HDLC/Frame Relay support for MPC8xx

[Rodolfo Giometti]

Hello,

I developed a driver to support the HDLC/Frame Relay transmission for
the MPC8xx/FADS. Currently the driver supports only the asynchronous
mode but, as soon as I have the proper hardware, I'll add the
synchronous mode too.

I posted my software hoping that it can be useful and hoping someone
will test and improve it! ;-p

Since my developing board is not the final product where the software
will work some features are actually not tested or not fully
implemented.

Please, feel free to write me back for any suggestions or
modifications.

This software is a part of a bigger project by Ascensit
<http://www.ascensit.com> to expand the current CPM support in
Linux. Our next steps will be:

* Add a better CPM subsystems support by adding a set of
  register/unregister functions and by adding a proc-filesystem support
  to track down who are using what.

* Add the synchronous HDLC support.

* Add support for other CPM subsystems like, for istance the I2C and
  so on.

* Other minor featurs in order to stabilize the CPM support.

INSTALL
=======

In order to have a working code I took a patched linux-2.4.17 from my
(great) colleague Christian Pellegrin who applied some patched from
denx and modified some code by himself.

Here the patch from vanilla linux-2.4.17 to linux-2.4.17-fads in order
to have a running code for the FADS developing board.

Warning! it is possible that this patch adds some extra unneeded code
since nor me nor Christian are able to find the patches that we used
to obtain the working code for the FADS... sorry! That was our fault!

Obviously if you already have a running kernel for the FADS you don't
need to apply this patch.

   http://www.ascensit.com/developers/ehdlc/patch-linux-2.4.17-fads.gz

Here the patch from linux-2.4.17-fads to linux-2.4.17-fads-fr in order
to have the right Frame Relay support.

   http://www.ascensit.com/developers/ehdlc/hdlc-2.5.1.patch.gz
   http://www.ascensit.com/developers/ehdlc/hdlc-S0.gz

Here the patch from linux-2.4.17-fads-fr to linux-2.4.17-fads-fr-ehdlc
in order to have my code! :-D

Please note that my patch doesn't modify the new Frame Relay support
provided by the above patch.

   http://www.ascensit.com/developers/ehdlc/patch-linux-2.4.17-fads-fr-ehdlc.gz

Obviously you have to apply the above patches in the same order as I
explained.

MY TESTS
========

The tests I made on my code were divided in two parts: one in order to
test asynchronous HDLC and one to test Frame Relay on asynchronous
HDLC.

I used only three wires in order to connect my two FADS each other,
and more precisely I used the PINS B2, B3 and B32 of the expansion
connector. Since I used only the TXD and RXD signals I didn't check
the options "CTS and CD input enabled" in order to have "CTS and CD
always asserted". Currently the driver uses only the SCC3.

In order to configure the HDLC subsystem I used the sethdlc program
version 1.08 (you can find that program on
http://www.ascensit.com/developers/ehdlc/sethdlc.c.gz).

Regarding the asynchronous HDLC test I used the following commands:

   /sbin/insmod /lib/modules/2.4.17/kernel/drivers/net/wan/syncppp.o
   /sbin/insmod /lib/modules/2.4.17/kernel/drivers/net/wan/hdlc.o
   /sbin/insmod /lib/modules/2.4.17/kernel/arch/ppc/8xx_io/ehdlc.o
   /sbin/sethdlc hdlc0 clock int rate 64000

   /sbin/sethdlc hdlc0 hdlc nrz no-parity
   /sbin/ifconfig hdlc0 192.168.1.1 pointopoint 192.168.1.2
      /sbin/ifconfig hdlc0 192.168.1.2 pointopoint 192.168.1.1   [on the other machine]

Then I used the normal ping command.

Regarding the Frame Relay (on asynchronous HDLC) I used the following
commands:

   /sbin/insmod /lib/modules/2.4.17/kernel/drivers/net/wan/syncppp.o
   /sbin/insmod /lib/modules/2.4.17/kernel/drivers/net/wan/hdlc.o
   /sbin/insmod /lib/modules/2.4.17/kernel/arch/ppc/8xx_io/ehdlc.o
   /sbin/sethdlc hdlc0 clock int rate 64000

   /sbin/sethdlc hdlc0 fr lmi ansi
      /sbin/sethdlc hdlc0 fr lmi ansi dce   [on the DCE]
   /sbin/sethdlc hdlc0 create 666
   /sbin/ifconfig hdlc0 up
   /sbin/ifconfig pvc0 192.168.1.1 pointopoint 192.168.1.2
      /sbin/ifconfig pvc0 192.168.1.2 pointopoint 192.168.1.1   [on the other machine]

Enjoy! :-D

Rodolfo

--
Programs and GNU solutions           e-mail:    giometti at linux.it
Linux Device Driver                             giometti at ascensit.com
Embedded Systems                     home page: giometti.oltrelinux.com
UNIX programming                     phone:     +39 329 7028903

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