techblog 

To get this working in FreeBSD you need to edit /boot/loader.conf and add the following lines

hifn_load="YES"
crypto_load="YES"
cryptodev_load="YES"

Reboot to make this take effect. (You may be able to use kldload to load the modules without rebooting)

Next add the utilities to test the card

cd /usr/src/tools/tools/crypto/
sudo make
sudo make install

Running hifnstats looks like this

hifnstats
input 6917304 bytes 9124 packets
output 6917304 bytes 9124 packets
invalid 0 nomem 0 abort 0
noirq 0 unaligned 0
totbatch 0 maxbatch 0
nomem: map 0 load 0 mbuf 0 mcl 0 cr 0 sd 0

You should see the card being used to accelerate ssh connections.