[PATCH v4 3/7] [RFC] arm/arm64: introduce is_dma_coherent

[Stefano Stabellini]

On Fri, 10 Oct 2014, Will Deacon wrote:
> On Fri, Oct 10, 2014 at 12:51:44PM +0100, Stefano Stabellini wrote:
> > Introduce a function to check whether a device is dma coherent.
> > 
> > Signed-off-by: Stefano Stabellini <stefano.stabellini at eu.citrix.com>
> > CC: linux at arm.linux.org.uk
> > CC: catalin.marinas at arm.com
> > CC: will.deacon at arm.com
> > CC: linux-arm-kernel at lists.infradead.org
> > ---
> >  arch/arm/include/asm/dma-mapping.h   |    6 ++++++
> >  arch/arm64/include/asm/dma-mapping.h |    5 +++++
> >  2 files changed, 11 insertions(+)
> > 
> > diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
> > index c45b61a..bededbb 100644
> > --- a/arch/arm/include/asm/dma-mapping.h
> > +++ b/arch/arm/include/asm/dma-mapping.h
> > @@ -126,6 +126,12 @@ static inline int set_arch_dma_coherent_ops(struct device *dev)
> >  	set_dma_ops(dev, &arm_coherent_dma_ops);
> >  	return 0;
> >  }
> > +
> > +static inline bool is_dma_coherent(struct device *dev)
> > +{
> > +    return (__generic_dma_ops(dev) == &arm_coherent_dma_ops);
> > +}
> 
> Hmm, what about the IOMMU ops?

Maybe I should check __generic_dma_ops(dev) != &arm_dma_ops?
Do you have any better suggestions?