Hi Rob,

On 01/03/2021 07:45, Irui Wang wrote:

On Wed, 2021-02-10 at 16:53 -0600, Rob Herring wrote:

quoted

On Wed, Feb 03, 2021 at 04:37:48PM +0800, Irui Wang wrote:

quoted

Adds dma-ranges property for DMA addresses translation.

Signed-off-by: Irui Wang <redacted>
---
 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.

Can you answer Irui's question? Just a reminder...

Much appreciated!

Regards,

	Hans

Regards

quoted

quoted

 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