[U-Boot-Users] Help--750FX,Cannot handle DEC or External Interrupt exception.U-Boot-1.1.1, ELDK3.0,RedHat

VanBaren, Gerald (AGRE) Gerald.VanBaren at smiths-aerospace.com
Fri Aug 27 14:26:59 CEST 2004

It isn't going to be the exception handling mechanism.

FAQ: http://www.denx.de/twiki/bin/view/DULG/UBootCrashAfterRelocation

Note to Wolfgang: I added some more text to the above link.  I was going to add a new section to the linux section of the FAQ to refer to the above link, but forgot how to add sections given your DULG structuring :-(.  I propose the following be added:

%SECTION0{name=LinxRandomCrash}% Linux crashes randomly

   Question:: On my board, linux crashes randomly or has random exceptions
    (especially floating point exceptions if it is a PowerPC processor). Why?

   Answer:: Quite likely your SDRAM initialization is bad. See
   UBootCrashAfterRelocation for more information.
   On a PowerPC, the instructions beginning with 0xFF are floating point
   instructions.  When your memory subsystem fails, the PowerPC is reading
   bad values (0xFF) and thus executing illegal floating point instructions.


> -----Original Message-----
> From: u-boot-users-admin at lists.sourceforge.net
> [mailto:u-boot-users-admin at lists.sourceforge.net]On Behalf Of haigao
> Sent: Friday, August 27, 2004 3:16 AM
> To: u-boot-users at lists.sourceforge.net
> Subject: Re: [U-Boot-Users] Help--750FX,Cannot handle DEC or External
> Interrupt exception.U-Boot-1.1.1, ELDK3.0,RedHat
> > My target platform is with 750FX and MPC107, 256M ram, a
> NS16c552 serial and also a Intel 82559 compatiable ethernet
> controller.
> >Which board configuration is this, and which version of U-Boot?
> U-Boot 1.1.1  ELDK3.0  RedHat9.0,
> I made our board's configuration file by copying and
> modifying the BAB7xx.h.
> > [And another question in anticipation of  your  reply  (a 
> new  board
> > configuration being ported by you based on an old version
> of U-Boot):
> > are you absolutely sure that your SDRAM init code is correct?]
> Yes, I am sure my SDRAM init code is correct, because I had
> Vxworks running on many pieces of boards for many days
> Also, I've coded a program to test SDRAM detailly, but on Vxworks.
> I have tested my situation for already many times. And found:
> 1) Sometimes, even program exception handling cannot work
> when I use "go 0x8000(or 0x9000, or 0x123456, or any other
> place"(Of course I examined the data there).
> 2)Sometimes, even I set IP bit in MSR register, exception
> handling also cannot work.
> 3)My hundreds of trying seemed ruleless.
> I guess,  the cause maybe the cache or exception handling mechanism ?
> And  can you tell me is there a successful case that U-Boot
> on 750FX or 750 can handle the exceptions normally?
> Thanks a lot for your reply.
> Best regards,
> gaohai

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