The socket services component is responsible for any system-specific initialization required by the flash devices at startup and for providing addressability to the flash devices (this applies mainly to windowed flash interfaces).
Before reading/writing the flash device, other components will use socket services to make sure the required address range can be accessed. On systems where the flash device is linearly mapped into the processor address space, addressability is trivial. On systems where the flash is either bank-switched or hidden behind some other interface (such as PCMCIA), addressability is more complicated.
The socket services component is the one that will require the most customization for your system.