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

[Marco Felsch <m.felsch@pengutronix.de>]

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.

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

> > That beeing said, is it worth tying to make it barebox unspecific and
> > try to upstream the binding. I had something like bootloader,status or
> > bl33,status in my mind.
> 
> I don't think the prospects for upstreaming are favorable. This doesn't describe
> hardware, but the fact that the barebox driver needs further work.

Good point!

> 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.

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
> >>>>
> >>>>
> >>>>
> >>>
> >>
> >>
> >> -- 
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> > 
> 
> 
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