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SubjectRe: [PATCH v4 2/2] arm64: dts: qcom: sdm845: Extend ranges and describe DMA space
Hi,

On Wed, Jan 16, 2019 at 8:30 PM Bjorn Andersson
<bjorn.andersson@linaro.org> wrote:
>
> For devices attached to an IOMMU, translation between IOVA and physical
> addresses is no longer 1:1 and dma-ranges should be specified to
> describe the available IOVA address space.
>
> On SDM845 the busses are implemented with 36 address bits, so dma-ranges
> must be defined to reduce the size of the IOVA address space from the 48
> bits supported by the SMMU. Without this DMA allocations may end up with
> IOVAs outside the valid range, that gets truncated by the bus between
> the device and its translation unit.
>
> Also extend ranges to describe the available address space.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>
> Changes since v3:
> - Split this out from patch 1.
> - Rewrote commit message from scratch
>
> arch/arm64/boot/dts/qcom/sdm845.dtsi | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>

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