Re: [PATCH 05/13] tty: serial: samsung: add gs101 earlycon support

Arnd Bergmann
2023-12-14T14:20:07Z

On Thu, Dec 14, 2023, at 13:52, Tudor Ambarus wrote:
> On 12/14/23 12:01, Arnd Bergmann wrote:
>> On Thu, Dec 14, 2023, at 11:52, Tudor Ambarus wrote:
>>> +static int __init gs101_early_console_setup(struct earlycon_device *device,
>>
>
> It works if in device tree one specifies the reg-io-width property and
> sets it to 4. If the reg-io-width is not specified, the iotype defaults
> to UPIO_MEM causing the SError interrupt on gs101 which makes the system
> unusable.

In the case of incorrect DT data like a missing reg-io-width property,
I would expect it to still fail once the regular console or tty takes
over from earlycon.

> Also, if the earlycon comes specified from the kernel params, the
> of_setup_earlycon() is no longer called and the earlycon will be set
> solely based on the kernel params buffer, thus allowing users to crash
> the kernel on wrong earlycon definitions.

But that in turn is the same as specifying any other incorrect earlycon.

> If you think the change is fine, I can amend the commit message with the
> description from above.

I'm still not convinced we need a special case here when everything else
just requires passing the correct data.

Arnd