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

[Sai Prakash Ranjan]

On 2019-11-01 22:55, Will Deacon wrote:
> On Fri, Nov 01, 2019 at 10:49:00PM +0530, Sai Prakash Ranjan wrote:
> > 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.
>
> Oh, I didn't realise that. Is there a MAINTAINERS update someplace? If 
> I
> run:
>
> $ ./scripts/get_maintainer.pl -f drivers/firmware/qcom_scm-64.c
>
> in linux-next, I get:
>
> Andy Gross <agross@xxxxxxxxxx> (maintainer:ARM/QUALCOMM SUPPORT)
> linux-arm-msm@xxxxxxxxxxxxxxx (open list:ARM/QUALCOMM SUPPORT)
> linux-kernel@xxxxxxxxxxxxxxx (open list)

It hasn't been updated yet then. I will leave it to Bjorn or Andy to 
comment on this.

-Sai

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