Flash services interface

The flash services interface, defined in the <fs/f3s_flash.h> header file, consists of the following functions:

Note: The values for the flags parameter are defined in <fs/s3s_flash.h>. The most important one is F3S_VERIFY_WRITE. If this is set, the routine must perform a read-back verification after the write as a double check that the write succeeded. Occasionally, however, the hardware reports success even when the write didn't work as expected.