Re: [PATCH 2/2] arm: dts: rk356x: rock3a: disable pcie3x2

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hi,

On 1/21/26 11:15, Marco Felsch wrote:
> On 26-01-21, Ahmad Fatoum wrote:
>> Hello Marco,
>>
>> On 1/21/26 10:16, Marco Felsch wrote:
>>> On 26-01-21, Ahmad Fatoum wrote:
>>>> With barebox as EFI loader, we always install the barebox DT in a configuration
>>>> table and leaves it to grub or whatever to decide whether it wants to use it or
>>>> if it wants to use another DT it finds itself.
>>>
>>> Ah, thanks for the explanation :) this wasn't clear to me. Maybe it's
>>> worth a comment when to use this within the barebox,status description.
>>
>> Whether the barebox DT is used for Linux or not is inconsequential though.
>> We want the barebox DT to be always _usable_ for Linux, even if it's not
>> used. I thus intentionally didn't list when barebox passes along its own
>> DT in the binding doc.
> 
> Get your point but at least your patch here wasn't clear to me in the
> first place. Therefore my question :) Now with the new barebox,status it
> isn't clear when to use this.
> 
> This could be sovled either via policy like: use barebox,status if
> you're going to toogle the status of an upstream-dt within the barebox.

The binding in patch 1 documents:

Use this property only for devices for which barebox has a driver, but
that barebox should not be probing on a per-board basis.

Do you have a suggestion how to make this clearer?

> Or via a comment within the DT to make it clear, why barebox,status is
> used.

I can also add a comment in addition to the commit message.

>> Normally, you would disable drivers that don't work for board, but we can't do that in
>> a multi defconfig, so we need to disable the device on a per-board basis.
>>
>> This is different than secure-status, where device availability is actually
>> dependent on the security mode of the system.
> 
> Right, I just wanted to point out, that downstream bindings or
> downstream behaviors hit us hard in the past. That beeing said, I don't
> see a problem for barebox,status.

Many of these issues would have been avoided had we used a barebox, prefix.

Cheers,
Ahmad


> 
> Regards,
>   Marco
> 
> 
>>
>> Cheers,
>> Ahmad
>>
>>>
>>>> The support for the Android fastboot's protocol boot command also doesn't pass
>>>> a DT and expects the bootloader to pass its.
>>>
>>> Good to know :)
>>>
>>> Thanks,
>>>   Marco
>>>
>>>>
>>>> Cheers,
>>>> Ahmad
>>>>>
>>>>> Regards,
>>>>>   Marco
>>>>>
>>>>>> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
>>>>>> ---
>>>>>>  arch/arm/dts/rk3568-rock-3a.dts | 4 ++++
>>>>>>  1 file changed, 4 insertions(+)
>>>>>>
>>>>>> diff --git a/arch/arm/dts/rk3568-rock-3a.dts b/arch/arm/dts/rk3568-rock-3a.dts
>>>>>> index bcbfab14a580..b7258d7e61b3 100644
>>>>>> --- a/arch/arm/dts/rk3568-rock-3a.dts
>>>>>> +++ b/arch/arm/dts/rk3568-rock-3a.dts
>>>>>> @@ -55,3 +55,7 @@ environment_sd: partition@408000 {
>>>>>>  		};
>>>>>>  	};
>>>>>>  };
>>>>>> +
>>>>>> +&pcie3x2 {
>>>>>> +	barebox,status = "disabled";
>>>>>> +};
>>>>>> -- 
>>>>>> 2.47.3
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>> -- 
>>>> Pengutronix e.K.                           |                             |
>>>> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
>>>> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
>>>> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
>>>>
>>>
>>
>>
>> -- 
>> Pengutronix e.K.                           |                             |
>> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
>> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
>> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
>>
> 


-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |