[ELDK] ELDK Linux 2.6.29, MPC885ADS and early console
Sylvain ANDRE
sandre at assystem.com
Mon May 4 09:48:46 CEST 2009
Hi Detlev,
I came back to my office this morning. I removed all my code from the
Linux kernel as you said and tried again with Linux post mortem.
Here is the result :
<6>Using Freescale MPC885 ADS machine description.
<6>Using Freescale MPC885 ADS machine description.
<5>Linux version 2.6.29-rc7(root at localhost.localdomain) (gcc version
4.2.2) #4 Mon May 4 09:25:51 CEST 2009
and nothing after (the previous error message disapeared).
But the console is still quiet.
Cheers.
Sylvain.
Detlev Zundel a écrit :
> Hi Sylvain,
>
>
>> finally I succeeded with your recipe, here is the result of the memory
>> dump : (concatenated ASCII only)
>>
>> <6>Using Freescale MPC885 ADS machine description.
>> <6>Using Freescale MPC885 ADS machine description.
>> <5>Linux version 2.6.29-rc7 (root at localhost.localdomain) (gcc version
>> 4.2.2) #3 Fri Apr 17 09:30:49 CEST 2009.
>> <1>Unable................................................ess 0xff000ad8.
>> <................................................................s of
>> bad area, sig: 11 [#1].
>> <4>Freescale MPC885................inked in:.<4>NIP
>>
>>
>> 0xFF000AD8 is the physical address of PEDAT I/O register. I use it to
>> drive LEDs. Perhaps it's the reason since the beginning ...
>>
>
> Yes indeed. Did you really to simply write to those addresses? This is
> bound to fail with (recent) Linux. Remember that Linux uses the MMU and
> you cannot use physical addresses easily. Usually you will want to do
> an "ioremap" for a physical address to install a translation and use the
> returned pointer. But even this is not so easy very early in the Linux
> boot process as the memory management implementing "ioremap" also needs
> to initialize itself.
>
> So I'd propose to remove all your code from the Linux kernel and try
> again now that you know how to get to the contents of the Linux
> logbuffer.
>
> Cheers
> Detlev
>
>
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