[PATCH 0/2] [B/snapdragon] [SRU] Dragonboard hangs after SMMU init

Paolo Pisati paolo.pisati at canonical.com
Thu Aug 29 12:32:12 UTC 2019

BugLink: https://bugs.launchpad.net/bugs/1841893


Ubuntu-snapdragon-4.15.0-1061.68 hangs during boot:

[ 1.856849] arm-smmu da0000.arm,smmu: probing hardware configuration...
[ 1.859296] arm-smmu da0000.arm,smmu: SMMUv2 with:
[ 1.865845] arm-smmu da0000.arm,smmu: stage 1 translation
[ 1.870658] arm-smmu da0000.arm,smmu: address translation ops
[ 1.876121] arm-smmu da0000.arm,smmu: non-coherent table walk
[ 1.881936] arm-smmu da0000.arm,smmu: (IDR0.CTTW overridden by FW configuration)
[ 1.887760] arm-smmu da0000.arm,smmu: stream matching with 4 register groups
[ 1.895337] arm-smmu da0000.arm,smmu: 2 context banks (0 stage-2 only)
[ 1.902455] arm-smmu da0000.arm,smmu: Supported page sizes: 0x63315000
[ 1.908852] arm-smmu da0000.arm,smmu: Stage-1: 32-bit VA -> 36-bit IPA
[hangs here]


During the Ubuntu-snapdragon-4.15.0-1061.68, the qcom smmuv2 implementation was replaced with an upstream generic version that didn't explicit clocks, power requirements and early init via IOMMU_OF_DECLARE() - reverting the upstream patch, and reapplying the original qcom patch that was dropped, fixes this hang.

How to test:

Try to boot a patched kernel and see if it reaches userspace.

Regression potential:

None, since the current kernel version doesn't boot at all.

Paolo Pisati (1):
  Revert "iommu/arm-smmu: Add support for qcom,smmu-v2 variant"

Vivek Gautam (1):
  iommu/arm-smmu: Add support for qcom,smmu-v2 variant

 .../devicetree/bindings/iommu/arm,smmu.txt         | 42 ++++++++++++++++++++++
 drivers/iommu/arm-smmu.c                           | 13 ++++++-
 2 files changed, 54 insertions(+), 1 deletion(-)


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