[v6,0/5] Add support for QCOM Core Power Reduction

Message

Niklas Cassel Nov. 19, 2019, 3:46 p.m. UTC

This series adds support for Core Power Reduction (CPR), a form of
Adaptive Voltage Scaling (AVS), found on certain Qualcomm SoCs.

This series is based on top of the qcs404 cpufreq patch series that
hasn't landed yet:
https://patchwork.kernel.org/project/linux-arm-msm/list/?series=173423
as well as that series' matching device tree changes:
https://patchwork.kernel.org/project/linux-arm-msm/list/?series=165457

For testing purposes, this patch series, including the dependencies
listed above, is available on the following git tag:
https://git.linaro.org/people/niklas.cassel/kernel.git/log/?h=cpr-v6

CPR is a technology that reduces core power on a CPU or on other device.
It reads voltage settings from efuses (that have been written in
production), it uses these voltage settings as initial values, for each
OPP.

After moving to a certain OPP, CPR monitors dynamic factors such as
temperature, etc. and adjusts the voltage for that frequency accordingly
to save power and meet silicon characteristic requirements.

This driver has been developed together with Jorge Ramirez-Ortiz, and
is based on an RFC by Stephen Boyd[1], which in turn is based on work
by others on codeaurora.org[2].

[1] https://lkml.org/lkml/2015/9/18/833
[2] https://source.codeaurora.org/quic/la/kernel/msm-4.14/tree/drivers/regulator/cpr-regulator.c?h=msm-4.14

Changes since v5:
-Removed pm_ops from platform_driver struct.
 (This was embarrassingly not properly removed in previous patch revision.)

Niklas Cassel (5):
  dt-bindings: power: avs: Add support for CPR (Core Power Reduction)
  power: avs: Add support for CPR (Core Power Reduction)
  arm64: dts: qcom: qcs404: Add CPR and populate OPP table
  arm64: defconfig: enable CONFIG_QCOM_CPR
  arm64: defconfig: enable CONFIG_ARM_QCOM_CPUFREQ_NVMEM

 .../bindings/power/avs/qcom,cpr.txt           |  130 ++
 MAINTAINERS                                   |    8 +
 arch/arm64/boot/dts/qcom/qcs404.dtsi          |  132 +-
 arch/arm64/configs/defconfig                  |    2 +
 drivers/power/avs/Kconfig                     |   15 +
 drivers/power/avs/Makefile                    |    1 +
 drivers/power/avs/qcom-cpr.c                  | 1754 +++++++++++++++++
 7 files changed, 2034 insertions(+), 8 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/power/avs/qcom,cpr.txt
 create mode 100644 drivers/power/avs/qcom-cpr.c

Comments

Ulf Hansson Nov. 20, 2019, noon UTC | #1

On Tue, 19 Nov 2019 at 16:46, Niklas Cassel <[e-mail]> wrote:
>
> This series adds support for Core Power Reduction (CPR), a form of
> Adaptive Voltage Scaling (AVS), found on certain Qualcomm SoCs.
>
> This series is based on top of the qcs404 cpufreq patch series that
> hasn't landed yet:
> https://patchwork.kernel.org/project/linux-arm-msm/list/?series=173423
> as well as that series' matching device tree changes:
> https://patchwork.kernel.org/project/linux-arm-msm/list/?series=165457
>
> For testing purposes, this patch series, including the dependencies
> listed above, is available on the following git tag:
> https://git.linaro.org/people/niklas.cassel/kernel.git/log/?h=cpr-v6
>
> CPR is a technology that reduces core power on a CPU or on other device.
> It reads voltage settings from efuses (that have been written in
> production), it uses these voltage settings as initial values, for each
> OPP.
>
> After moving to a certain OPP, CPR monitors dynamic factors such as
> temperature, etc. and adjusts the voltage for that frequency accordingly
> to save power and meet silicon characteristic requirements.
>
> This driver has been developed together with Jorge Ramirez-Ortiz, and
> is based on an RFC by Stephen Boyd[1], which in turn is based on work
> by others on codeaurora.org[2].
>
> [1] https://lkml.org/lkml/2015/9/18/833
> [2] https://source.codeaurora.org/quic/la/kernel/msm-4.14/tree/drivers/regulator/cpr-regulator.c?h=msm-4.14
>
> Changes since v5:
> -Removed pm_ops from platform_driver struct.
>  (This was embarrassingly not properly removed in previous patch revision.)
>
> Niklas Cassel (5):
>   dt-bindings: power: avs: Add support for CPR (Core Power Reduction)
>   power: avs: Add support for CPR (Core Power Reduction)
>   arm64: dts: qcom: qcs404: Add CPR and populate OPP table
>   arm64: defconfig: enable CONFIG_QCOM_CPR
>   arm64: defconfig: enable CONFIG_ARM_QCOM_CPUFREQ_NVMEM
>
>  .../bindings/power/avs/qcom,cpr.txt           |  130 ++
>  MAINTAINERS                                   |    8 +
>  arch/arm64/boot/dts/qcom/qcs404.dtsi          |  132 +-
>  arch/arm64/configs/defconfig                  |    2 +
>  drivers/power/avs/Kconfig                     |   15 +
>  drivers/power/avs/Makefile                    |    1 +
>  drivers/power/avs/qcom-cpr.c                  | 1754 +++++++++++++++++
>  7 files changed, 2034 insertions(+), 8 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/power/avs/qcom,cpr.txt
>  create mode 100644 drivers/power/avs/qcom-cpr.c
>
> --
> 2.23.0
>

For the series (except patch 2 that I provided some comment for), feel
free to add:

Reviewed-by: Ulf Hansson <[e-mail]>

Kind regards
Uffe