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Message-ID: <5321F647.1060506@redhat.com>
Date: Thu, 13 Mar 2014 19:17:43 +0100
From: Hans de Goede <hdegoede@...hat.com>
To: Thomas Gleixner <tglx@...utronix.de>,
Maxime Ripard <maxime.ripard@...e-electrons.com>
CC: linux-arm-kernel@...ts.infradead.org,
devicetree <devicetree@...r.kernel.org>,
linux-kernel@...r.kernel.org, linux-sunxi@...glegroups.com
Subject: Re: [PATCH v3 1/4] irq: Add a new IRQCHIP_EOI_THREADED flag
Hi,
On 03/13/2014 07:03 PM, Hans de Goede wrote:
> From: Thomas Gleixner <tglx@...utronix.de>
>
> This flag must be used in combination with handle_fasteoi_irq, when set
> handle_fasteoi_irq will delay the calling of chip->irq_eoi until the threaded
> handler has run.
>
> Reviewed-by: Hans de Goede <hdegoede@...hat.com>
> Tested-by: Hans de Goede <hdegoede@...hat.com>
> Signed-off-by: Hans de Goede <hdegoede@...hat.com>
Note: I just noticed that we should also update the comment above
kernel/irq/chip.c: cond_unmask_irq() to no longer mention its gets called
from handle_fasteoi_irq() as that is no longer true.
Regards,
Hans
> ---
> include/linux/irq.h | 3 +++
> kernel/irq/chip.c | 48 ++++++++++++++++++++++++++++++++++++++++--------
> kernel/irq/internals.h | 1 +
> kernel/irq/manage.c | 2 +-
> 4 files changed, 45 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/irq.h b/include/linux/irq.h
> index 7dc1003..0f036fb 100644
> --- a/include/linux/irq.h
> +++ b/include/linux/irq.h
> @@ -349,6 +349,8 @@ struct irq_chip {
> * IRQCHIP_ONOFFLINE_ENABLED: Only call irq_on/off_line callbacks
> * when irq enabled
> * IRQCHIP_SKIP_SET_WAKE: Skip chip.irq_set_wake(), for this irq chip
> + * IRQCHIP_ONESHOT_SAFE: One shot does not require mask/unmask
> + * IRQCHIP_EOI_THREADED: Chip requires eoi() on unmask in threaded mode
> */
> enum {
> IRQCHIP_SET_TYPE_MASKED = (1 << 0),
> @@ -357,6 +359,7 @@ enum {
> IRQCHIP_ONOFFLINE_ENABLED = (1 << 3),
> IRQCHIP_SKIP_SET_WAKE = (1 << 4),
> IRQCHIP_ONESHOT_SAFE = (1 << 5),
> + IRQCHIP_EOI_THREADED = (1 << 6),
> };
>
> /* This include will go away once we isolated irq_desc usage to core code */
> diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
> index dc04c16..6397df2 100644
> --- a/kernel/irq/chip.c
> +++ b/kernel/irq/chip.c
> @@ -281,6 +281,19 @@ void unmask_irq(struct irq_desc *desc)
> }
> }
>
> +void unmask_threaded_irq(struct irq_desc *desc)
> +{
> + struct irq_chip *chip = desc->irq_data.chip;
> +
> + if (chip->flags & IRQCHIP_EOI_THREADED)
> + chip->irq_eoi(&desc->irq_data);
> +
> + if (chip->irq_unmask) {
> + chip->irq_unmask(&desc->irq_data);
> + irq_state_clr_masked(desc);
> + }
> +}
> +
> /*
> * handle_nested_irq - Handle a nested irq from a irq thread
> * @irq: the interrupt number
> @@ -435,6 +448,27 @@ static inline void preflow_handler(struct irq_desc *desc)
> static inline void preflow_handler(struct irq_desc *desc) { }
> #endif
>
> +static void cond_unmask_eoi_irq(struct irq_desc *desc, struct irq_chip *chip)
> +{
> + if (!(desc->istate & IRQS_ONESHOT)) {
> + chip->irq_eoi(&desc->irq_data);
> + return;
> + }
> + /*
> + * We need to unmask in the following cases:
> + * - Oneshot irq which did not wake the thread (caused by a
> + * spurious interrupt or a primary handler handling it
> + * completely).
> + */
> + if (!irqd_irq_disabled(&desc->irq_data) &&
> + irqd_irq_masked(&desc->irq_data) && !desc->threads_oneshot) {
> + chip->irq_eoi(&desc->irq_data);
> + unmask_irq(desc);
> + } else if (!(chip->flags & IRQCHIP_EOI_THREADED)) {
> + chip->irq_eoi(&desc->irq_data);
> + }
> +}
> +
> /**
> * handle_fasteoi_irq - irq handler for transparent controllers
> * @irq: the interrupt number
> @@ -448,6 +482,8 @@ static inline void preflow_handler(struct irq_desc *desc) { }
> void
> handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
> {
> + struct irq_chip *chip = desc->irq_data.chip;
> +
> raw_spin_lock(&desc->lock);
>
> if (unlikely(irqd_irq_inprogress(&desc->irq_data)))
> @@ -473,18 +509,14 @@ handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
> preflow_handler(desc);
> handle_irq_event(desc);
>
> - if (desc->istate & IRQS_ONESHOT)
> - cond_unmask_irq(desc);
> + cond_unmask_eoi_irq(desc, chip);
>
> -out_eoi:
> - desc->irq_data.chip->irq_eoi(&desc->irq_data);
> -out_unlock:
> raw_spin_unlock(&desc->lock);
> return;
> out:
> - if (!(desc->irq_data.chip->flags & IRQCHIP_EOI_IF_HANDLED))
> - goto out_eoi;
> - goto out_unlock;
> + if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED))
> + chip->irq_eoi(&desc->irq_data);
> + raw_spin_unlock(&desc->lock);
> }
>
> /**
> diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
> index 001fa5b..e98bb56 100644
> --- a/kernel/irq/internals.h
> +++ b/kernel/irq/internals.h
> @@ -73,6 +73,7 @@ extern void irq_percpu_enable(struct irq_desc *desc, unsigned int cpu);
> extern void irq_percpu_disable(struct irq_desc *desc, unsigned int cpu);
> extern void mask_irq(struct irq_desc *desc);
> extern void unmask_irq(struct irq_desc *desc);
> +extern void unmask_threaded_irq(struct irq_desc *desc);
>
> extern void init_kstat_irqs(struct irq_desc *desc, int node, int nr);
>
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index 481a13c..9147fef 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -718,7 +718,7 @@ again:
>
> if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
> irqd_irq_masked(&desc->irq_data))
> - unmask_irq(desc);
> + unmask_threaded_irq(desc);
>
> out_unlock:
> raw_spin_unlock_irq(&desc->lock);
>
--
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