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

[Stephen Boyd]

Quoting Bjorn Andersson (2019-01-16 20:29:40)
> 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@xxxxxxxxxx>
> ---

Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>