Hi Robin, On 29.10.2020 16:34, Robin Murphy wrote: > A common idiom for .of_xlate is to use of_find_device_by_node() to > retrieve the relevant IOMMU instance data when translating IOMMU > specifiers for a client device. Although it's slightly roundabout, > this is simply looking up something we know exists - if it *were* > to return NULL, that would mean that no platform device is associated > with the given DT node, therefore the driver couldn't have probed > and called iommu_device_register() with the ops that .of_xlate was > called from in the first place. By construction, we can also assume > that the instance data for any registered IOMMU must be valid. > > This isn't necessarily obvious at first glance, though, so add some > comments to document these assumptions in-place. > > Suggested-by: Yu Kuai <yuku...@huawei.com> > Signed-off-by: Robin Murphy <robin.mur...@arm.com> > --- > drivers/iommu/arm/arm-smmu/qcom_iommu.c | 7 ++++--- > drivers/iommu/exynos-iommu.c | 15 ++++++--------- Acked-by: Marek Szyprowski <m.szyprow...@samsung.com> > drivers/iommu/ipmmu-vmsa.c | 13 ++++++------- > drivers/iommu/mtk_iommu.c | 8 ++++---- > drivers/iommu/rockchip-iommu.c | 5 ++++- > drivers/iommu/sun50i-iommu.c | 5 ++++- > 6 files changed, 28 insertions(+), 25 deletions(-) > > Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
_______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu