[RFC PATCH 11/11] arm64: dts: qcom: sm8650: Move Iris IOMMUs to child nodes

[Vikash Garodia]

The Iris VPU has separate streams with different IOVA constraints. The
non-pixel stream must be limited to the 0-600 MB IOVA range, while the
pixel stream can use the full IOVA space.
Using a single set of IOMMU entries for the Iris node does not describe
these per-stream limits and can allow accesses outside the supported
range, which may lead to device crashes. One such issue was reported at:
https://gitlab.freedesktop.org/drm/msm/-/work_items/100

Add non-pixel and pixel child nodes, move each stream ID to its
corresponding child node, and add a reserved IOVA range for the
non-pixel stream.

Co-developed-by: Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>
Signed-off-by: Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>
Signed-off-by: Vikash Garodia <vikash.garodia@xxxxxxxxxxxxxxxx>
---
 arch/arm64/boot/dts/qcom/sm8650.dtsi | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sm8650.dtsi b/arch/arm64/boot/dts/qcom/sm8650.dtsi
index 447b788fcbb96efc8b26a52a0606bc53dd29adfb..f9c03de1317f1c6a8e52bd897997ef7bd826926b 100644
--- a/arch/arm64/boot/dts/qcom/sm8650.dtsi
+++ b/arch/arm64/boot/dts/qcom/sm8650.dtsi
@@ -1849,6 +1849,10 @@ llcc_lpi_mem: llcc-lpi@ff800000 {
 			reg = <0 0xff800000 0 0x600000>;
 			no-map;
 		};
+
+		iris_resv: reservation-iris {
+			iommu-addresses = <&iris_non_pixel 0x0 0x0 0x0 0x25800000>;
+		};
 	};
 
 	smp2p-adsp {
@@ -5219,11 +5223,11 @@ &config_noc SLAVE_VENUS_CFG QCOM_ICC_TAG_ACTIVE_ONLY>,
 				      "xo",
 				      "core";
 
-			iommus = <&apps_smmu 0x1940 0>,
-				 <&apps_smmu 0x1947 0>;
-
 			dma-coherent;
 
+			#address-cells = <2>;
+			#size-cells = <2>;
+
 			/*
 			 * IRIS firmware is signed by vendors, only
 			 * enable on boards where the proper signed firmware
@@ -5231,6 +5235,15 @@ &config_noc SLAVE_VENUS_CFG QCOM_ICC_TAG_ACTIVE_ONLY>,
 			 */
 			status = "disabled";
 
+			iris_non_pixel: non-pixel {
+				iommus = <&apps_smmu 0x1940 0x0>;
+				memory-region = <&iris_resv>;
+			};
+
+			iris_pixel: pixel {
+				iommus = <&apps_smmu 0x1947 0x0>;
+			};
+
 			iris_opp_table: opp-table {
 				compatible = "operating-points-v2";
 

-- 
2.34.1