On 01/22/2018 12:09 PM, JeffyChen wrote:

Hi Randy,

On 01/22/2018 10:15 AM, JeffyChen wrote:

quoted

Hi Randy,

On 01/22/2018 09:18 AM, Randy Li wrote:

quoted

quoted

Also the power domain driver could manage the clocks as well, I would
suggest to use pm_runtime_*.

actually the clocks required by pm domain may not be the same as what we
want to control here, there might be some clocks only be needed when
accessing mmu registers.

but i'm not very sure about that, will confirm it with Simon Xue.

confirmed with Simon, there might be some iommus don't have a pd, and 

We use the pd to control the NIU node(not on upstream), without a pd or 
fake pd, none of the platform would work.

the CONFIG_PM could be disabled.I am hard to believe a modern platform can work without that.

so it might be better to control clocks in iommu driver itself.I won't insist how the version of the iommu patch on the upstream, I 

just post an idea here.
The version for kernel 4.4 is under internal review, the implementation 
has been modified many times.

I would suggest the managing clocks in pd is a more easy way and don't 
need to spare those thing in two places.

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-- 
Randy Li