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

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Message-ID: <DC9062E8-42E3-4139-99F9-157DEAF5DB7B@flygoat.com>
Date:   Wed, 25 Mar 2020 20:48:55 +0800
From:   Jiaxun Yang <jiaxun.yang@...goat.com>
To:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>
CC:     linux-mips@...r.kernel.org, Huacai Chen <chenhc@...ote.com>,
        Marc Zyngier <maz@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Allison Randal <allison@...utok.net>,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v8 06/11] irqchip: mips-cpu: Convert to simple domain



于 2020年3月25日 GMT+08:00 下午8:37:42, Thomas Bogendoerfer <tsbogend@...ha.franken.de> 写到:
>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@...goat.com>
>> Co-developed-by: Huacai Chen <chenhc@...ote.com>
>> Signed-off-by: Huacai Chen <chenhc@...ote.com>
>> Reviewed-by: Marc Zyngier <maz@...nel.org>
>> ---
>>  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