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

[Wolfgang Denk <wd@denx.de>]

Dear Albert,

In message <20130320145927.2031b913@lilith> you wrote:
> 
> I do understand what it does, but I still don't get why it should be
> done, since precisely payload control transfer happens through bootm and
> the like which already properly flush cache.

Full agrement.

> Is there an ARM multi-core target in U-Boot where U-Boot runs on
> one core but its payload shall be started on another, "un-booted",
> core, and which experiences issues due to the first core not flushing
> cache? If no existing target needs this, then this patch is useless. If
> there exists such a target and issue, then the right fix is not a shell
> command, it is a programmatic flush before the other core is enabled,
> so that it always sees correct RAM.

Agreed again.  As is, the patch was only adding dead code, as there
are no users of the feature.

<nitpick>
Also, it was added unconditionally which is a strict no-no as it just
adds code-bloat to everyone, without benefit.
</nitpick>

> Maybe this is some code that might come in handy for some future target
> not in U-Boot yes which will have the first core start a payload on
> another core? Then the previous argument applies (the fix should not be
> a shell command, it should be in source code), plus, the patch is dead
> code until and unless said target is also added in a single series.

Agreed!  Thanks.

Best regards,

Wolfgang Denk

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