netdev - Re: [RFC PATCH 06/11] iommu: arm-smmu: Remove Calxeda secure mode quirk

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Message-ID: <20200228102556.1dde016e@donnerap.cambridge.arm.com>
Date:   Fri, 28 Feb 2020 10:25:56 +0000
From:   Andre Przywara <andre.przywara@....com>
To:     Will Deacon <will@...nel.org>
Cc:     Rob Herring <robh@...nel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        soc@...nel.org, Robert Richter <rrichter@...vell.com>,
        Jon Loeliger <jdl@....com>, Alexander Graf <graf@...zon.com>,
        Matthias Brugger <mbrugger@...e.com>,
        Mark Langsdorf <mlangsdo@...hat.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        Borislav Petkov <bp@...en8.de>,
        Cornelia Huck <cohuck@...hat.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        "David S. Miller" <davem@...emloft.net>,
        devicetree@...r.kernel.org, Eric Auger <eric.auger@...hat.com>,
        Linux IOMMU <iommu@...ts.linux-foundation.org>,
        James Morse <james.morse@....com>,
        Jens Axboe <axboe@...nel.dk>, Joerg Roedel <joro@...tes.org>,
        kvm@...r.kernel.org, linux-clk <linux-clk@...r.kernel.org>,
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        <linux-ide@...r.kernel.org>,
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        Mauro Carvalho Chehab <mchehab@...nel.org>,
        netdev <netdev@...r.kernel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Robin Murphy <robin.murphy@....com>,
        Stephen Boyd <sboyd@...nel.org>,
        Tony Luck <tony.luck@...el.com>,
        Viresh Kumar <viresh.kumar@...aro.org>
Subject: Re: [RFC PATCH 06/11] iommu: arm-smmu: Remove Calxeda secure mode
 quirk

On Fri, 28 Feb 2020 10:04:47 +0000
Will Deacon <will@...nel.org> wrote:

Hi,

> On Tue, Feb 25, 2020 at 04:01:54PM -0600, Rob Herring wrote:
> > On Tue, Feb 18, 2020 at 11:20 AM Will Deacon <will@...nel.org> wrote:  
> > >
> > > On Tue, Feb 18, 2020 at 11:13:16AM -0600, Rob Herring wrote:  
> > > > Cc: Will Deacon <will@...nel.org>
> > > > Cc: Robin Murphy <robin.murphy@....com>
> > > > Cc: Joerg Roedel <joro@...tes.org>
> > > > Cc: iommu@...ts.linux-foundation.org
> > > > Signed-off-by: Rob Herring <robh@...nel.org>
> > > > ---
> > > > Do not apply yet.  
> > >
> > > Pleeeeease? ;)
> > >  
> > > >  drivers/iommu/arm-smmu-impl.c | 43 -----------------------------------
> > > >  1 file changed, 43 deletions(-)  
> > >
> > > Yes, I'm happy to get rid of this. Sadly, I don't think we can remove
> > > anything from 'struct arm_smmu_impl' because most implementations fall
> > > just short of perfect.
> > >
> > > Anyway, let me know when I can push the button and I'll queue this in
> > > the arm-smmu tree.  
> > 
> > Seems we're leaving the platform support for now, but I think we never
> > actually enabled SMMU support. It's not in the dts either in mainline
> > nor the version I have which should be close to what shipped in
> > firmware. So as long as Andre agrees, this one is good to apply.  
> 
> Andre? Can I queue this one for 5.7, please?

I was wondering how much of a pain it is to keep it in? AFAICS there are other users of the "impl" indirection. If those goes away, I would be happy to let Calxeda go.
But Eric had the magic DT nodes to get the SMMU working, and I used that before, with updating the DT either on flash or dynamically via U-Boot.

So I don't know exactly *how* desperate you are with removing this, or if there are other reasons than "negative diffstat", but if possible I would like to keep it in.

Cheers,
Andre.