[PATCH v13 07/10] firmware: psci: Implement vendor-specific resets as reboot-mode

[Shivendra Pratap]

On 7/28/2025 5:33 PM, Dmitry Baryshkov wrote:
> On 28/07/2025 14:52, Krzysztof Kozlowski wrote:
>> On 28/07/2025 11:44, Dmitry Baryshkov wrote:
>>> On Mon, Jul 28, 2025 at 06:53:14AM +0200, Krzysztof Kozlowski wrote:
>>>> On 27/07/2025 18:24, Shivendra Pratap wrote:
>>>>> +
>>>>> +static int __init psci_init_vendor_reset(void)
>>>>> +{
>>>>> +    struct reboot_mode_driver *reboot;
>>>>> +    struct device_node *np;
>>>>> +    int ret;
>>>>> +
>>>>> +    np = of_find_node_by_path("/psci/reboot-mode");
>>>>
>>>>
>>>> Why are you looking by full path, not by compatible? Is the ABI - above
>>>> path - expressed anywhere?
>>>
>>> PSCI node is required to have a node name of psci, it doesn't have MMIO,
>>
>> This is true
>>
>>> so it resides in the root node
>>
>> This might be or not might be true. It is not defined by ABI. Anyway,
>> you answered where the ABI would be documented, even though as I said it
>> is not (/psci is not), but does not answer to first part: why you are
>> not using compatibles which is always the preferred method?
> 
> That's a good question, I've added one from my side: why do we need an extra late_init call.
"psci" registers with reboot-mode which creates a class and a device under it for exposing
the sysfs.
psci_dt_init is called very early around setup_kernel. At that stage the class creating fails,
so psci cannot register with reboot-mode at this stage.
At early_init, the class creation is success, but the created class and the sysfs does not
enumerates under /sys/class/.
So i added explicit late_init call for this where the sysfs creation seems to work fine.
> 
>>
>>
>>> and the reboot-mode is defined in the
>>> previous patch. So, I'd assume, the path is defined.
>>
>> As I said, path is not. only psci/reboot-mode is.
> 
> Do we have an _actual_ use case where PSCI node is not at at root node? If not, it's obviously a deficiency of the schema. Could you please provide suggestions on how to describe that in DT schema?
> 
>