[PATCH kernel] powerpc/ioda: Use ibm,supported-tce-sizes for IOMMU page size mask

[Russell Currey]

On Wed, 2018-05-02 at 16:12 +1000, Alexey Kardashevskiy wrote:
> At the moment we assume that IODA2 and newer PHBs can always do
> 4K/64K/16M
> IOMMU pages, however this is not the case for POWER9 and now skiboot
> advertises the supported sizes via the device so we use that instead
> of hard coding the mask.
> 
> This falls back to the default mask if no "ibm,supported-tce-sizes"
> is provided. This removes 16MB from the defaults as it is not
> supported
> everywhere; the downside of this is that hugepages backed POWER8
> guests
> will fall back to 64K IOMMU pages until skiboot is updated.
> 
> Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>

Reviewed-by: Russell Currey <ruscur at russell.cc>