Message-ID: <d1d3c252-44e2-4e29-9aa2-7e789caf71b2@oss.qualcomm.com>
Date: Fri, 21 Nov 2025 14:12:33 +0530
From: Ekansh Gupta <ekansh.gupta@....qualcomm.com>
To: Nickolay Goppen <setotau@...nlining.org>,
        Konrad Dybcio <konrad.dybcio@....qualcomm.com>,
        Srinivas Kandagatla <srinivas.kandagatla@....qualcomm.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>
Cc: linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, ~postmarketos/upstreaming@...ts.sr.ht,
        linux@...nlining.org, Chenna Kesava Raju <chennak@....qualcomm.com>,
        Bharath Kumar <bkumar@....qualcomm.com>
Subject: Re: [PATCH v2 1/3] arm64: dts: qcom: sdm630/660: Add CDSP-related
 nodes



On 11/21/2025 1:48 PM, Nickolay Goppen wrote:
>
> 21.11.2025 11:11, Ekansh Gupta пишет:
>>
>> On 11/20/2025 5:17 PM, Konrad Dybcio wrote:
>>> On 11/20/25 11:54 AM, Ekansh Gupta wrote:
>>>> On 11/20/2025 1:27 PM, Nickolay Goppen wrote:
>>>>> 20.11.2025 07:55, Ekansh Gupta пишет:
>>>>>> On 11/20/2025 1:58 AM, Srinivas Kandagatla wrote:
>>>>>>> On 11/12/25 1:52 PM, Konrad Dybcio wrote:
>>>>>>>> On 11/10/25 6:41 PM, Srinivas Kandagatla wrote:
>>>>>>>>> On 11/3/25 12:52 PM, Konrad Dybcio wrote:
>>>>>>>>>> On 10/31/25 12:30 PM, Nickolay Goppen wrote:
>>>>>>>>>>> 24.10.2025 16:58, Nickolay Goppen пишет:
>>>>>>>>>>>> 24.10.2025 11:28, Konrad Dybcio пишет:
>>>>>>>>>>>>> On 10/23/25 9:51 PM, Nickolay Goppen wrote:
>>>>>>>>>>>>>> In order to enable CDSP support for SDM660 SoC:
>>>>>>>>>>>>>>     * add shared memory p2p nodes for CDSP
>>>>>>>>>>>>>>     * add CDSP-specific smmu node
>>>>>>>>>>>>>>     * add CDSP peripheral image loader node
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Memory region for CDSP in SDM660 occupies the same spot as
>>>>>>>>>>>>>> TZ buffer mem defined in sdm630.dtsi (which does not have CDSP).
>>>>>>>>>>>>>> In sdm660.dtsi replace buffer_mem inherited from SDM630 with
>>>>>>>>>>>>>> cdsp_region, which is also larger in size.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> SDM636 also doesn't have CDSP, so remove inherited from sdm660.dtsi
>>>>>>>>>>>>>> related nodes and add buffer_mem back.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Signed-off-by: Nickolay Goppen <setotau@...nlining.org>
>>>>>>>>>>>>>> ---
>>>>>>>>>>>>> [...]
>>>>>>>>>>>>>
>>>>>>>>>>>>>> +            label = "turing";
>>>>>>>>>>>>> "cdsp"
>>>>>>>>>>>> Ok, I'll change this in the next revision.
>>>>>>>>>>>>>> +            mboxes = <&apcs_glb 29>;
>>>>>>>>>>>>>> +            qcom,remote-pid = <5>;
>>>>>>>>>>>>>> +
>>>>>>>>>>>>>> +            fastrpc {
>>>>>>>>>>>>>> +                compatible = "qcom,fastrpc";
>>>>>>>>>>>>>> +                qcom,glink-channels = "fastrpcglink-apps-dsp";
>>>>>>>>>>>>>> +                label = "cdsp";
>>>>>>>>>>>>>> +                qcom,non-secure-domain;
>>>>>>>>>>>>> This shouldn't matter, both a secure and a non-secure device is
>>>>>>>>>>>>> created for CDSP
>>>>>>>>>>>> I've added this property, because it is used in other SoC's, such as SDM845 and SM6115 for both ADSP and CDSP
>>>>>>>>>>> Is this property not neccessary anymore?
>>>>>>>>>> +Srini?
>>>>>>>>> That is true, we do not require this for CDSP, as CDSP allows both
>>>>>>>>> unsigned and signed loading, we create both secured and non-secure node
>>>>>>>>> by default. May be we can provide that clarity in yaml bindings so that
>>>>>>>>> it gets caught during dtb checks.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> However in ADSP case, we only support singed modules, due to historical
>>>>>>>>> reasons how this driver evolved over years, we have this flag to allow
>>>>>>>>> compatiblity for such users.
>>>>>>>> Does that mean that we can only load signed modules on the ADSP, but
>>>>>>>> the driver behavior was previously such that unsigned modules were
>>>>>>>> allowed (which was presumably fine on devboards, but not on fused
>>>>>>>> devices)?
>>>>>>> Yes, its true that we allowed full access to adsp device nodes when we
>>>>>>> first started upstreaming fastrpc driver.
>>>>>>>
>>>>>>> irrespective of the board only signed modules are supported on the ADSP.
>>>>>>> I think there was one version of SoC i think 8016 or some older one
>>>>>>> which had adsp with hvx which can load unsigned modules for compute
>>>>>>> usecase only.
>>>>>>>
>>>>>>> I have added @Ekansh for more clarity.
>>>>>>>
>>>>>>> --srini
>>>>>> For all the available platforms, ADSP supports only signed modules. Unsigned
>>>>>> modules(as well as signed) are supported by CDSP and GDSP subsystems.
>>>>>>
>>>>>> qcom,non-secure-domain property marks the corresponding DSP as non-secure DSP.
>>>>>> The implications of adding this property would be the following:
>>>>>> on ADSP, SDSP, MDSP:
>>>>>> - Only non-secure device node(/dev/fastrpc-Xdsp) is created.
>>>>>> - Non-secure device node can be used for signed DSP PD offload.
>>>>>>
>>>>>> on CDSP, GDSP:
>>>>>> - Both secure(/dev/fastrpc-Xdsp-secure) and non-secure(/dev/fastrpc-Xdsp) devices
>>>>>>     are created, regardless of this property.
>>>>>> - Both the nodes can be used for signed and unsigned DSP PD offload.
>>>>>>
>>>>>> Note: If the property is not added for CDSP/GDSP, only secure device node can
>>>>>> be used for signed PD offload, if non-secure device is used, the request gets
>>>>>> rejected[1].
>>>>>>
>>>>>> [1] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/misc/fastrpc.c#n1245
>>>>>>
>>>>>> //Ekansh
>>>>> Does this mean that the qcom,non-secure-domain property should be dropped from both nodes?
>>>> I checked again and found that unsigned module support for CDSP is
>>>> not available on this platform. Given this, the safest approach would
>>>> be to add the property for both ADSP and CDSP, ensuring that all
>>>> created device nodes can be used for signed PD offload. I can provide
>>> The property allows *unsigned* PD offload though
>> I don't think I can directly relate this property to unsigned PD offload. This is just
>> defining what type of device node will be created and whether the channel is secure
>> or not. There is a possibility of making unsigned PD request(on CDSP/GDSP) irrespective
>> of whether this property is added or not. If DSP does not support unsigned offload, it
>> should return failures for such requests.
>>>> a more definitive recommendation once I know the specific use cases
>>>> you plan to run.
>>> Why would the usecase affect this?
>> I'm saying this as per past discussions where some application was relying on non-secure
>> device node on some old platform(on postmarketOS)[1] and having this property in place.
>> So if similar usecase is being enabled here, the property might be required[1].
>
> I'm testing these changes on postmarketOS. However, sensors aren't working through FastRPC on sdm660.
>
> Is it better to leave this property for both nodes? 
Yes, I would suggest to have it for both nodes here due to the previously provided reason.
>
>> [1] https://lkml.org/lkml/2024/8/15/117
>>> Konrad
>

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