Download the broadcom driver sta from following location.
http://www.broadcom.com/docs/linux_sta/hybrid-v35-nodebug-pcoem-6_30_223_248.tar.gz
Step2:
Setup the directory by untarring the proper tarball:
For 32 bit: hybrid-v35-nodebug-pcoem-portsrc.tar.gz
For 64 bit: hybrid-v35_64-nodebug-pcoem-portsrc.tar.gz
Example:
# mkdir hybrid_wl
# cd hybrid_wl
# tar xzf /hybrid-v35-nodebug-pcoem-portsrc.tar.gz or
/hybrid-v35_64-nodebug-pcoem-portsrc.tar.gz
Step3:
Build the driver as a Linux loadable kernel module (LKM):
# make clean (optional)
# make API=WEXT CONFIG_DEBUG_SECTION_MISMATCH=y
Step4:
modprobe wl
Then the wifi is enabled successfully