Hi,
I want to interface wifi module ESP8266 over SPI on A20-OLinuXIno-LIME2-4GB are the drivers available
If you're using Olimex image with newer 5.X kernel you'd find /dev/spidev1.0 and /dev/spidev2.0.
I'm not aware if Olimex image with kernel 3.X exposes spi.
Then read
https://github.com/OLIMEX/OLINUXINO/blob/master/DOCUMENTS/OLIMAGE/Olimage-guide.pdf
you can drive SPI via python installing pyA20Lime2
https://pypi.org/project/pyA20Lime2/
or via C