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

From: Stefano Stabellini
Date: Fri Oct 10 2014 - 09:06:36 EST


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@xxxxxxxxxxxxx>
> > CC: linux@xxxxxxxxxxxxxxxx
> > CC: catalin.marinas@xxxxxxx
> > CC: will.deacon@xxxxxxx
> > CC: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > ---
> > 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?
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