On Wed, 8 Sep 1999 10:12:51 -0400 (EDT)
Bill Paul <[EMAIL PROTECTED]> wrote:
> Well, yes, but I made some assumptions in order to do it. The assumption
> is that whatever the current speed setting is now, the link partner's
> speed setting is exactly opposite. So if I detect the condition, I first
> toggle the speed setting (if it's IFM_10_T, make it IFM_100_TX and vice-
> versa), then do a reset, then re-init the chip.
...hm... okay, I'll investigate this option.
> However, the main problem is keeping the chip from zapping memory that it
> doesn't own. Normally I use mbuf cluster buffers in the receive ring, but
> I would only tell the chip that the buffer was 1536 bytes long instead of
> 2048. But again, it seemed like the chip was DMAing much more data than
> it should have been and overruning the whole cluster. Since I needed to
> copy received packets in order to fix up the alignment anyway, I stopped
> using mbuf clusters and instead allocated my own 4K receive buffers and
> told the chip to DMA into those, on the theory that it may have been
> barfing up the entire contents of its FIFO memory which was more than
> 2048 bytes. Sure, most of the time you waste a lot of those 4K blocks,
> but at least when the chip freaks out it doesn't trash any memory that
> you don't know about.
Um. Ew. Okay. Sigh.
In NetBSD, we only copy if the system doesn't have __NO_STRICT_ALIGNMENT
(e.g. i386, m68k [we support some PCI m68k boxes], VAX [all those PCI
vaxes, you know!)... I'll have to see what I can do about all of this.
> Bleh. My experience with the PNIC shows that it does not handle
> multi-fragment transmits very well (i.e. a packet split across multiple
> buffers instead of just a single configuous buffer). Lite-On claims
> that they get pretty good transmit speed with the PNIC, however I'm
> certain they do their measurements using only single buffer transmits.
> I typically don't see more than about 80-85Mbps, though others using
> the Linux driver (which doesn't use multi-fragment transmits) have
> claimed better performance (90-95Mbps). On a whim, I decided one day
> to disable the code in pn_encap() that splits the outbound packet up
> amount multiple descriptors and just let it copy all packer fragments
> into a single buffer -- transmit performance actually got a little
> faster.
That's ... scary.
Y'know, since real 21143s are *still available* (Intel is still manufacturing
them!) you'd think the companies that used to put Tulips on their boards
would still use them ... oh well.
> My biggest problem with this stupid thing now is trying to get to work
> on the 486/66 that I'm currently using for testing. It has an old Integrated
> Micro Systems PCI bridge and the PNIC seems to have decided not to be
> friends with it: the machine tends to freeze up solid whenever the chip
> does any DMA, including just loading the setup frame.
It it trying to use Memory-Read-Multiple or Memory-Read-Line? Old (esp. 486)
PCI bridges were known to have problems with those PCI commands.
> http://www.freebsd.org/~wpaul/PNIC/pnic.ps.gz
Excellent! Thank you very much!
> I've also got a Winbond datasheet at:
>
> http://www.freebsd.org/~wpaul/Winbond/winbond.ps.gz
>
> The originals of both these documents were in M$ Turd format. :)
Already have this one; the Winbond datasheet is available at
www.winbond.com.tw in PDF form...
> All of the Winbond cards are essentially the same so the one you have
> should be enough -- mine is from a company called Trendware. The PNIC
> is a bit tougher to deal with because there are a couple of revisions:
> the original LinkSys PNIC cards use the 82c168 and the internal busted
> NWAY support (i.e. no MII transceiver). For these you have to fiddle
> with the GPIO bits to flip the relay on the card (yes, a relay) in order
Heh... I have a Kingston 21140 board that uses the PCS function to do
100baseTX, and you hear a relay flip on that board too :-)
On these PNIC boards which use the external ENDEC / PCS ... I guess you'd
be able to detect which flavor you have (for flipping the GPIO pins) using
the subsystem IDs in PCI configuration space... The PNIC doesn't use the
DEC-format SROM, unfortunately, so just getting CSR6 and CSR12 from the
SROM isn't an option...
> to select the right media. The trouble is LinkSys doesn't sell them
> anymore: the later cards use the 82c169, and now they've gone to the
> PNIC II. I had some 82c168 cards donated by FreeBSD users. I can part
> with one of them if you can't find one anywhere. As for the Macronix,
I would appreciate this... I haven't been able to find '168 boards at all.
> ideally you need one each of the 98713, 98713A and 98715A. The 98713
I have a '15A board... I know of a NetBSD user who has a '13 board (he
sent in patches to make it work with the `de' driver initially).
> look at the application notes from Macronix, they mention the "magic
> numbers" you need to program into CSR15 (I think). The original 98713
> needs one setting while the others require another setting. Macronix
> doesn't say what the magic values really do, so I just program them in
> and cross my fingers. (I'm considering adding some code to provide a fake
> MII interface to the 98713A and friends so that I can use the miibus code
> to control the media selection so that I can convert the whole driver
> to use the miibus layer.)
Yah, I have the Macronix data sheets...
Doing the NWAY register stuff as a simulated PHY is a good idea... should
sort-of work for the PNIC, too, and would save duplicating all that logic
that MII code already implements.
> Also, the PNIC II (LC82c115) is actually a Macronix chip with wake
> on lan and only a 128-bit multicast hash table. The LinkSys LNE100TX v2.0
> card that I have and the sample 98715A card look almost identical.
...I'll have to hunt down one of these cards.
> If you have a 98715A datasheet handy, you can use that as a reference
> when programming this chip; just remember about the smaller hash table.
> I'll stick a copy of my PNIC II datasheet at www.freebsd.org for you
> a little later -- I originally got my copy from LinkSys.
That's be great...
> As for ADMtek, I originally went looking at www.admtek.com.tw and just
> e-mailed one of the contacts that they list asking where I could buy a
> board in the U.S., since I already had the datasheet (the AL981 sheet is
> on their server). They turned out to be really eager to help me and sent
> me two cards directly. Again, I have to grope through my back e-mail to
> find the name of the guy I spoke too, but you can easily get in touch
> with them using the contact info on their site.
Ok, good to know, thanks.
> Cnet makes a couple of cards using clone tulip chips: the Pro110 and 120
> series. One of them uses the ASIX chip and the others use Macronix. I've
> been told you can sometimes find these at Fry's. Jaton Corporation makes
Okay... good to know...
> a board called the Jaton XpressNet what uses the Davicom DM9102. This
> is another chip with a pretty cruddy DMA engine.
Davicom ... Winbond-like?
Thanks a LOT for this info!
-- Jason R. Thorpe <[EMAIL PROTECTED]>
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