On 07/03/2019 17:24, Fabien DESSENNE wrote:
> Hi
>
>
>> -----Original Message-----
>> From: Marc Zyngier <marc.zyng...@arm.com>
>> Sent: jeudi 7 mars 2019 17:40
>> To: Fabien DESSENNE <fabien.desse...@st.com>; Thomas Gleixner
>> <t...@linutronix.de>; Jason Cooper <ja...@lakedaemon.net>; Maxime Coquelin
>> <mcoquelin.st...@gmail.com>; Alexandre TORGUE
>> <alexandre.tor...@st.com>; linux-kernel@vger.kernel.org; linux-stm32@st-md-
>> mailman.stormreply.com; linux-arm-ker...@lists.infradead.org
>> Cc: Benjamin GAIGNARD <benjamin.gaign...@st.com>
>> Subject: Re: [PATCH] irqchip: stm32: don't set rising configuration
>> registers at init
>>
>> On 07/03/2019 16:15, Fabien Dessenne wrote:
>>> The rising configuration status register (rtsr) is not banked.
>>> As it is shared with the co-processor, it should not be written at
>>> probe time, else the co-processor configuration will be lost.
>>>
>>> Signed-off-by: Fabien Dessenne <fabien.desse...@st.com>
>>
>> Fixes:?
>>
>>> ---
>>> drivers/irqchip/irq-stm32-exti.c | 5 -----
>>> 1 file changed, 5 deletions(-)
>>>
>>> diff --git a/drivers/irqchip/irq-stm32-exti.c
>>> b/drivers/irqchip/irq-stm32-exti.c
>>> index 6edfd4b..ff8a84f 100644
>>> --- a/drivers/irqchip/irq-stm32-exti.c
>>> +++ b/drivers/irqchip/irq-stm32-exti.c
>>> @@ -716,7 +716,6 @@ stm32_exti_chip_data *stm32_exti_chip_init(struct
>> stm32_exti_host_data *h_data,
>>> const struct stm32_exti_bank *stm32_bank;
>>> struct stm32_exti_chip_data *chip_data;
>>> void __iomem *base = h_data->base;
>>> - u32 irqs_mask;
>>>
>>> stm32_bank = h_data->drv_data->exti_banks[bank_idx];
>>> chip_data = &h_data->chips_data[bank_idx]; @@ -725,10 +724,6 @@
>>> stm32_exti_chip_data *stm32_exti_chip_init(struct stm32_exti_host_data
>>> *h_data,
>>>
>>> raw_spin_lock_init(&chip_data->rlock);
>>>
>>> - /* Determine number of irqs supported */
>>> - writel_relaxed(~0UL, base + stm32_bank->rtsr_ofst);
>>> - irqs_mask = readl_relaxed(base + stm32_bank->rtsr_ofst);
>>> -
>>
>> And I guess you don't need to find out the number of supported IRQs?
>
> That's correct, this informed is useless : irqs_mask is never used (it used
> to be output in a log for debug purpose.and the log has been removed)
>
>
>>
>> Also, a handful of lines down, you're writing again to the same register.
>> Why isn't
>> that a problem?
>
> It's obviously a problem : another patch is missing, I am going to add it in
> v2.
> Thanks for pointing this out!
You are also happily writing to that register in other places via
stm32_exti_set_bit and co. All that is done without any cooperation with
the coprocessor (whatever that is...), so I really wonder if it all
works by magic or luck...
Thanks,
M.
--
Jazz is not dead. It just smells funny...
