On Friday 30 October 2015 16:55:16 Timur Tabi wrote:
>
> On 10/30/2015 04:42 PM, Sinan Kaya wrote:
> >>
> >> if (WARN_ON(!pdev->dev.dma_mask))
> >> return -ENXIO;
> >>
> >> The dma mask has to always be set by the platform code before probe()
> >> is called. If it is not set, you are not allowed to perform DMA.
> >
> > I tested this on an ACPI platform BTW when I was working on the initial
> > implementation.
>
> PowerPC sets the mask to 32 bits by default:
>
> http://lxr.free-electrons.com/ident?i=arch_setup_pdev_archdata
>
> Should we do something similar in ARM64? Today, we have to manually set
> the DMA mask in all drivers.
We set the dma mask from the 'dma-ranges' property of the parent device,
but fall back to 32-bit because we did not manage to mandate this property
in time for all arm64 machines to use.
Arnd
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