Re: [PATCHv7 0/3] QCOM smmu-500 wait-for-safe handling for sdm845

[Sai Prakash Ranjan]

On 2019-11-01 22:01, Will Deacon wrote:
> On Fri, Sep 20, 2019 at 01:34:26PM +0530, Sai Prakash Ranjan wrote:
> > Previous version of the patches are at [1]:
> >
> > QCOM's implementation of smmu-500 on sdm845 adds a hardware logic 
> > called
> > wait-for-safe. This logic helps in meeting the invalidation 
> > requirements
> > from 'real-time clients', such as display and camera. This 
> > wait-for-safe
> > logic ensures that the invalidations happen after getting an ack from 
> > these
> > devices.
> > In this patch-series we are disabling this wait-for-safe logic from 
> > the
> > arm-smmu driver's probe as with this enabled the hardware tries to
> > throttle invalidations from 'non-real-time clients', such as USB and 
> > UFS.
> >
> > For detailed information please refer to patch [3/4] in this series.
> > I have included the device tree patch too in this series for someone 
> > who
> > would like to test out this. Here's a branch [2] that gets display on 
> > MTP
> > SDM845 device.
> >
> > This patch series is inspired from downstream work to handle 
> > under-performance
> > issues on real-time clients on sdm845. In downstream we add separate 
> > page table
> > ops to handle TLB maintenance and toggle wait-for-safe in tlb_sync 
> > call so that
> > achieve required performance for display and camera [3, 4].
>
> What's the plan for getting this merged? I'm not happy taking the 
> firmware
> bits without Andy's ack, but I also think the SMMU changes should go 
> via
> the IOMMU tree to avoid conflicts.
>
> Andy?

Bjorn maintains QCOM stuff now if I am not wrong and he has already 
reviewed the firmware bits. So I'm hoping you could take all these 
through IOMMU tree.

-Sai

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