Re: [PATCH] memory: tegra: add multi-socket support to the memory interconnect

[Krzysztof Kozlowski <krzk@kernel.org>]

On 27/05/2026 16:21, Sumit Gupta wrote:
> 
> On 27/05/26 18:25, Krzysztof Kozlowski wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> On 21/05/2026 16:05, Sumit Gupta wrote:
>>> -             err = icc_link_create(node, TEGRA_ICC_MC);
>>> +             err = tegra_mc_icc_link_create(node, node_id, TEGRA_ICC_MC);
>>>                if (err)
>>>                        goto remove_nodes;
>>>
>>> @@ -957,7 +969,13 @@ static int tegra_mc_probe(struct platform_device *pdev)
>>>        if (IS_ERR(mc->regs))
>>>                return PTR_ERR(mc->regs);
>>>
>>> -     mc->debugfs.root = debugfs_create_dir("mc", NULL);
>>> +     if (!mc_debugfs_root)
>> That's a probe path and you created a singletone. Looks like preventing
>> async probing for no real reason.
>>
>> I am very against singletons and debugfs does not look like justified
>> exception.
> 
> The singleton was added so multi-socket MC/EMC instances could
> share a "mc"/"emc" parent. I'll drop it in v2.
> 
> On single-socket SoCs, the "mc"/"emc" names will be unchanged.
> On multi-socket SoCs, each instance will create a top-level debugfs
> dir named with dev_name(). Same pattern in tegra186-emc.c.
> 
>    if (dev_to_node(mc->dev) == NUMA_NO_NODE)
>        mc->debugfs.root = debugfs_create_dir("mc", NULL);
>    else
>        mc->debugfs.root = debugfs_create_dir(dev_name(mc->dev), NULL);

You assume this is fully synced, so you as well could do a look up and
then use what you found or create new dir. If you think that is racy, so
is this approach... How are other drivers handling per-device debugfs
directories? Do they also create such in the top-level? I think no.



Best regards,
Krzysztof