Broadcom FW eng interview

After telephonic I got onsite call for FW eng MAC system team SJC USA from #broadcom. 7hrs (9-5) What to prep? Basic C coding data structures ( ll, hashtable, btree etc..) 802.11 specs wifi codes . FW Q ? Kernel./ MAC driver Q? What else ? Any suggestions will.be very helpful for me ? I am 8yrs exp , expecting staff engineer role there .