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ChainingBlockDevice Class Reference

ChainingBlockDevice Class Reference

Block device for chaining multiple block devices with the similar block sizes at sequential addresses. More...

#include <ChainingBlockDevice.h>

Inherits BlockDevice.

Public Member Functions

 ChainingBlockDevice (BlockDevice **bds, size_t bd_count)
 Lifetime of the memory block device.
template<size_t Size>
 ChainingBlockDevice (BlockDevice *(&bds)[Size])
 Lifetime of the memory block device.
virtual ~ChainingBlockDevice ()
 Lifetime of the memory 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 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.

Detailed Description

Block device for chaining multiple block devices with the similar block sizes at sequential addresses.

  #include "mbed.h"
  #include "HeapBlockDevice.h"
  #include "ChainingBlockDevice.h"

  // Create two smaller block devices with
  // 64 and 32 blocks of size 512 bytes
  HeapBlockDevice mem1(64*512, 512);
  HeapBlockDevice mem2(32*512, 512);

  // Create a block device backed by mem1 and mem2
  // contains 96 blocks of size 512 bytes
  BlockDevice *bds[] = {&mem1, &mem2};
  ChainingBlockDevice chainmem(bds);

Definition at line 48 of file ChainingBlockDevice.h.


Constructor & Destructor Documentation

ChainingBlockDevice ( BlockDevice **  bds,
size_t  bd_count 
)

Lifetime of the memory block device.

Parameters:
bdsArray of block devices to chain with sequential block addresses
bd_countNumber of block devices to chain
Note:
All block devices must have the same block size

Definition at line 20 of file ChainingBlockDevice.cpp.

ChainingBlockDevice ( BlockDevice *(&)  bds[Size] )

Lifetime of the memory block device.

Parameters:
bdsArray of block devices to chain with sequential block addresses
Note:
All block devices must have the same block size

Definition at line 65 of file ChainingBlockDevice.h.

virtual ~ChainingBlockDevice (  ) [virtual]

Lifetime of the memory block device.

Definition at line 74 of file ChainingBlockDevice.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 75 of file ChainingBlockDevice.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:
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 149 of file ChainingBlockDevice.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 188 of file ChainingBlockDevice.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 183 of file ChainingBlockDevice.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 178 of file ChainingBlockDevice.cpp.

int init (  ) [virtual]

Initialize a block device.

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

Implements BlockDevice.

Definition at line 31 of file ChainingBlockDevice.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 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:
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 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:
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 150 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 118 of file ChainingBlockDevice.cpp.

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

Read blocks from a block device.

Parameters:
bufferBuffer to write blocks to
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 87 of file ChainingBlockDevice.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 193 of file ChainingBlockDevice.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:
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

Definition at line 110 of file BlockDevice.h.