Re: [PATCH v2] irqchip: xilinx: Add support for multiple instances

[Michal Simek]

On 06. 02. 20 10:15, Marc Zyngier wrote:
> On 2020-02-06 09:11, Michal Simek wrote:
>> On 06. 02. 20 10:09, Marc Zyngier wrote:
>>> On 2020-02-06 07:06, Michal Simek wrote:
>>>> On 05. 02. 20 17:53, Marc Zyngier wrote:
>>>>> On 2020-02-05 14:05, Mubin Usman Sayyed wrote:
>>>
>>> [...]
>>>
>>>>>> Âunsigned int xintc_get_irq(void)
>>>>>> Â{
>>>>>> -ÂÂÂÂÂÂ unsigned int hwirq, irq = -1;
>>>>>> +ÂÂÂÂÂÂ int hwirq, irq = -1;
>>>>>>
>>>>>> -ÂÂÂÂÂÂ hwirq = xintc_read(IVR);
>>>>>> +ÂÂÂÂÂÂ hwirq = xintc_read(primary_intc->base + IVR);
>>>>>> ÂÂÂÂÂÂÂ if (hwirq != -1U)
>>>>>> -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ irq = irq_find_mapping(xintc_irqc->root_domain,
>>>>>> hwirq);
>>>>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ irq = irq_find_mapping(primary_intc->root_domain,
>>>>>> hwirq);
>>>>>>
>>>>>> ÂÂÂÂÂÂÂ pr_debug("irq-xilinx: hwirq=%d, irq=%d\n", hwirq, irq);
>>>>>
>>>>> I have the ugly feeling I'm reading the same code twice... Surely you
>>>>> can
>>>>> make these two functions common code.
>>>>
>>>> I have some questions regarding this.
>>>> I have updated one patchset which is adding support for Microblaze SMP.
>>>> And when I was looking at current wiring of this driver I have decided
>>>> to change it.
>>>>
>>>> I have enabled GENERIC_IRQ_MULTI_HANDLER and HANDLE_DOMAIN_IRQ.
>>>> This driver calls set_handle_irq(xil_intc_handle_irq)
>>>> and MB do_IRQ() call handle_arch_irq()
>>>> and IRQ routine here is using handle_domain_irq().
>>>>
>>>> I would expect that this chained IRQ handler can also use
>>>> handle_domain_irq().
>>>>
>>>> Is that correct understanding?
>>>
>>> handle_domain_irq() implies that you have a set of pt_regs, representing
>>> the context you interrupted. You can't fake that up, so I can't see how
>>> you use it in a chained context.
>>
>> ok. What's your recommendation for chained controller? Just go with
>> irq_find_mapping?
> 
> For now, yes. I have (distant) plans to improve this.

Thanks.
Michal