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arm64: dts: qcom: Remove "iommus" property from PCIe nodes

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Currently, most of the Qualcomm SoCs specify both "iommus" and "iommu-map"
properties for the PCIe nodes. First one passes the SMR mask to the iommu
driver and the latter specifies the SID for each PCIe device.

But with "iommus" property, the PCIe controller will be added to the
iommu group along with the devices. This makes no sense because the
controller will not initiate any DMA transaction on its own. And moreover,
it is not strictly required to pass the SMR mask to the iommu driver. If
the "iommus" property is not present, then the default mask of "0" would be
used which should work for all PCIe devices.

On the other side, if the SMR mask specified doesn't match the one expected
by the hypervisor, then all the PCIe transactions will end up triggering
"Unidentified Stream Fault" by the SMMU.

So to get rid of these hassles and also prohibit PCIe controllers from
adding to the iommu group, let's remove the "iommus" property from PCIe
nodes.

Reported-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/linux-arm-msm/20230227195535.GA749409-robh@kernel.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230308075648.134119-1-manivannan.sadhasivam@linaro.org
This commit is contained in:
Manivannan Sadhasivam 2023-03-08 13:26:48 +05:30 • committed by Bjorn Andersson
commit 6340b391e1
7 changed files with 0 additions and 15 deletions
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