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Message-ID: <d4a14fb9-849c-4236-9ec1-538f2944fb02@quicinc.com>
Date: Thu, 25 Jan 2024 15:46:33 +0530
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Subject: Re: [PATCH v6 00/12] Unregister critical branch clocks + some RPM
Content-Language: en-US
To: Konrad Dybcio <konrad.dybcio@linaro.org>,
        Bjorn Andersson
	<andersson@kernel.org>,
        Andy Gross <agross@kernel.org>,
        Michael Turquette
	<mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>, Rob Herring
	<robh+dt@kernel.org>,
        Krzysztof Kozlowski
	<krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>
CC: Marijn Suijten <marijn.suijten@somainline.org>,
        <linux-arm-msm@vger.kernel.org>, <linux-clk@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        Johan Hovold
	<johan+linaro@kernel.org>,
        Bryan O'Donoghue <bryan.odonoghue@linaro.org>
References: <20230717-topic-branch_aon_cleanup-v6-0-46d136a4e8d0@linaro.org>
From: Taniya Das <quic_tdas@quicinc.com>
In-Reply-To: <20230717-topic-branch_aon_cleanup-v6-0-46d136a4e8d0@linaro.org>
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Hi Konrad,

Thanks for your patch.

On 1/13/2024 8:20 PM, Konrad Dybcio wrote:
> On Qualcomm SoCs, certain branch clocks either need to be always-on, or
> should be if you're interested in touching some part of the hardware.
> 
> Using CLK_IS_CRITICAL for this purpose sounds like a genius idea,
> however that messes with the runtime pm handling - if a clock is
> marked as such, the clock controller device will never enter the
> "suspended" state, leaving the associated resources online, which in
> turn breaks SoC-wide suspend.

I am really curious to know a little more about the SoC-Wide Suspend not 
happening on these targets. Could you add more details here ?

The Resource Power Manager (RPM) is the main aggregator on these targets 
where the active & sleep votes on XO, shared rails (CX/MX) decide the 
SoC wide suspend. The High Level OS on our internal platforms never had 
any suspend issues due to clocks(GCC/GPUCC) or shared rails being kept 
enabled from the consumers.

> 
> This series aims to solve that on a couple SoCs that I could test the
> changes on and it sprinkles some runtime pm enablement atop these drivers.
> 

As CX is a shared resource/rail on these specific targets we definitely 
do not achieve any power saving with the runtime pm attached to these 
clock controllers, but I see a little more SW overhead. Though you could 
please add your observations/comments.

Removing the CLK_IS_CRITICAL is a good cleanup and moving them to probe 
is a good way to handle the always-on clocks.


> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
> ---
> Changes in v6:
> - Rebase (next-20240112)
> - Reorder qcom_branch_set_clk_en calls by register in "*: Unregister
>    critical clocks" (Johan)
> - Pick up tags
> - Link to v5: https://lore.kernel.org/r/20230717-topic-branch_aon_cleanup-v5-0-99942e6bf1ba@linaro.org
> 
> Changes in v5:
> - Change the "Keep the critical clocks always-on" comment to "Keep
>    some clocks always-on"
> - Add the same comment to commits unregistering clocks on 6115/6375/2290
> - Link to v4: https://lore.kernel.org/r/20230717-topic-branch_aon_cleanup-v4-0-32c293ded915@linaro.org
> 
> Changes in v4:
> - Add and unify the "/* Keep the critical clocks always-on */" comment
> - Rebase (next-20231222), also include 8650, X1E and 8280camcc drivers
> - Drop enabling runtime PM on GCC
> - Improve the commit message of "clk: qcom: gpucc-sm6115: Add runtime PM"
> - Link to v3: https://lore.kernel.org/r/20230717-topic-branch_aon_cleanup-v3-0-3e31bce9c626@linaro.org
> 
> Changes in v3:
> - Rebase (next-20231219)
> - Fix up a copypaste mistake in "gcc-sm6375: Unregister critical clocks" (bod)
> - Pick up tags
> - Link to v2: https://lore.kernel.org/r/20230717-topic-branch_aon_cleanup-v2-0-2a583460ef26@linaro.org
> 
> Changes in v2:
> - Rebase
> - Pick up tags
> - Fix up missing pm_runtime_put in SM6375 GCC (Johan)
> - Clarify the commit message of "Add runtime PM" commits (Johan)
> - "GPU_CCC" -> "GPU_CC" (oops)
> - Rebase atop next-20231129
>    - Also fix up camcc-sm8550 & gcc-sm4450
>    - Unify and clean up the comment style
>    - Fix missing comments in gcc-sc7180..
>    - Drop Johan's ack from "clk: qcom: Use qcom_branch_set_clk_en()"
> - Improve 6115 dt patch commit message (Bjorn)
> - Link to v1: https://lore.kernel.org/r/20230717-topic-branch_aon_cleanup-v1-0-27784d27a4f4@linaro.org
> 
> ---
> Konrad Dybcio (12):
>        clk: qcom: branch: Add a helper for setting the enable bit
>        clk: qcom: Use qcom_branch_set_clk_en()
>        clk: qcom: gcc-sm6375: Unregister critical clocks
>        clk: qcom: gpucc-sm6375: Unregister critical clocks
>        clk: qcom: gpucc-sm6115: Unregister critical clocks
>        clk: qcom: gpucc-sm6115: Add runtime PM
>        clk: qcom: gcc-sm6115: Unregister critical clocks
>        clk: qcom: gcc-qcm2290: Unregister critical clocks
>        arm64: dts: qcom: sm6375: Add VDD_CX to GCC
>        arm64: dts: qcom: qcm2290: Add VDD_CX to GCC
>        arm64: dts: qcom: sm6115: Add VDD_CX to GCC
>        arm64: dts: qcom: sm6115: Add VDD_CX to GPU_CC
>  >   arch/arm64/boot/dts/qcom/qcm2290.dtsi |   1 +
>   arch/arm64/boot/dts/qcom/sm6115.dtsi  |   3 +
>   arch/arm64/boot/dts/qcom/sm6375.dtsi  |   1 +
>   drivers/clk/qcom/camcc-sc8280xp.c     |   6 +-
>   drivers/clk/qcom/camcc-sm8550.c       |  10 +--
>   drivers/clk/qcom/clk-branch.h         |   7 ++
>   drivers/clk/qcom/dispcc-qcm2290.c     |   4 +-
>   drivers/clk/qcom/dispcc-sc7280.c      |   7 +-
>   drivers/clk/qcom/dispcc-sc8280xp.c    |   4 +-
>   drivers/clk/qcom/dispcc-sm6115.c      |   4 +-
>   drivers/clk/qcom/dispcc-sm8250.c      |   4 +-
>   drivers/clk/qcom/dispcc-sm8450.c      |   7 +-
>   drivers/clk/qcom/dispcc-sm8550.c      |   7 +-
>   drivers/clk/qcom/dispcc-sm8650.c      |   4 +-
>   drivers/clk/qcom/gcc-qcm2290.c        | 106 +++--------------------------
>   drivers/clk/qcom/gcc-sa8775p.c        |  25 +++----
>   drivers/clk/qcom/gcc-sc7180.c         |  22 +++---
>   drivers/clk/qcom/gcc-sc7280.c         |  20 +++---
>   drivers/clk/qcom/gcc-sc8180x.c        |  28 +++-----
>   drivers/clk/qcom/gcc-sc8280xp.c       |  25 +++----
>   drivers/clk/qcom/gcc-sdx55.c          |  12 ++--
>   drivers/clk/qcom/gcc-sdx65.c          |  13 ++--
>   drivers/clk/qcom/gcc-sdx75.c          |  10 +--
>   drivers/clk/qcom/gcc-sm4450.c         |  28 +++-----
>   drivers/clk/qcom/gcc-sm6115.c         | 124 +++-------------------------------
>   drivers/clk/qcom/gcc-sm6375.c         | 105 +++-------------------------
>   drivers/clk/qcom/gcc-sm7150.c         |  23 +++----
>   drivers/clk/qcom/gcc-sm8250.c         |  19 ++----
>   drivers/clk/qcom/gcc-sm8350.c         |  20 +++---
>   drivers/clk/qcom/gcc-sm8450.c         |  21 +++---
>   drivers/clk/qcom/gcc-sm8550.c         |  21 +++---
>   drivers/clk/qcom/gcc-sm8650.c         |  16 ++---
>   drivers/clk/qcom/gcc-x1e80100.c       |  16 ++---
>   drivers/clk/qcom/gpucc-sc7280.c       |   9 +--
>   drivers/clk/qcom/gpucc-sc8280xp.c     |   9 +--
>   drivers/clk/qcom/gpucc-sm6115.c       |  53 ++++++---------
>   drivers/clk/qcom/gpucc-sm6375.c       |  34 ++--------
>   drivers/clk/qcom/gpucc-sm8550.c       |  10 +--
>   drivers/clk/qcom/lpasscorecc-sc7180.c |   7 +-
>   drivers/clk/qcom/videocc-sm8250.c     |   6 +-
>   drivers/clk/qcom/videocc-sm8350.c     |  10 +--
>   drivers/clk/qcom/videocc-sm8450.c     |  13 ++--
>   drivers/clk/qcom/videocc-sm8550.c     |  13 ++--
>   43 files changed, 234 insertions(+), 653 deletions(-)
> ---
> base-commit: 8d04a7e2ee3fd6aabb8096b00c64db0d735bc874
> change-id: 20230717-topic-branch_aon_cleanup-6976c13fe71c
> 
> Best regards,

-- 
Thanks & Regards,
Taniya Das.