[U-Boot] [RFC PATCH] arm: arm926ejs: flush cache before disable it

Sughosh Ganu
2013-07-10T17:34:45Z

hi Albert,

On Wed Jul 10, 2013 at 02:30:30PM +0200, Albert ARIBAUD wrote:

> > > You are correct re the other policies of the DDI0198E (ARM926EJ-S
> > > TRM) MMU -- page 3-11, bits 3-2 of the section descriptor. Note however
> > > that you may have to refer to your specific SoC's TRM or equivalent, as
> > > the SoC designer may have defined its own system-level cache and MMU
> > > architecture.
> > >
> > > Note in any case that none of the policies mentioned in DDI0198E is
> > > described as read-allocate (let alone "read-allocate only" where writes
> > > would bypass the enabled cache); on the contrary, the only cache
> > > policies mentioned are write-through and write-back, both of which
> > > contradict cache bypass on write.
> >
> > I was referring to the cache allocation policy mentioned in section
> > 4.1 in the DDI0198E document -- this is also mentioned in table 12.1
> > in chapter 12 of the arm developers guide.
>
> Can you please quote the exact part of 4.1 which describes the cache
> policy and then explain what you think it means exactly?

I was referring to this particular point in section 4.1
"Allocate on read-miss is supported. The caches perform critical-word
first cache refilling."

Based on the cache line allocation policies described in section
12.3.3 in the arm developers guide, my interpretation of 'allocate on
read-miss' was as above.

-sughosh