On Wed, 2021-02-10 at 16:53 -0600, Rob Herring wrote: > On Wed, Feb 03, 2021 at 04:37:48PM +0800, Irui Wang wrote: > > Adds dma-ranges property for DMA addresses translation. > > > > Signed-off-by: Irui Wang <irui.wang@xxxxxxxxxxxx> > > --- > > Documentation/devicetree/bindings/media/mediatek-vcodec.txt | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/media/mediatek-vcodec.txt b/Documentation/devicetree/bindings/media/mediatek-vcodec.txt > > index f85276e629bf..e4644f8caee9 100644 > > --- a/Documentation/devicetree/bindings/media/mediatek-vcodec.txt > > +++ b/Documentation/devicetree/bindings/media/mediatek-vcodec.txt > > @@ -23,6 +23,8 @@ Required properties: > > - iommus : should point to the respective IOMMU block with master port as > > argument, see Documentation/devicetree/bindings/iommu/mediatek,iommu.txt > > for details. > > +- dma-ranges : describes how the physical address space of the IOMMU maps > > + to memory. > > dma-ranges is supposed to be in a bus/parent node. Dear Rob, The mt8192 iommu support 0~16GB iova. We separate it to four banks: 0~4G; 4G~8G; 8G~12G; 12G~16G. The "dma-ranges" could be used to adjust the bank we locate. If we don't set this property. The default range always is 0~4G. Here we don't have actual bus/parent concept here. And the iova requirement is for our HW. Thus put the property in our node. Is this OK? If this is ok for you, I will put this message in the commit message and binding in next version. Regards > > > One of the two following nodes: > > - mediatek,vpu : the node of the video processor unit, if using VPU. > > - mediatek,scp : the node of the SCP unit, if using SCP. > > -- > > 2.25.1 > >
