From: Valentin Schneider <valentin.schneider@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Jason Cooper <jason@lakedaemon.net>
Subject: Re: [RFC PATCH] irqchip/gic: Implement irq_chip->irq_retrigger()
Date: Fri, 10 Jul 2020 18:08:01 +0100 [thread overview]
Message-ID: <jhjr1tjl2mm.mognet@arm.com> (raw)
In-Reply-To: <87tuyfxria.wl-maz@kernel.org>
On 10/07/20 17:29, Marc Zyngier wrote:
> On Fri, 10 Jul 2020 15:56:42 +0100,
> Valentin Schneider <valentin.schneider@arm.com> wrote:
[...]
>> Implement irq_chip.irq_retrigger() for both GICs.
>
> Although I am very grateful for the whole documentation, I'd rather
> have a slightly more condensed changelog that documents the
> implementation of the retrigger callback! ;-)
>
Hah, indeed! I was relatively unsure about that whole thing, hence why I
sent it as RFC with a wall of text attached. I'll probably strip out the
GIC doc snippets for the "actual" changelog, and talk about the *contents*
of the patch some more.
>>
>> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
>> ---
>> drivers/irqchip/irq-gic-v3.c | 7 +++++++
>> drivers/irqchip/irq-gic.c | 6 ++++++
>> 2 files changed, 13 insertions(+)
>>
>> diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
>> index cc46bc2d634b..c025e8b51464 100644
>> --- a/drivers/irqchip/irq-gic-v3.c
>> +++ b/drivers/irqchip/irq-gic-v3.c
>> @@ -1207,6 +1207,11 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
>> #define gic_smp_init() do { } while(0)
>> #endif
>>
>> +static int gic_retrigger(struct irq_data *data)
>> +{
>> + return gic_irq_set_irqchip_state(data, IRQCHIP_STATE_PENDING, true);
>
> If I'm not mistaken, check_irq_resend() requires a non-zero return
> value if the retrigger has succeeded. So something like
>
> return !gic_irq_set_irqchip_state(data, IRQCHIP_STATE_PENDING, true);
>
> would be more appropriate.
>
Aye, you're right. And while we're at it, we probably still don't want to
fallback to irq_sw_resend() if the retrigger fails, so we should add some
irqd_set_handle_enforce_irqctx() somewhere in the GICs or plainly deselect
CONFIG_HARDIRQS_SW_RESEND.
I'm not very familiar with LPIs just yet, but seeing as they too use
handle_fasteoi_irq() and can't get retriggered, I'd rather play it safe.
This brings me to another point: while this boots just
fine, I didn't get to test out IRQs marked with IRQS_PENDING. IIUC
enable_irq_wake() should give me a decent trail - I see serial_core making
use of it. I'll go give suspend a try.
> Otherwise, looks good.
>
Thanks for having a look!
> Thanks,
>
> M.
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prev parent reply other threads:[~2020-07-10 17:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-10 14:56 [RFC PATCH] irqchip/gic: Implement irq_chip->irq_retrigger() Valentin Schneider
2020-07-10 16:29 ` Marc Zyngier
2020-07-10 17:08 ` Valentin Schneider [this message]
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