Message-ID: <dcb0b95f-92a9-a5f5-ee91-1b1d7123bd8d@ti.com>
Date:   Fri, 24 Sep 2021 12:25:20 -0500
From:   Suman Anna <s-anna@...com>
To:     Nishanth Menon <nm@...com>
CC:     Sinthu Raja <sinthu.raja@...tralsolutions.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Ohad Ben-Cohen <ohad@...ery.com>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-remoteproc@...r.kernel.org>,
        Sinthu Raja <sinthu.raja@...com>,
        "Nagalla, Hari" <hnagalla@...com>
Subject: Re: [PATCH V3 2/2] dt-bindings: remoteproc: k3-dsp: Remove
 board-specific compatible from DT example

On 9/24/21 11:29 AM, Nishanth Menon wrote:
> On 11:10-20210924, Suman Anna wrote:
>> Hi Sinthu,
>>
>> On 9/17/21 4:54 AM, Sinthu Raja wrote:
>>> From: Sinthu Raja <sinthu.raja@...com>
>>>
>>> The example includes a board-specific compatible property, this is
>>> wrong as the example should be board agnostic and gets in the way of
>>> additions for newer platforms. Replace the same with a generic soc
>>> node.
>>
>> What board specific property? This description looks wrong.
> 
> See https://lore.kernel.org/all/1631794913.472895.1119414.nullmailer@robh.at.kernel.org/
> 

Yes, I understand you are now trying to add/scale for a board compatible and
your patch is what triggered the warnings.

I see "ti,j721e" as an SoC compatible not board-specific.

>>
>>>
>>> Fixes: 2a2180206ab6 ("dt-bindings: remoteproc: Add bindings for C66x DSPs on TI K3 SoCs")
>>
>> What error are you trying to fix exactly? The example used below is actually how
>> it exactly appears in the J721E dts files, and there are no errors with
>> dt_binding_check.
> 
> The rproc binding should have nothing to do with j721e SoC node
> description. it should describe the rproc node that is described in
> binding.

You can go back and look at my original dt-binding submissions and the reasons
for me to add a root-cell. They are to suppress the warnings seen with using two
address-cells in the DSP example nodes which use the actual node definitions
from the J721E SoC.

v1:
https://patchwork.kernel.org/project/linux-remoteproc/patch/20200325201839.15896-2-s-anna@ti.com/
v2:
https://patchwork.kernel.org/project/linux-remoteproc/patch/20200521001006.2725-3-s-anna@ti.com/
v3:
https://patchwork.kernel.org/project/linux-remoteproc/patch/20200612224914.7634-5-s-anna@ti.com/

> 
>>
>> This is more a cleanup than a fix.  You can look through the original binding
>> submission patches to see why it is done like this.
> 
> This is blocking any updates we would want to do in k3.yaml.

One other way would have been to just add the new enforced compatible (since you
are actually changing the k3.yaml binding and diverging from what was there
before) here along with your updates, if you didn't want to add it in the
previous compatible way.

FWIW, there are no dt_binding_check errors on this binding before your
modifications, that's why I am asking what is the "Fixes" with the original patch.

>>
>> If this is triggered by the changes you are making to k3.yaml file as part of
>> the J721E EAIK changes, then you probably may want to look at how you are doing
> 
>> that again. Looks like the k3.yaml file is being modified now to enforce
>> "board-compatible", "soc-compatible" which may have triggered an error in this file.
>>
>> Please evaluate if you need to modify it to support just the "soc-compatible" as
>> one of the items.
> 
> See above link. This is not to do with eaik / sk. I am trying to
> standardize the board definitions in yaml for k3 and this binding
> specifically is getting in the way.

Yeah finally. I remember I had asked you about why we are doing it differently
between AM65x and J721E/J7200. +1 for the direction.

> 
> 
> I still don't understand what your contention is here. Are you arguing
> that the binding example is correct and should be tied to a platform?

I am not saying it should be tied to a platform, but I have used the example as
it appears on J721E SoCs. I am commenting that it is not a "Fixes:" and the
patch description needs updates.

> 
> 
> Yes, I know I can introduce oneOf and a little more intricate solution,
> 	but besides that, i disagree that a rproc binding should even
> 	have SoC specific top level node description in it.

Please see the reasoning in the original submissions. I could not use 2
address-cells and size-cells without the top-level node additions, and I didn't
want to use bogus examples.

Yes, the intricate solution would not have triggered the warning in this
example, but your current change is also breaking your previous compatibility. I
understand that the reality is always actually a "board-compatible",
"soc-compatible", but as per your previous k3.yaml definition, all one needed
was just a "ti,j721e" compatible in their dts files. Changing it now and calling
the usage in this example "wrong" is not right either IMO.


> a) rproc.yaml does'nt even describe the SoC. soc.yaml does.
> b) The node property examples are supposed to be examples not tied to a
>    specific SoC.

I would rather not use a completely bogus example since it is not very useful
for customers trying to understand the binding. My philosophy has always been to
define an example as it appears on an actual SoC so that it is easier for
customers to comprehend the binding and example while comparing it to actual dts
nodes.

regards
Suman

> 
>>> Signed-off-by: Sinthu Raja <sinthu.raja@...com>
>>> ---
>>>
>>> Changes since V2:
>>> * review comment updates, including simplifying the changes, commit
>>>   message and $subject updates.
>>>
>>> V2: https://lore.kernel.org/all/20210818074030.1877-1-sinthu.raja@ti.com/
>>> V1: https://lore.kernel.org/all/20210817152005.21575-1-sinthu.raja@ti.com/
>>>
>>>  .../devicetree/bindings/remoteproc/ti,k3-dsp-rproc.yaml       | 4 +---
>>>  1 file changed, 1 insertion(+), 3 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/remoteproc/ti,k3-dsp-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/ti,k3-dsp-rproc.yaml
>>> index 6070456a7b67..5ec6505ac408 100644
>>> --- a/Documentation/devicetree/bindings/remoteproc/ti,k3-dsp-rproc.yaml
>>> +++ b/Documentation/devicetree/bindings/remoteproc/ti,k3-dsp-rproc.yaml
>>> @@ -133,9 +133,7 @@ unevaluatedProperties: false
>>>  
>>>  examples:
>>>    - |
>>> -    / {
>>> -        model = "Texas Instruments K3 J721E SoC";
>>> -        compatible = "ti,j721e";
>>> +    soc {
>>
>> While this may be resolving the dt_bindings_check you might be seeing with the
>> modified k3.yaml, note that "soc" property is not used on K3 dts files, you
>> might be creating confusion for people who look at this example and the actual
>> usage.
> 
> 
> It is a common usage model. NOTE: these are example nodes and NOT meant
> as SoC representation. I dont see the confusion.
> 

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