Re: [PATCH v3 0/8] clk: qcom: msm8996: add support for the CBF clock

[Konrad Dybcio <konrad.dybcio@linaro.org>]

On 20.01.2023 23:22, Simon Glass wrote:
> Hi Dmitry,
> 
> On Fri, 20 Jan 2023 at 15:18, Dmitry Baryshkov
> <dmitry.baryshkov@linaro.org> wrote:
>>
>> On 20/01/2023 17:08, Simon Glass wrote:
>>> Hi Dmitry,
>>>
>>> On Thu, 19 Jan 2023 at 23:14, Dmitry Baryshkov
>>> <dmitry.baryshkov@linaro.org> wrote:
>>>>
>>>> On MSM8996 two CPU clusters are interconnected using the Core Bus
>>>> Fabric (CBF). In order for the CPU clusters to function properly, it
>>>> should be clocked following the core's frequencies to provide adequate
>>>> bandwidth. On the other hand the CBF's clock rate can be used by other
>>>> drivers (e.g. by the pending SPDM driver to provide input on the CPU
>>>> performance).
>>>>
>>>> Thus register CBF as a clock (required for CPU to boot) and add a tiny
>>>> interconnect layer on top of it to let cpufreq/opp scale the CBF clock.
>>>>
>>>> Dependencies: [1]
>>>>
>>>> [1] https://lore.kernel.org/linux-arm-msm/20230111191453.2509468-1-dmitry.baryshkov@linaro.org/
>>>>
>>>> Changes since v2:
>>>> - Added interconnect-related bindings
>>>> - Switched CPU and CBF clocks to RPM_SMD_XO_A_CLK_SRC
>>>>
>>>> Changes since v1:
>>>> - Relicensed schema to GPL-2.0 + BSD-2-Clause (Krzysztof)
>>>> - Changed clock driver to use parent_hws (Konrad)
>>>> - Fixed indentation in CBF clock driver (Konrad)
>>>> - Changed MODULE_LICENSE of CBF clock driver to GPL from GPL-v2
>>>> - Switched CBF to use RPM_SMD_XO_CLK_SRC as one of the parents
>>>> - Enabled RPM_SMD_XO_CLK_SRC on msm8996 platform and switch to it from
>>>>    RPM_SMD_BB_CLK1 clock
>>>>
>>>> Dmitry Baryshkov (8):
>>>>    dt-bindings: clock: qcom,msm8996-cbf: Describe the MSM8996 CBF clock
>>>>      controller
>>>>    dt-bindints: interconnect/msm8996-cbf: add defines to be used by CBF
>>>>    clk: qcom: add msm8996 Core Bus Framework (CBF) support
>>>>    clk: qcom: cbf-msm8996: scale CBF clock according to the CPUfreq
>>>>    clk: qcom: smd-rpm: provide RPM_SMD_XO_CLK_SRC on MSM8996 platform
>>>>    arm64: qcom: dts: msm8996 switch from RPM_SMD_BB_CLK1 to
>>>>      RPM_SMD_XO_CLK_SRC
>>>>    arm64: dts: qcom: msm8996: add CBF device entry
>>>>    arm64: dts: qcom: msm8996: scale CBF clock according to the CPUfreq
>>>>
>>>>   .../bindings/clock/qcom,msm8996-cbf.yaml      |  53 ++
>>>>   arch/arm64/boot/dts/qcom/msm8996.dtsi         |  72 ++-
>>>>   drivers/clk/qcom/Makefile                     |   2 +-
>>>>   drivers/clk/qcom/clk-cbf-8996.c               | 458 ++++++++++++++++++
>>>>   drivers/clk/qcom/clk-smd-rpm.c                |   2 +
>>>>   .../interconnect/qcom,msm8996-cbf.h           |  12 +
>>>>   6 files changed, 591 insertions(+), 8 deletions(-)
>>>>   create mode 100644 Documentation/devicetree/bindings/clock/qcom,msm8996-cbf.yaml
>>>>   create mode 100644 drivers/clk/qcom/clk-cbf-8996.c
>>>>   create mode 100644 include/dt-bindings/interconnect/qcom,msm8996-cbf.h
>>>>
>>>> --
>>>> 2.39.0
>>>>
>>>
>>> Could you please tell me which dev board this is targeting and where I
>>> can get one?
>>
>> This is targeting db820c, which is available from arrow.com. Note, this
>> patchset is related only msm8996 aka Snapdragon 820, it has limited
>> applicability to msm8996-pro and is of no concern to most of other chipsets.
> 
> Thanks!
> 
>>
>>> Also could you please point me to the SoC documentation?
>>
>> https://developer.qualcomm.com/hardware/apq-8096sg/tools
> 
> Which doc has the register descriptions for I2C, etc.? I am not seeing it.
Not public.

Konrad
> 
> Regards,
> Simon