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Subject[PATCH v9 0/5] iommu/arm-smmu: Add runtime pm/sleep support
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.
As not all implementations support clock/power gating, we are checking
for a valid 'smmu->dev's pm_domain' to conditionally enable the runtime
power management for such smmu implementations that can support it.

This series 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 [1].

With conditional runtime pm now, we avoid touching dev->power.lock
in fastpaths for smmu implementations that don't need to do anything
useful with pm_runtime.
This lets us to use the much-argued pm_runtime_get_sync/put_sync()
calls in map/unmap callbacks so that the clients do not have to
worry about handling any of the arm-smmu's power.

Previous version of this patch series is @ [5].

* Removed 'rpm_supported' flag, instead checking on pm_domain
to enable runtime pm.
* Creating device link only when the runtime pm is enabled, as we
don't need a device link besides managing the power dependency
between supplier and consumer devices.
* Introducing a patch to add device_link_find() API that finds
and existing link between supplier and consumer devices.
Also, made necessary change to device_link_add() to use this API.
* arm_smmu_remove_device() now uses this device_link_find() to find
the device link between smmu device and the master device, and then
delete this link.
* Dropped the destroy_domain_context() fix [8] as it was rather,
introducing catastrophically bad problem by destroying
'good dev's domain context.
* Added 'Reviwed-by' tag for Tomasz's review.

* Major change -
- Added a flag 'rpm_supported' which each platform that supports
runtime pm, can enable, and we enable runtime_pm over arm-smmu
only when this flag is set.
- Adding the conditional pm_runtime_get/put() calls to .map, .unmap
and .attach_dev ops.
- Dropped the patch [6] that exported pm_runtim_get/put_suupliers(),
and also dropped the user driver patch [7] for these APIs.

* Clock code further cleanup
- doing only clk_bulk_enable() and clk_bulk_disable() in runtime pm
callbacks. We shouldn't be taking a slow path (clk_prepare/unprepare())
from these runtime pm callbacks. Thereby, moved clk_bulk_prepare() to
arm_smmu_device_probe(), and clk_bulk_unprepare() to
- clk data filling to a common method arm_smmu_fill_clk_data() that
fills the clock ids and number of clocks.

* Addressed other nits and comments
- device_link_add() error path fixed.
- Fix for checking negative error value from pm_runtime_get_sync().
- Documentation redo.

* Added another patch fixing the error path in arm_smmu_attach_dev()
to destroy allocated domain context.

* Addressed review comments given by Robin Murphy -
- Added device_link_del() in .remove_device path.
- Error path cleanup in arm_smmu_add_device().
- Added pm_runtime_get/put_sync() in .remove path, and replaced
pm_runtime_force_suspend() with pm_runtime_disable().
- clk_names cleanup in arm_smmu_init_clks()
* Added 'Reviewed-by' given by Rob H.

* Added Ack given by Rafael to first patch in the series.
* Addressed Rob Herring's comment for adding soc specific compatible
string as well besides 'qcom,smmu-v2'.

* Dropped runtime pm calls from "arm_smmu_unmap" op as discussed over
the list [3] for the last patch series.
* Added a patch to export pm_runtime_get/put_suppliers() APIs to the
series as agreed with Rafael [4].
* 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
* 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.

* 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.

* 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

* Split the patches little differently.

* Addressed comments.

* Removed the patch #4 [2] from previous post
for arm-smmu context save restore. Planning to
post this separately after reworking/addressing Robin's

* 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.


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 (2):
driver core: Find an existing link between two devices
iommu/arm-smmu: Add support for qcom,smmu-v2 variant

.../devicetree/bindings/iommu/arm,smmu.txt | 42 +++++
drivers/base/core.c | 30 +++-
drivers/iommu/arm-smmu.c | 198 +++++++++++++++++++--
include/linux/device.h | 2 +
4 files changed, 259 insertions(+), 13 deletions(-)

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