[U-Boot] [Patch v4 2/5] ARMv8: Adjust MMU setup

Mark Rutland
2014-06-10T09:15:40Z

Hi,

Apologies for the delay in replying.

On Fri, Jun 06, 2014 at 11:14:23PM +0100, York Sun wrote:
> On 06/06/2014 01:17 PM, York Sun wrote:
> > On 06/06/2014 10:32 AM, Mark Rutland wrote:
> >>>> How is TCR_EL2.SH0 (or TCR_EL1.SH*) configured?
> >>>>
> >>>> You'll only need to flush the cache if they're configured non shareable.
> >>>
> >>> It is configured as non shareable.
> >>
> >> Is there any reason not to configure them as inner shareable? That way
> >> the MMU will look in the D-cache, and you won't have to spend time
> >> flushing them.
> >>
> >
> > Mark,
> >
> > I appreciate the reminder. I tried on our emulator. With inner share set for TCR
> > SH0 bits, u-boot works with the flushing, but doesn't work without flushing. It
> > went to exception.
> >
> > Can you share more information about the inner share? I need to follow up with
> > our designer to confirm.
> >
>
> A second thought, do I need to set the first MMU table so DDR is inner shareable?

I assume you mean configuring MAIR_ELx such that the mapping covering
DDR is cacheable for the inner shareable domain? If so, yes.

Cheers,
Mark.