[LinuxBIOS] Support for VIA K8T890/VT8237

[Rudolf Marek]

Hello,

Anyone is working on VIA K8T890/VT8237? + K8. I have in plan to start in near
future. I'm missing the datasheet for the K8T890. Do you think I will need it?
Maybe just writing the PCI registers to match the BIOS values would be enough?
My board is Asus A8V-E SE. My BIOS ROM is 512KB. (PMC 49... perhaps it should
work with flashrom).

If someone wants to help with that it would be cool. Some hint is bellow ;)

Please keep me CCed.

Rudolf

jtrg -B - "uggc://jjj.ivn.pbz.gj/ra/erfbheprf/qbjaybnq-pragre/puvcfrgf/" | terc
rgf/puv | njx -S" '{cevag $4}' | juvyr ernq yvar; qb jtrg
uggc://jjj.ivn.pbz.gj/$yvar; qbar

[Corey Osgood]

Rudolf Marek wrote:
> Hello,
>
> Anyone is working on VIA K8T890/VT8237? + K8. I have in plan to start in near
> future. I'm missing the datasheet for the K8T890. Do you think I will need it?
> Maybe just writing the PCI registers to match the BIOS values would be enough?
> My board is Asus A8V-E SE. My BIOS ROM is 512KB. (PMC 49... perhaps it should
> work with flashrom).

For now, you should be fine without the K8T890 datasheet, as it's *just*
the PCI-Express controller. Your first problem will be supporting the
via 8237 southbridge, which, if you have all those docs, should be
fairly easy. After that, you'll have to work out DRAM initialization,
which is done by the K8 (already supported in linuxbios). Once you've
done all that, PCI-Express will be your next step, but I don't know much
about that (I don't own any PCI-E stuff yet).

I'm amazed that noone has gone and gotten vt8237 up and running yet, as
it seems that it's used on a lot of motherboards these days, from the
latest via epia-m's to cheaper C7, K7 and K8 boards.

-Corey

[Peter Stuge]

On Sun, Mar 25, 2007 at 12:16:41AM -0400, Corey Osgood wrote:
> I'm amazed that noone has gone and gotten vt8237 up and running
> yet, as it seems that it's used on a lot of motherboards these
> days, from the latest via epia-m's to cheaper C7, K7 and K8 boards.

I have the hardware, but not the time. I think that's true for most
others too. :\

Great if someone wants to tackle it! :)

//Peter

[Rudolf Marek]

Hi all,

Ok I subscribed ;)
> For now, you should be fine without the K8T890 datasheet, as it's *just*
> the PCI-Express controller.

It has a V-Link registers too. (To support communication with VT8237). This
seems to be compatible with CN400. I dont figured out yet what are the PCIe regs.
> Your first problem will be supporting the
> via 8237 southbridge, which, if you have all those docs, should be
> fairly easy.

Stephan wrote on IRC he might have time to do that too. I will keep with him in
touch. (As for the docs ... hfr gur uvagf). I think I will start with it after
10th of April.
> After that, you'll have to work out DRAM initialization,
> which is done by the K8 (already supported in linuxbios). Once you've
> done all that, PCI-Express will be your next step, but I don't know much
> about that (I don't own any PCI-E stuff yet).

Yep. Sounds as reasonable plan. I have seen in archive people asking for the
kickstart stuff. I would like to ask too ;) I need to know how to fill in proper
way the "root complex" structure for my board. Is there such information
somewhere? Thanks.
> I'm amazed that noone has gone and gotten vt8237 up and running yet, as
> it seems that it's used on a lot of motherboards these days, from the
> latest via epia-m's to cheaper C7, K7 and K8 boards.

Just for the record, there are at least 3 PCI ids for the VT8237, so we might
support all of them. I think just  (I know because of i2c support for lm-sensors).

And my last question, do you support (infrastucture) the clockchips and custom
FSB/HTT/mem ratios? I have a bit overclocked system (255 instead of 200 freq -
all other divisors set up to match original freq). I dont need to change
voltages, so I think I need only to change the HTT link divisors, mem divisors
and ClockChip at 0x69)

Thanks,
Rudolf

[Stefan Reinauer]

* Rudolf Marek  [070325 12:42]:
> Yep. Sounds as reasonable plan. I have seen in archive people asking
> for the kickstart stuff. I would like to ask too ;) I need to know how
> to fill in proper way the "root complex" structure for my board. Is
> there such information somewhere? Thanks.

There is very old documentation at
http://www.openbios.org/LinuxBIOS-AMD64.pdf
The sources are in the v2 tree, any updates are welcome.

For the K8T890 you might want to copy a CK804 board and modify it to
match the topology of your board, since it looks they are reasonably
similar in design.
> And my last question, do you support (infrastucture) the clockchips and custom
> FSB/HTT/mem ratios? I have a bit overclocked system (255 instead of 200 freq -
> all other divisors set up to match original freq). I dont need to change
> voltages, so I think I need only to change the HTT link divisors, mem divisors
> and ClockChip at 0x69)

There's no overclocking "infrastructure" for that. But since you have
the source code, you can add any overclocking bits you want at any
time during startup.