Re: [PATCH 2/2] arm64: avoid increasing DMA masks above what hardware supports

From	Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/2] arm64: avoid increasing DMA masks above what hardware supports
Date	2017-01-12 07:10 +0100
Message-ID	<sYGKe-t5-11@gated-at.bofh.it> (permalink)
References	<sYvYt-1Uj-21@gated-at.bofh.it> <sYvYt-1Uj-23@gated-at.bofh.it> <sYvYt-1Uj-19@gated-at.bofh.it> <sYytk-3x3-37@gated-at.bofh.it>
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>> @@ -959,6 +990,15 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>>         if (!dev->archdata.dma_ops)
>>                 dev->archdata.dma_ops = &swiotlb_dma_ops;
>>  
>> +       /*
>> +        * Whatever the parent bus can set. A device must not set
>> +        * a DMA mask larger than this.
>> +        */
>> +       if (enforce_range)
>> +               dev->archdata.parent_dma_mask = size - 1;
>> +       else
>> +               dev->archdata.parent_dma_mask = DMA_BIT_MASK(64);
>> +
>>         dev->archdata.dma_coherent = coherent;
>>         __iommu_setup_dma_ops(dev, dma_base, size, iommu);
>>
> 
> Could we just pass the mask instead of the size here?

We don't want to change API now.

Nikita

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[PATCH 2/2] arm64: avoid increasing DMA masks above what hardware supports Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-11 19:40 +0100
  Re: [PATCH 2/2] arm64: avoid increasing DMA masks above what hardware supports Arnd Bergmann <arnd@arndb.de> - 2017-01-11 22:20 +0100
    Re: [PATCH 2/2] arm64: avoid increasing DMA masks above what hardware  supports Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-12 07:10 +0100

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