[U-Boot-Users] Cache issue on MPC8xx

[Qichen Huang]

hi,
-- Another  option is to make sure you run your codewithout using
any  U-Boot  services  (and  interrupts  disabled)  and disable DC before
returning.

I did so, but still couldn't get D-Cache enabled.


On 8/24/06, Wolfgang Denk <wd at denx.de> wrote:
>
> In message <b4ebaa9d0608240455p26c28d4ey2ebf3768f986c8c2 at mail.gmail.com>
> you wrote:
> >
> > I want to apply some simple tests on MPC855T and need to turn on both
> > instruction- and data-cache. I have used the codes in
> cpu/mpc8xx/start.S(as
>
> Please read the README to understand why this is not so easy.
>
> > follows), but it crashes while trying to write IDC_ENABLE to DC_CST. Do
> I
> > have to enable the MMU first? If so,
>
> This is one option, but it may require lots of changes everywhere  in
> the  8xx  drivers.  Another  option is to make sure you run your code
> without using any  U-Boot  services  (and  interrupts  disabled)  and
> disable DC before returning.
>
> > how? I have tried the code in
> > linuxppc_2_4_devel/arch/ppc/kernel/head_8xx.S, it also crashes while
> > trying to write MSR_DR|MSR_IR to msr.
>
> U-Boot is not Linux, so no big surprise...
>
> Best regards,
>
> Wolfgang Denk
>
> --
> Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
> There are certain things men must do to remain men.
>         -- Kirk, "The Ultimate Computer", stardate 4929.4
>
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