[OpenWrt-Devel] lantiq DSL drivers / firmware info

Aleksander Wałęski olewales at gmail.com
Mon May 25 02:00:08 EDT 2015

Good news! It works.
Furthermore, I could only get it to work on my line with this new
driver. I tried old driver with 6 different firmwares (VDSL fw
versions: 3.2.8, 3.4.A, 4.6.D, 4.7.9, 6.8.4, 7.4.3). Older ones got me
as far as "full_init [0x380]" but then process was interrupted and
started all over again. I suspect that DSLAM I am connected to could
not negotiate parameters it wanted from modem. Newer firmwares on the
other hand just sit at "idle request [0xFF]". Probably they are not
compatible with old driver version. This is quite interesting because
they are reports from people running openwrt Lantiq devices on VDSL2
lines from my ISP (Orange Polska).

With the new driver and lastest firmware (from W9980) I got showtime
right away, I didn't even have to touch any configuration. As I
discovered, that's because this combination of driver/firmware
(probably mostly firmware) seems to ignore all magic numbers passed by
dsl_control. It behaves the same regardless of what I provide to
vdsl_cpe_control as init bits (-i) or low level configuration file
(-l). -M parameter also seems unnecessary. Firmware either has some
hard coded values which match my connection, or more likely, it
performs autodetection of line parameters. This makes sense because
W9980 is sold worldwide and has to support all configurations
imaginable. Unfortunately TP-LINK firmware seems to be mostly bunch of
binaries talking to one another (in this case /lib/libcmm.so seems to
call dsl_cpe_control) so passive analysis is not easy. Maybe someone
could try to spy on firmware running on actual device.

This of course should be confirmed by few people (preferably on vastly
different connections) before sending patch upstream, but if it turns
out to be true it will greatly simplify xDSL configuration on Lantiq
devices. My dsl_control script currently looks like this (also on
pastebin if line wraping messes with it: http://pastebin.com/G0jUQMxL)


#!/bin/sh /etc/rc.common
# Copyright (C) 2015 OpenWrt.org

# needs to start before the atm layer which starts at 50

EXTRA_COMMANDS="status lucistat"
EXTRA_HELP="    status  Get DSL status information
        lucistat  Get status information if lua friendly format"


[ -f /lib/functions/lantiq_dsl.sh ] && . /lib/functions/lantiq_dsl.sh

start() {

        config_load network
        config_get firmware dsl firmware
        config_get xfer_mode dsl xfer_mode

        [ -z "${xfer_mode}" ] && xfer_mode=ptm

        case "${xfer_mode}" in
                insmod ltq_atm_vr9
                insmod ltq_ptm_vr9

        [ -z "${firmware}" ] && firmware=/lib/firmware/vdsl.bin
        [ -f "${firmware}" ] || {
                echo failed to find $firmware
                return 1

        service_start /sbin/vdsl_cpe_control \
                        -i  \
                        -n /sbin/dsl_notify.sh \
                        -f ${firmware} \
                        -A /lib/firmware/vdsl.scr

stop() {

        service_stop /sbin/vdsl_cpe_control


Got rid of most of the things. Whats left:
1. Module loading. Tried to just load both modules even if we don't
use them but then kernel complains about IRQ conflict and crashes
badly soon afterwards.
2. Firmware path. Hardcoding this would not be very elegant but we
could remove it from network configuration file while reworking
firmware installation script (it will be necessary eventually)
3. dsl_notify stuff
4. -i command line switch. No "init bits" need to follow but it seems
that it has to be there.
5. VDSL autoboot script (more on that below).

TP-LINK includes vdsl.scr, which according to comment, enables ReTx in
both directions. I have not noticed any change in my setup after
enabling this but it think we should include this to maintain
potentially the same performance.

On the side note. Lantiq modem achieves a bit lower sync rates than
router provided by my ISP (about 22Mbit / 3.5Mbit vs 25Mbit/4Mbit) but
I am willing to make this sacrifice for having full control over
hardware and configuration. I am seriously concerned about performance
though. I managed to get 130Mbit/s from iperf over wired connection. I
have yet to check NAT/routing performance but routing between subnets
on gigabit ethernet I was hoping to do seems to be out of question.

On Sun, May 24, 2015 at 6:04 PM, Martin Blumenstingl
<martin.blumenstingl at googlemail.com> wrote:
>> Waiting impatiently for this new patch. For now I can say that I have
>> problems with old driver combined with newest TP-LINK dsl firmware on
>> VDSL line. Once I establish known working configuration I'll build fw
>> with latest driver and test again.
> New patch is ready: [0]
> Let me know if VDSL works with this driver for you.
> Then we can think of how to get the new version into OpenWrt.
> [0] https://gist.github.com/xdarklight/2986587133d97892a4b3/download
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