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

From: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>
To: Vivek Gautam <vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
Cc: mark.rutland-5wv7dgnIgG8@public.gmane.org,
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	alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
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	sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org,
	robin.murphy-5wv7dgnIgG8@public.gmane.org,
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Subject: Re: [PATCH v16 2/5] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device
Date: Mon, 1 Oct 2018 13:58:55 +0100	[thread overview]
Message-ID: <20181001125854.GB31488@arm.com> (raw)
In-Reply-To: <20180830144541.17740-3-vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>

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?

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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