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Public Member Functions | Static Public Member Functions
BufferedBlockDevice Class Reference

Block device for allowing 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:
BlockDevice

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...
 
bool is_valid_read (bd_addr_t addr, bd_size_t size) const
 Convenience function for checking block read validity. More...
 
bool is_valid_program (bd_addr_t addr, bd_size_t size) const
 Convenience function for checking block program validity. More...
 
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 BlockDeviceget_default_instance ()
 Return the default block device. More...
 

Detailed Description

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

Definition at line 36 of file BufferedBlockDevice.h.

Constructor & Destructor Documentation

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

Parameters
bdBlock device to back the BufferedBlockDevice
virtual ~BufferedBlockDevice ( )
virtual

Lifetime of the memory-buffered block device.

Member Function Documentation

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.

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
addrAddress of block to begin erasing
sizeSize to erase in bytes, must be a multiple of erase block size
Returns
0 on success, negative error code on failure

Reimplemented from BlockDevice.

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().

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.

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
addrAddress within the erasable block
Returns
Size of an erasable block in bytes
Note
Must be a multiple of the program size

Reimplemented from BlockDevice.

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.

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.

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.

virtual const char* get_type ( ) const
virtual

Get the underlying BlockDevice class type.

Returns
A string representing the underlying BlockDevice class type

Implements BlockDevice.

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.

bool is_valid_erase ( bd_addr_t  addr,
bd_size_t  size 
) const
inherited

Convenience function for checking block erase validity.

Parameters
addrAddress of block to begin erasing
sizeSize to erase in bytes
Returns
True if erase is valid for underlying block device

Definition at line 229 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
addrAddress of block to begin writing to
sizeSize to write in bytes
Returns
True if program is valid for underlying block device

Definition at line 215 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
addrAddress of block to begin reading from
sizeSize to read in bytes
Returns
True if read is valid for underlying block device

Definition at line 201 of file BlockDevice.h.

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
bufferBuffer of data to write to blocks
addrAddress of block to begin writing to
sizeSize to write in bytes, must be a multiple of program block size
Returns
0 on success, negative error code on failure

Implements BlockDevice.

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

Read blocks from the memory-buffered block device.

Parameters
bufferBuffer to read blocks into
addrAddress of block to begin reading from
sizeSize to read in bytes, must be a multiple of read block size
Returns
0 on success, negative error code on failure

Implements BlockDevice.

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.

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.

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
addrAddress of block to mark as unused
sizeSize 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.

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