Physical length of flash mapping

configname: CONFIG_MTD_PHYSMAP_LEN

Linux Kernel Configuration
└─>Device Drivers
└─>Memory Technology Device (MTD) support
└─>Mapping drivers for chip access
└─>Physical length of flash mapping
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
This is the total length of the mapping of the flash chips on
your particular board. If there is space, or aliases, in the
physical memory map between the chips, this could be larger
than the total amount of flash present. Refer to the memory
map which should hopefully be in the documentation for your
board.