Message-ID: <d5972f14-6558-4e7a-9b1e-8e899ef72fcd@oss.qualcomm.com>
Date: Fri, 21 Nov 2025 13:28:09 +0530
From: Ekansh Gupta <ekansh.gupta@....qualcomm.com>
To: Nickolay Goppen <setotau@...nlining.org>,
        Srinivas Kandagatla <srinivas.kandagatla@....qualcomm.com>,
        Konrad Dybcio <konrad.dybcio@....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 11/20/2025 4:52 PM, Nickolay Goppen wrote:
> 20.11.2025 13:54, Ekansh Gupta пишет:
>>
>> 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
>> a more definitive recommendation once I know the specific use cases
>> you plan to run.
>
> It would be nice to have some testing instructions or how-to, something simple as "hello world" to be able to test it, to see if it works at all 
There are some test pre-builts available here along with how-to instructions:
https://github.com/qualcomm/fastrpc/tree/development/test

You can try running calculator from here for basic offload testing. 
>
>
>> //Ekansh
>>>>>> Konrad
>

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