Jan Kiszka wrote:
Thinus Viljoen wrote:
Good day
We intend to use RTnet in a compactPCI-based system. We have narrowed the
possible Single Board Computers (SBC) down to the following 5 options:
(LAN interface chip, SBC Manufacturer, SBC Part number)
Intel 82546EB, Kontron, CP6000
Intel 82546GB, Advantech, MIC-3369C-M0
Intel 82573E, Advantech, MIC-3390
Intel 82541PI, Concurrent technologies, PP-332/021
Looks like the e1000 driver is in charge here. I put Roman in the CC as
he happened to ask for the same driver a few days ago.
All the cards support Linux, which (I would assume) implies that they have
Linux LAN drivers.
I have the following questions w.r.t. LAN drivers for RTnet:
1. Will any of the above work with RTnet "out of the box"? From the RTnet
documentation I have read it does not seem that there are RTnet drivers for any of the
above LAN chips?
Nope.
2. Have anybody had success running RTnet with one of the above LAN chips or
SBCs?
3. Are there any of the above LAN chips that have known problems under RTnet?
4. How difficult will it be to adapt the supplied Linux LANop drivers for RTnet for
someone with limited Linux driver coding experience? (I see README.drvporting gives some
guidelines, I'm just a bit worried about the sentence "Some points may not apply to
every driver, some may have to be added for others.")
Surely those remarks express the unknown variables of an RTnet port. The
most critical part is identifying and potentially converting the
synchronisation scheme of the driver, both internally and with the
hardware. The rest is, indeed, some kind of intelligent search&replace
as described in the porting doc.
It all melts down that you have to gain full control over the time your
driver spends a) in its transmission routine and b) in the interrupt
handler under any feasible RTnet load or other driver activity
(startup/shutdown e.g.). The e100 copes with unbounded hardware delays
by reducing the maximum waiting time e.g. This happens under the
assumption that related error conditions do not occur on a
(TDMA-)managed network, and the last years of practical use showed that
this is valid.
Unfortunately, such kind of conversion could not yet be applied to the
3c59x driver which has a more complex logic, and its timing is widely
unknown to us. But that's basically the only exception we faced so far -
further driver conversions depend on someone to work on it and to have
the hardware for intensively testing it.
So, the first step of a potential port must be analysing those two
critical routines of the e1000 as well as all invoked subroutines and to
understand their locking dependencies. If one of you (or both
cooperatively) is willing to start working on this, I can only invite to
discuss your findings here (or better on rtnet-developers). In this case
I could jump in and comment on it as well as far as time permits. The
analysis should not take too much time, and afterwards you can decide if
porting is feasible and how much effort it will likely require.
Thanks
Thinus Viljoen
Electronic Engineer
Aerospace Systems, a division of Denel
http://www.kentron.co.za
(P.S. Sorry about the footer, which I am sure my company will add. I don't have
any control over it)
One is getting used to it. ;)
Jan
Hi Jan, Thinus,
in general, I am planning to work on the e1000, but I need some more
time to understand all the concepts (especially under high load wich
currently and simply freezes my P4).
Further, I will only need a subset of rtnet (TX), whilst RX is not
important to me. However, if I start with the e1000, I will [try to]
make it compliant to RTNet and define out things that I do not need, so
the community gets back some work.
Jan, is there any chance to get you into a chat or 15 min. voice
conversation about that topic (and maybe others)?
Take care,
Roman
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