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Message-ID: <alpine.DEB.2.02.1403131442480.18573@ionos.tec.linutronix.de>
Date: Thu, 13 Mar 2014 15:32:05 +0100 (CET)
From: Thomas Gleixner <tglx@...utronix.de>
To: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
cc: Hans de Goede <hdegoede@...hat.com>,
LKML <linux-kernel@...r.kernel.org>,
Carlo Caione <carlo.caione@...il.com>,
Russell King <linux@....linux.org.uk>
Subject: Re: [PATCH] irq: Add a new IRQF_ACK_BEFORE_UNMASK irq flagq
On Thu, 13 Mar 2014, Sebastian Andrzej Siewior wrote:
> One side note: Since we need to specify IRQCHIP_EOI_THREADED and
> handle_fasteoi_late_irq() as the handler, would it be easily doable to use
> the handle_fasteoi_irq() handler and skip the EOI in the threaded mode?
> But if it creates a mess then leave it as it is.
Yeah, I was looking into that already. Patch below.
To resemble the late version you need to add IRQCHIP_EOI_THREADED and
IRQCHIP_EOI_IF_HANDLED to your irq chip.
Thanks,
tglx
Index: tip/include/linux/irq.h
===================================================================
--- tip.orig/include/linux/irq.h
+++ tip/include/linux/irq.h
@@ -355,6 +355,8 @@ 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),
@@ -363,6 +365,7 @@ 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 */
Index: tip/kernel/irq/chip.c
===================================================================
--- tip.orig/kernel/irq/chip.c
+++ tip/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(struc
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(struc
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, str
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);
}
/**
Index: tip/kernel/irq/internals.h
===================================================================
--- tip.orig/kernel/irq/internals.h
+++ tip/kernel/irq/internals.h
@@ -74,6 +74,7 @@ extern void irq_percpu_enable(struct irq
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);
Index: tip/kernel/irq/manage.c
===================================================================
--- tip.orig/kernel/irq/manage.c
+++ tip/kernel/irq/manage.c
@@ -748,7 +748,7 @@ 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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