linux-kernel - Re: [PATCH v16 2/5] iommu/arm-smmu: Invoke pm

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Date:   Tue, 2 Oct 2018 10:58:31 +0530
From:   Vivek Gautam <vivek.gautam@...eaurora.org>
To:     Will Deacon <will.deacon@....com>
Cc:     Joerg Roedel <joro@...tes.org>, "robh+dt" <robh+dt@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        "list@....net:IOMMU DRIVERS <iommu@...ts.linux-foundation.org>, Joerg
        Roedel <joro@...tes.org>," <iommu@...ts.linux-foundation.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        alex.williamson@...hat.com, Mark Rutland <mark.rutland@....com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Rob Clark <robdclark@...il.com>,
        Linux PM <linux-pm@...r.kernel.org>,
        freedreno <freedreno@...ts.freedesktop.org>, sboyd@...nel.org,
        Tomasz Figa <tfiga@...omium.org>,
        Jordan Crouse <jcrouse@...eaurora.org>,
        Sricharan R <sricharan@...eaurora.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Archit Taneja <architt@...eaurora.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH v16 2/5] iommu/arm-smmu: Invoke pm_runtime during probe,
 add/remove device

On Tue, Oct 2, 2018 at 9:44 AM Vivek Gautam <vivek.gautam@...eaurora.org> wrote:
>
> Hi Will,
>
> On Mon, Oct 1, 2018 at 6:29 PM Will Deacon <will.deacon@....com> wrote:
> >
> > Hi Vivek,
> >
> > On Thu, Aug 30, 2018 at 08:15:38PM +0530, Vivek Gautam wrote:
> > > From: Sricharan R <sricharan@...eaurora.org>
> > >
> > > The smmu device probe/remove and add/remove master device callbacks
> > > gets called when the smmu is not linked to its master, that is without
> > > the context of the master device. So calling runtime apis in those places
> > > separately.
> > > Global locks are also initialized before enabling runtime pm as the
> > > runtime_resume() calls device_reset() which does tlb_sync_global()
> > > that ultimately requires locks to be initialized.
> > >
> > > Signed-off-by: Sricharan R <sricharan@...eaurora.org>
> > > [vivek: Cleanup pm runtime calls]
> > > Signed-off-by: Vivek Gautam <vivek.gautam@...eaurora.org>
> > > Reviewed-by: Tomasz Figa <tfiga@...omium.org>
> > > Tested-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
> > > ---
> > >  drivers/iommu/arm-smmu.c | 89 +++++++++++++++++++++++++++++++++++++++++++-----
> > >  1 file changed, 81 insertions(+), 8 deletions(-)
> >
> > This doesn't apply on my tree[1], possibly because I've got Robin's non-strict
> > invalidation queued there. However, that got me thinking -- how does this
> > work in conjunction with the timer-based TLB invalidation? Do we need to
> > rpm_{get,put} around flush_iotlb_all()? If so, do we still need the calls
> > in map/unmap when non-strict mode is in use?

For map/unmap(), i think there would be no harm in having additional
power.usage_count even for the non-strict mode.
So, I will just add rpm{get,put} in arm_smmu_flush_iotlb_all(), and
arm_smmu_iotlb_sync().

Regards
Vivek

>
> I haven't tested things with flush queues, but from what it looks like
> both .flush_iotlb_all, and .iotlb_sync callbacks need rpm_get/put().
> I will respin the patches.
>
> Thanks
> Vivek
> >
> > Will
> >
> > [1] https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=for-joerg/arm-smmu/updates
>
>
>
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation



-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation