Re: [PATCH/RFC 01/09] iommu/ipmmu-vmsa: Disable IPMMU when address expansion is not needed

[Magnus Damm <magnus.damm@gmail.com>]

Hi Geert,
On Thu, Feb 21, 2019 at 1:10 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Magnus,
>
> On Wed, Feb 20, 2019 at 3:55 PM Magnus Damm <magnus.damm@gmail.com> wrote:
> > From: Magnus Damm <damm+renesas@opensource.se>
> >
> > Add a memory bank location check to the whitelist handling.
> >
> > Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
>
> Thanks for your patch!

Thanks for feedback!

> > --- 0001/drivers/iommu/ipmmu-vmsa.c
> > +++ work/drivers/iommu/ipmmu-vmsa.c     2019-02-20 22:59:28.589893396 +0900
>
> > @@ -797,6 +798,12 @@ static bool ipmmu_slave_whitelist(struct
> >         if (!soc_device_match(soc_rcar_gen3_whitelist))
> >                 return false;
> >
> > +       /* In case all system memory fits within 32 bits of physical space
> > +        * then assume the IPMMU will not be needed for address expansion.
> > +        */
> > +       if (memblock_end_of_DRAM() <= SZ_4G)
>
> Can this give a compiler warning on arm32 when CONFIG_ARM_LPAE=n?

Not sure how, can you elaborate?

To test this I actually installed a new arm32 compiler but I failed to
trigger any warnings.

Thanks,

/ magnus