Hello,
On 2015-01-26 12:00, Joerg Roedel wrote:
Hi Laurent,
On Sun, Jan 25, 2015 at 05:38:22PM +0200, Laurent Pinchart wrote:
IOMMU groups still seem a bit unclear to me. Will Deacon has nicely explained
what they represent in
http://lists.infradead.org/pipermail/linux-arm-kernel/2014-December/310816.html.
The IOMMU core doesn't make groups
mandatory, but requires them in some code paths.
For example the coldplug device add function add_iommu_group() called for all
devices already registered when bus_set_iommu() is called will try to warn of
devices added multiple times with a WARN_ON(dev->iommu_group). Another example
is the iommu_bus_notifier() function which will call the remove_device()
operation only when dev->iommu_group isn't NULL.
I'm thus unsure whether groups should be made mandatory, or whether the IOMMU
core should be fixed to make them really optional (or, third option, whether
there's something I haven't understood properly).
My plan is to make IOMMU groups mandatory. I am currently preparing and
RFC patch-set to introduce default-domains (which will be per group). So
when all IOMMU drivers are converted to make use of default domains the
iommu groups will be mandatory.
Thanks for the comment, I will implement all that will be needed for it
to exynos
iommu driver, but I would like to ask if you plan to merge my existing
patches for
exynos iommu driver to your tree?
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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