On Tue, Jan 24, 2012 at 10:57:01AM +0100, Hiroshi Doyu wrote:

quoted

Why do you completly ignore the size parameter in this function (and
in the unmap part below)?
According to the page-sizes you export to the generic layer size can be
4k or 4M. You need to take care of that in this function.

I'll drop 4MB support here once. I'll make another patch for 4MB page
support later.

Okay, so when you only export 4k everything should be fine.

quoted

Hmm, this looks like there is a 1-1 mapping between hardware SMMU
devices and domains. This is not consistent with IOMMU-API semantics
where a domain can contain devices behind different SMMUs. Please fix
that.

I'm a bit confused with the concept of "domain". I thought that
"domain" is equivalent to a "virtual address space". Usually a IOMMU
device provides a virtual address space for multiple client
devices. IOW, a IOMMU device provides a virtual address space, which
can be shared with multiple client devices.

Actually Tegra SMMU case, a single IOMMU device has 4 different
virtual address speace("smmu_as"). Each "smmu_as" has its own virtual
address space. "smmu_as[i]" has mutiple "smmu_client" devices.

  smmu_as[i] == domain[i]

I don't understand why "a domain can contain devices behind different
SMMUs" because those client devices belong to different virtual
address spaces, and they should belong to different "domains".

Could you please explain a bit more about "domain"?

A domain is, as you said, a virtual address space for IO devices. But
the important point is, an arbitrary number of devices can be part of a
domain. This also means that the devices can be behind different
hardware SMMUs. In this case your driver needs to program the page-table
pointer into more than one SMMU to give devices behind different SMMUs
the same address space.


	Joerg

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