[PATCH v2 09/12] arm64: dts: qcom: sm8550: Add Iris 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

Describe the two streams as "non-pixel" and "pixel" subnodes so each gets
its own IOMMU domain, with stream 0x1940 becoming non-pixel and 0x1947
becoming pixel. Point the non-pixel subnode at a reserved-memory node
whose "iommu-addresses" covers [0, 0x25800000), which excludes the low
600 MB from that domain's IOVA allocator and keeps its allocations above
the boundary the stream can address. The reservation node carries no
"reg", so it is a pure IOVA carve-out rather than a memory mapping. The
pixel stream is left free to use the whole range.

qcs8550 discards the inherited reserved-memory node with /delete-node/,
so it needs its own copy of the reservation for the non-pixel subnode
phandle to resolve.

The video-codec node also gains '#address-cells' and '#size-cells' of 2,
which set the cell widths used to parse the "iommu-addresses" entry that
refers to the non-pixel subnode, and an empty "dma-ranges" declaring the
1:1 DMA translation into the parent. 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>
---
 arch/arm64/boot/dts/qcom/qcs8550.dtsi |  4 ++++
 arch/arm64/boot/dts/qcom/sm8550.dtsi  | 19 +++++++++++++++++--
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/qcs8550.dtsi b/arch/arm64/boot/dts/qcom/qcs8550.dtsi
index f0acdd0b1e9384e684a90f7f49cf63633cd70d53..db0f539bc3d0a2e83b58b3929a05f0e44d9d513f 100644
--- a/arch/arm64/boot/dts/qcom/qcs8550.dtsi
+++ b/arch/arm64/boot/dts/qcom/qcs8550.dtsi
@@ -158,5 +158,9 @@ mpss_dsm_mem: mpss-dsm-region@d4d00000 {
 			reg = <0x0 0xd4d00000 0x0 0x3300000>;
 			no-map;
 		};
+
+		iris_resv: reservation-iris {
+			iommu-addresses = <&iris_non_pixel 0x0 0x0 0x0 0x25800000>;
+		};
 	};
 };
diff --git a/arch/arm64/boot/dts/qcom/sm8550.dtsi b/arch/arm64/boot/dts/qcom/sm8550.dtsi
index 7599b7b7e645f389f817c2694317ba12998992a5..4c8ad7f026fe536fe6dd69b015f1e79edcbb60f6 100644
--- a/arch/arm64/boot/dts/qcom/sm8550.dtsi
+++ b/arch/arm64/boot/dts/qcom/sm8550.dtsi
@@ -1087,6 +1087,10 @@ hyp_ext_reserved_mem: hyp-ext-reserved-region@ff700000 {
 			reg = <0 0xff700000 0 0x100000>;
 			no-map;
 		};
+
+		iris_resv: reservation-iris {
+			iommu-addresses = <&iris_non_pixel 0x0 0x0 0x0 0x25800000>;
+		};
 	};
 
 	smp2p-adsp {
@@ -3690,10 +3694,12 @@ &config_noc SLAVE_VENUS_CFG QCOM_ICC_TAG_ACTIVE_ONLY>,
 			resets = <&gcc GCC_VIDEO_AXI0_CLK_ARES>;
 			reset-names = "bus";
 
-			iommus = <&apps_smmu 0x1940 0>,
-				 <&apps_smmu 0x1947 0>;
 			dma-coherent;
 
+			#address-cells = <2>;
+			#size-cells = <2>;
+			dma-ranges;
+
 			/*
 			 * IRIS firmware is signed by vendors, only
 			 * enable on boards where the proper signed firmware
@@ -3701,6 +3707,15 @@ &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