the SMBus transactions.
  @param  SmBusAddress    The address that encodes the SMBUS Slave Address,
                          SMBUS Command, SMBUS Data Length, and PEC.
  @param  Length          Signifies the number of bytes that this operation will
                          do. The maximum number of bytes can be revision specific
                          and operation specific.
  @param  Buffer          Contains the value of data to execute to the SMBus slave
                          device. Not all operations require this argument. The
                          length of this buffer is identified by Length.
  @param  Status          Return status for the executed command.
                          This is an optional parameter and may be NULL.

  @return The actual number of bytes that are executed for this operation.

**/
UINTN
InternalSmBusExec (
  IN     EFI_SMBUS_OPERATION  SmbusOperation,
  IN     UINTN                SmBusAddress,
  IN     UINTN                Length,
  IN OUT VOID                 *Buffer,
  OUT RETURN_STATUS           *Status        OPTIONAL
  )
{
  EFI_PEI_SMBUS2_PPI        *SmbusPpi;
  RETURN_STATUS             ReturnStatus;
  EFI_SMBUS_DEVICE_ADDRESS  SmbusDeviceAddress;

  SmbusPpi                              = InternalGetSmbusPpi ();
  SmbusDeviceAddress.SmbusDeviceAddress = SMBUS_LIB_SLAVE_ADDRESS (SmBusAddress);

  ReturnStatus = SmbusPpi->Execute (
                             SmbusPpi,
                             SmbusDeviceAddress,
                             SMBUS_LIB_COMMAND (SmBusAddress),
                             SmbusOperation,
                             SMBUS_LIB_PEC (SmBusAddress),
                             &Length,
                             Buffer
                             );
  if (Status != NULL) {
    *Status = ReturnStatus;
  }

  return Length;
}