linux-kernel - Re: [PATCH v16 0/5] iommu/arm-smmu: Add runtime pm/sleep support

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Message-ID: <CAFp+6iFzU3vG+HZ-7drNG7fyv6PY-W-9To5-rZeLo7M3p4=2rg@mail.gmail.com>
Date:   Mon, 1 Oct 2018 14:36:24 +0530
From:   Vivek Gautam <vivek.gautam@...eaurora.org>
To:     Will Deacon <will.deacon@....com>
Cc:     Mark Rutland <mark.rutland@....com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>, alex.williamson@...hat.com,
        Linux PM <linux-pm@...r.kernel.org>, sboyd@...nel.org,
        freedreno <freedreno@...ts.freedesktop.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        open list <linux-kernel@...r.kernel.org>,
        "list@....net:IOMMU DRIVERS <iommu@...ts.linux-foundation.org>, Joerg
        Roedel <joro@...tes.org>," <iommu@...ts.linux-foundation.org>,
        "robh+dt" <robh+dt@...nel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        Robin Murphy <robin.murphy@....com>,
        Ulf Hansson <ulf.hansson@...aro.org>
Subject: Re: [PATCH v16 0/5] iommu/arm-smmu: Add runtime pm/sleep support

Hi Will,

On Fri, Sep 28, 2018 at 7:27 PM Will Deacon <will.deacon@....com> wrote:
>
> Hi Vivek,
>
> On Thu, Aug 30, 2018 at 08:15:36PM +0530, Vivek Gautam wrote:
> > This series provides the support for turning on the arm-smmu's
> > clocks/power domains using runtime pm. This is done using
> > device links between smmu and client devices. The device link
> > framework keeps the two devices in correct order for power-cycling
> > across runtime PM or across system-wide PM.
> >
> > With addition of a new device link flag DL_FLAG_AUTOREMOVE_SUPPLIER [7],
> > the device links created between arm-smmu and its clients will be
> > automatically purged when arm-smmu driver unbinds from its device.
> >
> > As not all implementations support clock/power gating, we are checking
> > for a valid 'smmu->dev's pm_domain' to conditionally enable the runtime
> > power management for such smmu implementations that can support it.
> > Otherwise, the clocks are turned to be always on in .probe until .remove.
> > With conditional runtime pm now, we avoid touching dev->power.lock
> > in fastpaths for smmu implementations that don't need to do anything
> > useful with pm_runtime.
> > This lets us to use the much-argued pm_runtime_get_sync/put_sync()
> > calls in map/unmap callbacks so that the clients do not have to
> > worry about handling any of the arm-smmu's power.
> >
> > This series also adds support for Qcom's arm-smmu-v2 variant that
> > has different clocks and power requirements.
> >
> > Previous version of this patch series is @ [1].
> >
> > Build tested the series based on 4.19-rc1.
>
> I'm going to send my pull request to Joerg early next week (probably
> Monday), but I'm not keen to include this whilst it has outstanding comments
> from Ulf. Your errata workaround patch is in a similar situation, with
> outstanding comments from Robin.

I am going to address Ulf's comments for pm_runtime_force_suspend/resume()
calls in system sleep callbacks and respin the series unless he has any more
comments regarding the early/late nature of suspend/resume.
So will it do if I respin the series today after waiting for Ulf?

The workaround series is going for a discussion now, so i think it can wait.
Thanks

Best regards
Vivek
>
> Will
> _______________________________________________
> iommu mailing list
> iommu@...ts.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/iommu

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