ppc platform for AMCC-440EPx - ELDK to the rescue

ppc platform for AMCC-440EPx - ELDK to the rescue

[Steve Heflin]

I finally resolved my nightmare of getting linux-2.6.24/5... to work 
on my AMCC-440Epx - Sequoia spinoff board. Following a clue I derived 
from a reply from Wolfgang Denx, I went to the DENX Engineering site 
where I discoved and downloaded the ELDK for the ppc_4xxFP. the ELDK 
uses the ppc platform instead of the powerpc platform.  FINALLY the 
early debugging console output worked, which doesn't work at all 
using the powerpc platform (and yes, I had the correct port address 
configured).  After that, I was able to see that it was the 
"setup_hose" function called from /arch/ppc/platforms/4xx/sequoia.c 
that caused my board to hang. This Sequoia spinoff board has the PCI 
Host Bridge disabled which I didn't realize until that point.

Looking back at the powerpc platform, I don't see how to disable the 
Host Bridge initialization without disabling the entire PCI 
bus.  This board does have 2 devices hooked on the PCI bus, just no 
need for a Host Bridge.

Also, I fail to see what the DTS virtualization layer of the hardware 
buys us. When debugging, it's so much harder to use than the ppc 
platform's straight forward and standard methodologies.  I can't 
understand to goal to eliminate the ppc platform, especially given 
the fact that DENX's ELDK is still using it with Linux 2.6.24.2 !!

Best Regards to all,
Special Thanks to Wolfgang Denx,
Steve Heflin

Re: ppc platform for AMCC-440EPx - ELDK to the rescue

[Scott Wood]

Steve Heflin wrote:
> After that, I was able to see that it was the "setup_hose" function 
> called from /arch/ppc/platforms/4xx/sequoia.c that caused my board to 
> hang. This Sequoia spinoff board has the PCI Host Bridge disabled which 
> I didn't realize until that point.
> 
> Looking back at the powerpc platform, I don't see how to disable the 
> Host Bridge initialization without disabling the entire PCI bus.  This 
> board does have 2 devices hooked on the PCI bus, just no need for a Host 
> Bridge.

And how do you propose to talk to said PCI devices without configuring 
the host bridge?

> Also, I fail to see what the DTS virtualization layer of the hardware 
> buys us.

Maintainability.  Ease of porting to new hardware.

> When debugging, it's so much harder to use than the ppc 
> platform's straight forward and standard methodologies.  I can't 
> understand to goal to eliminate the ppc platform,

Are you volunteering to maintain it, including the rest of us not having 
to care when we change something in common code that breaks it?

> especially given the 
> fact that DENX's ELDK is still using it with Linux 2.6.24.2 !!

Take that up with Denx.

-Scott

Re: ppc platform for AMCC-440EPx - ELDK to the rescue

[Wolfgang Denk]

In message <20080326130837.762DBDE2FB@ozlabs.org> you wrote:
> I finally resolved my nightmare of getting linux-2.6.24/5... to work 
> on my AMCC-440Epx - Sequoia spinoff board. Following a clue I derived 
> from a reply from Wolfgang Denx, I went to the DENX Engineering site 
> where I discoved and downloaded the ELDK for the ppc_4xxFP. the ELDK 
> uses the ppc platform instead of the powerpc platform.  FINALLY the 

This is not exactly correct. Actually it supports both.

> Also, I fail to see what the DTS virtualization layer of the hardware 
> buys us. When debugging, it's so much harder to use than the ppc 
> platform's straight forward and standard methodologies.  I can't 
> understand to goal to eliminate the ppc platform, especially given 
> the fact that DENX's ELDK is still using it with Linux 2.6.24.2 !!

You miss the fact that the ELDK has full  support  for  arch/powerpc,
and  that  some  board configurations in our kernel (for example, all
MPC5200 based ones)  are  available  in  arch/powerpc  configurations
only.

But then - what's the difference? All it takes is a  redefinition  of
the ARCH envrionment variable in your shell...

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@denx.de
I've got a bad feeling about this.

RE: ppc platform for AMCC-440EPx - ELDK to the rescue

[Dave Cogley]

Wolfgang,

Could you provide an explanation between the two architectures in the ELDK?


I am also using a Sequoia "spin off" and am trying to determine why I would
want to use the "powerpc" architecture vs. the "ppc" architecture.  

Thanks,
Dave

-----Original Message-----
From: linuxppc-embedded-bounces+dcogley=uslinc.com@ozlabs.org
[mailto:linuxppc-embedded-bounces+dcogley=uslinc.com@ozlabs.org] On Behalf
Of Wolfgang Denk
Sent: Wednesday, March 26, 2008 3:23 PM
To: Steve Heflin
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: ppc platform for AMCC-440EPx - ELDK to the rescue

In message <20080326130837.762DBDE2FB@ozlabs.org> you wrote:
> I finally resolved my nightmare of getting linux-2.6.24/5... to work 
> on my AMCC-440Epx - Sequoia spinoff board. Following a clue I derived 
> from a reply from Wolfgang Denx, I went to the DENX Engineering site 
> where I discoved and downloaded the ELDK for the ppc_4xxFP. the ELDK 
> uses the ppc platform instead of the powerpc platform.  FINALLY the 

This is not exactly correct. Actually it supports both.

> Also, I fail to see what the DTS virtualization layer of the hardware 
> buys us. When debugging, it's so much harder to use than the ppc 
> platform's straight forward and standard methodologies.  I can't 
> understand to goal to eliminate the ppc platform, especially given 
> the fact that DENX's ELDK is still using it with Linux 2.6.24.2 !!

You miss the fact that the ELDK has full  support  for  arch/powerpc,
and  that  some  board configurations in our kernel (for example, all
MPC5200 based ones)  are  available  in  arch/powerpc  configurations
only.

But then - what's the difference? All it takes is a  redefinition  of
the ARCH envrionment variable in your shell...

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@denx.de
I've got a bad feeling about this.
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Re: ppc platform for AMCC-440EPx - ELDK to the rescue

[Josh Boyer]

On Wed, 26 Mar 2008 15:56:23 -0700
"Dave Cogley" <dcogley@uslinc.com> wrote:

> Wolfgang,
> 
> Could you provide an explanation between the two architectures in the ELDK?
> 
> 
> I am also using a Sequoia "spin off" and am trying to determine why I would
> want to use the "powerpc" architecture vs. the "ppc" architecture.  

arch/ppc is being removed entirely from the kernel.org kernels in June.

josh

Re: ppc platform for AMCC-440EPx - ELDK to the rescue

[Josh Boyer]

On Wed, 26 Mar 2008 09:08:03 -0400
Steve Heflin <sheflin@newagemicro.com> wrote:

>  FINALLY the 
> early debugging console output worked, which doesn't work at all 
> using the powerpc platform (and yes, I had the correct port address 
> configured). 

It should work.  It did when the board support was first brought in to
arch/powerpc. If it doesn't now, I consider that a regression that needs
fixing, at least for Sequoia itself.
 
> Looking back at the powerpc platform, I don't see how to disable the 
> Host Bridge initialization without disabling the entire PCI 
> bus.  This board does have 2 devices hooked on the PCI bus, just no 
> need for a Host Bridge.

As Scott said, how would you talk to any PCI device without the host
bridge being configured and enabled?

> Also, I fail to see what the DTS virtualization layer of the hardware 
> buys us. When debugging, it's so much harder to use than the ppc 
> platform's straight forward and standard methodologies.  I can't 

There are tradeoffs, yes.

> understand to goal to eliminate the ppc platform, especially given 
> the fact that DENX's ELDK is still using it with Linux 2.6.24.2 !!

The ELDK uses both arch/ppc and arch/powerpc.  I consider them quite
reasonable people, and foresee them eventually switching to
arch/powerpc over time.  In fact, their efforts are a large part of the
continued progress of 4xx on arch/powerpc.

josh

Re: ppc platform for AMCC-440EPx - ELDK to the rescue

[Steve Heflin]

>In reply to my message <20080326130837.762DBDE2FB@ozlabs.org>
> > I finally resolved my nightmare of getting linux-2.6.24/5... to work
> > on my AMCC-440Epx - Sequoia spinoff board. Following a clue I derived
> > from a reply from Wolfgang Denx, I went to the DENX Engineering site
> > where I discoved and downloaded the ELDK for the ppc_4xxFP. the ELDK
> > uses the ppc platform instead of the powerpc platform.  FINALLY the
Wolfgang replied At 06:22 PM 3/26/2008:
>This is not exactly correct. Actually it supports both.

Ah thank you for that info.  I only said what I said because the 
4xxFP installation set things up to use the arch/ppc and to my 
delight, it worked!  I look forward to and will do all I can to help 
get the arch/powerpc platform working on my Sequoia spin-off board.

I sent you email regarding my inability to do a ELDK build from 
scratch, did you get that? I'm trying to build it under a fully 
updated Fedora 7 system, and it hits the error:
   LD unable to locate -lssabi_krb5 .  Any clue?

thanks so much for your help,
Steve