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Subject: Re: [PATCH V14 14/15] irqchip / ACPI: Introduce ACPI_IRQ_MODEL_LPIC
 for LoongArch
To:     Marc Zyngier <maz@kernel.org>
Cc:     Thomas Gleixner <tglx@linutronix.de>, linux-kernel@vger.kernel.org,
        Hanjun Guo <guohanjun@huawei.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Huacai Chen <chenhuacai@loongson.cn>
References: <1656837932-18257-1-git-send-email-lvjianmin@loongson.cn>
 <1656837932-18257-15-git-send-email-lvjianmin@loongson.cn>
 <87y1x5krjd.wl-maz@kernel.org>
From:   Jianmin Lv <lvjianmin@loongson.cn>
Message-ID: <f76927be-8c8c-5bbe-ef5c-a63f4a09b29c@loongson.cn>
Date:   Fri, 8 Jul 2022 11:17:59 +0800
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On 2022/7/7 下午8:59, Marc Zyngier wrote:
> On Sun, 03 Jul 2022 09:45:31 +0100,
> Jianmin Lv <lvjianmin@loongson.cn> wrote:
>>
>> For LoongArch, ACPI_IRQ_MODEL_LPIC is introduced, and then the
>> callback acpi_get_gsi_domain_id and acpi_gsi_to_irq_fallback are
>> implemented.
>>
>> The acpi_get_gsi_domain_id callback returns related fwnode handle
>> of irqdomain for different GSI range.
>>
>> The acpi_gsi_to_irq_fallback will create new mapping for gsi when
>> the mapping of it is not found.
>>
>> Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
>> ---
>>   drivers/acpi/bus.c                  |  3 +++
>>   drivers/irqchip/irq-loongarch-cpu.c | 37 +++++++++++++++++++++++++++++++++++++
>>   include/linux/acpi.h                |  1 +
>>   3 files changed, 41 insertions(+)
>>
>> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
>> index 86fa61a..63fbf00 100644
>> --- a/drivers/acpi/bus.c
>> +++ b/drivers/acpi/bus.c
>> @@ -1145,6 +1145,9 @@ static int __init acpi_bus_init_irq(void)
>>   	case ACPI_IRQ_MODEL_PLATFORM:
>>   		message = "platform specific model";
>>   		break;
>> +	case ACPI_IRQ_MODEL_LPIC:
>> +		message = "LPIC";
>> +		break;
>>   	default:
>>   		pr_info("Unknown interrupt routing model\n");
>>   		return -ENODEV;
>> diff --git a/drivers/irqchip/irq-loongarch-cpu.c b/drivers/irqchip/irq-loongarch-cpu.c
>> index c2f7411..1b241d7 100644
>> --- a/drivers/irqchip/irq-loongarch-cpu.c
>> +++ b/drivers/irqchip/irq-loongarch-cpu.c
>> @@ -15,6 +15,41 @@
>>   
>>   static struct irq_domain *irq_domain;
>>   
>> +static int lpic_gsi_to_irq(u32 gsi)
>> +{
>> +	/* Only pch irqdomain transferring is required for LoongArch. */
>> +	if (gsi >= GSI_MIN_PCH_IRQ && gsi <= GSI_MAX_PCH_IRQ)
>> +		return acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH);
>> +	return -1;
> 
> The expected return value on failure is 0 (which indicates that no
> interrupt was mapped). Here, things will break as acpi_gsi_to_irq()
> stores the result as unsigned, and compares the result to 0.
> 

Ok, thanks, I'll change the return value to 0 on failure and change 
return type to unsigned int.


> 	M.
>