Re: [PATCH 2/2] arm64: avoid increasing DMA masks above what hardware supports
From: Arnd Bergmann
Date: Wed Jan 11 2017 - 16:14:31 EST
On Wednesday, January 11, 2017 9:31:52 PM CET Nikita Yushchenko wrote:
> @@ -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?
Arnd