Re: [PATCH v8 06/11] irqchip: mips-cpu: Convert to simple domain

[Jiaxun Yang]

ä 2020å3æ25æ GMT+08:00 äå8:37:42, Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> åå:
>On Wed, Mar 25, 2020 at 11:54:59AM +0800, Jiaxun Yang wrote:
>> The old code is using legacy domain to setup irq_domain for CPU
>interrupts
>> which requires irq_desc to be preallocated.
>> 
>> However, when MIPS_CPU_IRQ_BASE >= 16, irq_desc for CPU IRQs may end
>up
>> unallocated and lead to incorrect behavior.
>> 
>> Thus we convert the legacy domain to simple domain which can allocate
>> irq_desc during initialization.
>> 
>> Signed-off-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
>> Co-developed-by: Huacai Chen <chenhc@xxxxxxxxxx>
>> Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx>
>> Reviewed-by: Marc Zyngier <maz@xxxxxxxxxx>
>> ---
>>  drivers/irqchip/irq-mips-cpu.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/irqchip/irq-mips-cpu.c
>b/drivers/irqchip/irq-mips-cpu.c
>> index 95d4fd8f7a96..c3cf7fa76424 100644
>> --- a/drivers/irqchip/irq-mips-cpu.c
>> +++ b/drivers/irqchip/irq-mips-cpu.c
>> @@ -251,7 +251,7 @@ static void __init __mips_cpu_irq_init(struct
>device_node *of_node)
>>  	clear_c0_status(ST0_IM);
>>  	clear_c0_cause(CAUSEF_IP);
>>  
>> -	irq_domain = irq_domain_add_legacy(of_node, 8, MIPS_CPU_IRQ_BASE,
>0,
>> +	irq_domain = irq_domain_add_simple(of_node, 8, MIPS_CPU_IRQ_BASE,
>>  					   &mips_cpu_intc_irq_domain_ops,
>>  					   NULL);
>
>this breaks at least IP30 and guess it will break every platform where
>MIPS_CPU_IRQ_BASE == 0. add_legacy will always do
>irq_domain_associate_many(),
>while add_simple doesn't do it, if first_irq == 0.
>
>Marc, what is the reason not doing it all the time ? What's the correct
>way here to work with irq_domain_add_simple() in this case ?
 
I guess there is a inconsistent about whether IRQ 0 is a valid IRQ.

In many places we consider IRQ 0 is invalid but here it should be valid.

Thanks.


>
>Thomas.

-- 
Jiaxun Yang