linux-kernel - Re: [PATCH v8 3/3] PCI: uniphier: Add misc interrupt handler to invoke PME and AER

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Date:   Fri, 23 Jul 2021 18:36:21 +0900
From:   Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
To:     Pali Rohár <pali@...nel.org>
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <helgaas@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Rob Herring <robh@...nel.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
        Marc Zyngier <maz@...nel.org>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Jassi Brar <jaswinder.singh@...aro.org>,
        Masami Hiramatsu <masami.hiramatsu@...aro.org>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v8 3/3] PCI: uniphier: Add misc interrupt handler to
 invoke PME and AER

Hi Pali,

On 2021/07/23 17:37, Pali Rohár wrote:
> On Friday 23 July 2021 15:59:12 Kunihiko Hayashi wrote:
>> Hi Pali,
>>
>> On 2021/07/23 2:26, Pali Rohár wrote:
>>> On Friday 23 July 2021 01:54:10 Kunihiko Hayashi wrote:
>>>> On 2021/07/18 9:51, Pali Rohar wrote:
>>>>>>> IMO this should be modelled with a separate IRQ domain and chip for
>>>>>>> the root port (yes this implies describing the root port in the dts
>>>>>>> file with a separate msi-parent).
>>>>>>>
>>>>>>> This series as it stands is a kludge.
>>>>>>
>>>>>> I see. However I need some time to consider the way to separate IRQ domain.
>>>>>> Is there any idea or example to handle PME/AER with IRQ domain?
>>>>>
>>>>> Seems that you are dealing with very similar issues as me with aardvark
>>>>> driver.
>>>>>
>>>>> As an inspiration look at my aardvark patch which setup separate IRQ
>>>>> domain for PME, AER and HP interrupts:
>>>>> https://lore.kernel.org/linux-pci/20210506153153.30454-32-pali@kernel.org/
>>>>>
>>>>> Thanks to custom driver map_irq function, it is not needed to describe
>>>>> root port with separate msi-parent in DTS.
>>>>
>>>> I need to understand your solution, though, this might be the same situation as my driver.
>>>
>>> I think it is very very similar as aardvark also returns zero as hw irq
>>> number (and it is not possible to change it).
>>>
>>> So simple solution for you is also to register separate IRQ domain for
>>> Root Port Bridge and then re-trigger interrupt with number 0 (which you
>>> wrote that is default) as:
>>>
>>>       virq = irq_find_mapping(priv->irq_domain, 0);
>>>       generic_handle_irq(virq);
>>>
>>> in your uniphier_pcie_misc_isr() function.
>>
>> I'm not sure "register separate IRQ domain for Root Port Bridge".
>> Do you mean that your suggestion is to create new IRQ domain, and add this domain to root port?
> 
> Yes.
> 
>> Or could you show me something example?
> 
> I have already sent link to patch above which it implements for
> pci-aardvark.c driver.
> 
> https://lore.kernel.org/linux-pci/20210506153153.30454-32-pali@kernel.org/

Thank you for the example.

> In device prove callback register domain by irq_domain_add_linear().
> In bridge map_irq() callback use irq_create_mapping() for Root Port
> device (and otherwise default of_irq_parse_and_map_pci()). And in
> uniphier_pcie_misc_isr() retrigger interrupt into new domain.

I understand it late.
The main point is to replace bridge->map_irq() with private own map_irq().

> 
>> The re-trigger part is the same method as v5 patch I wrote.
> 
> Just you need to specify that new/private IRQ domain into
> irq_find_mapping() call.

I'll try to replace the events with new IRQ domain.

Thank you,

---
Best Regards
Kunihiko Hayashi