[coreboot] Coreboot on the Thinkpad T61p ?

[Sven Schnelle]

Hi Patrick,

Patrick Arnoux <parnoux at adelphia.net> writes:

> On 07/16/11 01:55 PM, Peter Stuge wrote:
>> Patrick Arnoux wrote:
>>>> we don't have any documentation for the i965 (crestline) Memory
>>>> Controller
>>> Not sure if this is the relevant document,
>> ..
>>> Mobile Intel® 965 Express
>>> Chipset Family
>>> Datasheet
>> It isn't. This is only a shallow overview of the chipset. The
>> neccessary documentation requires two levels of NDAs with Intel
>> which in turn requires a solid business case. Further, having access
>> to the right application engineers within Intel during development
>> can easily make the difference of several man-months of forward and
>> reverse engineering, trial and error and guesswork. (Ie. the NDAed
>> docs are also not exhaustive.
>
> This "shallow overview" weighs in at over 500 pages. I guess it means
> we are not in Kansas anymore. These NDAed docs must rival "War and Peace".
>
> As I am still very much interested in the T61, and if you all don't
> mind, I would like to ask a couple of questions :
> A) My first thought was to start from the T60, modify whatever
> needed to be and thank you ma'am
> Simplistic, yes, but are the T60 and T61 so fundamentally
> different that this is never going to fly.

Well, you have write the code for the i965. As long as you don't get
your hands on the real Datasheets and/or the Intel Memory Reference
code you have to do a lot of reverse engineering. Reverse engineering
would be really hard, and it is most likely not job for one month.

>     B) Besides the i965 Controller, what other chips do we need
> documentation for on the T61 ?

Everything else should mostly work, and probably only needs some slight
adjustments. The Embedded controllers in the T61 are the same as in the
T60/X60. The Register space for that probably just differ in a few bits
to support stuff that isn't present in the T60.

>     C) If I can get to the point where control is handed over to the
> on disk Boot Block (mind you, this
>         can be USB, DVD, CD, PCMCIA, or Hard disk), do I care anymore
> about the BIOS. Does an
>         Operating System ;Solaris, Linux, Unix or whatever just goes
> on about its business and really
>         couldn't give two hoots about whether and what kind of BIOS
> exists on the machine.
>     D) If there are indeed system calls made to the BIOS, what are
> they and what are the affected chips.
>     E) What is the minimum level of hardware initialization that needs
> to be done in order to be able to
>         load an OS.
>     F) Bottom line, I am not interested in an all singing, all dancing
> BIOS, I just want to load the OS and
>         to paraphrase a quote from Linus T. I just ran into, he just
> wants the BIOS to load the OS and get
>         the double F out of the way!

Especially on a Laptop you want to have a full featured BIOS/ACPI code,
because without it you have no Suspend, Power Management and similar
stuff. But that's not the problem - Most of the stuff is already working
in coreboot.

As mentioned above the challenge is to support the i956 Memory
Controller. If someone manages to write the code to support it,
everything else is pretty simple.

Cheers,

Sven