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

[Konrad Dybcio <konrad.dybcio@linaro.org>]

On 31.03.2023 15:14, Dylan Van Assche wrote:
> 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?
Yep, let's not stray into the unknown..

Konrad
> 
>> 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
>