[RFC PATCH powerpc] Fix a dma_mask issue of vio

[Benjamin Herrenschmidt]

On Wed, 2013-11-20 at 23:23 +0000, Russell King - ARM Linux wrote:
> Li Zong's patch works around the issue of a failing dma_set_mask(),
> but as I've already said elsewhere, the real fix is to get whatever
> created the struct device to initialise the dev->dma_mask with a
> bus default.
> 
> Using dma_coerce_xxx() merely makes the problem "go away" papering
> over the issue - it's fine to do it this way, but someone should still
> fix the broken code creating these devices...

Ok, they are created by the vio bus core, so it should be doing the
job here of setting the dma_mask pointer to a proper value.

Li, can you take care of that ? Look at other bus types we have in
there such as the macio bus etc...

Cheers,
Ben.