Re: [PATCH v2 14/31] arm64: DMA mapping API

From: Catalin Marinas
Date: Tue Aug 21 2012 - 09:06:14 EST


On Wed, Aug 15, 2012 at 01:40:06AM +0100, Olof Johansson wrote:
> On Tue, Aug 14, 2012 at 06:52:15PM +0100, Catalin Marinas wrote:
> > +static inline struct dma_map_ops *get_dma_ops(struct device *dev)
> > +{
> > + if (unlikely(!dev) || !dev->archdata.dma_ops)
> > + return dma_ops;
> > + else
> > + return dev->archdata.dma_ops;
> > +}
>
> Does it make sense to add the concept of a global dma ops on arm64,
> instead of requiring the dma ops pointer per device similar to how
> some other platforms do it (including powerpc)? For devices that lack
> archdata.dma_ops, dma_supported() should return 0 (and the other ops
> should return error).

If the device doesn't have archdata.dma_ops we return the default
implementation which is currently based on swiotlb. Do you mean that
this shouldn't be the case and just let the device always set
archdata.dma_ops?

--
Catalin
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