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

Vivek Gautam
2018-01-09T10:02:09Z

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(-)