mpc860 vs. mpc860T

mpc860 vs. mpc860T

[Steven Vacca]

I have 2 bds., the BD #1 is custom designed and based very
closely on the design of the BD #2.  The main difference
is BD #1 uses an mpc860T and BD #2 uses an mpc860.

Both have 32 Meg DRAM, 50MHz.

I can use the exact same Flash Boot code on each,
and download the exact same Linux kernel and app to each.

BD #2 (mpc860) works perfectly, all the way thru to the app
executing threads, etc.

BD #1 (mpc860T) works up until at various points between when
the kernel initializes itself, and the app execution begins, it gets
exception errors, usually something similar to the following:

  Kernel panic: kernel access of bad area pc c0023634 lr c00235ec
                      address 813F004C tsk kswapd/5
or,

  Kernel panic: ramdisk: request list destroyed

Does anyone know of any differences between the 2 CPU's, other than
the mpc860T's internal FEC section and the MII interface on port D, that
might cause such problems?

Thanks,

Steven

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RE: mpc860 vs. mpc860T

[Steven Vacca]

OK, here goes.

My 860T rev is:  duht-duhduh-duuuuuhh: XPC860TZP50B3  :>(

I guess that means I'll need some workarounds.

My embedded linux kernel is Redhat's mpc8xx-2.2.13, so
maybe porting in some workarounds might not be too painful.
Could I please get access to your workarounds, Magnus?

Thanks,

Steven



-----Original Message-----
From:	Magnus Damm [SMTP:damm@opensource.se]
Sent:	Tuesday, January 15, 2002 4:56 AM
To:	svacca@valcom.com
Subject:	Re: mpc860 vs. mpc860T

Early 860T cpu:s have lots of silicon bugs.
Check out the revision information and the errata.

If you have a 860TB3 or earlier you need workarounds.

Funny notice:
On one of the first 860T revisions it wasn't possible to
use the CPM and the fec at the same time...

One other problem I remember was related to SPR:s and
trashed cache...

I do have workarounds in my kernel, but they are for a
2.2.16-kernel.

Good luck /

Magnus

Steven Vacca wrote:
>
> I have 2 bds., the BD #1 is custom designed and based very
> closely on the design of the BD #2.  The main difference
> is BD #1 uses an mpc860T and BD #2 uses an mpc860.
>
> Both have 32 Meg DRAM, 50MHz.
>
> I can use the exact same Flash Boot code on each,
> and download the exact same Linux kernel and app to each.
>
> BD #2 (mpc860) works perfectly, all the way thru to the app
> executing threads, etc.
>
> BD #1 (mpc860T) works up until at various points between when
> the kernel initializes itself, and the app execution begins, it gets
> exception errors, usually something similar to the following:
>
>   Kernel panic: kernel access of bad area pc c0023634 lr c00235ec
>                       address 813F004C tsk kswapd/5
> or,
>
>   Kernel panic: ramdisk: request list destroyed
>
> Does anyone know of any differences between the 2 CPU's, other than
> the mpc860T's internal FEC section and the MII interface on port D, that
> might cause such problems?
>
> Thanks,
>
> Steven
>

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

RE: mpc860 vs. mpc860T

[Steven Vacca]

I did a complete search for CONFIG_8xx_CPU6, and
truncated variations, in my mpc8xx-2.2.13 kernel, and
could not find it.  It doesn't show up as a cfg option either.
Even a grep on CONFIG_8xx doesn't show anything
resembling that.  Could it be in there and accessible
in an alternative way?

Steven

-----Original Message-----
From:	Wolfgang Denk [SMTP:wd@denx.de]
Sent:	Tuesday, January 15, 2002 9:01 AM
To:	svacca@valcom.com
Subject:	Re: mpc860 vs. mpc860T

Dear Steven,

in message <01C19DA2.0031A1C0.svacca@valcom.com> you wrote:
>
> My 860T rev is:  duht-duhduh-duuuuuhh: XPC860TZP50B3  :>(
>
> I guess that means I'll need some workarounds.

Right.

> My embedded linux kernel is Redhat's mpc8xx-2.2.13, so
> maybe porting in some workarounds might not be too painful.
> Could I please get access to your workarounds, Magnus?

Ummm... the CONFIG_8xx_CPU6 kernel  configuation  option  (workaround
for  CPU6  Silicon  Errata  (860  Pre  Rev.  C  et  al.)) was already
available with 2.2.13 kernels;  you  may  check  it  RH  bothered  to
include it. If so, just enable it.

Hope that helps,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Lead me not into temptation... I can find it myself.

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RE: mpc860 vs. mpc860T

[Steven Vacca]

Yes!  Yes!  Success!

I transferred the CONFIG_8xx_CPU6 patches from the
linuxPPC sources into my kernel and that solved my
problems with the old version of the 860T.

"Thanks a quadrillion for your help!"
     /
  \O/
   \/      <---- Steven
 _/\_



-----Original Message-----
From:	Wolfgang Denk [SMTP:wd@denx.de]
Sent:	Tuesday, January 15, 2002 9:37 AM
To:	svacca@valcom.com
Subject:	Re: mpc860 vs. mpc860T

In message <01C19DA6.994D3370.svacca@valcom.com> you wrote:
>
> I did a complete search for CONFIG_8xx_CPU6, and
> truncated variations, in my mpc8xx-2.2.13 kernel, and
> could not find it.  It doesn't show up as a cfg option either.
> Even a grep on CONFIG_8xx doesn't show anything
> resembling that.  Could it be in there and accessible
> in an alternative way?

Sorry, I never checked RH's sources (which are pretty old anyway);  I
have no idea if they provide alternative configuration options.

You can grab some  of  the  other  8xx  enabled  source  trees  (like
MontaVista's  or  ours - see ftp://ftp.denx.de/pub/LinuxPPC/usr/src/)
and extract the necessary changes (or compare if they _are_ available
in your RH code, but under a different name.

There are only 4 files affected:

	arch/ppc/8xx_io/Config.in
	arch/ppc/kernel/head.S
	arch/ppc/kernel/time.h
	include/asm-ppc/pgtable.h

Hope this helps,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
This is now.  Later is later.

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/