[PATCH 09/10] fdtgrep: Allow propagating properties up to supernodes

[Quentin Schulz]

Hi Manorit,

On 7/10/24 8:15 AM, Manorit Chawdhry wrote:
> Hi Simon,
> 
> On 09:36-20231217, Simon Glass wrote:
>> The existing bootph binding is defined such that properties in a
>> subnode are also implied in the supernode also, as in this example:
>>
>>     buttons {
>>        /* bootph,pre-ram is implied by btn1 */
>>        compatible = "gpio-keys";
>>
>>        btn1 {
>>           bootph,pre-ram;
>>           gpios = <&gpio_a 3 0>;
>>           label = "button1";
>>           linux,code = <BTN_1>;
>>        };
>>
>> Provide an option to implement this in fdtgrep.
>>
>> Signed-off-by: Simon Glass <sjg at chromium.org>
> 
> Coming back to this patch as am facing some issues with the bootph-all
> propagation to the parent nodes [0]. We have a dmsc/sms node in our
> devices and it is a parent node of k3_pds, k3_clks, k3_reset.
> 
> During U-boot proper we are initializing the serial console and during
> that time we have to make some calls to our Device manager for clocks
> and power domains. With the DT modelling, the clocks and power domains
> come under the device manager node ( dmsc/sms ) but interestingly that
> driver is not getting probed while putting bootph-all in the child
> nodes. Do you know anything about this? I thought putting it in child
> node will propagate it to the parent nodes as well so it'll be probed as
> well. We are having to put bootph-all explicitely in the dmsc/sms node
> for it to work.
> 

I haven't followed the whole thread but it seems to match something I 
looked into recently.

The properties aren't actually propagated. What happens is that this 
option is used to NOT delete parents (or rather, their properties) of a 
node with the passed bootph- property. This is only useful for TPL and 
SPL device trees which are stripped down versions of the full U-Boot 
DTB. The parent nodes also incidentally do not have this property added, 
they just are merely allowed to exist.

fdtgrep needs to be reworked to allow passing the bootph- properties to 
the parent nodes. I quickly looked into it a few weeks ago and it didn't 
seem like a 5min job to me. This would be also beneficial for U-Boot 
proper pre-relocation stage, which suffers from missing bootph- 
properties in parent nodes (been there recently) as well.

Cheers,
Quentin