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[v2,2/2] arm64: dts: qcom: sc8280xp: Describe the PCIe SMMUv3

Message ID 20231219-topic-8280_smmuv3-v2-2-c67bd3226687@linaro.org
State New
Headers show
Series Describe SC8280XP PCIe SMMU | expand

Commit Message

Konrad Dybcio March 9, 2024, 1:31 p.m. UTC
SC8280XP actually has a third SMMU, which can be seen in e.g. the IORT
ACPI table and is used for the PCIe hosts.

Unfortunately though, the secure firmware seems to be configured in a
way such that Linux can't touch it, not even read back the ID registers.
It also seems like the SMMU is configured to run in some sort of bypass
mode, completely opaque to the OS.

Describe it so that one can configure it when running Linux as a
hypervisor (e.g with [1]) and for hardware description completeness.

[1] https://github.com/TravMurav/slbounce
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 arch/arm64/boot/dts/qcom/sc8280xp.dtsi | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
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Patch

diff --git a/arch/arm64/boot/dts/qcom/sc8280xp.dtsi b/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
index a5b194813079..28edd30a9c04 100644
--- a/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc8280xp.dtsi
@@ -4648,6 +4648,22 @@  cci3_i2c1_sleep: cci3-i2c1-sleep-pins {
 			};
 		};
 
+		pcie_smmu: iommu@14f80000 {
+			compatible = "qcom,sc8280xp-smmu-v3", "arm,smmu-v3";
+			reg = <0 0x14f80000 0 0x80000>;
+			interrupts = <GIC_SPI 951 IRQ_TYPE_EDGE_RISING>,
+				     <GIC_SPI 955 IRQ_TYPE_EDGE_RISING>,
+				     <GIC_SPI 953 IRQ_TYPE_EDGE_RISING>;
+			interrupt-names = "eventq",
+					  "gerror",
+					  "cmdq-sync";
+			#iommu-cells = <1>;
+			dma-coherent;
+
+			/* The hypervisor prevents register access from Linux */
+			status = "reserved";
+		};
+
 		apps_smmu: iommu@15000000 {
 			compatible = "qcom,sc8280xp-smmu-500", "arm,mmu-500";
 			reg = <0 0x15000000 0 0x100000>;