Re: [PATCH RFC 0/5] ARM: Raspberry Pi 4 DMA support

Nicolas Saenz Julienne
2019-10-15T07:48:26Z

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On Mon, 2019-10-14 at 21:59 +0100, Catalin Marinas wrote:
> On Mon, Oct 14, 2019 at 08:31:02PM +0200, Nicolas Saenz Julienne wrote:
> > the Raspberry Pi 4 offers up to 4GB of memory, of which only the first
> > is DMA capable device wide. This forces us to use of bounce buffers,
> > which are currently not very well supported by ARM's custom DMA ops.
> > Among other things the current mechanism (see dmabounce.c) isn't
> > suitable for high memory. Instead of fixing it, this series introduces a
> > way of selecting dma-direct as the default DMA ops provider which allows
> > for the Raspberry Pi to make use of swiotlb.
>
> I presume these patches go on top of this series:
>
> http://lkml.kernel.org/r/20190911182546.17094-1-nsaenzjulienne@suse.de

Yes, forgot to mention it. It's relevant for the first patch.

>
> which I queued here:
>
>
https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/log/?h=for-next/zone-dma

Thanks!

A little off topic but I was wondering if you have a preferred way to refer to
the arm architecture in a way that it unambiguously excludes arm64 (for example
arm32 would work).

Regards,
Nicolas

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