Block device for managing a Master Boot Record https://en.wikipedia.org/wiki/Master_boot_record. More...

#include <MBRBlockDevice.h>

Public Member Functions
	MBRBlockDevice (BlockDevice *bd, int part)
	Lifetime of the block device.
virtual	~MBRBlockDevice ()
	Lifetime of the block device.
virtual int	init ()
	Initialize a block device.
virtual int	deinit ()
	Deinitialize a block device.
virtual int	read (void *buffer, bd_addr_t addr, bd_size_t size)
	Read blocks from a block device.
virtual int	program (const void *buffer, bd_addr_t addr, bd_size_t size)
	Program blocks to a block device.
virtual int	erase (bd_addr_t addr, bd_size_t size)
	Erase blocks on a block device.
virtual bd_size_t	get_read_size () const
	Get the size of a readable block.
virtual bd_size_t	get_program_size () const
	Get the size of a programable block.
virtual bd_size_t	get_erase_size () const
	Get the size of a eraseable block.
virtual bd_size_t	size () const
	Get the total size of the underlying device.
virtual bd_addr_t	get_partition_start () const
	Get the offset of the partition on the underlying block device.
virtual bd_addr_t	get_partition_stop () const
	Get size of partition on underlying block device.
virtual uint8_t	get_partition_type () const
	Get 8-bit type of the partition.
virtual int	get_partition_number () const
	Get the partition number.
virtual int	trim (bd_addr_t addr, bd_size_t size)
	Mark blocks as no longer in use.
bool	is_valid_read (bd_addr_t addr, bd_size_t size) const
	Convenience function for checking block read validity.
bool	is_valid_program (bd_addr_t addr, bd_size_t size) const
	Convenience function for checking block program validity.
bool	is_valid_erase (bd_addr_t addr, bd_size_t size) const
	Convenience function for checking block erase validity.
Static Public Member Functions
static int	partition (BlockDevice *bd, int part, uint8_t type, bd_addr_t start)
	Format the MBR to contain the following partition.
static int	partition (BlockDevice *bd, int part, uint8_t type, bd_addr_t start, bd_addr_t stop)
	Format the MBR to contain the following partition.

Detailed Description

Block device for managing a Master Boot Record https://en.wikipedia.org/wiki/Master_boot_record.

Here is an example of partitioning a heap backed block device

  #include "mbed.h"
  #include "HeapBlockDevice.h"
  #include "MBRBlockDevice.h"

  // Create a block device with 64 blocks of size 512
  HeapBlockDevice mem(64*512, 512);

  // Partition into two partitions with ~half the blocks
  MBRBlockDevice::partition(&mem, 1, 0x83, 0*512, 32*512);
  MBRBlockDevice::partition(&mem, 2, 0x83, 32*512);

  // Create a block device that maps to the first 32 blocks (excluding MBR block)
  MBRBlockDevice part1(&mem, 1);

  // Create a block device that maps to the last 32 blocks
  MBRBlockDevice part2(&mem, 2);

Here is a more realistic example where the MBRBlockDevice is used to partition a region of space on an SD card. When plugged into a computer, the partitions will be recognized appropriately.

  #include "mbed.h"
  #include "SDBlockDevice.h"
  #include "MBRBlockDevice.h"
  #include "FATFileSystem.h"

  // Create an SD card
  SDBlockDevice sd(s0, s1, s2, s3);

  // Create a partition with 1 GB of space
  MBRBlockDevice::partition(&sd, 1, 0x83, 0, 1024*1024);

  // Create the block device that represents the partition
  MBRBlockDevice part1(&sd, 1);

  // Format the partition with a FAT filesystem
  FATFileSystem::format(&part1);

  // Create the FAT filesystem instance, files can now be written to
  // the FAT filesystem in partition 1
  FATFileSystem fat("fat", &part1);

Definition at line 86 of file MBRBlockDevice.h.

Constructor & Destructor Documentation

MBRBlockDevice	(	BlockDevice *	bd,
		int	part
	)

Lifetime of the block device.

Parameters:

bd	Block device to back the MBRBlockDevice
part	Partition to use, 1-4

Definition at line 182 of file MBRBlockDevice.cpp.

virtual ~MBRBlockDevice ( ) [virtual]

Lifetime of the block device.

Definition at line 128 of file MBRBlockDevice.h.

Member Function Documentation

int deinit ( ) [virtual]

Deinitialize a block device.

Returns:: 0 on success or a negative error code on failure

Implements BlockDevice.

Definition at line 232 of file MBRBlockDevice.cpp.

int erase	(	bd_addr_t	addr,
		bd_size_t	size
	)		`[virtual]`

Erase blocks on a block device.

The state of an erased block is undefined until it has been programmed

Parameters:

addr	Address of block to begin erasing
size	Size to erase in bytes, must be a multiple of erase block size

Returns:: 0 on success, negative error code on failure

Reimplemented from BlockDevice.

Definition at line 249 of file MBRBlockDevice.cpp.

bd_size_t get_erase_size ( ) const [virtual]

Get the size of a eraseable block.

Returns:: Size of a eraseable block in bytes

Note:: Must be a multiple of the program size

Reimplemented from BlockDevice.

Definition at line 265 of file MBRBlockDevice.cpp.

int get_partition_number ( ) const [virtual]

Get the partition number.

Returns:: The partition number, 1-4

Definition at line 290 of file MBRBlockDevice.cpp.

bd_size_t get_partition_start ( ) const [virtual]

Get the offset of the partition on the underlying block device.

Returns:: Offset of the partition on the underlying device

Definition at line 275 of file MBRBlockDevice.cpp.

bd_size_t get_partition_stop ( ) const [virtual]

Get size of partition on underlying block device.

Returns:: Size of the partition on the underlying device

Definition at line 280 of file MBRBlockDevice.cpp.

uint8_t get_partition_type ( ) const [virtual]

Get 8-bit type of the partition.

Returns:: 8-bit type of partition assigned during format

Definition at line 285 of file MBRBlockDevice.cpp.

bd_size_t get_program_size ( ) const [virtual]

Get the size of a programable block.

Returns:: Size of a programable block in bytes

Note:: Must be a multiple of the read size

Implements BlockDevice.

Definition at line 260 of file MBRBlockDevice.cpp.

bd_size_t get_read_size ( ) const [virtual]

Get the size of a readable block.

Returns:: Size of a readable block in bytes

Implements BlockDevice.

Definition at line 255 of file MBRBlockDevice.cpp.

int init ( ) [virtual]

Initialize a block device.

Returns:: 0 on success or a negative error code on failure

Implements BlockDevice.

Definition at line 188 of file MBRBlockDevice.cpp.

bool is_valid_erase	(	bd_addr_t	addr,
		bd_size_t	size
	)		const `[inherited]`

Convenience function for checking block erase validity.

Parameters:

addr	Address of block to begin erasing
size	Size to erase in bytes

Returns:: True if erase is valid for underlying block device

Definition at line 178 of file BlockDevice.h.

bool is_valid_program	(	bd_addr_t	addr,
		bd_size_t	size
	)		const `[inherited]`

Convenience function for checking block program validity.

Parameters:

addr	Address of block to begin writing to
size	Size to write in bytes

Returns:: True if program is valid for underlying block device

Definition at line 164 of file BlockDevice.h.

bool is_valid_read	(	bd_addr_t	addr,
		bd_size_t	size
	)		const `[inherited]`

Convenience function for checking block read validity.

Parameters:

addr	Address of block to begin reading from
size	Size to read in bytes

Returns:: True if read is valid for underlying block device

Definition at line 150 of file BlockDevice.h.

int partition	(	BlockDevice *	bd,
		int	part,
		uint8_t	type,
		bd_addr_t	start
	)		`[static]`

Format the MBR to contain the following partition.

Parameters:

bd	Block device to partition
part	Partition to use, 1-4
type	8-bit partition type to identitfy partition's contents
start	Start block address to map to block 0 of partition, negative addresses are calculated from the end of the underlying block devices. Block 0 is implicitly ignored from the range to store the MBR.

Returns:: 0 on success or a negative error code on failure

Note:: This is the same as partition(bd, part, type, start, bd->size())

Definition at line 121 of file MBRBlockDevice.cpp.

int partition	(	BlockDevice *	bd,
		int	part,
		uint8_t	type,
		bd_addr_t	start,
		bd_addr_t	stop
	)		`[static]`

Format the MBR to contain the following partition.

Parameters:

bd	Block device to partition
part	Partition to use, 1-4
type	8-bit partition type to identitfy partition's contents
start	Start block address to map to block 0 of partition, negative addresses are calculated from the end of the underlying block devices. Block 0 is implicitly ignored from the range to store the MBR.
stop	End block address to mark the end of the partition, this block is not mapped, negative addresses are calculated from the end of the underlying block device.

Returns:: 0 on success or a negative error code on failure

Definition at line 151 of file MBRBlockDevice.cpp.

int program	(	const void *	buffer,
		bd_addr_t	addr,
		bd_size_t	size
	)		`[virtual]`

Program blocks to a block device.

The blocks must have been erased prior to being programmed

Parameters:

buffer	Buffer of data to write to blocks
addr	Address of block to begin writing to
size	Size to write in bytes, must be a multiple of program block size

Returns:: 0 on success, negative error code on failure

Implements BlockDevice.

Definition at line 243 of file MBRBlockDevice.cpp.

int read	(	void *	buffer,
		bd_addr_t	addr,
		bd_size_t	size
	)		`[virtual]`

Read blocks from a block device.

Parameters:

buffer	Buffer to read blocks into
addr	Address of block to begin reading from
size	Size to read in bytes, must be a multiple of read block size

Returns:: 0 on success, negative error code on failure

Implements BlockDevice.

Definition at line 237 of file MBRBlockDevice.cpp.

bd_size_t size ( ) const [virtual]

Get the total size of the underlying device.

Returns:: Size of the underlying device in bytes

Implements BlockDevice.

Definition at line 270 of file MBRBlockDevice.cpp.

virtual int trim	(	bd_addr_t	addr,
		bd_size_t	size
	)		`[virtual, inherited]`

Mark blocks as no longer in use.

This function provides a hint to the underlying block device that a region of blocks is no longer in use and may be erased without side effects. Erase must still be called before programming, but trimming allows flash-translation-layers to schedule erases when the device is not busy.

Parameters:

addr	Address of block to mark as unused
size	Size to mark as unused in bytes, must be a multiple of erase block size

Returns:: 0 on success, negative error code on failure

Definition at line 110 of file BlockDevice.h.

Type:	Program
Mbed OS support:	Mbed OS
Created:	23 Feb 2019
Imports:	43
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	0
Followers:	1

MBRBlockDevice Class Reference

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

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MBRBlockDevice Class Reference

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Repository toolbox

Repository details

Important Information for this Arm website

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