Re: [PATCH v3 2/4] dts: arm64: qcom: sdm845: add SLPI FastRPC support

[Dylan Van Assche <me@dylanvanassche.be>]

On Fri, 2023-03-31 at 14:20 +0200, Konrad Dybcio wrote:
> 
> 
> On 31.03.2023 11:36, Dylan Van Assche wrote:
> > Hi Konrad,
> > 
> > On Fri, 2023-03-31 at 04:03 +0200, Konrad Dybcio wrote:
> > > 
> > > 
> > > On 30.03.2023 18:53, Dylan Van Assche wrote:
> > > > Qualcomm SDM845 SoC features a SLPI DSP which uses FastRPC
> > > > through
> > > > an allocated memory region to load files from the host
> > > > filesystem
> > > > such as sensor configuration files.
> > > > 
> > > > Add a FastRPC node at /dev/fastrpc-sdsp and a DMA region,
> > > > similar
> > > > to
> > > > downstream, to allow userspace to communicate with the SLPI via
> > > > the
> > > > FastRPC interface for initializing the sensors on the SLPI.
> > > > 
> > > > Signed-off-by: Dylan Van Assche <me@dylanvanassche.be>
> > > > ---
> > > >  arch/arm64/boot/dts/qcom/sdm845.dtsi | 24
> > > > ++++++++++++++++++++++++
> > > >  1 file changed, 24 insertions(+)
> > > > 
> > > > diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi
> > > > b/arch/arm64/boot/dts/qcom/sdm845.dtsi
> > > > index 3b547cb7aeb8..8ea4944f3ad6 100644
> > > > --- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
> > > > +++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
> > > > @@ -878,6 +878,14 @@ mdata_mem: mpss-metadata {
> > > >                         size = <0 0x4000>;
> > > >                         no-map;
> > > >                 };
> > > > +
> > > > +               fastrpc_mem: fastrpc {
> > > > +                       compatible = "shared-dma-pool";
> > > > +                       reusable;
> > > Please move it last to get a nice reverse-Christmas-tree layout.
> > > 
> > 
> > Will fix in v4.
> > 
> > > > +                       alloc-ranges = <0 0x00000000 0
> > > > 0xffffffff>;
> > > Would there be any issues with it starting over (1<<31 - 1)?
> > > 
> > 
> > You mean a bigger region then, like the whole CMA region then?
> > AFAIK,
> > the SLPI always use the same region expecting it to be in this
> > range.
> > However, I cannot confirm more, as I have no insights in the
> > firmware
> > running on there, this all comes from finding out what it exactly
> > does
> > on downstream.
> I was asking about the <.. 0 0xfff.f> part specifically, as that
> means
> it can't be allocated above 4 gigs. But I guess it's just how qcom
> envisioned it.
> 

I think it is limited by qcom, but I cannot be entirely sure :)
In any case, for v4, do I keep 0xffffffff?

> Also, please use 0x0 in alloc-ranges as well, this is all addresses/
> reg sizes.
> 
> Konrad

Yes, will use 0x0 instead of 0.

Dylan

> > 
> > > > +                       alignment = <0 0x400000>;
> > > Please use 0x0 for the 0 here, as it's essentially reg.size with
> > > size-cells = 2
> > 
> > Will fix in v4.
> > 
> > > 
> > > > +                       size = <0 0x1000000>;
> > > Ditto
> > 
> > Will fix in v4.
> > 
> > > 
> > > > +               };
> > > >         };
> > > >  
> > > >         adsp_pas: remoteproc-adsp {
> > > > @@ -3344,6 +3352,22 @@ glink-edge {
> > > >                                 label = "dsps";
> > > >                                 qcom,remote-pid = <3>;
> > > >                                 mboxes = <&apss_shared 24>;
> > > > +
> > > > +                               fastrpc {
> > > > +                                       compatible =
> > > > "qcom,fastrpc";
> > > > +                                       qcom,glink-channels =
> > > > "fastrpcglink-apps-dsp";
> > > > +                                       label = "sdsp";
> > > > +                                       qcom,non-secure-domain;
> > > > +                                       qcom,vmids = <0x3 0xF
> > > > 0x5
> > > > 0x6>;
> > > Please use the recently-introduced header and depend on (and
> > > make a patch atop)
> > > 
> > > https://lore.kernel.org/linux-arm-msm/8685b710-b74d-556a-815d-0ffef2b0eeff@linaro.org/T/#t
> > > 
> > > Konrad
> > > 
> > > > +                                       memory-region =
> > > > <&fastrpc_mem>;
> > > > +                                       #address-cells = <1>;
> > > > +                                       #size-cells = <0>;
> > > > +
> > > > +                                       compute-cb@0 {
> > > > +                                               compatible =
> > > > "qcom,fastrpc-compute-cb";
> > > > +                                               reg = <0>;
> > > > +                                       };
> > > > +                               };
> > > >                         };
> > > >                 };
> > > >  
> > 
> > Kind regards,
> > Dylan