OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLibInternal.h

   1 /** @file
   2   Internal interfaces specific to the QemuFwCfgLib instances in OvmfPkg.
   3
   4   Copyright (C) 2016, Red Hat, Inc.
   5   Copyright (C) 2017, Advanced Micro Devices. All rights reserved
   6
   7   SPDX-License-Identifier: BSD-2-Clause-Patent
   8
   9 **/
  10
  11 #ifndef __QEMU_FW_CFG_LIB_INTERNAL_H__
  12 #define __QEMU_FW_CFG_LIB_INTERNAL_H__
  13
  14 /**
  15   Returns a boolean indicating if the firmware configuration interface is
  16   available for library-internal purposes.
  17
  18   This function never changes fw_cfg state.
  19
  20   @retval    TRUE   The interface is available internally.
  21   @retval    FALSE  The interface is not available internally.
  22 **/
  23 BOOLEAN
  24 InternalQemuFwCfgIsAvailable (
  25   VOID
  26   );
  27
  28
  29 /**
  30   Returns a boolean indicating whether QEMU provides the DMA-like access method
  31   for fw_cfg.
  32
  33   @retval    TRUE   The DMA-like access method is available.
  34   @retval    FALSE  The DMA-like access method is unavailable.
  35 **/
  36 BOOLEAN
  37 InternalQemuFwCfgDmaIsAvailable (
  38   VOID
  39   );
  40
  41 /**
  42   Transfer an array of bytes, or skip a number of bytes, using the DMA
  43   interface.
  44
  45   @param[in]     Size     Size in bytes to transfer or skip.
  46
  47   @param[in,out] Buffer   Buffer to read data into or write data from. Ignored,
  48                           and may be NULL, if Size is zero, or Control is
  49                           FW_CFG_DMA_CTL_SKIP.
  50
  51   @param[in]     Control  One of the following:
  52                           FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.
  53                           FW_CFG_DMA_CTL_READ  - read from fw_cfg into Buffer.
  54                           FW_CFG_DMA_CTL_SKIP  - skip bytes in fw_cfg.
  55 **/
  56 VOID
  57 InternalQemuFwCfgDmaBytes (
  58   IN     UINT32   Size,
  59   IN OUT VOID     *Buffer OPTIONAL,
  60   IN     UINT32   Control
  61   );
  62
  63 #endif