[MPC8260] accessing I/Os while MMU is off

[vincent poirson]

Well, I forgot one operand in the addis instruction
but otherwise my code is OK. I checked that the right
PDATC adress was in the GPR.
I also forgot to say that my code works when I put it
in a interrupt handler in a normal kernel module.
What I do not understand is why the kernel keeps going
in machine check exception when I try to load PDATC
contents or store a value in PDATC.



 --- None Atall <linux_meis at yahoo.com> a écrit : > You
missed a small shift... :)
>
> -----------------------
> li r16,r16,0x10
> li r13, 0xf001
> slw  r13,r13,r16
> addis r13, 0x0d50
> stw r14, 0(r13)
> -----------------------
>
>                    Dimitris.
>
> --- vincent poirson <poirsonv at yahoo.fr> wrote:
> >
> > Hello,
> >
> > I want to change my PDATC value while in
> > HardwareInterrupt code (in kernel/head.S) where
> MMU
> > is
> > off. So I simply do :
> > li r13, 0x0d50
> > addis r13, 0xf001
> > stw r14, 0(r13)
> > // where 0xf0010d50 is my PDATC adress and r14 the
> > value I want to store
> > I do not understand why my kernel crahes and goes
> in
> > machine exception. Surprisingly, I can change
> PDATC
> > with BDI2000 but not with assembler code. Is this
> an
> > adress translation problem ?
> > Am I missing something obvious ? Any help will be
> > appreciated.
> >
> > Thanks in advance.
> >
> >
> >
>
>
> =====
>
------------------------------------------------------------
> -Dhmhtrios Meidanis
> -Degree in Mathematics, University of the Aegean.
> -Master in Computer Architecture and Digital
>  Systems, University of Crete.
>  Greece.
>
------------------------------------------------------------
>


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