Re: [Freedreno] [PATCH] iommu/arm-smmu: Add a init_context_bank implementation hook

From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Will Deacon <will@kernel.org>, Jordan Crouse <jcrouse@codeaurora.org>
Cc: linux-arm-msm@vger.kernel.org,
	Robin Murphy <robin.murphy@arm.com>,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	freedreno@lists.freedesktop.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [Freedreno] [PATCH] iommu/arm-smmu: Add a init_context_bank implementation hook
Date: Tue, 14 Jul 2020 10:07:56 +0530	[thread overview]
Message-ID: <928c0e7a22e9b193774b1e35fbe98762@codeaurora.org> (raw)
In-Reply-To: <20200713191310.GD3815@jcrouse1-lnx.qualcomm.com>

On 2020-07-14 00:43, Jordan Crouse wrote:
> On Mon, Jul 13, 2020 at 08:03:32PM +0100, Will Deacon wrote:
>> On Mon, Jul 13, 2020 at 11:00:32AM -0600, Jordan Crouse wrote:
>> > On Mon, Jul 13, 2020 at 04:11:23PM +0100, Will Deacon wrote:
>> > > On Thu, Jun 11, 2020 at 04:36:56PM -0600, Jordan Crouse wrote:
>> > > > Add a new implementation hook to allow the implementation specific code
>> > > > to tweek the context bank configuration just before it gets written.
>> > > > The first user will be the Adreno GPU implementation to turn on
>> > > > SCTLR.HUPCF to ensure that a page fault doesn't terminating pending
>> > > > transactions. Doing so could hang the GPU if one of the terminated
>> > > > transactions is a CP read.
>> > > >
>> > > > This depends on the arm-smmu adreno SMMU implementation [1].
>> > > >
>> > > > [1] https://patchwork.kernel.org/patch/11600943/
>> > > >
>> > > > Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
>> > > > ---
>> > > >
>> > > >  drivers/iommu/arm-smmu-qcom.c | 13 +++++++++++++
>> > > >  drivers/iommu/arm-smmu.c      | 28 +++++++++++++---------------
>> > > >  drivers/iommu/arm-smmu.h      | 11 +++++++++++
>> > > >  3 files changed, 37 insertions(+), 15 deletions(-)
>> > >
>> > > This looks straightforward enough, but I don't want to merge this without
>> > > a user and Sai's series has open questions afaict.
>> >
>> > Not sure what you mean by a user in this context?
>> > Are you referring to https://patchwork.kernel.org/patch/11628541/?
>> 
>> Right, this post was just a single patch in isolation, whereas it was
>> reposted over at:
>> 
>> https://lore.kernel.org/r/cdcc6a1c95a84e774790389dc8b3b7feeee490dc.1593344119.git.saiprakash.ranjan@codeaurora.org
>> 
>> so I'll ignore this one. Sorry, I'm just really struggling to keep 
>> track
>> of what is targetting 5.9, and I don't have tonnes of time to sift 
>> through
>> the backlog of duplicate postings :(
> 
> Yeah, that is our fault. There are too many cooks in the kitchen.
> 
> We need to pick either system cache or split pagetable and serialize
> the other on top of it to get the impl code going and then build from 
> there.
> This particular patch can happily hang out in the background until the 
> rest is
> resolved.
> 

My bad, sorry. Let us get split pagetable support reviewed first, then I 
can post
system cache support on top of it. As jordan said, this patch can 
hibernate until
those get resolved.

Thanks,
Sai

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