[PATCH 0/4] Use just one DTS file for all Espressobin variants

[Andre Heider]

On 02/12/2020 11:35, Stefan Roese wrote:
> On 02.12.20 10:12, Pali Rohár wrote:
>> On Wednesday 02 December 2020 09:09:15 Stefan Roese wrote:
>>> On 02.12.20 01:33, Pali Rohár wrote:
>>>> On Wednesday 25 November 2020 19:20:06 Pali Rohár wrote:
>>>>> This patch series change Espressobin code to use in U-Boot just one 
>>>>> DTS
>>>>> file for all Espressobin variants. Therefore DT compatible string
>>>>> globalscale,espressobin-emmc is not used anymore as it is not needed.
>>>>>
>>>>> It means that setup and compilation of U-Boot for Espressobin is less
>>>>> complicated and more simple. As there is no need to check for HW 
>>>>> details
>>>>> and just one U-Boot binary would work for all Espressobin variants.
>>>>>
>>>>> First two patches just revert previous eMMC support and next two 
>>>>> patches
>>>>> add support for eMMC in way that just one DTS file is used and fdtfile
>>>>> env variable is correctly set for any Espressobin variant.
>>>>>
>>>>> We have tested that fdtfile env variable is correctly set on 
>>>>> Espressobin
>>>>> variants with eMMC, without eMMC, with DDR3 RAM and also with DDR4 
>>>>> RAM.
>>>>> Also that eMMC is working on Espressobin variant with eMMC.
>>>>
>>>> Stefan, could you please review this patch series?
>>>
>>> I like the approach in general to simplify things. One comment though:
>>>
>>> AFAICT, Linux uses multiple dts/dtsi files for espressobin. So your
>>> approach to move to one single file contradicts the (planned after
>>> comphy conversion) move to the Linux dts/dtsi files.
>>
>> After comphy conversion we can use e.g. Linux dtsi file and create one
>> main U-Boot dts file which would contain all nodes enabled and in U-Boot
>> code disable nodes which are not present/relevant. This patch series
>> allows to detect all variants v5, v7, with emmc, without emmc; so we can
>> reconstruct dts file at U-Boot runtime. In Linux we also simplified dts
>> files as much as possible, so all options are in common dtsi file and
>> only variant relevant changes (enable/disable nodes) are in dts files.
> 
> I see. So let's please wait for Andre, if he has some comments on this.
> 
> Thanks,
> Stefan
> 
>>>> Andre, are you fine with these changes? I would like to get your
>>>> acknowledgment or review comment what needs to be changed or 
>>>> improved as
>>>> this patch series basically rework your code (which is first reverted
>>>> and them implemented in different way).
>>>
>>> Yes. Andre please also comment on this.

This is a nice simplification. Pali had this idea before, and I 
hesitated because of two questions I don't have the answer to:
- Can we just try to detect an emmc chip on an unpopulated board without 
any drawbacks?
- What about power consumption? Does this unnecessarily waste power on 
non-emmc boards because something is still powered up?

But if noone sees an issue with that I don't have any objections.

I think this set could be simplified though. Instead of the first two 
reverts, just remove the non-emmc dts and rename the emmc dts. That's 
less churn and keeps the dtsi for future syncing with linux.

Thanks,
Andre

>>>
>>> Thanks,
>>> Stefan
>>>
>>>>> Pali Rohár (4):
>>>>>     Revert "arm64: dts: armada-3720-espressobin: split common parts to
>>>>>       .dtsi"
>>>>>     Revert "arm64: dts: a3720: add support for espressobin with 
>>>>> populated
>>>>>       emmc"
>>>>>     arm: mvebu: Espressobin: Add support for emmc into dts file
>>>>>     arm: mvebu: Espressobin: Detect presence of emmc at runtime
>>>>>
>>>>>    arch/arm/dts/Makefile                         |   1 -
>>>>>    arch/arm/dts/armada-3720-espressobin-emmc.dts |  44 -----
>>>>>    arch/arm/dts/armada-3720-espressobin.dts      | 186 
>>>>> +++++++++++++++++-
>>>>>    arch/arm/dts/armada-3720-espressobin.dtsi     | 167 
>>>>> ----------------
>>>>>    board/Marvell/mvebu_armada-37xx/board.c       |   6 +-
>>>>>    doc/README.marvell                            |   7 +-
>>>>>    6 files changed, 186 insertions(+), 225 deletions(-)
>>>>>    delete mode 100644 arch/arm/dts/armada-3720-espressobin-emmc.dts
>>>>>    delete mode 100644 arch/arm/dts/armada-3720-espressobin.dtsi
>>>>>
>>>>> -- 
>>>>> 2.20.1
>>>>>
>>>
>>>
>>> Viele Grüße,
>>> Stefan
>>>
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> 
> 
> Viele Grüße,
> Stefan
>