[PATCH] powerpc/crash: Allow direct printing on kexec

[John Ogness]

On 2024-10-21, Ryo Takakura <ryotkkr98 at gmail.com> wrote:
>> Rather than removing the deferring, it would be better to convert the
>> console you are using to the new NBCON API. Then it would be able to
>> print direct and safe during panic. (printk_deferred does not affect
>> NBCON consoles.) What console driver are you using that you want to
>> see the messages on?
>
> I was working on qemu ppc64 this time but I am usually working on 
> Raspberry Pi 4 (mostly for fun and study) which uses either of 
> bcm2835-aux-uart or amba-pl011. It would be really nice to see them 
> working as nbcon!
> I am thinking of taking a look at [0] but If there were any other 
> references, I would really like to look into as well.
>
> [0] https://lore.kernel.org/lkml/87wn3zsz5x.fsf@jogness.linutronix.de/

The lastest version of the series is here [1]. The series is still
undergoing revisions, however the changes are 8250-specific. The API for
nbcon consoles is already available since 6.12-rc1. You are certainly
welcome to try to convert one of those Raspi 4 drivers to the nbcon
interface. I would be happy to review it.

John Ogness

[1] https://lore.kernel.org/lkml/20240913140538.221708-1-john.ogness@linutronix.de