[U-Boot] Uboot and mpc8536 - questions and confusions

[U-Boot] Uboot and mpc8536 - questions and confusions

[Mark Pearson]

Hi,

First posting to this mailing list so apologies if I make any mailing
list etiquette mistakes.

I'm doing bring up on a new MPC8536 based board and hitting headaches
and had a few questions.

First off is any recommendations/advice on what version of uboot I
should be using? I've got the uboot from freescale SDK (1.3.4) which
has plenty wrong with it and the 2009.11 from denx which is
unfortunately giving me some headaches. Previous experience is that
Freescale not only release buggy software, but that it also doesn't
support the things they say it does (PCIe on 8378 jumps to mind) so
I've leaned to using denx latest as at it's maintained. Freescale
claim they don't submit all their fixes to denx, but I know for sure
they don't release fixes they sign off on the denx stream to their
customers so I'm somewhat bemused as to what I'm supposed to do. To
any freescale engineers reading this - please advise me as your
customer support sometimes seem as confused as I am :-)

More importantly, specifically my current problem is that on this
board we have some DDR (1G) with multiple chip selects and it seems
that both chip selects won't work together. If I have both configured
then I don't boot past trap_init() - it fails to read the code it
copied into the top of memory. If I pretend that I actually only have
half the memory (512M) I can use either chip select and it's fine. On
top of this as soon as I able 36 bit address support, which we want to
use, I also fail in trap_init() - but this time when the code writes
the exception vector code to offset 0x100. Wierd huh.

The Freescale 1.3.4 version works just fine for 32 bit addressing -
but doesn't have 36 bit addressing support in yet (and I suspect it's
missing other stuff too).

Any answers or advice to the above very gratefully received. Is there
a patch I missed?

Thanks

Mark

[U-Boot] Uboot and mpc8536 - questions and confusions

[Wolfgang Denk]

Dear Mark Pearson,

In message <n2u43723ca11004121731x93705e65y92ca522ec7d77315@mail.gmail.com> you wrote:
> 
> First off is any recommendations/advice on what version of uboot I
> should be using? I've got the uboot from freescale SDK (1.3.4) which
> has plenty wrong with it and the 2009.11 from denx which is
> unfortunately giving me some headaches. Previous experience is that
> Freescale not only release buggy software, but that it also doesn't
> support the things they say it does (PCIe on 8378 jumps to mind) so
> I've leaned to using denx latest as at it's maintained. Freescale

Please note that this is not a "DENX" version but the mainline
repository, i. e. the "official" community supported version.

> More importantly, specifically my current problem is that on this
> board we have some DDR (1G) with multiple chip selects and it seems
> that both chip selects won't work together. If I have both configured
> then I don't boot past trap_init() - it fails to read the code it
> copied into the top of memory. If I pretend that I actually only have
> half the memory (512M) I can use either chip select and it's fine. On
> top of this as soon as I able 36 bit address support, which we want to
> use, I also fail in trap_init() - but this time when the code writes
> the exception vector code to offset 0x100. Wierd huh.

Not weird at all. Correctly initializing the memory controller is one
of the most complicated taks during a  port of U-Boot, and by far the
most error prone.

> Any answers or advice to the above very gratefully received. Is there
> a patch I missed?

I recommend to base any work on the current version (top of tree) of
the git repository, and to stay in sync with this repo (i. e. pull
frequently from it).  As for your problem, these seem to be "normal"
topics for a port. Feel free to ask specific questions ...

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Calm down, it's *__only* ones and zeroes.