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BufferedBlockDevice Class Reference

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>

Inherits BlockDevice.

Public Member Functions

 BufferedBlockDevice (BlockDevice *bd)
 Lifetime of the memory block device.
virtual ~BufferedBlockDevice ()
 Lifetime of a block device.
virtual int init ()
 Initialize a block device.
virtual int deinit ()
 Deinitialize a block device.
virtual int sync ()
 Ensure data on storage is in sync with the driver.
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 int trim (bd_addr_t addr, bd_size_t size)
 Mark blocks as no longer in use.
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 programmable block.
virtual bd_size_t get_erase_size () const
 Get the size of an erasable block.
virtual bd_size_t get_erase_size (bd_addr_t addr) const
 Get the size of an erasable block given address.
virtual int get_erase_value () const
 Get the value of storage when erased.
virtual bd_size_t size () const
 Get the total size of the underlying device.
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.

Protected Member Functions

int flush ()
 Flush data in cache.

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 31 of file BufferedBlockDevice.h.


Constructor & Destructor Documentation

Lifetime of the memory block device.

Parameters:
bdBlock device to back the BufferedBlockDevice

Definition at line 27 of file BufferedBlockDevice.cpp.

~BufferedBlockDevice (  ) [virtual]

Lifetime of a block device.

Definition at line 32 of file BufferedBlockDevice.cpp.


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 56 of file BufferedBlockDevice.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, 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.

Definition at line 183 of file BufferedBlockDevice.cpp.

int flush (  ) [protected]

Flush data in cache.

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

Definition at line 63 of file BufferedBlockDevice.cpp.

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.

Definition at line 210 of file BufferedBlockDevice.cpp.

bd_size_t get_erase_size ( bd_addr_t  addr ) const [virtual]

Get the size of an erasable block 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.

Definition at line 215 of file BufferedBlockDevice.cpp.

int get_erase_value (  ) const [virtual]

Get the value of storage when 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.

Definition at line 220 of file BufferedBlockDevice.cpp.

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.

Definition at line 205 of file BufferedBlockDevice.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 200 of file BufferedBlockDevice.cpp.

int init (  ) [virtual]

Initialize a block device.

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

Implements BlockDevice.

Definition at line 37 of file BufferedBlockDevice.cpp.

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 213 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 199 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 185 of file BlockDevice.h.

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:
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.

Definition at line 120 of file BufferedBlockDevice.cpp.

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

Read blocks from a 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.

Definition at line 84 of file BufferedBlockDevice.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 225 of file BufferedBlockDevice.cpp.

int sync (  ) [virtual]

Ensure data on storage is in sync with the driver.

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

Reimplemented from BlockDevice.

Definition at line 75 of file BufferedBlockDevice.cpp.

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.

Definition at line 189 of file BufferedBlockDevice.cpp.