From: Maxime Coquelin <mcoquelin.stm32@gmail.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Jason Cooper <jason@lakedaemon.net>,
Marc Zyngier <marc.zyngier@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Rob Herring <robh+dt@kernel.org>,
"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Daniel Thompson <daniel.thompson@linaro.org>,
Bruno Herrera <bruherrera@gmail.com>,
Lee Jones <lee.jones@linaro.org>
Subject: Re: [PATCH v2 2/9] drivers: irqchip: Add STM32 external interrupts support
Date: Tue, 19 Apr 2016 10:00:29 +0200 [thread overview]
Message-ID: <CALszF6AKS2-SxQKTM-hrVfB2tMZS_21jRx9HtnHVACO1o=1Fgw@mail.gmail.com> (raw)
In-Reply-To: <CACRpkdaiE1cJM6uq_bQuRS2NJTwniPREBsgwuxEjRjB5yTfc9Q@mail.gmail.com>
Hi Linus,
Sorry for the late reply, I was off last week.
2016-04-08 11:38 GMT+02:00 Linus Walleij <linus.walleij@linaro.org>:
> On Thu, Mar 31, 2016 at 5:09 PM, Maxime Coquelin
> <mcoquelin.stm32@gmail.com> wrote:
>
>> +static void stm32_irq_handler(struct irq_desc *desc)
>> +{
>> + struct irq_domain *domain = irq_desc_get_handler_data(desc);
>> + struct irq_chip_generic *gc = domain->gc->gc[0];
>> + struct irq_chip *chip = irq_desc_get_chip(desc);
>> + unsigned long pending;
>> + int n;
>> +
>> + chained_irq_enter(chip, desc);
>> +
>> + pending = irq_reg_readl(gc, EXTI_PR);
>> + for_each_set_bit(n, &pending, BITS_PER_LONG) {
>> + generic_handle_irq(irq_find_mapping(domain, n));
>> + }
>> +
>> + chained_irq_exit(chip, desc);
>> +}
>
> Is this one of those cases where you should re-read the status register
> on every iteration, so as to avoid exiting and immediately re-entering
> the irq handler?
>
> C.g irq-vic.c:
>
> static int handle_one_vic(struct vic_device *vic, struct pt_regs *regs)
> {
> u32 stat, irq;
> int handled = 0;
>
> while ((stat = readl_relaxed(vic->base + VIC_IRQ_STATUS))) {
> irq = ffs(stat) - 1;
> handle_domain_irq(vic->domain, irq, regs);
> handled = 1;
> }
>
> return handled;
> }
Indeed, it would be better doing it like this.
Do you think I could even do this with two nested loops to reduce the
number of reg accesses?
It would look like this (just compiled, not tested):
static void stm32_irq_handler(struct irq_desc *desc)
{
struct irq_domain *domain = irq_desc_get_handler_data(desc);
struct irq_chip_generic *gc = domain->gc->gc[0];
struct irq_chip *chip = irq_desc_get_chip(desc);
unsigned long pending;
int n;
chained_irq_enter(chip, desc);
while ((pending = irq_reg_readl(gc, EXTI_PR))) {
for_each_set_bit(n, &pending, BITS_PER_LONG) {
generic_handle_irq(irq_find_mapping(domain, n));
}
}
chained_irq_exit(chip, desc);
}
Thanks,
Maxime
next prev parent reply other threads:[~2016-04-19 8:00 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-31 15:09 [PATCH v2 0/9] Add STM32 EXTI interrupt controller support Maxime Coquelin
2016-03-31 15:09 ` [PATCH v2 1/9] Documentation: dt-bindings: Document STM32 EXTI controller bindings Maxime Coquelin
2016-04-04 5:15 ` Rob Herring
2016-04-04 14:32 ` Maxime Coquelin
2016-03-31 15:09 ` [PATCH v2 2/9] drivers: irqchip: Add STM32 external interrupts support Maxime Coquelin
2016-04-08 9:38 ` Linus Walleij
2016-04-19 8:00 ` Maxime Coquelin [this message]
2016-04-29 8:45 ` Linus Walleij
2016-04-08 9:47 ` Linus Walleij
2016-03-31 15:09 ` [PATCH v2 3/9] ARM: STM32: Select external interrupts controller Maxime Coquelin
2016-03-31 15:09 ` [PATCH v2 4/9] ARM: dts: Add EXTI controller node to stm32f429 Maxime Coquelin
2016-03-31 15:09 ` [PATCH v2 5/9] Documentation: dt-bindings: Add IRQ related properties of STM32 pinctrl Maxime Coquelin
2016-04-04 5:15 ` Rob Herring
2016-03-31 15:09 ` [PATCH v2 6/9] pinctrl: Add IRQ support to STM32 gpios Maxime Coquelin
2016-04-08 9:43 ` Linus Walleij
2016-04-19 9:04 ` Maxime Coquelin
2016-04-29 8:53 ` Linus Walleij
2016-04-29 8:55 ` Linus Walleij
2016-04-29 11:19 ` Maxime Coquelin
2016-04-30 11:32 ` Linus Walleij
2016-05-02 8:32 ` Maxime Coquelin
2016-03-31 15:09 ` [PATCH v2 7/9] ARM: dts: Add GPIO irq support to STM2F429 Maxime Coquelin
2016-03-31 15:09 ` [PATCH v2 8/9] ARM: dts: Declare push button as GPIO key on stm32f429 Disco board Maxime Coquelin
2016-03-31 15:09 ` [PATCH v2 9/9] ARM: config: Enable GPIO Key driver in stm32_defconfig Maxime Coquelin
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