[PATCH 04/22] arm64: dts: qcom: hamoa: Reserve low IOVA range for Iris

From: Daniel J Blueman <[email protected]>

On X1-family hamoa platforms, the Iris VPU reserves IOVA addresses
below 0x25800000 (600MB), primarily for secure non-pixel buffers. DMA
into that range, from any other stream id would triggers unhandled SMMU
page faults that cause spontaneous device reboots. This is readily
reproduced with one or more browser tabs driving multiple concurrent
video decode streams.

Add a reserved-memory IOVA reservation node covering [0, 0x25800000]
and reference it from the Iris node so the IOMMU layer keeps DMA
allocations above that boundary.

Link: https://github.com/qualcomm-linux/kernel-topics/issues/1157#issuecomment-4458933574
Fixes: 9065340ac04d ("arm64: dts: qcom: x1e80100: Add IRIS video codec")
Cc: [email protected]
Signed-off-by: Daniel J Blueman <[email protected]>
Signed-off-by: Vikash Garodia <[email protected]>
---
 arch/arm64/boot/dts/qcom/hamoa.dtsi | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/qcom/hamoa.dtsi b/arch/arm64/boot/dts/qcom/hamoa.dtsi
index 8a96ea1bdb9c4c409b2af997680d8c13fed0643e..87f424765d513c97b06303bceb75ca9f176d2ace 100644
--- a/arch/arm64/boot/dts/qcom/hamoa.dtsi
+++ b/arch/arm64/boot/dts/qcom/hamoa.dtsi
@@ -666,6 +666,17 @@ smem_mem: smem@ffe00000 {
 			hwlocks = <&tcsr_mutex 3>;
 			no-map;
 		};
+
+		/*
+		 * The Iris VPU reserves IOVA below 0x25800000 (600MB),
+		 * primarily for non-pixel buffers using different Stream IDs.
+		 * DMA into that range triggers unhandled SMMU faults and
+		 * spontaneous reboots, so reserve it to keep IOMMU
+		 * allocations above this boundary.
+		 */
+		iris_iova: iris-iova {
+			iommu-addresses = <&iris 0x0 0x0 0x0 0x25800000>;
+		};
 	};
 
 	qup_opp_table_100mhz: opp-table-qup100mhz {
@@ -5439,7 +5450,7 @@ &config_noc SLAVE_VENUS_CFG QCOM_ICC_TAG_ACTIVE_ONLY>,
 			interconnect-names = "cpu-cfg",
 					     "video-mem";
 
-			memory-region = <&video_mem>;
+			memory-region = <&video_mem>, <&iris_iova>;
 
 			resets = <&gcc GCC_VIDEO_AXI0_CLK_ARES>;
 			reset-names = "bus";

-- 
2.34.1