This is a driver for high-speed SCC boards, i.e. those supporting
DMA on one port. You usually use those boards to connect your
computer to an amateur radio modem (such as the WA4DSY 56kbps
modem), in order to send and receive AX.25 packet radio network
traffic.

Currently, this driver supports Ottawa PI/PI2, Paccomm/Gracilis
PackeTwin, and S5SCC/DMA boards. They are detected automatically.
If you have one of these cards, say Y here and read the AX25-HOWTO,
available from <http://www.tldp.org/docs.html#howto>.

This driver can operate multiple boards simultaneously. If you
compile it as a module (by saying M instead of Y), it will be called
dmascc. If you don't pass any parameter to the driver, all
possible I/O addresses are probed. This could irritate other devices
that are currently not in use. You may specify the list of addresses
to be probed by "dmascc.io=addr1,addr2,..." (when compiled into the
kernel image) or "io=addr1,addr2,..." (when loaded as a module). The
network interfaces will be called dmascc0 and dmascc1 for the board
detected first, dmascc2 and dmascc3 for the second one, and so on.

Before you configure each interface with ifconfig, you MUST set
certain parameters, such as channel access timing, clock mode, and
DMA channel. This is accomplished with a small utility program,
dmascc_cfg, available at
<http://www.linux-ax25.org/wiki/Ax25-tools>. Please be sure to
get at least version 1.27 of dmascc_cfg, as older versions will not
work with the current driver.

source code:

drivers/net/hamradio/dmascc.c