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RE: [ECOS] Redboot causes PCI abort in Linux Ixp425


The situation isn't quite clear to me from your original email.  Are you
saying you've got 2 boards, one GW2345 and one custom?  The GW2345 works
fine.  The custom one works fine with the GW2345 redboot and linux, but
doesn't work whith the custom redboot and linux?  Pls clarify.

Sounds to me like your PCI configuration during redboot is wrong (or at
least is different that what the original does).  You should dump the
PCI config of the GW2345 (from redboot, before booting linux) and dump
the PCi config of the custom board (again redboot, not linux) and post
that.

-----Original Message-----
From: ecos-devel-owner@ecos.sourceware.org
[mailto:ecos-devel-owner@ecos.sourceware.org] On Behalf Of Ravi modgekar
Sent: Wednesday, March 22, 2006 9:21 AM
To: Stephen Goadhouse; ecos-devel@sourceware.org;
ecos-discuss@sourceware.org
Subject: RE: [ECOS] Redboot causes PCI abort in Linux Ixp425

Hi Stephen,
   Data abort exception during PCI scan is ok.But in
my case, the abort does not happen while scanning the
bus , but it happens while accessing the device!!!!
   Basically Linux does the PCI enumeration at the
boot time and sets up the device properly.There is
absolutely no problem while scanning.The abort happens
only when you try to access the PCI device.Now when
you are trying to access the device , there is no
question of scanning the bus again.
  I am wondering , if I am missing something else in
the redboot .I also don't see any need to scan the PCI
bus in the redboot, since linux is re doing it for
me.what could be wrong.
  By the way, I think even the ADI coyote board does
not scan the PCI bus in Redboot.

Regds
Ravi
   

--- Stephen Goadhouse
<stephen.goadhouse@adiengineering.com> wrote:

> 
> Xscale processors, and perhaps other ARM-based
> processors, will get a
> data abort exception while scanning the PCI bus. 
> This is normal.  To
> scan the bus, the system should be trying to read
> every available PCI
> configuration slot address to see if a device is
> there.  If no device is
> there, you'll get a data abort exception because
> technically the PCI
> transaction did not complete (no target to handle
> the PCI configuration
> read).  Typically, this is handled by installing a
> data abort exception
> handler prior to scanning the bus that gracefully
> handles these
> exceptions during PCI bus scan.  Another alternative
> with the IXP425 may
> be to setup its internal PCI bridge so that it
> returns 0xFFFFFFFF instead
> of doing a data abort.  I have not looked at the
> ixp425 manual in a
> while, but I am fairly certain that it has this
> ability.  I would expect
> that's what your old RedBoot did to handle this so
> that Linux would not
> have to.  Receiving 0xFFFFFFFF when reading
> non-existent PCI slots is
> what happens in a PC environment and I'm fairly
> certain that is what
> Linux typically expects.   
> 
> 
>
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
>  
> _/  Stephen Goadhouse                 Work: (434)
> 978-2888 x254 _/
> _/  Senior Staff Engineer 
> stephen.goadhouse@adiengineering.com _/
> _/  ADI Engineering              
> http://www.adiengineering.com _/
>
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
> 
> 
> 
> > -----Original Message-----
> > From: ecos-discuss-owner@ecos.sourceware.org 
> > [mailto:ecos-discuss-owner@ecos.sourceware.org] On
> Behalf Of 
> > Ravi modgekar
> > Sent: Thursday, March 16, 2006 1:04 AM
> > To: ecos-devel@sourceware.org;
> ecos-discuss@sourceware.org
> > Subject: [ECOS] Redboot causes PCI abort in Linux
> Ixp425
> > 
> > Hi,
> >    I have an  IXP425 based board based on
> Gateworks
> > GW2345 board.This
> > board already had a redboot image programmed 
> through which 
> > we could easily load linux and work on it.
> >   Now I have compiled the redboot for our IXP
> based board 
> > from the Avila redboot sources.With this newly
> compiled 
> > redboot I am able to
> > boot linux, but unfortunately the PCI   cribs and
> the
> > linux crashes
> > with PCI abort. The error message being "!!!
> > abort_handler addr =
> > 0x40015000 ,isr = 0x0 , status = 0x22a0".
> > Interestingly the same Linux
> > image works fine with the old redboot ,for which
> we don't 
> > have the source code.
> >   Has anybody in this list faced this problem.Am I
> missing 
> > configuring something in the Redboot  which is
> causing the 
> > PCI abort.I have tried with completely disabling
> PCI 
> > interface , but I still see this problem.
> > 
> >  any pointers !!!
> > 
> > Regds
> > Ravi
> > 
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