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SubjectRe: [PATCH v8 06/11] irqchip: mips-cpu: Convert to simple domain
On 2020-03-25 14:31, Jiaxun Yang wrote:
> 于 2020年3月25日 GMT+08:00 下午10:15:16, Marc Zyngier <maz@kernel.org> 写到:
>> On 2020-03-25 13:59, Jiaxun Yang wrote:
>>
>> [...]
>>
>>>>> So probably we can use legacy domain when MIPS IRQ BASE is in the
>>>>> range of legacy IRQ
>>>>> and switch to simple domain when it's not in that range?
>>>>
>>>> No, see below.
>>>>
>>>>> Here in Loongson systems IRQ 0-15 is occupied by I8259 so I did
>> this
>>>>> hack.
>>>>
>>>> Well, if you have to consider which Linux IRQ gets assigned,
>>>> then your platform is definitely not ready for non-legacy
>>>> irqdomains. Just stick to legacy for now until you have removed
>>>> all the code that knows the hwirq mapping.
>>>
>>> Thanks.
>>>
>>> So I have to allocate irq_desc here in driver manually?
>>
>> No, you are probably better off just dropping this patch, as MIPS
>> doesn't seem to be ready for a wholesale switch to virtual interrupts.
>
> It can't work without this patch.
>
> Legacy domain require IRQ number within 0-15
> however it's already occupied by i8259 or "HTPIC" driver.
>
> Previously Loongson even didn't enable IRQ domain so it's not a
> problem.

Then your platform is breaking some fundamental assumption that the rest
of the MIPS architecture seem to rely on. You could test for the base
IRQ being 0 and create a legacy domain in this case, but that's really
a horrible hack.

I'm pretty worried about having to address this just 4 days away from
the merge window TBH, as this code hasn't been in -next at all.

That's really Thomas' call, but I'm not very enthusiastic.

M.
--
Jazz is not dead. It just smells funny...

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