Re: [PATCH v5 5/6] arm64: dts: qcom: Add support for QCS9075 Ride & Ride-r3

[Krzysztof Kozlowski]

On 06/03/2025 09:17, Wasim Nazir wrote:
> On Mon, Mar 03, 2025 at 08:46:55AM +0100, Krzysztof Kozlowski wrote:
>> On 27/02/2025 08:37, Wasim Nazir wrote:
>>> On Wed, Jan 15, 2025 at 09:35:34AM +0100, Krzysztof Kozlowski wrote:
>>>> On 15/01/2025 06:48, Wasim Nazir wrote:
>>>>>> The the SoC, I am asking about the board. Why each of them is for
>>>>>> example r3?
>>>>>>
>>>>>> So this is not sufficient explanation, nothing about the board, and
>>>>>> again just look Renesas and NXP.
>>>>>>
>>>>>
>>>>> Hi Krzysztof,
>>>>>
>>>>> sa8775p(AUTO), qcs9100(IOT), qcs9075(IOT) are different SoCs based on
>>>>> safety capabilities and memory map, serving different purpose.
>>>>> Ride & Ride-r3 are different boards based on ethernet capabilities and
>>>>> are compatible with all the SoCs mentioned.
>>>>
>>>
>>> Hi Krzysztof,
>>>
>>>> Compatible? What does it mean for a board?
>>>>
>>>
>>> Ride board is based on multiple daughter cards (SOC-card, display,
>>> camera, ethernet, pcie, sensor, etc.).
>>>
>>> The SOC is not directly soldered to Ride board, instead SOC is soldered
>>> on SIP (System in Package) card which can be mounted on SOC-daughter card of
>>> Ride board.
>>> 	- SoC => SIP-card => SOC-daughter-card (Ride)
>>
>>
>> So basically pretty like other designs using SoM.
>>
>>>
>>> Together with SIP cards and other daughter cards we are creating different
>>> <soc>-Ride Variants with differences in memory map & thermal mitigations.
>>>
>>> The SIP card consists of SOC, PMIC & DDR and it is pin compatible to the
>>> SOC daughter card of <soc>-Ride board. Only SOC is changing accross SIP
>>> cards, except an additional third party SIL-PMIC for SAIL, which is not
>>> present in QCS9075 Ride.
>>
>> Just like every SoM
>>
>>>
>>> Other daughter cards remains same for <soc>-Ride variants, except
>>> ethernet card which is different for <soc>-Ride rev3 variants.
>>>
>>> So the Ride board (combination of daughter cards) is same across the SIP,
>>> while SOC on SIP card is changing which can be sa8775p, qcs9100 or qcs9075.
>>>
>>>> Third time: did you look how other vendors do it?
>>>>
>>>
>>> Yes, we have reviewed other vendors. However, please feel free to share
>>> any specific reference you would like us to follow.
>>>
>>> Here are few reference files we found from other vendors where similar
>>> tasks are performed which includes code refactoring and HW modularity:
>>>  - Freescale: fsl-ls208xa.dtsi, fsl-ls2088a.dtsi, fsl-ls2081a-rdb.dts
>>
>> That's an unexpected choice - I would rather look at dozen of SoMs for
>> iMX platforms.
>>
>>>  - Renesas: white-hawk-common.dtsi, r8a779g0-white-hawk.dts
>>>  - Rockchip: px30-engicam-common.dtsi, px30-engicam-ctouch2.dtsi,
>>>    px30-engicam-px30-core-ctouch2.dts
>>>
>>> In our case along with describing the HW, code refactoring is also done
>>> which might be causing confusion, but we are ready for any inputs for
>>> correction.
>>
>> I don't understand why this was not properly described since beginning.
>> You had the hardware in your hands and went with incomplete or even
>> incorrect hardware description.
>>
>>>
>>> Putting this pictorial diagram for updated DT structure depicting our HW.
>>>  - qcs9xxx-module.dtsi specifying QCS9xxx based SIP card/module having
>>>    SoC, PMICs, Memory-map updates.
>>>  - qcom-ride-common.dtsi specifying ride daughter boards, here we are
>>>    doing code refactoring also as this is common for all ride boards.
>>>  - qcom-ride-ethernet-aqr115c.dtso specifying ethernet overlay board which
>>>    uses 2.5G phy and can be overlayed to ride boards to get ride-r3.
>>>    By default ride uses 1G phy.
>>>  - qcs9075-iq-9075-evk.dts is the new name for RB8 as per new product
>>>    name. We will be changing this in next patch series.
>>>
>>> +-----------------------------------------------------------------------------------------------------------------------------------------------+
>>> |                                                                                                                                               |
>>> |                                                          sa8775p.dtsi                                                                         |
>>> |                                                              |                                                                                |
>>> |                                    +-------------------------+-----------------------+                                                        |
>>> |                                    |                         |                       |                                                        |
>>> |                                    v                         |                       v                                                        |
>>> |                             qcs9075-module.dtsi              |                qcs9100-module.dtsi                                             |
>>
>> So this is the SoM?
> 
> Yes this is SoM.
> 
>>
>>> |                                    |                         |                       |                                                        |
>>> |                                    v                         v                       v                                                        |
>>> |                                  (IOT)                    (AUTO)                   (IOT)                                                      |
>>> |                                    |                         |                       |                                                        |
>>> |             +----------------------+                         |                       |                                                        |
>>> |             |                      |                         |                       |                                                        |
>>> |             |                      | +-------------------------+-----------------------+-------------------< qcom-ride-common.dtsi            |
>>
>> Which piece of actual hardware is represented in qcom-ride-common?
>>
> 
> All daughter cards like SOC-card, display, camera, ethernet, pcie, sensor, etc.

No, I asked about the name of the hardware, datasheet, ID or picture.
Common DTSI represents somoething, not just because you wanted to add
something you had in downstream.


> 
>>> |             |                      | |                       | |                     | |                                                      |
>>> |             v                      v v                       v v                     v v                                                      |
>>> |  qcs9075-iq-9075-evk.dts     qcs9075-ride.dts         sa8775p-ride.dts         qcs9100-ride.dts                                               |
>>> |                                    |                         |                       |                                                        |
>>> |                                    | +-------------------------+-----------------------+-------------------< qcom-ride-ethernet-aqr115c.dtso  |
>>> |                                    | |                       | |                     | |                                                      |
>>> |                                    v v                       v v                     v v                                                      |
>>> |                             qcs9075-ride-r3.dts      sa8775p-ride-r3.dts      qcs9100-ride-r3.dts                                             |
>>
>> I think I gave already few times that answer: No. You cannot reference
>> from a module.c another .c file. You cannot reference DTS from DTS.
>>
>> Strictly speaking you can, of course, but you must not. That's not how
>> source code is done to be manageable and readable.
> 
> Ah the arrow is leading to confusion.
> 
> Actually we are not including dts here instead *.dtso file will be
> overlayed to *-ride.dts to generate *-ride-r3.dts.
> 
> Below is the correct arrow sequence.

And the overlay represents what exactly? Different board? No, that's not
how overlays should be used.

You have different board, you have different DTS.


> 
> |  qcs9075-iq-9075-evk.dts     qcs9075-ride.dts         sa8775p-ride.dts         qcs9100-ride.dts                                               |
> |                                    |                         |                       |                                                        |
> |                                    +-------------------------+-----------------------+---------------------< qcom-ride-ethernet-aqr115c.dtso  |
> |                                    |                         |                       |                                                        |
> |                                    v                         v                       v                                                        |
> |                             qcs9075-ride-r3.dts      sa8775p-ride-r3.dts      qcs9100-ride-r3.dts                                             |
> 
>>
>>> |                                                                                                                                               |
>>> +-----------------------------------------------------------------------------------------------------------------------------------------------+
>>>
>>>>>
>>>>> With the combination of these 3 SoCs and 2 boards, we have 6 platforms,
>>>>> all of which we need.
>>>>> - sa8775p-ride.dts is auto grade Ride platform with safety feature.
>>>>> - qcs9100-ride.dts is IOT grade Ride platform with safety feature.
>>>>> - qcs9075-ride.dts is IOT grade Ride platform without safety feature.
>>>>>
>>>>> Since the Ride-r3 boards are essentially Ride boards with Ethernet
>>>>> modifications, we can convert the Ride-r3 DTS to overlays.
>>>> How one board can be with multiple SoCs? If it is soldered, it's close
>>>> to impossible - that's just not the same board. If it is not soldered,
>>>> why you are not explaining it? What is Ride board? What is there? What
>>>> can go there? How it can be used in other SoCs? Or for which SoCs? Is
>>>> there a datasheet available?
>>>>
>>>
>>> As our SoC is based on SIP card and SIP card is compatible with Ride
>>> board, we could able to use same Ride board (which is combination of
>>> multiple daughter cards) with multiple SIP cards.
>>> These SIP cards can be of sa8775p, qcs9100 or qcs9075 SOC.
>>
>> Describe properly the hardware - if you have a module or SIP if you
>> decide not to use industry-standard naming (but why...), then describe
>> it in DTSI.
> 
> We refer to it as ‘module’ in our datasheet, so I use the same term
> here. Thanks for pointing it out; we can proceed with the SoM name.
> 
> Below is the updated diagram:
> +-----------------------------------------------------------------------------------------------------------------------------------------------+
> |                                                                                                                                               |
> |                                                          sa8775p.dtsi                                                                         |
> |                                                              |                                                                                |
> |                                    +-------------------------+-----------------------+                                                        |
> |                                    |                         |                       |                                                        |
> |                                    v                         |                       v                                                        |
> |                             qcs9075-som.dtsi                 |                qcs9100-som.dtsi                                                |
> |                                    |                         |                       |                                                        |
> |                                    v                         v                       v                                                        |
> |                                  (IOT)                    (AUTO)                   (IOT)                                                      |
> |                                    |                         |                       |                                                        |
> |             +----------------------+                         |                       |                                                        |
> |             |                      |                         |                       |                                                        |
> |             |                      | +-------------------------+-----------------------+-------------------< qcom-ride-common.dtsi            |
> |             |                      | |                       | |                     | |                                                      |
> |             v                      v v                       v v                     v v                                                      |
> |  qcs9075-iq-9075-evk.dts     qcs9075-ride.dts         sa8775p-ride.dts         qcs9100-ride.dts                                               |
> |                                    |                         |                       |                                                        |
> |                                    +-------------------------+-----------------------+---------------------< qcom-ride-ethernet-aqr115c.dtso  |
> |                                    |                         |                       |                                                        |
> |                                    v                         v                       v                                                        |
> |                             qcs9075-ride-r3.dts      sa8775p-ride-r3.dts      qcs9100-ride-r3.dts                                             |
> |                                                                                                                                               |
> +-----------------------------------------------------------------------------------------------------------------------------------------------+


Several companies solved it - most of NXP vendors, many Renesas etc. I
really do not get why this needs so much talk and you cannot learn from
their architecture how SoM should be represented.

Best regards,
Krzysztof