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   Returns a boolean indicating whether QEMU provides the DMA-like access method
  30   for fw_cfg.
  31
  32   @retval    TRUE   The DMA-like access method is available.
  33   @retval    FALSE  The DMA-like access method is unavailable.
  34 **/
  35 BOOLEAN
  36 InternalQemuFwCfgDmaIsAvailable (
  37   VOID
  38   );
  39
  40 /**
  41   Transfer an array of bytes, or skip a number of bytes, using the DMA
  42   interface.
  43
  44   @param[in]     Size     Size in bytes to transfer or skip.
  45
  46   @param[in,out] Buffer   Buffer to read data into or write data from. Ignored,
  47                           and may be NULL, if Size is zero, or Control is
  48                           FW_CFG_DMA_CTL_SKIP.
  49
  50   @param[in]     Control  One of the following:
  51                           FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.
  52                           FW_CFG_DMA_CTL_READ  - read from fw_cfg into Buffer.
  53                           FW_CFG_DMA_CTL_SKIP  - skip bytes in fw_cfg.
  54 **/
  55 VOID
  56 InternalQemuFwCfgDmaBytes (
  57   IN     UINT32  Size,
  58   IN OUT VOID    *Buffer OPTIONAL,
  59   IN     UINT32  Control
  60   );
  61
  62 #endif