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                COMX drivers for the 2.2 kernel

Originally written by: Tivadar Szemethy, 

Currently maintained by: Gergely Madarasz 

Last change: 21/06/1999.

INTRODUCTION

This document describes the software drivers and their use for the

COMX line of synchronous serial adapters for Linux version 2.2.0 and

above.

The cards are produced and sold by ITC-Pro Ltd. Budapest, Hungary

For further info contact 

or http://www.itc.hu (mostly in Hungarian).

The firmware files and software are available from ftp://ftp.itc.hu

Currently, the drivers support the following cards and protocols:

COMX (2x64 kbps intelligent board)

CMX (1x256 + 1x128 kbps intelligent board)

HiCOMX (2x2Mbps intelligent board)

LoCOMX (1x512 kbps passive board)

MixCOM (1x512 or 2x512kbps passive board with a hardware watchdog an

        optional BRI interface and optional flashROM (1-32M))

SliceCOM        (1x2Mbps channelized E1 board)

PciCOM  (X21)

At the moment of writing this document, the (Cisco)-HDLC, LAPB, SyncPPP and

Frame Relay (DTE, rfc1294 IP encapsulation with partially implemented Q933a

LMI) protocols are available as link-level protocol.

X.25 support is being worked on.

USAGE

Load the comx.o module and the hardware-specific and protocol-specific

modules you'll need into the running kernel using the insmod utility.

This creates the /proc/comx directory.

See the example scripts in the 'etc' directory.

/proc INTERFACE INTRO

The COMX driver set has a new type of user interface based on the /proc

filesystem which eliminates the need for external user-land software doing

IOCTL calls.

Each network interface or device (i.e. those ones you configure with 'ifconfig'

and 'route' etc.) has a corresponding directory under /proc/comx. You can

dynamically create a new interface by saying 'mkdir /proc/comx/comx0' (or you

can name it whatever you want up to 8 characters long, comx[n] is just a

convention).

Generally the files contained in these directories are text files, which can

be viewed by 'cat filename' and you can write a string to such a file by

saying 'echo _string_ >filename'. This is very similar to the sysctl interface.

Don't use a text editor to edit these files, always use 'echo' (or 'cat'

where appropriate).

When you've created the comx[n] directory, two files are created automagically

in it: 'boardtype' and 'protocol'. You have to fill in these files correctly

for your board and protocol you intend to use (see the board and protocol

descriptions in this file below or the example scripts in the 'etc' directory).

After filling in these files, other files will appear in the directory for

setting the various hardware- and protocol-related informations (for example

irq and io addresses, keepalive values etc.) These files are set to default

values upon creation, so you don't necessarily have to change all of them.

When you're ready with filling in the files in the comx[n] directory, you can

configure the corresponding network interface with the standard network

configuration utilities. If you're unable to bring the interfaces up, look up

the various kernel log files on your system, and consult the messages for

a probable reason.

EXAMPLE

To create the interface 'comx0' which is the first channel of a COMX card:

insmod comx

# insmod comx-hw-comx ; insmod comx-proto-ppp  (these are usually

autoloaded if you use the kernel module loader)

mkdir /proc/comx/comx0

echo comx >/proc/comx/comx0/boardtype

echo 0x360 >/proc/comx/comx0/io         <- jumper-selectable I/O port

echo 0x0a >/proc/comx/comx0/irq         <- jumper-selectable IRQ line

echo 0xd000 >/proc/comx/comx0/memaddr   <- software-configurable memory

                                           address. COMX uses 64 KB, and this

                                           can be: 0xa000, 0xb000, 0xc000,

                                           0xd000, 0xe000. Avoid conflicts

                                           with other hardware.

cat /proc/comx/comx0/firmware <- the firmware for the card

echo HDLC >/proc/comx/comx0/protocol    <- the data-link protocol

echo 10 >/proc/comx/comx0/keepalive     <- the keepalive for the protocol

ifconfig comx0 1.2.3.4 pointopoint 5.6.7.8 netmask 255.255.255.255 <-

                                           finally configure it with ifconfig

Check its status:

cat /proc/comx/comx0/status

If you want to use the second channel of this board:

mkdir /proc/comx/comx1

echo comx >/proc/comx/comx1/boardtype

echo 0x360 >/proc/comx/comx1/io

echo 10 >/proc/comx/comx1/irq

echo 0xd000 >/proc/comx/comx1/memaddr

echo 1 >/proc/comx/comx1/channel        <- channels are numbered

                                           as 0 (default) and 1

Now, check if the driver recognized that you're going to use the other

channel of the same adapter:

cat /proc/comx/comx0/twin

comx1

cat /proc/comx/comx1/twin

comx0

You don't have to load the firmware twice, if you use both channels of

an adapter, just write it into the channel 0's /proc firmware file.

Default values: io 0x360 for COMX, 0x320 (HICOMX), irq 10, memaddr 0xd0000

THE LOCOMX HARDWARE DRIVER

The LoCOMX driver doesn't require firmware, and it doesn't use memory either,

but it uses DMA channels 1 and 3. You can set the clock rate (if enabled by

jumpers on the board) by writing the kbps value into the file named 'clock'.

Set it to 'external' (it is the default) if you have external clock source.

(Note: currently the LoCOMX driver does not support the internal clock)

THE COMX, CMX AND HICOMX DRIVERS

On the HICOMX, COMX and CMX, you have to load the firmware (it is different for

the three cards!). All these adapters can share the same memory

address (we usually use 0xd0000). On the CMX you can set the internal

clock rate (if enabled by jumpers on the small adapter boards) by writing

the kbps value into the 'clock' file. You have to do this before initializing

the card. If you use both HICOMX and CMX/COMX cards, initialize the HICOMX

first. The I/O address of the HICOMX board is not configurable by any

method available to the user: it is hardwired to 0x320, and if you have to

change it, consult ITC-Pro Ltd.

THE MIXCOM DRIVER

The MixCOM board doesn't require firmware, the driver communicates with

it through I/O ports. You can have three of these cards in one machine.

THE SLICECOM DRIVER

The SliceCOM board doesn't require firmware. You can have 4 of these cards

in one machine. The driver doesn't (yet) support shared interrupts, so

you will need a separate IRQ line for every board.

Read linux/Documentation/networking/slicecom.txt for help on configuring

this adapter.

THE HDLC/PPP LINE PROTOCOL DRIVER

The HDLC/SyncPPP line protocol driver uses the kernel's built-in syncppp

driver (syncppp.o). You don't have to manually select syncppp.o when building

the kernel, the dependencies compile it in automatically.

EXAMPLE

(setting up hw parameters, see above)

# using HDLC:

echo hdlc >/proc/comx/comx0/protocol

echo 10 >/proc/comx/comx0/keepalive     <- not necessary, 10 is the default

ifconfig comx0 1.2.3.4 pointopoint 5.6.7.8 netmask 255.255.255.255

(setting up hw parameters, see above)

# using PPP:

echo ppp >/proc/comx/comx0/protocol

ifconfig comx0 up

ifconfig comx0 1.2.3.4 pointopoint 5.6.7.8 netmask 255.255.255.255

THE LAPB LINE PROTOCOL DRIVER

For this, you'll need to configure LAPB support (See 'LAPB Data Link Driver' in

'Network options' section) into your kernel (thanks to Jonathan Naylor for his

excellent implementation).

comx-proto-lapb.o provides the following files in the appropriate directory

(the default values in parens): t1 (5), t2 (1), n2 (20), mode (DTE, STD) and

window (7). Agree with the administrator of your peer router on these

settings (most people use defaults, but you have to know if you are DTE or

DCE).

EXAMPLE

(setting up hw parameters, see above)

echo lapb >/proc/comx/comx0/protocol

echo dce >/proc/comx/comx0/mode         <- DCE interface in this example

ifconfig comx0 1.2.3.4 pointopoint 5.6.7.8 netmask 255.255.255.255

THE FRAME RELAY PROTOCOL DRIVER

You DON'T need any other frame relay related modules from the kernel to use

COMX-Frame Relay. This protocol is a bit more complicated than the others,

because it allows to use 'subinterfaces' or DLCIs within one physical device.

First you have to create the 'master' device (the actual physical interface)

as you would do for other protocols. Specify 'frad' as protocol type.

Now you can bring this interface up by saying 'ifconfig comx0 up' (or whatever

you've named the interface). Do not assign any IP address to this interface

and do not set any routes through it.

Then, set up your DLCIs the following way: create a comx interface for each

DLCI you intend to use (with mkdir), and write 'dlci' to the 'boardtype' file,

and 'ietf-ip' to the 'protocol' file. Currently, the only supported

encapsulation type is this (also called as RFC1294/1490 IP encapsulation).

Write the DLCI number to the 'dlci' file, and write the name of the physical

COMX device to the file called 'master'.

Now you can assign an IP address to this interface and set routes using it.

See the example file for further info and example config script.

Notes: this driver implements a DTE interface with partially implemented

Q933a LMI.

You can find an extensively commented example in the 'etc' directory.

FURTHER /proc FILES

boardtype:

Type of the hardware. Valid values are:

 'comx', 'hicomx', 'locomx', 'cmx', 'slicecom'.

protocol:

Data-link protocol on this channel. Can be: HDLC, LAPB, PPP, FRAD

status:

You can read the channel's actual status from the 'status' file, for example

'cat /proc/comx/comx3/status'.

lineup_delay:

Interpreted in seconds (default is 1). Used to avoid line jitter: the system

will consider the line status 'UP' only if it is up for at least this number

of seconds.

debug:

You can set various debug options through this file. Valid options are:

'comx_events', 'comx_tx', 'comx_rx', 'hw_events', 'hw_tx', 'hw_rx'.

You can enable a debug options by writing its name prepended by a '+' into

the debug file, for example 'echo +comx_rx >comx0/debug'.

Disabling an option happens similarly, use the '-' prefix

(e.g. 'echo -hw_rx >debug').

Debug results can be read from the debug file, for example:

tail -f /proc/comx/comx2/debug