Re: [PATCH 2/5] common: deep-probe: support specifying support in DT

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

Hi Marco,

On 28.05.25 17:46, Marco Felsch wrote:
> On 25-05-28, Ahmad Fatoum wrote:
>> Hi,
>>
>> On 5/28/25 17:24, Marco Felsch wrote:
>>> On 25-05-28, Ahmad Fatoum wrote:
>>>> New boards should be deep probe enabled by default, which is currently
>>>> done via board code. We want to support second stage boot on new boards
>>>> without board code however, which means we need the possibility to make
>>>> deep probe opt-out instead of opt-in.
>>>>
>>>> Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
>>>> ---
>>
>> [snip]
>>
>>>> +	/* deep probe requires resources to be described in DT */
>>>> +	root = of_get_root_node();
>>>> +	if (!root)
>>>> +		return false;
>>>
>>> 	if (!root) {
>>> 		boardstate = DEEP_PROBE_NOT_SUPPORTED;
>>
>> No, the omission is intentional. I want to repeat the check for the
>> root node on every call to avoid issues where this function is
>> called once too early.
> 
> Good point albeit I wouldn't assume that this happens.
> 
> Also what if caller-1 receives "no" does the "no-deep-probe-handling"
> accordingly and shortly after caller-2 receives "yes". Sounds like a
> source of trouble. 

If a driver requests a resource and it is not available, it returns
-EPROBE_DEFER, even with deep probe enabled, so I think barebox
shouldn't handle such a case too badly.

> Anyway could we add a comment that this is intentional please?

Done for v2.

Thanks,
Ahmad

> 
> Regards,
>   Marco
> 
> 
>>
>>>> -	boardstate = DEEP_PROBE_NOT_SUPPORTED;
>>>> -	pr_info("not activated\n");
>>>> -	return false;
>>>
>>> Can we please add a comment about the below if-else, e.g. referencing
>>> the barebox,deep-probe.rst as well?
>>
>> Yes, will do for v2.
>>
>> Thanks for reviewing,
>> Ahmad
>> -- 
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>>
>>
> 


-- 
Pengutronix e.K.                           |                             |
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