Bug#1065611: Additional support for SolidRun HoneyComb

[Diederik de Haas <didi.debian@cknow.org>]

Hi Josua,

On Thursday, 18 January 2024 17:40:38 CET Josua Mayer wrote:
> LX2160 SoC early silicon revisions have a pci-e generation 4 controller.
> It requires a different driver from newer gen-3 silicon.
> 
> This affects the SolidRun Honeycomb Workstation which
> is otherwise fully supported in Debian.

I cloned bug report #1061116 into #1065611 to discuss some additional support 
for the SolidRun HoneyComb.

I analyzed the HoneyComb dts file and the following included .dtsi files:
- arch/arm64/boot/dts/freescale/fsl-lx2160a-clearfog-itx.dtsi
- arch/arm64/boot/dts/freescale/fsl-lx2160a-cex7.dtsi
- arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi

If I exclude the kernel modules from 1061116 and 1061117, then I still have 
the following list of additional modules to enable:
- drivers/edac: Enable EDAC_MPC85XX
- drivers/hwmon/pmbus: Enable PMBUS, SENSORS_PMBUS and
  SENSORS_LTC2978 as modules
- drivers/nvmem: Enable NVMEM_LAYERSCAPE_SFP as module
- drivers/rtc: Enable RTC_DRV_FSL_FTM_ALARM as module
- drivers/soc/fsl: Enable FSL_RCPM

If you agree that this is a good list I can make a MR to get them enabled.
A MR for 1061116 and 1061117 has just been merged in our 'master' branch.

But I ran into an issue when looking at the ``EDAC_MPC85XX`` stanza 
in``drivers/edac/Kconfig``:
``depends on FSL_SOC && EDAC=y``

But ``FSL_SOC`` is (only) defined in ``arch/powerpc/Kconfig``, which means 
``EDAC_MPC85XX`` can not be enabled on ``arm64``. 
That module was found based on ``compatible = "fsl,qoriq-memory-controller"``, 
which sounds like something you would want to have.

Upstream commit ea2eb9a8b6207ee4 has the following commit message:
```
    EDAC, fsl-ddr: Separate FSL DDR driver from MPC85xx
    
    The mpc85xx-compatible DDR controllers are used on ARM-based SoCs too.
    Carve out the DDR part from the mpc85xx EDAC driver in preparation to
    support both architectures.
```
Which I interpret as all (?) the preparations for supporting both powerpc and 
ARM were made, but they forgot to update the strict dependency of 
``EDAC_MPC85XX`` to powerpc to actually support both architectures?

Can you shed some light on this?

Cheers,
  Diederik

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