Re: [PATCH v2 1/3] arm64: dts: qcom: sdm630/660: Add CDSP-related nodes

[Nickolay Goppen]

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@xxxxxxxxxxxxxx>
> > > > > > > > > > > ---
> > > > > > > > > > [...]
> > > > > > > > > >
> > > > > > > > > > > +            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


> //Ekansh
> > > > > Konrad

--
Best regards,
Nickolay