Re: Specifying the console device using an alias

Re: Specifying the console device using an alias

[Simon Glass]

(correct list)

On 14 August 2014 21:42, Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
> Hi,
>
> In U-Boot we currently specify the console device (typically serial)
> using something like:
>
> aliases {
>    console = "/serial@1234";
> }
>
> But the question has come up as to whether this should be done another
> way. I see the "linux.stdout" property in the /chosen node.
>
> I am concerned that making use of the /chosen node in U-Boot might
> confuse a lot of people, since this node is normally used to provide
> selections for the OS to use when booting. If we did use /chosen, then
> linux,stdout seems plain wrong but perhaps u-boot,stdout could be used
> instead.
>
> Does anyone have an opinion about this? It would be good to work this
> out soon before it proliferates into more code.
>
> Regards,
> Simon
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Re: Specifying the console device using an alias

[Simon Glass]

+Stephen

On 14 August 2014 22:02, Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
> (correct list)
>
> On 14 August 2014 21:42, Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
>> Hi,
>>
>> In U-Boot we currently specify the console device (typically serial)
>> using something like:
>>
>> aliases {
>>    console = "/serial@1234";
>> }
>>
>> But the question has come up as to whether this should be done another
>> way. I see the "linux.stdout" property in the /chosen node.
>>
>> I am concerned that making use of the /chosen node in U-Boot might
>> confuse a lot of people, since this node is normally used to provide
>> selections for the OS to use when booting. If we did use /chosen, then
>> linux,stdout seems plain wrong but perhaps u-boot,stdout could be used
>> instead.
>>
>> Does anyone have an opinion about this? It would be good to work this
>> out soon before it proliferates into more code.
>>
>> Regards,
>> Simon
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Re: Specifying the console device using an alias

[Simon Glass]

+Even more people (thanks Stephen)

On 15 August 2014 11:22, Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
> +Stephen
>
> On 14 August 2014 22:02, Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
>> (correct list)
>>
>> On 14 August 2014 21:42, Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
>>> Hi,
>>>
>>> In U-Boot we currently specify the console device (typically serial)
>>> using something like:
>>>
>>> aliases {
>>>    console = "/serial@1234";
>>> }
>>>
>>> But the question has come up as to whether this should be done another
>>> way. I see the "linux.stdout" property in the /chosen node.
>>>
>>> I am concerned that making use of the /chosen node in U-Boot might
>>> confuse a lot of people, since this node is normally used to provide
>>> selections for the OS to use when booting. If we did use /chosen, then
>>> linux,stdout seems plain wrong but perhaps u-boot,stdout could be used
>>> instead.
>>>
>>> Does anyone have an opinion about this? It would be good to work this
>>> out soon before it proliferates into more code.
>>>
>>> Regards,
>>> Simon
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Re: Specifying the console device using an alias

[Sascha Hauer]

Simon,

On Thu, Aug 14, 2014 at 10:02:10PM -0600, Simon Glass wrote:
> (correct list)
> 
> On 14 August 2014 21:42, Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
> > Hi,
> >
> > In U-Boot we currently specify the console device (typically serial)
> > using something like:
> >
> > aliases {
> >    console = "/serial@1234";
> > }
> >
> > But the question has come up as to whether this should be done another
> > way. I see the "linux.stdout" property in the /chosen node.
> >
> > I am concerned that making use of the /chosen node in U-Boot might
> > confuse a lot of people, since this node is normally used to provide
> > selections for the OS to use when booting. If we did use /chosen, then
> > linux,stdout seems plain wrong but perhaps u-boot,stdout could be used
> > instead.

See ePAPR. There's a stdout-path property specified, without linux,
prefix.

Sascha

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Re: Specifying the console device using an alias

[Simon Glass]

Hi Sascha,

On 18 August 2014 13:19, Sascha Hauer <s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> wrote:
>
> Simon,
>
> On Thu, Aug 14, 2014 at 10:02:10PM -0600, Simon Glass wrote:
>> (correct list)
>>
>> On 14 August 2014 21:42, Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
>> > Hi,
>> >
>> > In U-Boot we currently specify the console device (typically serial)
>> > using something like:
>> >
>> > aliases {
>> >    console = "/serial@1234";
>> > }
>> >
>> > But the question has come up as to whether this should be done another
>> > way. I see the "linux.stdout" property in the /chosen node.
>> >
>> > I am concerned that making use of the /chosen node in U-Boot might
>> > confuse a lot of people, since this node is normally used to provide
>> > selections for the OS to use when booting. If we did use /chosen, then
>> > linux,stdout seems plain wrong but perhaps u-boot,stdout could be used
>> > instead.
>
> See ePAPR. There's a stdout-path property specified, without linux,
> prefix.

Yes, I see that, but linux doesn't use it AFAICT. Are you suggesting
that U-Boot should? Or should we use 'u-boot,stdout-path' in /chosen?
See my question immediately above about /chosen.

Regards,
Simon
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Re: Specifying the console device using an alias

[Fabio Estevam]

On Wed, Aug 20, 2014 at 2:25 PM, Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:

> Yes, I see that, but linux doesn't use it AFAICT. Are you suggesting
> that U-Boot should? Or should we use 'u-boot,stdout-path' in /chosen?
> See my question immediately above about /chosen.

Linux use stdout-path property specified, without linux prefix.

Check for example:
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/arch/arm/boot/dts/imx6qdl-sabresd.dtsi?id=refs/tags/v3.16.1

/ {
chosen {
stdout-path = &uart1;
};
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Re: Specifying the console device using an alias

[Simon Glass]

Hi Fabio,

On 20 August 2014 10:39, Fabio Estevam <festevam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On Wed, Aug 20, 2014 at 2:25 PM, Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
>
>> Yes, I see that, but linux doesn't use it AFAICT. Are you suggesting
>> that U-Boot should? Or should we use 'u-boot,stdout-path' in /chosen?
>> See my question immediately above about /chosen.
>
> Linux use stdout-path property specified, without linux prefix.
>
> Check for example:
> https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/arch/arm/boot/dts/imx6qdl-sabresd.dtsi?id=refs/tags/v3.16.1
>
> / {
> chosen {
> stdout-path = &uart1;
> };

OK great. This seems to have happened very recently in Linux. I was
looking at 3.14 but I see that in the current master about half of the
.dts files have droped the 'linux' prefix.

So assuming that the U-Boot console should be the same as Linux, then
it sounds like it is OK to use this feature. That's good enough to get
me going.

Thanks,
Simon
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