linux-kernel - Re: [PATCH v2 1/2] irqchip: stm32: Optimizes and cleans up stm32-exti irq

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Message-ID: <CAFvLkMTzaFODziZC3fFGYu+F=RuMBx5tFgA1q2UFSk4KyfuU5A@mail.gmail.com>
Date:   Fri, 23 Feb 2018 18:37:04 +0100
From:   Radosław Pietrzyk <radoslaw.pietrzyk@...il.com>
To:     Ludovic BARRE <ludovic.barre@...com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Benjamin Gaignard <benjamin.gaignard@...aro.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        open list <linux-kernel@...r.kernel.org>,
        "moderated list:ARM/STM32 ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>, linux-gpio@...r.kernel.org
Subject: Re: [PATCH v2 1/2] irqchip: stm32: Optimizes and cleans up stm32-exti irq_domain

I don't fully get it to be honest. If interrupt is pending it must
have been enabled (unmasked) and requires to be handled acked. It will
be acked by irq_chip.irq_ack handler within the edge handler.
Therefore this additional acking is meaningless.

2018-02-23 16:46 GMT+01:00 Ludovic BARRE <ludovic.barre@...com>:
> hi Radoslaw
>
> The gpio-keys tests it's now functional on H7, great.
> However the gpio-key test only the bank1 (like stm32f429).
> Like the H7 introduce the multi-bank management,
> we must perform complementary test.
>
> comment below about ack in handler
>
>
> On 02/23/2018 09:31 AM, Radoslaw Pietrzyk wrote:
>>
>> - discards setting handle_simple_irq handler for hierarchy interrupts
>> - removes acking in chained irq handler as this is done by
>> irq_chip itself inside handle_edge_irq
>> - removes unneeded irq_domain_ops.xlate callback
>>
>> Signed-off-by: Radoslaw Pietrzyk <radoslaw.pietrzyk@...il.com>
>> ---
>>   drivers/irqchip/irq-stm32-exti.c | 13 -------------
>>   1 file changed, 13 deletions(-)
>>
>> diff --git a/drivers/irqchip/irq-stm32-exti.c
>> b/drivers/irqchip/irq-stm32-exti.c
>> index 36f0fbe..8013a87 100644
>> --- a/drivers/irqchip/irq-stm32-exti.c
>> +++ b/drivers/irqchip/irq-stm32-exti.c
>> @@ -79,13 +79,6 @@ static unsigned long stm32_exti_pending(struct
>> irq_chip_generic *gc)
>>         return irq_reg_readl(gc, stm32_bank->pr_ofst);
>>   }
>>   -static void stm32_exti_irq_ack(struct irq_chip_generic *gc, u32 mask)
>> -{
>> -       const struct stm32_exti_bank *stm32_bank = gc->private;
>> -
>> -       irq_reg_writel(gc, mask, stm32_bank->pr_ofst);
>> -}
>> -
>>   static void stm32_irq_handler(struct irq_desc *desc)
>>   {
>>         struct irq_domain *domain = irq_desc_get_handler_data(desc);
>> @@ -106,7 +99,6 @@ static void stm32_irq_handler(struct irq_desc *desc)
>>                         for_each_set_bit(n, &pending, IRQS_PER_BANK) {
>>                                 virq = irq_find_mapping(domain, irq_base +
>> n);
>>                                 generic_handle_irq(virq);
>> -                               stm32_exti_irq_ack(gc, BIT(n));
>
>
> the while loop " while ((pending = " has been introduce while original
> upstream of this driver in V2 to V3
> https://patchwork.ozlabs.org/patch/604190/
> https://patchwork.ozlabs.org/patch/665242/
>
> the "ack" is needed to acknowledge the irq which are handled and which is
> not the original irq for which we enter.
>
>>                         }
>>                 }
>>         }
>> @@ -176,16 +168,12 @@ static int stm32_irq_set_wake(struct irq_data *data,
>> unsigned int on)
>>   static int stm32_exti_alloc(struct irq_domain *d, unsigned int virq,
>>                             unsigned int nr_irqs, void *data)
>>   {
>> -       struct irq_chip_generic *gc;
>>         struct irq_fwspec *fwspec = data;
>>         irq_hw_number_t hwirq;
>>         hwirq = fwspec->param[0];
>> -       gc = irq_get_domain_generic_chip(d, hwirq);
>>         irq_map_generic_chip(d, virq, hwirq);
>> -       irq_domain_set_info(d, virq, hwirq, &gc->chip_types->chip, gc,
>> -                           handle_simple_irq, NULL, NULL);
>
>
> I see if it is not disturb the multi-bank.
>
>>         return 0;
>>   }
>> @@ -200,7 +188,6 @@ static void stm32_exti_free(struct irq_domain *d,
>> unsigned int virq,
>>     struct irq_domain_ops irq_exti_domain_ops = {
>>         .map    = irq_map_generic_chip,
>> -       .xlate  = irq_domain_xlate_onetwocell,
>>         .alloc  = stm32_exti_alloc,
>>         .free   = stm32_exti_free,
>>   };
>>
>
> BR
> Ludo