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FlashSimBlockDevice class hierarchy

The FlashSimBlockDevice class is a block device adapator, whose purpose is to simulate the behavior of a flash component if the underlying block device doesn't support such a behavior. This includes the following:

  • Support the erase API (fills the erase unit with the predefined erase value).
  • Only allow programming of erased area or ones whose content is the same as the one given by the user.
  • Support the get\_erase\_value API, returning the predefined erase value.

The constructor requires the following:

  • bd - Block device to back the FlashSimBlockDevice.
  • erase_value - Value given to each byte of the erase unit following an erase operation (defaults to 0xFF).

To configure this class, please see our BlockDevice configuration documentation.

FlashSimBlockDevice class reference

Public Member Functions
 FlashSimBlockDevice (BlockDevice *bd, uint8_t erase_value=0xFF)
 Constructor. More...
virtual int init ()
 Initialize a block device. More...
virtual int deinit ()
 Deinitialize the block device. More...
virtual int sync ()
 Ensure data on storage is in sync with the driver. More...
virtual int read (void *buffer, bd_addr_t addr, bd_size_t size)
 Read blocks from the block device. More...
virtual int program (const void *buffer, bd_addr_t addr, bd_size_t size)
 Program blocks to the block device. More...
virtual int erase (bd_addr_t addr, bd_size_t size)
 Erase blocks on the block device. 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 given address. More...
virtual int get_erase_value () const
 Get the value of storage when 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 BlockDevice class type. More...
virtual int trim (bd_addr_t addr, bd_size_t size)
 Mark blocks as no longer in use. 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 BlockDeviceget_default_instance ()
 Return the default block device. More...

FlashSimBlockDevice example

This FlashSimBlockDevice example takes a HeapBlockDevice and turns it into a simulated flash BD.

    int erase_unit_size = 512;
    HeapBlockDevice heap_bd(4 * erase_unit_size, 1, 4, erase_unit_size);
    FlashSimBlockDevice flash_bd(&heap_bd, blank);

    // This initializes the flash simulator block device (as well as the underlying heap block device)
    int err = flash_bd.init();

    uint8_t buf[16];
    for (int i = 0; i < sizeof(buf); i++) {
        buf[i] = i;

    // This will fail, as erase unit in address 0 has not been erased
    err = flash_bd.program(buf, 0, sizeof(buf));

    // Erase the erase unit at address 0
    err = flash_bd.erase(0, erase_unit_size);

    // This will succeed now after erasing
    err = flash_bd.program(buf, 0, sizeof(buf));
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