[PATCH v2 02/12] dt-bindings: media: qcom,sm8550-iris: Add context bank subnodes

[Vikash Garodia]

The VPU issues DMA through several SMMU streams, and the hardware does
not give every stream the same addressable range. The non-pixel stream
is restricted to use 0-600MB of IOVA space, while the pixel stream can
address the full range:
    +-----------------------------------------------------------+
    | non-pixel stream addressable range (600 MB - 3.5 GB)      |
    | 0x25800000 - 0xe0000000                                   |
    +-----------------------------------------------------------+
    | pixel stream addressable range (0 - 3.5 GB)               |
    | 0x00000000 - 0xe0000000                                   |
    +-----------------------------------------------------------+
A single "iommus" property on the video-codec node puts every stream in
one IOMMU domain sharing one IOVA allocator, so nothing keeps a
non-pixel buffer above 600 MB. Once an allocation lands below that
boundary the hardware faults, which shows up as unhandled SMMU page
faults and spontaneous reboots:
https://gitlab.freedesktop.org/drm/msm/-/work_items/100

Reference qcom,venus-common.yaml, which describes the per-stream context
bank subnodes, and drop "iommus" from the required list. The common
schema accepts either the flat "iommus" or the "non-pixel" and "pixel"
subnode pair, so device trees that have not been converted still
validate.

Update the example to the subnode form, which also picks up the two
supporting properties the subnodes need on the parent video-codec node,
'#address-cells' and '#size-cells' of 2 and an empty "dma-ranges". Both
are described in the common schema change.

Fixes: 41661853ae8e ("arm64: dts: qcom: sm8550: add iris DT node")
Cc: stable@xxxxxxxxxxxxxxx
Co-developed-by: Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>
Signed-off-by: Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>
Tested-by: Daniel J Blueman <daniel@xxxxxxxxx>
Signed-off-by: Vikash Garodia <vikash.garodia@xxxxxxxxxxxxxxxx>
---
 .../devicetree/bindings/media/qcom,sm8550-iris.yaml    | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml b/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml
index 0400ca1bff05dcef6b742c3fbf77e38adca9f280..3d8ff5677bd4fb7f3619a95b1c5f6f9eaf39b32c 100644
--- a/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml
+++ b/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml
@@ -98,10 +98,10 @@ required:
   - interconnect-names
   - resets
   - reset-names
-  - iommus
   - dma-coherent
 
 allOf:
+  - $ref: qcom,venus-common.yaml#
   - if:
       properties:
         compatible:
@@ -177,12 +177,24 @@ examples:
         resets = <&gcc GCC_VIDEO_AXI0_CLK_ARES>;
         reset-names = "bus";
 
-        iommus = <&apps_smmu 0x1940 0x0000>,
-                 <&apps_smmu 0x1947 0x0000>;
         dma-coherent;
 
         operating-points-v2 = <&iris_opp_table>;
 
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        dma-ranges;
+
+        non-pixel {
+            iommus = <&apps_smmu 0x1940 0x0000>;
+            memory-region = <&iris_resv>;
+        };
+
+        pixel {
+            iommus = <&apps_smmu 0x1947 0x0000>;
+        };
+
         iris_opp_table: opp-table {
             compatible = "operating-points-v2";
 

-- 
2.34.1