This series provides the support for turning on the arm-smmu's
clocks/power domains using runtime pm. This is done using
device links between smmu and client devices. The device link
framework keeps the two devices in correct order for power-cycling
across runtime PM or across system-wide PM.
With addition of a new device link flag DL_FLAG_AUTOREMOVE_SUPPLIER [7],
the device links created between arm-smmu and its clients will be
automatically purged when arm-smmu driver unbinds from its device.
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.
Otherwise, the clocks are turned to be always on in .probe until .remove.
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.
This series also adds support for Qcom's arm-smmu-v2 variant that
has different clocks and power requirements.
Previous version of this patch series is @ [1].
Build tested the series based on 4.19-rc1.
[v16]
* Addressed review comments from Rob about soc specific compatibles.
* Removed pm_runtime_get/put calls from arm_smmu_device_probe(), as
doing a runtime_get() eventually calls arm_smmu_device_reset().
arm_smmu_device_reset() should be called only after
arm_smmu_device_cfg_probe().
Enabling the clocks by default in the probe, and using
pm_runtime_set_active() as suggested by Tomasz to disable the
clocks when pm_runtime is enabled.
[v15]
* Added a list of valid values of '' in "qcom,-smmu-v2"
compatible string as pointed out by Robin, and Rob in the thread [8]:
* Added Srini's Tested-by.
* Separated out the dt-bindings change from driver change into a new
patch as suggested by new checkpatch warning.
Rob, I took the liberty of removing your Reviewed-by (for your
comment on '') for the new dt-bindings patch 4/5.
Please feel free to review it again. Thanks!
[v14]
* Moved arm_smmu_device_reset() from arm_smmu_pm_resume() to
arm_smmu_runtime_resume() so that the pm_resume callback calls
only runtime_resume to resume the device.
This should take care of restoring the state of smmu in systems
in which smmu lose register state on power-domain collapse.
[v13]
Addressing Rafael's comments:
* Added .suspend pm callback to disable the clocks in system wide suspend.
* Added corresponding clock enable in .resume pm callback.
* Explicitly enabling/disabling the clocks now when runtime PM is disabled.
* device_link_add() doesn't depend on pm_runtime_enabled() as we can
use device links across system suspend/resume too.
Addressing Robin's comments:
* Making device_link_add failures as non-fatal.
* Removed IOMMU_OF_DECLARE() declaration as we don't need this after Rob's
patch that removed all of these declarations.
[v12]
* Use new device link's flag introduced in [7] -
DL_FLAG_AUTOREMOVE_SUPPLIER. With this devices links are automatically
purged when arm-smmu driver unbinds.
* Using pm_runtime_force_suspend() instead of pm_runtime_disable() to
avoid following warning from arm_smmu_device_remove()
[295711.537507] [ cut here ]
[295711.544226] Unpreparing enabled smmu_mdp_ahb_clk
[295711.549099] WARNING: CPU: 0 PID: 1 at ../drivers/clk/clk.c:697
clk_core_unprepare+0xd8/0xe0
...
[295711.674073] Call trace:
[295711.679454] clk_core_unprepare+0xd8/0xe0
[295711.682059] clk_unprepare+0x28/0x40
[295711.685964] clk_bulk_unprepare+0x28/0x40
[295711.689701] arm_smmu_device_remove+0x88/0xd8
[295711.693692] arm_smmu_device_shutdown+0xc/0x18
[295711.698120] platform_drv_shutdown+0x20/0x30
[v11]
* Some more cleanups for device link. We don't need an explicit
delete for device link from the driver, but just set the flag
DL_FLAG_AUTOREMOVE.
device_link_add() API description says -
"If the DL_FLAG_AUTOREMOVE is set, the link will be removed
automatically when the consumer device driver unbinds."
* Addressed the comments for 'smmu' in arm_smmu_map/unmap().
* Dropped the patch [6] that introduced device_link_del_dev() API.
[v10]
* Introduce device_link_del_dev() API to delete the link between
given consumer and supplier devices. The users of device link
do not need to store link pointer to delete the link later.
They can straightaway use this API by passing consumer and
supplier devices.
* Made corresponding changes to arm-smmu driver patch handling the
device links.
* Dropped the patch [5] that was
