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

From: Jordan Crouse <jcrouse@codeaurora.org>
To: Will Deacon <will@kernel.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: Mon, 13 Jul 2020 13:13:10 -0600	[thread overview]
Message-ID: <20200713191310.GD3815@jcrouse1-lnx.qualcomm.com> (raw)
In-Reply-To: <20200713190331.GA3444@willie-the-truck>

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.

Jordan

> Will
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> Freedreno mailing list
> Freedreno@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/freedreno

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