Block device which allows minimal read and program sizes (of 1) for the underlying BD using a buffer on the heap. More...

#include <BufferedBlockDevice.h>

Inheritance diagram for BufferedBlockDevice:

Public Member Functions
	BufferedBlockDevice (BlockDevice *bd)
	Lifetime of a memory-buffered block device wrapping an underlying block device. More...

virtual	~BufferedBlockDevice ()
	Lifetime of the memory-buffered block device. More...

virtual int	init ()
	Initialize a buffered-memory block device and its underlying block device. More...

virtual int	deinit ()
	Deinitialize the buffered-memory block device and its underlying block device. More...

virtual int	sync ()
	Ensure that data on the underlying storage block device is in sync with the memory-buffered block device. More...

virtual int	read (void *buffer, bd_addr_t addr, bd_size_t size)
	Read blocks from the memory-buffered block device. More...

virtual int	program (const void *buffer, bd_addr_t addr, bd_size_t size)
	Program data to the memory-buffered block device. More...

virtual int	erase (bd_addr_t addr, bd_size_t size)
	Erase blocks from the memory-buffered block device. More...

virtual int	trim (bd_addr_t addr, bd_size_t size)
	Mark blocks as no longer in use. More...

virtual bd_size_t	get_read_size () const
	Get the size of a readable block. More...

virtual bd_size_t	get_program_size () const
	Get the size of a programmable block. More...

virtual bd_size_t	get_erase_size () const
	Get the size of an erasable block. More...

virtual bd_size_t	get_erase_size (bd_addr_t addr) const
	Get the size of an erasable block of a given address. More...

virtual int	get_erase_value () const
	Get the value of storage data after being erased. More...

virtual bd_size_t	size () const
	Get the total size of the underlying device. More...

virtual const char *	get_type () const
	Get the underlying BlockDevice class type. More...

virtual bool	is_valid_read (bd_addr_t addr, bd_size_t size) const
	Convenience function for checking block read validity. More...

virtual bool	is_valid_program (bd_addr_t addr, bd_size_t size) const
	Convenience function for checking block program validity. More...

virtual bool	is_valid_erase (bd_addr_t addr, bd_size_t size) const
	Convenience function for checking block erase validity. More...

Static Public Member Functions
static BlockDevice *	get_default_instance ()
	Return the default block device. More...

Detailed Description

Block device which allows minimal read and program sizes (of 1) for the underlying BD using a buffer on the heap.

This essentially "simulates" a byte-programmable device like a NOR flash or an EEPROM, using a non-byte-programmable device like an SD card or NAND flash.

Note: While the read and write size of the buffered block device will always be 1, the erase size is the same as the underlying block device. In other words, you still must erase in the hardware erase sector size.

Definition at line 39 of file BufferedBlockDevice.h.

Constructor & Destructor Documentation

◆ BufferedBlockDevice()

BufferedBlockDevice ( BlockDevice * bd )

Lifetime of a memory-buffered block device wrapping an underlying block device.

Parameters

bd	Block device to back the BufferedBlockDevice

◆ ~BufferedBlockDevice()

virtual ~BufferedBlockDevice ( )

virtual

Lifetime of the memory-buffered block device.

Member Function Documentation

◆ init()

virtual int init ( )

virtual

Initialize a buffered-memory block device and its underlying block device.

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

Implements BlockDevice.

◆ deinit()

virtual int deinit ( )

virtual

Deinitialize the buffered-memory block device and its underlying block device.

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

Implements BlockDevice.

◆ sync()

virtual int sync ( )

virtual

Ensure that data on the underlying storage block device is in sync with the memory-buffered block device.

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

Reimplemented from BlockDevice.

◆ read()

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

virtual

Read blocks from the memory-buffered 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.

◆ program()

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

virtual

Program data to the memory-buffered block device.

The write address blocks must be 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.

◆ erase()

virtual int erase	(	bd_addr_t	addr,
		bd_size_t	size
	)

virtual

Erase blocks from the memory-buffered block device.

The state of an erased block is undefined until it has been programmed, unless get_erase_value returns a non-negative byte value.

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.

◆ trim()

virtual int trim	(	bd_addr_t	addr,
		bd_size_t	size
	)

virtual

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

Reimplemented from BlockDevice.

◆ get_read_size()

virtual 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.

◆ get_program_size()

virtual bd_size_t get_program_size ( ) const

virtual

Get the size of a programmable block.

Returns: Size of a programmable block in bytes

Note: Must be a multiple of the read size

Implements BlockDevice.

◆ get_erase_size() [1/2]

virtual bd_size_t get_erase_size ( ) const

virtual

Get the size of an erasable block.

Returns: Size of an erasable block in bytes

Note: Must be a multiple of the program size

Reimplemented from BlockDevice.

◆ get_erase_size() [2/2]

virtual bd_size_t get_erase_size ( bd_addr_t addr ) const

virtual

Get the size of an erasable block of a given address.

Parameters

addr	Address within the erasable block

Returns: Size of an erasable block in bytes

Note: Must be a multiple of the program size

Reimplemented from BlockDevice.

◆ get_erase_value()

virtual int get_erase_value ( ) const

virtual

Get the value of storage data after being erased.

If get_erase_value returns a non-negative byte value, the underlying storage is set to that value when erased, and storage containing that value can be programmed without another erase.

Returns: The value of storage when erased, or -1 if you can't rely on the value of erased storage

Reimplemented from BlockDevice.

◆ size()

virtual bd_size_t size ( ) const

virtual

Get the total size of the underlying device.

Returns: Size of the underlying device in bytes

Implements BlockDevice.

◆ get_type()

virtual const char * get_type ( ) const

virtual

Get the underlying BlockDevice class type.

Returns: A string representing the underlying BlockDevice class type

Implements BlockDevice.

◆ get_default_instance()

static BlockDevice * get_default_instance ( )

staticinherited

Return the default block device.

Returns the default block device based on the configuration JSON. Use the components in target.json or application config to change the default block device.

An application can override all target settings by implementing BlockDevice::get_default_instance() - the default definition is weak, and calls get_target_default_instance().

◆ is_valid_read()

virtual bool is_valid_read	(	bd_addr_t	addr,
		bd_size_t	size
	)		const

virtualinherited

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

Reimplemented in SlicingBlockDevice.

Definition at line 207 of file BlockDevice.h.

◆ is_valid_program()

virtual bool is_valid_program	(	bd_addr_t	addr,
		bd_size_t	size
	)		const

virtualinherited

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

Reimplemented in SlicingBlockDevice.

Definition at line 221 of file BlockDevice.h.

◆ is_valid_erase()

virtual bool is_valid_erase	(	bd_addr_t	addr,
		bd_size_t	size
	)		const

virtualinherited

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

Reimplemented in SlicingBlockDevice, and FlashIAPBlockDevice.

Definition at line 235 of file BlockDevice.h.

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ BufferedBlockDevice()

◆ ~BufferedBlockDevice()

Member Function Documentation

◆ init()

◆ deinit()

◆ sync()

◆ read()

◆ program()

◆ erase()

◆ trim()

◆ get_read_size()

◆ get_program_size()

◆ get_erase_size() [1/2]

◆ get_erase_size() [2/2]

◆ get_erase_value()

◆ size()

◆ get_type()

◆ get_default_instance()

◆ is_valid_read()

◆ is_valid_program()

◆ is_valid_erase()