[U-Boot] [RFC] command/cache: Add flush_cache command

[Albert ARIBAUD <albert.u.boot@aribaud.net>]

Hi Tom,

On Fri, 22 Mar 2013 10:29:04 -0400, Tom Rini <trini@ti.com> wrote:

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> On 03/22/2013 10:03 AM, Wolfgang Denk wrote:
> > Dear Tom,
> > 
> > In message <514C4BE8.10508@ti.com> you wrote:
> >> 
> >> It seems like we're going around and around with one point not 
> >> being addressed.  When using 'go', how do you know the size to 
> >> flush?  And since Scott is talking about performance testing 
> >> apps, the cache should not be disabled (unless we expect all 
> >> standalone apps to enable the cache, in which case we need to 
> >> provide something in the jump table to make that easy and 
> >> document this change).
> > 
> > I also wonder about this. To me it appears much easier to use a 
> > IH_TYPE_STANDALONE image, which 1) provides the needed size 
> > information and 2) can be used with bootm, so the required 
> > additional steps (flush caches, release CPU) can be handled in 
> > bootm subcommands.
> 
> But that then circles us back to Scott's other point of "go" is broken
> then and it is the recommended way to start standalone applications.

I am not sure I understand how exactly go is broken, or how the bootm
proposal from Wolfgang circles back to a brokennness of 'go'. I am
not even sure of the exact scenario. How many cores are we dealing with
here, and what does each core do in sequence?

> Scott, part of the problem here is that we have multiple cores, yes?
> Say core0 is the one that read things in from NOR to DDR, core1 is the
> one that will be running things.

That's one possible scenario but I would like more detail before we
look for a solution.

Amicalement,
-- 
Albert.