Hi Robin,

Thnaks for your reply.

On 01/11/2018 08:24 PM, Robin Murphy wrote:

Hi Jeffy,

On 11/01/18 11:14, JeffyChen wrote:

quoted

Hi Marek,

Thanks for your reply.

On 01/11/2018 05:40 PM, Marek Szyprowski wrote:

quoted

Hi Jeffy,

On 2018-01-11 09:22, Jeffy Chen wrote:

quoted

With the probe-deferral mechanism, early initialisation hooks are no
longer needed.

Suggested-by: Robin Murphy <robin.murphy@arm.com>

In fact, shortly after I said that I had a "how hard can it be?" moment
and took a crack at it myself - sorry, I should probably have cc'd you
on that series[1].

hmmm, i'll drop this patch in the next version.

and maybe rebase my patch[9] (iommu/rockchip: Use OF_IOMMU to attach 
devices automatically) on that series

quoted

quoted

quoted

Signed-off-by: Jeffy Chen <redacted>
---

  drivers/iommu/arm-smmu-v3.c  |  2 +-
  drivers/iommu/arm-smmu.c     | 12 ++++++------
  drivers/iommu/exynos-iommu.c |  2 +-

For Exynos IOMMU:
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>

IPMMU and MSM IOMMU are no longer multi-platform safe after this patch.
It breaks them in the same way as my commit 928055a01b3f ("iommu/exynos:
Remove custom platform device registration code") broke Exynos IOMMU.

You need a similar fix for them:
https://www.spinics.net/lists/arm-kernel/msg627648.html

hmmm, right, i did saw this fix in the rockchip iommu driver too.

and there're also some other iommu drivers put bus_set_iommu in their
probe() to avoid that.

maybe we can do it in the iommu framework?

for example:
1/ add a bus type member to struct iommu_device
2/ and a iommu_device_set_bus()
3/ do the bus_set_iommu stuff in iommu_device_register()
4/ undo bus_set_iommu in iommu_device_unregister()

Ultimately we'd like to get rid of the bus relationship altogether, so I
don't think it's really worth adding more infrastructure around it.
Having of-iommu-based drivers set bus ops at probe time, and others
conditionally from an initcall, is pretty clean and simple, so I'd
rather stick with that approach for now.

ok, make sense:)

Robin.

[1]
https://lists.linuxfoundation.org/pipermail/iommu/2018-January/025395.html