MdePkg/Include/Protocol/RamDisk.h

/** @file
  This file defines the EFI RAM Disk Protocol.

  Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
  which accompanies this distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

  @par Revision Reference:
  This Protocol is introduced in UEFI Specification 2.6

**/

#ifndef __RAM_DISK_PROTOCOL_H__
#define __RAM_DISK_PROTOCOL_H__

//
// EFI RAM Disk Protocol GUID value
//
#define EFI_RAM_DISK_PROTOCOL_GUID \
  { 0xab38a0df, 0x6873, 0x44a9, { 0x87, 0xe6, 0xd4, 0xeb, 0x56, 0x14, 0x84, 0x49 }};

//
// Forward reference for pure ANSI compatability
//
typedef struct _EFI_RAM_DISK_PROTOCOL  EFI_RAM_DISK_PROTOCOL;

/**
  Register a RAM disk with specified address, size and type.

  @param[in]  RamDiskBase    The base address of registered RAM disk.
  @param[in]  RamDiskSize    The size of registered RAM disk.
  @param[in]  RamDiskType    The type of registered RAM disk. The GUID can be
                             any of the values defined in section 9.3.6.9, or a
                             vendor defined GUID.
  @param[in]  ParentDevicePath
                             Pointer to the parent device path. If there is no
                             parent device path then ParentDevicePath is NULL.
  @param[out] DevicePath     On return, points to a pointer to the device path
                             of the RAM disk device.
                             If ParentDevicePath is not NULL, the returned
                             DevicePath is created by appending a RAM disk node
                             to the parent device path. If ParentDevicePath is
                             NULL, the returned DevicePath is a RAM disk device
                             path without appending. This function is
                             responsible for allocating the buffer DevicePath
                             with the boot service AllocatePool().

  @retval EFI_SUCCESS             The RAM disk is registered successfully.
  @retval EFI_INVALID_PARAMETER   DevicePath or RamDiskType is NULL.
                                  RamDiskSize is 0.
  @retval EFI_ALREADY_STARTED     A Device Path Protocol instance to be created
                                  is already present in the handle database.
  @retval EFI_OUT_OF_RESOURCES    The RAM disk register operation fails due to
                                  resource limitation.

**/
typedef
EFI_STATUS
(EFIAPI *EFI_RAM_DISK_REGISTER_RAMDISK) (
  IN UINT64                       RamDiskBase,
  IN UINT64                       RamDiskSize,
  IN EFI_GUID                     *RamDiskType,
  IN EFI_DEVICE_PATH              *ParentDevicePath     OPTIONAL,
  OUT EFI_DEVICE_PATH_PROTOCOL    **DevicePath
  );

/**
  Unregister a RAM disk specified by DevicePath.

  @param[in] DevicePath      A pointer to the device path that describes a RAM
                             Disk device.

  @retval EFI_SUCCESS             The RAM disk is unregistered successfully.
  @retval EFI_INVALID_PARAMETER   DevicePath is NULL.
  @retval EFI_UNSUPPORTED         The device specified by DevicePath is not a
                                  valid ramdisk device path and not supported
                                  by the driver.
  @retval EFI_NOT_FOUND           The RAM disk pointed by DevicePath doesn't
                                  exist.

**/
typedef
EFI_STATUS
(EFIAPI *EFI_RAM_DISK_UNREGISTER_RAMDISK) (
  IN  EFI_DEVICE_PATH_PROTOCOL    *DevicePath
  );

///
/// RAM Disk Protocol structure.
///
struct _EFI_RAM_DISK_PROTOCOL {
  EFI_RAM_DISK_REGISTER_RAMDISK        Register;
  EFI_RAM_DISK_UNREGISTER_RAMDISK      Unregister;
};

///
/// RAM Disk Protocol GUID variable.
///
extern EFI_GUID gEfiRamDiskProtocolGuid;

#endif