Re: [PATCH v16 2/5] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device

From: Vivek Gautam <vivek.gautam@codeaurora.org>
To: Will Deacon <will.deacon@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>, "robh+dt" <robh+dt@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	"list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>,
	Joerg Roedel <joro@8bytes.org>,"
	<iommu@lists.linux-foundation.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>,
	alex.williamson@redhat.com, Mark Rutland <mark.rutland@arm.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Rob Clark <robdclark@gmail.com>,
	Linux PM <linux-pm@vger.kernel.org>,
	freedreno <freedreno@lists.freedesktop.org>,
	sboyd@kernel.org, Tomasz Figa <tfiga@chromium.org>,
	Jordan Crouse <jcrouse@codeaurora.org>,
	Sricharan R <sricharan@codeaurora.org>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Archit Taneja <architt@codeaurora.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>
Subject: Re: [PATCH v16 2/5] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device
Date: Tue, 2 Oct 2018 10:58:31 +0530	[thread overview]
Message-ID: <CAFp+6iFpm05Uu8HkYCC+O+gYwFwvxirc6=e6oOed+ZJk6QLDPw@mail.gmail.com> (raw)
In-Reply-To: <CAFp+6iGkudBtZFfk4ST+k9OMRSGgU=pzVGC4QaSmPb+Xkdp3Xw@mail.gmail.com>

On Tue, Oct 2, 2018 at 9:44 AM Vivek Gautam <vivek.gautam@codeaurora.org> wrote:
>
> Hi Will,
>
> On Mon, Oct 1, 2018 at 6:29 PM Will Deacon <will.deacon@arm.com> wrote:
> >
> > Hi Vivek,
> >
> > On Thu, Aug 30, 2018 at 08:15:38PM +0530, Vivek Gautam wrote:
> > > From: Sricharan R <sricharan@codeaurora.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@codeaurora.org>
> > > [vivek: Cleanup pm runtime calls]
> > > Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
> > > Reviewed-by: Tomasz Figa <tfiga@chromium.org>
> > > Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.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

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