Re: [PATCH v5 0/6] iommu/arm-smmu: Add runtime pm/sleep support

Rafael J. Wysocki
2018-01-09T11:24:38Z

On Tuesday, January 9, 2018 11:01:43 AM CET 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 the
> recently introduced device links patches, which lets the smmu's
> runtime to follow the master's runtime pm, so the smmu remains
> powered only when the masters use it.
>
> It also adds support for Qcom's arm-smmu-v2 variant that
> has different clocks and power requirements.
>
> Took some reference from the exynos runtime patches [2].
>
> Previous version of the patchset [1].
>
> After much discussion [4] over the use of pm_runtime_get/put() in
> .unmap op path for the arm-smmu, and after disussing over more than
> a couple of approaches to address this, we are putting forward the
> changes *without* using pm_runtime APIs in 'unmap'. Rather, letting
> the client device take the control of powering on/off the connected
> iommu through pm_runtime_get(put)_suppliers() APIs for the scnerios
> when the iommu power can't be directly controlled by clients through
> device links.
> Rafael has agreed to export the suppliers APIs [5].
>
> [V5]
> * Dropped runtime pm calls from "arm_smmu_unmap" op as discussed over
> the list [4] for the last patch series.
> * Added a patch to export pm_runtime_get/put_suppliers() APIs to the
> series as agreed with Rafael [5].
> * Added the related patch for msm drm iommu layer to use
> pm_runtime_get/put_suppliers() APIs in msm_mmu_funcs.
> * Dropped arm-mmu500 clock patch since that would break existing
> platforms.
> * Changed compatible 'qcom,msm8996-smmu-v2' to 'qcom,smmu-v2' to reflect
> the IP version rather than the platform on which it is used.
> The same IP is used across multiple platforms including msm8996,
> and sdm845 etc.
> * Using clock bulk APIs to handle the clocks available to the IP as
> suggested by Stephen Boyd.
> * The first patch in v4 version of the patch-series:
> ("iommu/arm-smmu: Fix the error path in arm_smmu_add_device") has
> already made it to mainline.
>
> [V4]
> * Reworked the clock handling part. We now take clock names as data
> in the driver for supported compatible versions, and loop over them
> to get, enable, and disable the clocks.
> * Using qcom,msm8996 based compatibles for bindings instead of a generic
> qcom compatible.
> * Refactor MMU500 patch to just add the necessary clock names data and
> corresponding bindings.
> * Added the pm_runtime_get/put() calls in .unmap iommu op (fix added by
> Stanimir on top of previous patch version.
> * Added a patch to fix error path in arm_smmu_add_device()
> * Removed patch 3/5 of V3 patch series that added qcom,smmu-v2 bindings.
>
> [V3]
> * Reworked the patches to keep the clocks init/enabling function
> separately for each compatible.
>
> * Added clocks bindings for MMU40x/500.
>
> * Added a new compatible for qcom,smmu-v2 implementation and
> the clock bindings for the same.
>
> * Rebased on top of 4.11-rc1
>
> [V2]
> * Split the patches little differently.
>
> * Addressed comments.
>
> * Removed the patch #4 [3] from previous post
> for arm-smmu context save restore. Planning to
> post this separately after reworking/addressing Robin's
> feedback.
>
> * Reversed the sequence to disable clocks than enabling.
> This was required for those cases where the
> clocks are populated in a dependent order from DT.
>
> [1] https://www.spinics.net/lists/arm-kernel/msg567488.html
> [2] https://lkml.org/lkml/2016/10/20/70
> [3] https://patchwork.kernel.org/patch/9389717/
> [4] https://patchwork.kernel.org/patch/9827825/
> [5] https://patchwork.kernel.org/patch/10102445/
>
> Sricharan R (3):
> iommu/arm-smmu: Add pm_runtime/sleep ops
> iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device
> iommu/arm-smmu: Add the device_link between masters and smmu
>
> Vivek Gautam (3):
> base: power: runtime: Export pm_runtime_get/put_suppliers
> iommu/arm-smmu: Add support for qcom,smmu-v2 variant
> drm/msm: iommu: Replace runtime calls with runtime suppliers
>
> .../devicetree/bindings/iommu/arm,smmu.txt | 35 ++++++
> drivers/base/power/runtime.c | 2 +
> drivers/gpu/drm/msm/msm_iommu.c | 16 +--
> drivers/iommu/arm-smmu.c | 124 ++++++++++++++++++++-
> 4 files changed, 163 insertions(+), 14 deletions(-)

I need some time to review the series.

Thanks,
Rafael