linux-kernel - Re: [PATCH v2 00/10] Fix up icc clock rate calculation on some platforms

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Date:   Fri, 4 Aug 2023 19:31:11 +0300
From:   Georgi Djakov <djakov@...nel.org>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, quic_okukatla@...cinc.com
Cc:     Marijn Suijten <marijn.suijten@...ainline.org>,
        linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org
Subject: Re: [PATCH v2 00/10] Fix up icc clock rate calculation on some
 platforms

Hi Konrad,

On 31.07.23 13:52, Konrad Dybcio wrote:
> Certain platforms require that some buses (or individual nodes) make
> some additional changes to the clock rate formula, throwing in some
> magic, Qualcomm-defined coefficients, to account for "inefficiencies".

Maybe some links to the downstream code would help to better check and
understand this. Adding also Odelu in case he has any comments on the
patches.

Thanks,
Georgi

> Add the framework for it and utilize it on a couple SoCs.
> 
> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
> ---
> Changes in v2:
> - Use the (arguably less favourable but necessary for precission) 100/x
>    instead of x/100 for ib coefficient, update values in consequent
>    patches to reflect that
> - Rename "_percent" to "_coeff" because of /\
> - Add the necessary code to support per-node clocks
> - Add the necessary code to support per-node coefficients
> - Hook up the CPUSS<->GNoC clock on QCM2290
> - Update EBI node on QCM2290
> - Link to v1: https://lore.kernel.org/r/20230726-topic-icc_coeff-v1-0-31616960818c@linaro.org
> 
> ---
> Konrad Dybcio (10):
>        interconnect: qcom: icc-rpm: Add AB/IB calculations coefficients
>        interconnect: qcom: icc-rpm: Separate out clock rate calulcations
>        interconnect: qcom: icc-rpm: Let nodes drive their own bus clock
>        interconnect: qcom: icc-rpm: Check for node-specific rate coefficients
>        interconnect: qcom: qcm2290: Hook up MAS_APPS_PROC's bus clock
>        interconnect: qcom: qcm2290: Set AB coefficients
>        interconnect: qcom: qcm2290: Update EBI channel configuration
>        interconnect: qcom: sdm660: Set AB/IB coefficients
>        interconnect: qcom: msm8996: Set AB/IB coefficients
>        clk: qcom: smd-rpm: Move CPUSS_GNoC clock to interconnect
> 
>   drivers/clk/qcom/clk-smd-rpm.c             | 16 ++++--
>   drivers/interconnect/qcom/icc-rpm-clocks.c |  6 ++
>   drivers/interconnect/qcom/icc-rpm.c        | 92 ++++++++++++++++++++++++------
>   drivers/interconnect/qcom/icc-rpm.h        | 15 +++++
>   drivers/interconnect/qcom/msm8996.c        |  8 ++-
>   drivers/interconnect/qcom/qcm2290.c        |  9 ++-
>   drivers/interconnect/qcom/sdm660.c         |  4 ++
>   7 files changed, 124 insertions(+), 26 deletions(-)
> ---
> base-commit: ec89391563792edd11d138a853901bce76d11f44
> change-id: 20230726-topic-icc_coeff-b053d5409b9f
> 
> Best regards,