Re: [PATCH 1/2] of: Fix DMA mask generation

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From	Christoph Hellwig <hch@lst.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/2] of: Fix DMA mask generation
Date	Fri, 11 Aug 2017 20:00:02 +0200
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On Fri, Aug 11, 2017 at 05:29:56PM +0100, Robin Murphy wrote:
> Historically, DMA masks have suffered some ambiguity between whether
> they represent the range of physical memory a device can access, or the
> address bits a device is capable of driving, particularly since on many
> platforms the two are equivalent. Whilst there are some stragglers left
> (dma_max_pfn(), I'm looking at you...), the majority of DMA code has
> been cleaned up to follow the latter definition, not least since it is
> the only one which makes sense once IOMMUs are involved.

I think it always was supposed to be the latter, but that doesn't mean
that everyone got the message :)

> Either of these patches alone should be sufficient to un-break RPi3,
> and they apply independently, so I'm quite happy for one to go in as a
> fix now and the other to wait for 4.14.

This one is something I'm comfortable feeding to Linus for 4.13
if I get a few ACKs from people familar with the OF code and intended
meaning of the ranges in the device tree.

Thread

[PATCH 1/2] of: Fix DMA mask generation Robin Murphy <robin.murphy@arm.com> - 2017-08-11 18:40 +0200
  [PATCH 2/2] of: Restrict DMA configuration Robin Murphy <robin.murphy@arm.com> - 2017-08-11 18:40 +0200
    Re: [PATCH 2/2] of: Restrict DMA configuration Christoph Hellwig <hch@lst.de> - 2017-08-11 20:10 +0200
    Re: [PATCH 2/2] of: Restrict DMA configuration Rob Herring <robh+dt@kernel.org> - 2017-08-14 22:10 +0200
      Re: [PATCH 2/2] of: Restrict DMA configuration Robin Murphy <robin.murphy@arm.com> - 2017-08-15 12:20 +0200
        Re: [PATCH 2/2] of: Restrict DMA configuration Rob Herring <robh+dt@kernel.org> - 2017-08-15 16:30 +0200
  Re: [PATCH 1/2] of: Fix DMA mask generation Christoph Hellwig <hch@lst.de> - 2017-08-11 20:00 +0200
  Re: [PATCH 1/2] of: Fix DMA mask generation Rob Herring <robh+dt@kernel.org> - 2017-08-14 23:20 +0200
    Re: [PATCH 1/2] of: Fix DMA mask generation Christoph Hellwig <hch@lst.de> - 2017-08-17 10:30 +0200

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