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SubjectRe: [PATCH v2 1/2] arm64: dts: broadcom: clear the warnings caused by empty dma-ranges
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On Fri, 16 Oct 2020 17:08:32 +0800, Zhen Lei <thunder.leizhen@huawei.com> wrote:
> The scripts/dtc/checks.c requires that the node have empty "dma-ranges"
> property must have the same "#address-cells" and "#size-cells" values as
> the parent node. Otherwise, the following warnings is reported:
>
> arch/arm64/boot/dts/broadcom/stingray/stingray-usb.dtsi:7.3-14: Warning \
> (dma_ranges_format): /usb:dma-ranges: empty "dma-ranges" property but \
> its #address-cells (1) differs from / (2)
> arch/arm64/boot/dts/broadcom/stingray/stingray-usb.dtsi:7.3-14: Warning \
> (dma_ranges_format): /usb:dma-ranges: empty "dma-ranges" property but \
> its #size-cells (1) differs from / (2)
>
> Arnd Bergmann figured out why it's necessary:
> Also note that the #address-cells=<1> means that any device under
> this bus is assumed to only support 32-bit addressing, and DMA will
> have to go through a slow swiotlb in the absence of an IOMMU.
>
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> ---

Applied to devicetree-arm64/next, thanks!
--
Florian

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