linux-kernel - Re: [PATCH v6 07/11] arm64: dts: qcom: sm6115: Add Crypto Engine support

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Message-ID: <8c754bc2-abb3-faaa-0ab5-2c1991dfc2a6@linaro.org>
Date:   Fri, 19 May 2023 12:42:23 +0200
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Bhupesh Sharma <bhupesh.sharma@...aro.org>,
        Stephan Gerhold <stephan@...hold.net>
Cc:     linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        agross@...nel.org, linux-kernel@...r.kernel.org,
        linux-crypto@...r.kernel.org, andersson@...nel.org,
        bhupesh.linux@...il.com, krzysztof.kozlowski@...aro.org,
        robh+dt@...nel.org, vladimir.zapolskiy@...aro.org,
        rfoss@...nel.org, neil.armstrong@...aro.org, djakov@...nel.org
Subject: Re: [PATCH v6 07/11] arm64: dts: qcom: sm6115: Add Crypto Engine
 support



On 19.05.2023 12:22, Bhupesh Sharma wrote:
> Hi Stephan,
> 
> On Fri, 19 May 2023 at 15:40, Stephan Gerhold <stephan@...hold.net> wrote:
>>
>> Hi Bhupesh,
>>
>> Not sure if this is the latest version of this series since it's pretty
>> old but I didn't find a new one. Just came here because you mentioned
>> RB1/RB2 [1] in my bam_dma patch and they don't have any BAM defined
>> upstream yet.
>>
>> [1]: https://lore.kernel.org/linux-arm-msm/CAH=2Ntw0BZH=RGp14mYLhX7D6jV5O5eDKRQbby=uCy85xMDU_g@mail.gmail.com/
>>
>> On Wed, Apr 05, 2023 at 12:58:32PM +0530, Bhupesh Sharma wrote:
>>> Add crypto engine (CE) and CE BAM related nodes and definitions to
>>> 'sm6115.dtsi'.
>>>
>>> Signed-off-by: Bhupesh Sharma <bhupesh.sharma@...aro.org>
>>> ---
>>>  arch/arm64/boot/dts/qcom/sm6115.dtsi | 22 ++++++++++++++++++++++
>>>  1 file changed, 22 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/qcom/sm6115.dtsi b/arch/arm64/boot/dts/qcom/sm6115.dtsi
>>> index 2a51c938bbcb..ebac026b4cc7 100644
>>> --- a/arch/arm64/boot/dts/qcom/sm6115.dtsi
>>> +++ b/arch/arm64/boot/dts/qcom/sm6115.dtsi
>>> @@ -650,6 +650,28 @@ usb_hsphy: phy@...3000 {
>>>                       status = "disabled";
>>>               };
>>>
>>> +             cryptobam: dma-controller@...4000 {
>>> +                     compatible = "qcom,bam-v1.7.4", "qcom,bam-v1.7.0";
>>> +                     reg = <0x0 0x01b04000 0x0 0x24000>;
>>> +                     interrupts = <GIC_SPI 247 IRQ_TYPE_LEVEL_HIGH>;
>>> +                     #dma-cells = <1>;
>>> +                     qcom,ee = <0>;
>>> +                     qcom,controlled-remotely;
>>> +                     num-channels = <8>;
>>> +                     qcom,num-ees = <2>;
>>> +                     iommus = <&apps_smmu 0x94 0x11>,
>>> +                              <&apps_smmu 0x96 0x11>;
>>> +             };
>>> +
>>> +             crypto: crypto@...a000 {
>>> +                     compatible = "qcom,sm6115-qce", "qcom,sm8150-qce", "qcom,qce";
>>> +                     reg = <0x0 0x01b3a000 0x0 0x6000>;
>>> +                     dmas = <&cryptobam 6>, <&cryptobam 7>;
>>> +                     dma-names = "rx", "tx";
>>> +                     iommus = <&apps_smmu 0x94 0x11>,
>>> +                              <&apps_smmu 0x96 0x11>;
>>
>> Shouldn't you have clocks = <&rpmcc RPM_SMD_CE1_CLK> here to make sure
>> the clock for the crypto engine is on? Your binding patch (PATCH 06/11)
>> says "Crypto Engine block on Qualcomm SoCs SM6115 and QCM2290 do not
>> require clocks strictly" but doesn't say why.
>>
>> Make sure you don't rely on having rpmcc keep unused clocks on
>> permanently. This is the case at the moment, but we would like to change
>> this [2]. Adding new users that rely on this broken behavior would just
>> make this effort even more complicated.
>>
>> If you also add the clock to the cryptobam then you should be able to
>> see the advantage of my bam_dma patch [3]. It allows you to drop
>> "num-channels" and "qcom,num-ees" from the cryptobam in your changes
>> above because it can then be read directly from the BAM registers.
> 
> Thanks for pointing this out. Actually that's why I was using your
> patch while testing with RB1/RB2 :)
> 
> Yes, so the background is that I am preparing a new version of this
> crypto enablement patchset.
> Also your assumption about the clocks being turned on by the firmware
> is true for RB1/RB2 devices, so enabling them via Linux is optional as
> per Qualcomm enggs.
This is not necessarily true. Currently it's kept always-on on
by clk_smd_rpm_handoff, but that's a hack from 10 years ago when smd
was still new.

> 
> So, I am testing the new patchset right now with 'clock' entries
> provided in the .dtsi and see if that causes any issue / improvement
> (etc.)
It won't change since it's on anyway, but that won't be a given for long.

Konrad
> 
> Will come back with updates (and a new version of this patchset) soon.
> 
> Regards,
> Bhupesh
> 
>> Thanks,
>> Stephan
>>
>> [2]: https://lore.kernel.org/linux-arm-msm/20230303-topic-rpmcc_sleep-v2-0-ae80a325fe94@linaro.org/
>> [3]: https://lore.kernel.org/linux-arm-msm/20230518-bamclk-dt-v1-1-82f738c897d9@gerhold.net/