[PATCH 0/2] iommu/qcom+msm: Use identity domain for display/GPU

[Rob Clark]

Similar to what is already done in arm-smmu-qcom, match display and GPU
compatible strings to pick identity domain type for them.

So far, we have an "evil twin" domain kicking around after drm/msm
attaches it's own domain.  Until now, that has been relatively harmless.
But it becomes a problem with [1] when we start using sg_dma_len()/
sg_dma_address() for setting up mappings.  Which is required to avoid
problems with CONFIG_DMABUF_DEBUG (dma_buf_wrap_sg_table()).

The first patch is at least compile tested.. msm_iommu seems to be
armv7-only.

If there are devices with bootloader splash, we may also need some
work on qcom_iommu_identity_attach() and/or msm_iommu_identity_attach()
to put the context bank into bypass instead of disabling it?  Not sure,
but that is probably going to require someone with such hardware at
hand.

[1] https://patchwork.freedesktop.org/series/175619/

Rob Clark (2):
  iommu/qcom: Use identity domain for GPU and display
  iommu/msm: Use identity domain for GPU and display

 drivers/iommu/arm/arm-smmu/qcom_iommu.c | 18 ++++++++++++++++++
 drivers/iommu/msm_iommu.c               | 16 ++++++++++++++++
 2 files changed, 34 insertions(+)

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2.56.0