Message-ID: <vlvieye2nwrh77l74rxlusuc2cwos754b7c7a5hfrjl6eothsb@4xftv36j7utj>
Date: Fri, 21 Nov 2025 14:06:29 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Ekansh Gupta <ekansh.gupta@....qualcomm.com>
Cc: 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>, 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 Fri, Nov 21, 2025 at 01:28:09PM +0530, Ekansh Gupta wrote:
> 
> 
> 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. 

But this would test the signed binaries.

-- 
With best wishes
Dmitry

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