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

[Wasim Nazir <quic_wasimn@quicinc.com>]

On Sat, Mar 29, 2025 at 05:48:00AM +0100, Krzysztof Kozlowski wrote:
> On 20/03/2025 12:45, Wasim Nazir wrote:
> > Hi Krzysztof,
> > 
> >>>>
> >>>> 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.
> >>
> > 
> > Currently we don't have any datasheet or document which is publicly
> > available, so I will try my best to describe our HW.
> > 
> > Ride is a modular hardware system with several smaller daughter cards
> > connected to single backplane board and each daughter card is stacked on
> > top of each other. I will try to explain each daughter card with HW
> > components and how it is connected to construct the ride-hw.
> > 
> > Backplane board:
> >   - It contains an MCU (Aurix TC397), CAN/LIN transceiver,
> > 	Audio/GNSS/IMU-I2C signals, Fan header
> >   - It holds & connects all the daughter cards.
> > 
> > SoC card:
> >   - It contains:
> >     - SoM:
> >       - One of QCS9075M/QCS9100M/QAM8775p SoM.
> > 	  - Each SoM is composed of either qcs9075/qcs9100/sa8775p SoC, along
> > 		with DDR & PMICs.
> >       - Each SoM can be mounted to same SoC-daughter card of ride-hw.
> >     - In addition to SoM, it also has
> >       - 4x UART, 2x USB 3.1 & 1x USB 2.0
> >       - Memory: 1x OSPI, 2x UFS-3.1
> >       - Debug: JTAG/QDSS header
> >       - PCIe0, PCIe1 & Display signals
> >       - Reset button
> >   - It is connected to backplain board via B2B connector.
> > 
> > Display card:
> >   - It contains:
> >     - 4 eDP ports & 2 DSI-DP bridge
> >     - I2C GPIO expander & I2C switch
> >   - It is connected to SoC-card via B2B connector.
> > 
> > Camera card:
> >   - It contains:
> >     - 4 Quad DE-serializer, each supporting 4 MIPI CSI inputs
> >     - Total upto 16 Cameras ports are supported.
> >   - It is connected to backplain board via B2B connector.
> > 
> > Ethernet card:
> >   - There are two variants of ethernet card each with different
> > 	capabilities:
> >     - [Ethernet-v1] card contains:
> >       - 2x 1G RGMII phy, 2x 1G SGMII phy(enabled currently)
> > 	  - Total 4 phy supported, only 2 phy are enabled and it is used in
> > 		ride.
> >     - [Ethernet-v2] card contains:
> > 	  - 2x 1G RGMII phy, 2x 2.5G HSGMII(enabled currently) & 10G PCIe based
> > 		MAC+PHY controller
> > 	  - Total 5 phy supported, only 2 phy are enabled and it is used in
> > 		ride-r3.
> >   - Either [Ethernet-v1] or [Ethernet-v2] is connected to backplain board
> > 	via B2B connector.
> > 
> > PCIe card:
> >   - It contains:
> >     - PCIe connections to SoC-card
> > 	- NVME, 2x WLBT module QCA6696/QCA6698 (Wi-Fi & bluetooth solution) &
> > 	  GNSS module
> >   - It is connected to backplain board via B2B connector & PCIe signals are
> > 	connected to SoC card via flyover cables.
> > 
> > Sensor Card:
> >   - It contains 3-Axix compass & 6-Axis 3D IMU (accel/gyro) module which
> > 	are communicating via I2C
> >   - It is connected to backplain board via B2B connector.
> > 
> > Front panel card:
> >   - It does not contain any active circuitry, only ports are available
> >     - Audio-in/out ports
> >     - USB hub ports
> >     - CAN/LIN ports
> >     - 12V power off switch
> >   - It is connected to backplain board via ribbon cable.
> > 
> >>
> >>>
> > 
> >>>> |             |                      | +-------------------------+-----------------------+-----------------< sa8775p-ride-common.dtsi           |
> >>
> >>
> >> There is no ride-common hardware. If there is, send us any proof of its
> >> existence. all your statements here show you want to create some
> >> structure because you like it. I don't think you get my questions. You
> >> painted diagram of DTS, not hardware.
> >>
> >> We talk about hardware. Not your DTS. Drop all DTSI, DTS, DTSO from here
> >> and show us the hardware.
> >>
> > 
> > Considering outlined h/w description, following are ride configuration
> > variation each platform supporting:
> > 
> > Between qcs9075, qcs9100 & sa8775p ride/ride-r3 boards, SoM is changing;
> 
> Define these as SoMs then.

sure

> 
> > And between ride & ride-r3 ethernet is changing.
> 
> Different ethernet cards can be also represented as cards - their own
> DTSI. But there is no soc-card with one or other ethernet, so do not
> create fake structure just because downstream had it.
> 

Ok, will proceed with dtsi for v1/v2 ethernet cards and use it for ride &
ride-r3 respectively.

> 
> > Excluding these differences all other cards i.e SoC, display, camera, PCIe,
> > sensor, front & backplain are same and are refactored in ride-common.
> > If any variant of these cards comes up in future we need to refactor
> > ride-common accordingly. I will try to outline this as clearly as possible
> > in next commit log.
> > 
> > Considering current outlines of all daughter cards, following defines
> > ride/ride-r3 variant boards:
> >   - sa8775p ride    : QAM8775p SoM + [Ethernet-v1] + other daughter cards
> >   - sa8775p ride-r3 : QAM8775p SoM + [Ethernet-v2] + other daughter cards
> >   - qcs9100 ride-r3 : QCS9100M SoM + [Ethernet-v2] + other daughter cards
> >   - qcs9075 ride-r3 : QCS9075M SoM + [Ethernet-v2] + other daughter cards
> > 
> > Since we don't have a document yet which formally describes
> > qcs9075/qcs9100 ride board with [Ethernet-v1] card, I shall be dropping
> > this particular variant in next patch series and re-send after complete
> > documentation is available.
> > 
> >>> 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.
> >>
> > 
> > No the overlay is not a different ride board. This overlay represents
> > [Ethernet-v2] card which is different than [Ethernet-v1] card.
> 
> Different cards is not an overlay. Overlay is for added cards, but you
> replace here the card.
> 

Understood, will proceed with dtsi way of adding ethernet cards for
ride & ride-r3 boards.

>
>

Based on current understanding, here is the final structure for the dts
& dtsi, representing all variant of boards.

Ethernet cards are represented using dtsi as:
  - [Ethernet-v1] card: sa8775p-ride-ethernet-88ea1512.dtsi
  - [Ethernet-v2] card: sa8775p-ride-ethernet-aqr115c.dtsi

+-------------------------------------------------------------------------------------------------------------------------------------------------------+
|                                                                                                                                                       |
|                                                           sa8775p.dtsi                                                                                |
|                                                                 |                                                                                     |
|                                       +-------------------------+-----------------------+                                                             |
|                                       |                         |                       |                                                             |
|                                       v                         |                       v                                                             |
|                                qcs9075-som.dtsi         qam8775p-som.dtsi        qcs9100-som.dtsi                                                     |
|                                       |                         |                       |                                                             |
|                                       v                         v                       v                                                             |
|                                     (IOT)                    (AUTO)                   (IOT)                                                           |
|                                       |                         |                       |                                                             |
|             +-------------------------+                         |                       |                                                             |
|             |                         |                         |                       |                                                             |
|             |                         | +-------------------------+-----------------------+---------------< sa8775p-ride-ethernet-88ea1512.dtsi       |
|             |                         | |                       | |                     | |                                                           |
|             |                         | | +-------------------------+-----------------------+----------+--< sa8775p-ride-common.dtsi                  |
|             |                         | | |                     | | |                   | | |          |                                              |
|             |                         | | |          +----------+ | |                   | | |          |                                              |
|             |                         | | |          |          | | |                   | | |          |                                              |
|             v                         v v v          |          v v v                   v v v          |                                              |
|  qcs9075-iq-9075-evk.dts         qcs9075-ride.dts    |     sa8775p-ride.dts        qcs9100-ride.dts    |                                              |
|                                                      |                                                 |                                              |
|                                                      | +-----------------------------------------------+                                              |
|                                                      | |                                                                                              |
|                                                      | | +------------------------------------------------< sa8775p-ride-ethernet-aqr115c.dtsi        |
|                                                      | | |                                                                                            |
|                                                      v v v                                                                                            |
|                                              sa8775p-ride-r3.dts                                                                                      |
|                                                                                                                                                       |
+-------------------------------------------------------------------------------------------------------------------------------------------------------+

Please let us know if we can proceed with the change.


Thanks & regards,
Wasim

> Best regards,
> Krzysztof