MdePkg/Include/Protocol/RamDisk.h

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

  Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

  @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