On Fri, Mar 31, 2017 at 1:54 PM, Will Deacon <will.deacon@xxxxxxx> wrote: > On Thu, Mar 09, 2017 at 09:05:43PM +0530, Sricharan R 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 symmu's >> runtime to follow the master's runtime pm, so the smmu remains >> powered only when the masters use it. > > Do you have any numbers for the power savings you achieve with this? > How often do we actually manage to stop the SMMU clocks on an SoC with > a handful of masters? > > In other words, is this too coarse-grained to be useful, or is it common > that all the devices upstream of the SMMU are suspended? well, if you think about a phone/tablet with a command mode panel, pretty much all devices will be suspended most of the time ;-) maybe it's a different case with servers.. unfortunately we have to share the same driver across both.. BR, -R > Thanks, > > Will > >> >> Took some reference from the exynos runtime patches [2]. >> Tested this with MDP, GPU, VENUS devices on apq8096-db820c board. >> >> Previous version of the patchset [1]. >> >> [V3] >> * Reworked the patches to keep the clocks init/enabling function >> seperately 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/linux-arm-msm/msg23870.html >> [2] https://lkml.org/lkml/2016/10/20/70 >> [3] https://patchwork.kernel.org/patch/9389717/ >> >> Sricharan R (5): >> iommu/arm-smmu: Add pm_runtime/sleep ops >> iommu/arm-smmu: Add support for MMU40x/500 clocks >> drivers: arm-smmu: Add clock support for QCOM_SMMUV2 >> iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device >> iommu/arm-smmu: Add the device_link between masters and smmu >> >> .../devicetree/bindings/iommu/arm,smmu.txt | 35 +++ >> drivers/iommu/arm-smmu.c | 349 ++++++++++++++++++++- >> 2 files changed, 373 insertions(+), 11 deletions(-) >> >> -- >> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation >> > _______________________________________________ > iommu mailing list > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx > https://lists.linuxfoundation.org/mailman/listinfo/iommu -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
