[U-Boot] [PATCH v2 12/19] arm: Add control over cachability of memory regions

Simon Glass
2012-07-11T05:01:59Z

Hi Stephen,

On Fri, Jun 15, 2012 at 1:49 AM, Stephen Warren <swarren@wwwdotorg.org>wrote:

> On 06/13/2012 10:19 AM, Simon Glass wrote:
> > Add support for adjusting the cachability of an L1 section by updating
> > the MMU. The mmu_set_region_dcache() function allows drivers to make
> > these changes after the MMU is set up.
> >
> > It is implemented only for ARMv7 at present.
> >
> > This is needed for LCD support, where we want to make the LCD frame
> buffer
> > write-through (or off) rather than write-back.
>
> Wouldn't performance be significantly better if the region was fully
> cached, but flushed after each display surface update?
>

That is the setting used on Tegra, yes. This function permits selection of
the three options.

Regards,
Simon