Re: [PATCH v2 1/2] irqchip/stm32: Add irq retrigger support

[Alexandre Torgue <alexandre.torgue@st.com>]

On 2/19/20 12:43 PM, Marc Zyngier wrote:
> On 2020-02-19 11:33, Alexandre Torgue wrote:
>> Fix Marc email address
>>
>> On 2/18/20 2:12 PM, Alexandre Torgue wrote:
>>> This commit introduces retrigger support for stm32_ext_h chip.
>>> It consists to rise the GIC interrupt mapped to an EXTI line.
>>>
>>> Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>
>>>
>>> diff --git a/drivers/irqchip/irq-stm32-exti.c 
>>> b/drivers/irqchip/irq-stm32-exti.c
>>> index e00f2fa27f00..c971d115edb4 100644
>>> --- a/drivers/irqchip/irq-stm32-exti.c
>>> +++ b/drivers/irqchip/irq-stm32-exti.c
>>> @@ -604,12 +604,24 @@ static void stm32_exti_h_syscore_deinit(void)
>>>       unregister_syscore_ops(&stm32_exti_h_syscore_ops);
>>>   }
>>>   +static int stm32_exti_h_retrigger(struct irq_data *d)
>>> +{
>>> +    struct stm32_exti_chip_data *chip_data = 
>>> irq_data_get_irq_chip_data(d);
>>> +    const struct stm32_exti_bank *stm32_bank = chip_data->reg_bank;
>>> +    void __iomem *base = chip_data->host_data->base;
>>> +    u32 mask = BIT(d->hwirq % IRQS_PER_BANK);
>>> +
>>> +    writel_relaxed(mask, base + stm32_bank->swier_ofst);
>>> +
>>> +    return irq_chip_retrigger_hierarchy(d);
> 
> Calling irq_chip_retrigger_hierarchy here is really odd. If the write
> above has the effect of making the interrupt pending again, why do you
> need to force the retrigger any further?

To be honest, as we use hierarchical irq_chip, I thought it was the way 
to follow (to retrigger parent irq_chip). It makes maybe no sens here.
The most important to regenerate gic interrupt (associate to the exti 
line) is to write in SWIER register.

Alex

> 
>              M.