Firmware Block Services to support emulating non-volatile variables by pretending that a memory buffer is storage for the NV variables.
Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent
Definition in file Fvb.c.
Erases and initializes a firmware volume block.
The EraseBlocks() function erases one or more blocks as denoted by the variable argument list. The entire parameter list of blocks must be verified before erasing any blocks. If a block is requested that does not exist within the associated firmware volume (it has a larger index than the last block of the firmware volume), the EraseBlocks() function must return the status code EFI_INVALID_PARAMETER without modifying the contents of the firmware volume. Implementations should be mindful that the firmware volume might be in the WriteDisabled state. If it is in this state, the EraseBlocks() function must return the status code EFI_ACCESS_DENIED without modifying the contents of the firmware volume. All calls to EraseBlocks() must be fully flushed to the hardware before the EraseBlocks() service returns.
- Parameters
-
| This | Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance. |
| ... | The variable argument list is a list of tuples. Each tuple describes a range of LBAs to erase and consists of the following:
- An EFI_LBA that indicates the starting LBA
- A UINTN that indicates the number of blocks to erase
|
The list is terminated with an EFI_LBA_LIST_TERMINATOR. For example, the following indicates that two ranges of blocks (5-7 and 10-11) are to be erased: EraseBlocks (This, 5, 3, 10, 2, EFI_LBA_LIST_TERMINATOR);
- Return values
-
| EFI_SUCCESS | The erase request was successfully completed. |
| EFI_ACCESS_DENIED | The firmware volume is in the WriteDisabled state. |
| EFI_DEVICE_ERROR | The block device is not functioning correctly and could not be written. The firmware device may have been partially erased. |
| EFI_INVALID_PARAMETER | One or more of the LBAs listed in the variable argument list do not exist in the firmware volume. |
Definition at line 307 of file Fvb.c.
Reads the specified number of bytes into a buffer from the specified block.
The Read() function reads the requested number of bytes from the requested block and stores them in the provided buffer. Implementations should be mindful that the firmware volume might be in the ReadDisabled state. If it is in this state, the Read() function must return the status code EFI_ACCESS_DENIED without modifying the contents of the buffer. The Read() function must also prevent spanning block boundaries. If a read is requested that would span a block boundary, the read must read up to the boundary but not beyond. The output parameter NumBytes must be set to correctly indicate the number of bytes actually read. The caller must be aware that a read may be partially completed.
- Parameters
-
| This | Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance. |
| Lba | The starting logical block index from which to read. |
| Offset | Offset into the block at which to begin reading. |
| NumBytes | Pointer to a UINTN. At entry, *NumBytes contains the total size of the buffer. At exit, *NumBytes contains the total number of bytes read. |
| Buffer | Pointer to a caller-allocated buffer that will be used to hold the data that is read. |
- Return values
-
| EFI_SUCCESS | The firmware volume was read successfully and contents are in Buffer. |
| EFI_BAD_BUFFER_SIZE | Read attempted across an LBA boundary. On output, NumBytes contains the total number of bytes returned in Buffer. |
| EFI_ACCESS_DENIED | The firmware volume is in the ReadDisabled state. |
| EFI_DEVICE_ERROR | The block device is not functioning correctly and could not be read. |
Definition at line 519 of file Fvb.c.
Writes the specified number of bytes from the input buffer to the block.
The Write() function writes the specified number of bytes from the provided buffer to the specified block and offset. If the firmware volume is sticky write, the caller must ensure that all the bits of the specified range to write are in the EFI_FVB_ERASE_POLARITY state before calling the Write() function, or else the result will be unpredictable. This unpredictability arises because, for a sticky-write firmware volume, a write may negate a bit in the EFI_FVB_ERASE_POLARITY state but cannot flip it back again. In general, before calling the Write() function, the caller should call the EraseBlocks() function first to erase the specified block to write. A block erase cycle will transition bits from the (NOT)EFI_FVB_ERASE_POLARITY state back to the EFI_FVB_ERASE_POLARITY state. Implementations should be mindful that the firmware volume might be in the WriteDisabled state. If it is in this state, the Write() function must return the status code EFI_ACCESS_DENIED without modifying the contents of the firmware volume. The Write() function must also prevent spanning block boundaries. If a write is requested that spans a block boundary, the write must store up to the boundary but not beyond. The output parameter NumBytes must be set to correctly indicate the number of bytes actually written. The caller must be aware that a write may be partially completed. All writes, partial or otherwise, must be fully flushed to the hardware before the Write() service returns.
- Parameters
-
| This | Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance. |
| Lba | The starting logical block index to write to. |
| Offset | Offset into the block at which to begin writing. |
| NumBytes | Pointer to a UINTN. At entry, *NumBytes contains the total size of the buffer. At exit, *NumBytes contains the total number of bytes actually written. |
| Buffer | Pointer to a caller-allocated buffer that contains the source for the write. |
- Return values
-
| EFI_SUCCESS | The firmware volume was written successfully. |
| EFI_BAD_BUFFER_SIZE | The write was attempted across an LBA boundary. On output, NumBytes contains the total number of bytes actually written. |
| EFI_ACCESS_DENIED | The firmware volume is in the WriteDisabled state. |
| EFI_DEVICE_ERROR | The block device is malfunctioning and could not be written. |
Definition at line 435 of file Fvb.c.
1.9.6