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   This program and the accompanying materials are licensed and made available
   8   under the terms and conditions of the BSD License which accompanies this
   9   distribution.  The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
  13   WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15 **/
  16
  17 #ifndef __QEMU_FW_CFG_LIB_INTERNAL_H__
  18 #define __QEMU_FW_CFG_LIB_INTERNAL_H__
  19
  20 /**
  21   Returns a boolean indicating if the firmware configuration interface is
  22   available for library-internal purposes.
  23
  24   This function never changes fw_cfg state.
  25
  26   @retval    TRUE   The interface is available internally.
  27   @retval    FALSE  The interface is not available internally.
  28 **/
  29 BOOLEAN
  30 InternalQemuFwCfgIsAvailable (
  31   VOID
  32   );
  33
  34
  35 /**
  36   Returns a boolean indicating whether QEMU provides the DMA-like access method
  37   for fw_cfg.
  38
  39   @retval    TRUE   The DMA-like access method is available.
  40   @retval    FALSE  The DMA-like access method is unavailable.
  41 **/
  42 BOOLEAN
  43 InternalQemuFwCfgDmaIsAvailable (
  44   VOID
  45   );
  46
  47 /**
  48   Transfer an array of bytes, or skip a number of bytes, using the DMA
  49   interface.
  50
  51   @param[in]     Size     Size in bytes to transfer or skip.
  52
  53   @param[in,out] Buffer   Buffer to read data into or write data from. Ignored,
  54                           and may be NULL, if Size is zero, or Control is
  55                           FW_CFG_DMA_CTL_SKIP.
  56
  57   @param[in]     Control  One of the following:
  58                           FW_CFG_DMA_CTL_WRITE - write to fw_cfg from Buffer.
  59                           FW_CFG_DMA_CTL_READ  - read from fw_cfg into Buffer.
  60                           FW_CFG_DMA_CTL_SKIP  - skip bytes in fw_cfg.
  61 **/
  62 VOID
  63 InternalQemuFwCfgDmaBytes (
  64   IN     UINT32   Size,
  65   IN OUT VOID     *Buffer OPTIONAL,
  66   IN     UINT32   Control
  67   );
  68
  69 #endif