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

From: Vivek Gautam <vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
To: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>
Cc: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
	<devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Archit Taneja <architt-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	Jordan Crouse <jcrouse-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
	Linux PM <linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	sboyd-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
	freedreno
	<freedreno-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>,
	Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>,
	"Rafael J. Wysocki" <rjw-LthD3rsA81gm4RdzfppkhA@public.gmane.org>,
	open list <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Tomasz Figa <tfiga-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	"list-Y9sIeH5OGRo@public.gmane.org:IOMMU DRIVERS
	<iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
	Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>,
	"
	<iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
	robh+dt <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Rob Clark <robdclark-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	linux-arm-msm
	<linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Sricharan R <sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>,
	Marek Szyprowski
	<m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
Subject: Re: [PATCH v16 2/5] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device
Date: Tue, 2 Oct 2018 09:44:54 +0530	[thread overview]
Message-ID: <CAFp+6iGkudBtZFfk4ST+k9OMRSGgU=pzVGC4QaSmPb+Xkdp3Xw@mail.gmail.com> (raw)
In-Reply-To: <20181001125854.GB31488-5wv7dgnIgG8@public.gmane.org>

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?

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

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