[PATCH v3 0/4] irq: sun4i IRQ 0 / ENMI fixes

[PATCH v3 0/4] irq: sun4i IRQ 0 / ENMI fixes

[Hans de Goede]

Hi All,

Here is v3 of my sun4i IRQ 0 / ENMI fixes patch-set, changelog below:

v2:

PATCH 1/4 irq: Add handle_fasteoi_late_irq irq handler
New patch by Thomas Gleixner, adding a new irq handler with the "call eoi
after the irq-handler has run its course" behavior we need to avoid double
irqs on the ENMI.

PATCH 2/4 irqchip: sun4i: Fix irq 0 not working
Modified to avoid spurious calls to the irq 0 handler, as suggested by Maxime.

PATCH 3/4 irqchip: sun4i: Fix a comment about mask register
Added Maxime's Acked-by

PATCH 4/4 irqchip: sun4i: Use handle_fasteoi_late_irq for the
New patch switching the handler for irq 0 over to the new
handle_fasteoi_late_irq handler, thereby fixing the double interrupts issue


v3:

PATCH 1/4 irq: Add a new IRQCHIP_EOI_THREADED flag
New patch by Thomas Gleixner, replacing his "irq: Add handle_fasteoi_late_irq
irq handler" patch.

PATCH 2/4 irqchip: sun4i: Fix irq 0 not working
Added Maxime's Acked-by

PATCH 4/4 irqchip: sun4i: Don't ack IRQs != 0, fix acking of IRQ
New patch replacing my "irqchip: sun4i: Use handle_fasteoi_late_irq ..."
patch. This also drops acking for IRQ != 0. I've done both changes in
one patch to avoid regressing for IRQ 0.


Thanks for all the help to all involved.

Regards,

Hans

[PATCH v3 0/4] irq: sun4i IRQ 0 / ENMI fixes

[Hans de Goede]

Hi All,

Here is v3 of my sun4i IRQ 0 / ENMI fixes patch-set, changelog below:

v2:

PATCH 1/4 irq: Add handle_fasteoi_late_irq irq handler
New patch by Thomas Gleixner, adding a new irq handler with the "call eoi
after the irq-handler has run its course" behavior we need to avoid double
irqs on the ENMI.

PATCH 2/4 irqchip: sun4i: Fix irq 0 not working
Modified to avoid spurious calls to the irq 0 handler, as suggested by Maxime.

PATCH 3/4 irqchip: sun4i: Fix a comment about mask register
Added Maxime's Acked-by

PATCH 4/4 irqchip: sun4i: Use handle_fasteoi_late_irq for the
New patch switching the handler for irq 0 over to the new
handle_fasteoi_late_irq handler, thereby fixing the double interrupts issue


v3:

PATCH 1/4 irq: Add a new IRQCHIP_EOI_THREADED flag
New patch by Thomas Gleixner, replacing his "irq: Add handle_fasteoi_late_irq
irq handler" patch.

PATCH 2/4 irqchip: sun4i: Fix irq 0 not working
Added Maxime's Acked-by

PATCH 4/4 irqchip: sun4i: Don't ack IRQs != 0, fix acking of IRQ
New patch replacing my "irqchip: sun4i: Use handle_fasteoi_late_irq ..."
patch. This also drops acking for IRQ != 0. I've done both changes in
one patch to avoid regressing for IRQ 0.


Thanks for all the help to all involved.

Regards,

Hans

[PATCH v3 0/4] irq: sun4i IRQ 0 / ENMI fixes

[Hans de Goede]

Hi All,

Here is v3 of my sun4i IRQ 0 / ENMI fixes patch-set, changelog below:

v2:

PATCH 1/4 irq: Add handle_fasteoi_late_irq irq handler
New patch by Thomas Gleixner, adding a new irq handler with the "call eoi
after the irq-handler has run its course" behavior we need to avoid double
irqs on the ENMI.

PATCH 2/4 irqchip: sun4i: Fix irq 0 not working
Modified to avoid spurious calls to the irq 0 handler, as suggested by Maxime.

PATCH 3/4 irqchip: sun4i: Fix a comment about mask register
Added Maxime's Acked-by

PATCH 4/4 irqchip: sun4i: Use handle_fasteoi_late_irq for the
New patch switching the handler for irq 0 over to the new
handle_fasteoi_late_irq handler, thereby fixing the double interrupts issue


v3:

PATCH 1/4 irq: Add a new IRQCHIP_EOI_THREADED flag
New patch by Thomas Gleixner, replacing his "irq: Add handle_fasteoi_late_irq
irq handler" patch.

PATCH 2/4 irqchip: sun4i: Fix irq 0 not working
Added Maxime's Acked-by

PATCH 4/4 irqchip: sun4i: Don't ack IRQs != 0, fix acking of IRQ
New patch replacing my "irqchip: sun4i: Use handle_fasteoi_late_irq ..."
patch. This also drops acking for IRQ != 0. I've done both changes in
one patch to avoid regressing for IRQ 0.


Thanks for all the help to all involved.

Regards,

Hans

[PATCH v3 1/4] irq: Add a new IRQCHIP_EOI_THREADED flag

[Hans de Goede]

From: Thomas Gleixner <tglx@linutronix.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@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 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);
-- 
1.9.0

[PATCH v3 1/4] irq: Add a new IRQCHIP_EOI_THREADED flag

[Hans de Goede]

From: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>

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-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Tested-by: Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 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);
-- 
1.9.0

[PATCH v3 1/4] irq: Add a new IRQCHIP_EOI_THREADED flag

[Hans de Goede]

From: Thomas Gleixner <tglx@linutronix.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@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 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);
-- 
1.9.0

[PATCH v3 2/4] irqchip: sun4i: Fix irq 0 not working

[Hans de Goede]

SUN4I_IRQ_VECTOR_REG containing 0 can mean one of 3 things:
1) no more irqs pending
2) irq 0 pending
3) spurious irq

So if we immediately get a reading of 0, check the irq-pending reg
to differentiate between 2 and 3. We only do this once to avoid
the extra check in the common case of 1) hapening after having
read the vector-reg once.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 drivers/irqchip/irq-sun4i.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index a5438d8..5c25048 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -140,10 +140,24 @@ static asmlinkage void __exception_irq_entry sun4i_handle_irq(struct pt_regs *re
 {
 	u32 irq, hwirq;
 
+	/*
+	 * hwirq == 0 can mean one of 3 things:
+	 * 1) no more irqs pending
+	 * 2) irq 0 pending
+	 * 3) spurious irq
+	 * So if we immediately get a reading of 0, check the irq-pending reg
+	 * to differentiate between 2 and 3. We only do this once to avoid
+	 * the extra check in the common case of 1 hapening after having
+	 * read the vector-reg once.
+	 */
 	hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
-	while (hwirq != 0) {
+	if (hwirq == 0 &&
+		  !(readl(sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0)) & BIT(0)))
+		return;
+
+	do {
 		irq = irq_find_mapping(sun4i_irq_domain, hwirq);
 		handle_IRQ(irq, regs);
 		hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
-	}
+	} while (hwirq != 0);
 }
-- 
1.9.0

[PATCH v3 2/4] irqchip: sun4i: Fix irq 0 not working

[Hans de Goede]

SUN4I_IRQ_VECTOR_REG containing 0 can mean one of 3 things:
1) no more irqs pending
2) irq 0 pending
3) spurious irq

So if we immediately get a reading of 0, check the irq-pending reg
to differentiate between 2 and 3. We only do this once to avoid
the extra check in the common case of 1) hapening after having
read the vector-reg once.

Signed-off-by: Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Acked-by: Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
---
 drivers/irqchip/irq-sun4i.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index a5438d8..5c25048 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -140,10 +140,24 @@ static asmlinkage void __exception_irq_entry sun4i_handle_irq(struct pt_regs *re
 {
 	u32 irq, hwirq;
 
+	/*
+	 * hwirq == 0 can mean one of 3 things:
+	 * 1) no more irqs pending
+	 * 2) irq 0 pending
+	 * 3) spurious irq
+	 * So if we immediately get a reading of 0, check the irq-pending reg
+	 * to differentiate between 2 and 3. We only do this once to avoid
+	 * the extra check in the common case of 1 hapening after having
+	 * read the vector-reg once.
+	 */
 	hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
-	while (hwirq != 0) {
+	if (hwirq == 0 &&
+		  !(readl(sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0)) & BIT(0)))
+		return;
+
+	do {
 		irq = irq_find_mapping(sun4i_irq_domain, hwirq);
 		handle_IRQ(irq, regs);
 		hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
-	}
+	} while (hwirq != 0);
 }
-- 
1.9.0

[PATCH v3 2/4] irqchip: sun4i: Fix irq 0 not working

[Hans de Goede]

SUN4I_IRQ_VECTOR_REG containing 0 can mean one of 3 things:
1) no more irqs pending
2) irq 0 pending
3) spurious irq

So if we immediately get a reading of 0, check the irq-pending reg
to differentiate between 2 and 3. We only do this once to avoid
the extra check in the common case of 1) hapening after having
read the vector-reg once.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 drivers/irqchip/irq-sun4i.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index a5438d8..5c25048 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -140,10 +140,24 @@ static asmlinkage void __exception_irq_entry sun4i_handle_irq(struct pt_regs *re
 {
 	u32 irq, hwirq;
 
+	/*
+	 * hwirq == 0 can mean one of 3 things:
+	 * 1) no more irqs pending
+	 * 2) irq 0 pending
+	 * 3) spurious irq
+	 * So if we immediately get a reading of 0, check the irq-pending reg
+	 * to differentiate between 2 and 3. We only do this once to avoid
+	 * the extra check in the common case of 1 hapening after having
+	 * read the vector-reg once.
+	 */
 	hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
-	while (hwirq != 0) {
+	if (hwirq == 0 &&
+		  !(readl(sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0)) & BIT(0)))
+		return;
+
+	do {
 		irq = irq_find_mapping(sun4i_irq_domain, hwirq);
 		handle_IRQ(irq, regs);
 		hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
-	}
+	} while (hwirq != 0);
 }
-- 
1.9.0

[PATCH v3 3/4] irqchip: sun4i: Fix a comment about mask register initialization

[Hans de Goede]

The comment was claiming that we were masking all irqs, while the code actually
*un*masks all of them.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 drivers/irqchip/irq-sun4i.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index 5c25048..8a2fbee 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -109,7 +109,7 @@ static int __init sun4i_of_init(struct device_node *node,
 	writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(1));
 	writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(2));
 
-	/* Mask all the interrupts */
+	/* Unmask all the interrupts, ENABLE_REG(x) is used for masking */
 	writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(0));
 	writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(1));
 	writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(2));
-- 
1.9.0

[PATCH v3 3/4] irqchip: sun4i: Fix a comment about mask register initialization

[Hans de Goede]

The comment was claiming that we were masking all irqs, while the code actually
*un*masks all of them.

Signed-off-by: Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Acked-by: Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
---
 drivers/irqchip/irq-sun4i.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index 5c25048..8a2fbee 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -109,7 +109,7 @@ static int __init sun4i_of_init(struct device_node *node,
 	writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(1));
 	writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(2));
 
-	/* Mask all the interrupts */
+	/* Unmask all the interrupts, ENABLE_REG(x) is used for masking */
 	writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(0));
 	writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(1));
 	writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(2));
-- 
1.9.0

[PATCH v3 3/4] irqchip: sun4i: Fix a comment about mask register initialization

[Hans de Goede]

The comment was claiming that we were masking all irqs, while the code actually
*un*masks all of them.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 drivers/irqchip/irq-sun4i.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index 5c25048..8a2fbee 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -109,7 +109,7 @@ static int __init sun4i_of_init(struct device_node *node,
 	writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(1));
 	writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(2));
 
-	/* Mask all the interrupts */
+	/* Unmask all the interrupts, ENABLE_REG(x) is used for masking */
 	writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(0));
 	writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(1));
 	writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(2));
-- 
1.9.0

[PATCH v3 4/4] irqchip: sun4i: Don't ack IRQs != 0, fix acking of IRQ 0

[Hans de Goede]

All IRQs except for IRQ 0 seem to not need acking, so drop acking for them.

The ENMI needs to have the ack done *after* clearing the interrupt source,
otherwise we will get a spurious interrupt for each real interrupt.

So use the new IRQCHIP_EOI_THREADED flag for this in combination with
handle_fasteoi_irq. This uses a separate irq_chip struct for IRQ 0,
since we only want this behavior for IRQ 0.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/irqchip/irq-sun4i.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index 8a2fbee..a0ed1ea 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -76,16 +76,29 @@ static void sun4i_irq_unmask(struct irq_data *irqd)
 
 static struct irq_chip sun4i_irq_chip = {
 	.name		= "sun4i_irq",
-	.irq_ack	= sun4i_irq_ack,
 	.irq_mask	= sun4i_irq_mask,
 	.irq_unmask	= sun4i_irq_unmask,
 };
 
+/* IRQ 0 / the ENMI needs a late eoi call */
+static struct irq_chip sun4i_irq_chip_enmi = {
+	.name		= "sun4i_irq",
+	.irq_eoi	= sun4i_irq_ack,
+	.irq_mask	= sun4i_irq_mask,
+	.irq_unmask	= sun4i_irq_unmask,
+	.flags		= IRQCHIP_EOI_THREADED | IRQCHIP_EOI_IF_HANDLED,
+};
+
 static int sun4i_irq_map(struct irq_domain *d, unsigned int virq,
 			 irq_hw_number_t hw)
 {
-	irq_set_chip_and_handler(virq, &sun4i_irq_chip,
-				 handle_level_irq);
+	if (hw == 0)
+		irq_set_chip_and_handler(virq, &sun4i_irq_chip_enmi,
+					 handle_fasteoi_irq);
+	else
+		irq_set_chip_and_handler(virq, &sun4i_irq_chip,
+					 handle_level_irq);
+
 	set_irq_flags(virq, IRQF_VALID | IRQF_PROBE);
 
 	return 0;
-- 
1.9.0

[PATCH v3 4/4] irqchip: sun4i: Don't ack IRQs != 0, fix acking of IRQ 0

[Hans de Goede]

All IRQs except for IRQ 0 seem to not need acking, so drop acking for them.

The ENMI needs to have the ack done *after* clearing the interrupt source,
otherwise we will get a spurious interrupt for each real interrupt.

So use the new IRQCHIP_EOI_THREADED flag for this in combination with
handle_fasteoi_irq. This uses a separate irq_chip struct for IRQ 0,
since we only want this behavior for IRQ 0.

Signed-off-by: Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 drivers/irqchip/irq-sun4i.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index 8a2fbee..a0ed1ea 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -76,16 +76,29 @@ static void sun4i_irq_unmask(struct irq_data *irqd)
 
 static struct irq_chip sun4i_irq_chip = {
 	.name		= "sun4i_irq",
-	.irq_ack	= sun4i_irq_ack,
 	.irq_mask	= sun4i_irq_mask,
 	.irq_unmask	= sun4i_irq_unmask,
 };
 
+/* IRQ 0 / the ENMI needs a late eoi call */
+static struct irq_chip sun4i_irq_chip_enmi = {
+	.name		= "sun4i_irq",
+	.irq_eoi	= sun4i_irq_ack,
+	.irq_mask	= sun4i_irq_mask,
+	.irq_unmask	= sun4i_irq_unmask,
+	.flags		= IRQCHIP_EOI_THREADED | IRQCHIP_EOI_IF_HANDLED,
+};
+
 static int sun4i_irq_map(struct irq_domain *d, unsigned int virq,
 			 irq_hw_number_t hw)
 {
-	irq_set_chip_and_handler(virq, &sun4i_irq_chip,
-				 handle_level_irq);
+	if (hw == 0)
+		irq_set_chip_and_handler(virq, &sun4i_irq_chip_enmi,
+					 handle_fasteoi_irq);
+	else
+		irq_set_chip_and_handler(virq, &sun4i_irq_chip,
+					 handle_level_irq);
+
 	set_irq_flags(virq, IRQF_VALID | IRQF_PROBE);
 
 	return 0;
-- 
1.9.0

[PATCH v3 4/4] irqchip: sun4i: Don't ack IRQs != 0, fix acking of IRQ 0

[Hans de Goede]

All IRQs except for IRQ 0 seem to not need acking, so drop acking for them.

The ENMI needs to have the ack done *after* clearing the interrupt source,
otherwise we will get a spurious interrupt for each real interrupt.

So use the new IRQCHIP_EOI_THREADED flag for this in combination with
handle_fasteoi_irq. This uses a separate irq_chip struct for IRQ 0,
since we only want this behavior for IRQ 0.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/irqchip/irq-sun4i.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index 8a2fbee..a0ed1ea 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -76,16 +76,29 @@ static void sun4i_irq_unmask(struct irq_data *irqd)
 
 static struct irq_chip sun4i_irq_chip = {
 	.name		= "sun4i_irq",
-	.irq_ack	= sun4i_irq_ack,
 	.irq_mask	= sun4i_irq_mask,
 	.irq_unmask	= sun4i_irq_unmask,
 };
 
+/* IRQ 0 / the ENMI needs a late eoi call */
+static struct irq_chip sun4i_irq_chip_enmi = {
+	.name		= "sun4i_irq",
+	.irq_eoi	= sun4i_irq_ack,
+	.irq_mask	= sun4i_irq_mask,
+	.irq_unmask	= sun4i_irq_unmask,
+	.flags		= IRQCHIP_EOI_THREADED | IRQCHIP_EOI_IF_HANDLED,
+};
+
 static int sun4i_irq_map(struct irq_domain *d, unsigned int virq,
 			 irq_hw_number_t hw)
 {
-	irq_set_chip_and_handler(virq, &sun4i_irq_chip,
-				 handle_level_irq);
+	if (hw == 0)
+		irq_set_chip_and_handler(virq, &sun4i_irq_chip_enmi,
+					 handle_fasteoi_irq);
+	else
+		irq_set_chip_and_handler(virq, &sun4i_irq_chip,
+					 handle_level_irq);
+
 	set_irq_flags(virq, IRQF_VALID | IRQF_PROBE);
 
 	return 0;
-- 
1.9.0

Re: [PATCH v3 1/4] irq: Add a new IRQCHIP_EOI_THREADED flag

[Hans de Goede]

Hi,

On 03/13/2014 07:03 PM, Hans de Goede wrote:
> From: Thomas Gleixner <tglx@linutronix.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@redhat.com>
> Tested-by: Hans de Goede <hdegoede@redhat.com>
> Signed-off-by: Hans de Goede <hdegoede@redhat.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);
> 

Re: [PATCH v3 1/4] irq: Add a new IRQCHIP_EOI_THREADED flag

[Hans de Goede]

Hi,

On 03/13/2014 07:03 PM, Hans de Goede wrote:
> From: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
> 
> 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-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Tested-by: Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Signed-off-by: Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

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);
> 

[PATCH v3 1/4] irq: Add a new IRQCHIP_EOI_THREADED flag

[Hans de Goede]

Hi,

On 03/13/2014 07:03 PM, Hans de Goede wrote:
> From: Thomas Gleixner <tglx@linutronix.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@redhat.com>
> Tested-by: Hans de Goede <hdegoede@redhat.com>
> Signed-off-by: Hans de Goede <hdegoede@redhat.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);
> 

[tip:irq/core] genirq: Add a new IRQCHIP_EOI_THREADED flag

[tip-bot for Thomas Gleixner]

Commit-ID:  328a4978df833249b099c9875738d7b72042ffe1
Gitweb:     http://git.kernel.org/tip/328a4978df833249b099c9875738d7b72042ffe1
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 13 Mar 2014 19:03:51 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 14 Mar 2014 13:43:33 +0100

genirq: Add a new IRQCHIP_EOI_THREADED flag

The flag is necessary for interrupt chips which require an ACK/EOI
after the handler has run. In case of threaded handlers this needs to
happen after the threaded handler has completed before the unmask of
the interrupt.

The flag is only unseful in combination with the handle_fasteoi_irq
flow control handler.

It can be combined with the flag IRQCHIP_EOI_IF_HANDLED, so the EOI is
not issued when the interrupt is disabled or in progress.

Tested-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-sunxi@googlegroups.com
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: http://lkml.kernel.org/r/1394733834-26839-2-git-send-email-hdegoede@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/irq.h    |  2 ++
 kernel/irq/chip.c      | 48 ++++++++++++++++++++++++++++++++++++++++--------
 kernel/irq/internals.h |  1 +
 kernel/irq/manage.c    |  2 +-
 4 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 67ace7a..d278838 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -356,6 +356,7 @@ struct irq_chip {
  *				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),
@@ -364,6 +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 */
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 17b6717..ddf1ffe 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -74,6 +74,7 @@ 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 de1a8ed..2486a4c 100644
--- a/kernel/irq/manage.c
+++ b/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);

[tip:irq/core] irqchip: sun4i: Fix irq 0 not working

[tip-bot for Hans de Goede]

Commit-ID:  56af0416b00f6edc7845a7b3f2ef179e385c8e15
Gitweb:     http://git.kernel.org/tip/56af0416b00f6edc7845a7b3f2ef179e385c8e15
Author:     Hans de Goede <hdegoede@redhat.com>
AuthorDate: Thu, 13 Mar 2014 19:03:52 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 14 Mar 2014 13:43:33 +0100

irqchip: sun4i: Fix irq 0 not working

SUN4I_IRQ_VECTOR_REG containing 0 can mean one of 3 things:

1) no more irqs pending
2) irq 0 pending
3) spurious irq

So if we immediately get a reading of 0, check the irq-pending reg
to differentiate between 2 and 3. We only do this once to avoid
the extra check in the common case of 1) hapening after having
read the vector-reg once.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-sunxi@googlegroups.com
Link: http://lkml.kernel.org/r/1394733834-26839-3-git-send-email-hdegoede@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 drivers/irqchip/irq-sun4i.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index 1599955..7ae85ec 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -140,10 +140,24 @@ static void __exception_irq_entry sun4i_handle_irq(struct pt_regs *regs)
 {
 	u32 irq, hwirq;
 
+	/*
+	 * hwirq == 0 can mean one of 3 things:
+	 * 1) no more irqs pending
+	 * 2) irq 0 pending
+	 * 3) spurious irq
+	 * So if we immediately get a reading of 0, check the irq-pending reg
+	 * to differentiate between 2 and 3. We only do this once to avoid
+	 * the extra check in the common case of 1 hapening after having
+	 * read the vector-reg once.
+	 */
 	hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
-	while (hwirq != 0) {
+	if (hwirq == 0 &&
+		  !(readl(sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0)) & BIT(0)))
+		return;
+
+	do {
 		irq = irq_find_mapping(sun4i_irq_domain, hwirq);
 		handle_IRQ(irq, regs);
 		hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
-	}
+	} while (hwirq != 0);
 }

[tip:irq/core] irqchip: sun4i: Fix a comment about mask register initialization

[tip-bot for Hans de Goede]

Commit-ID:  649ff46e5e29868e915354ed1e9bebcf0faec3ae
Gitweb:     http://git.kernel.org/tip/649ff46e5e29868e915354ed1e9bebcf0faec3ae
Author:     Hans de Goede <hdegoede@redhat.com>
AuthorDate: Thu, 13 Mar 2014 19:03:53 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 14 Mar 2014 13:43:33 +0100

irqchip: sun4i: Fix a comment about mask register initialization

The comment was claiming that we were masking all irqs, while the code actually
*un*masks all of them.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-sunxi@googlegroups.com
Link: http://lkml.kernel.org/r/1394733834-26839-4-git-send-email-hdegoede@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 drivers/irqchip/irq-sun4i.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index 7ae85ec..60a28c6 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -109,7 +109,7 @@ static int __init sun4i_of_init(struct device_node *node,
 	writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(1));
 	writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(2));
 
-	/* Mask all the interrupts */
+	/* Unmask all the interrupts, ENABLE_REG(x) is used for masking */
 	writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(0));
 	writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(1));
 	writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(2));

[tip:irq/core] irqchip: sun4i: Don't ack IRQs > 0, fix acking of IRQ 0

[tip-bot for Hans de Goede]

Commit-ID:  e9df9e221665d40928e25a02c2700ac12eda7270
Gitweb:     http://git.kernel.org/tip/e9df9e221665d40928e25a02c2700ac12eda7270
Author:     Hans de Goede <hdegoede@redhat.com>
AuthorDate: Thu, 13 Mar 2014 19:03:54 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 14 Mar 2014 13:43:33 +0100

irqchip: sun4i: Don't ack IRQs > 0, fix acking of IRQ 0

All IRQs except for IRQ 0 seem to not need acking, so drop acking for them.

The ENMI needs to have the ack done *after* clearing the interrupt source,
otherwise we will get a spurious interrupt for each real interrupt.

So use the new IRQCHIP_EOI_THREADED flag for this in combination with
handle_fasteoi_irq. This uses a separate irq_chip struct for IRQ 0,
since we only want this behavior for IRQ 0.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-sunxi@googlegroups.com
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: http://lkml.kernel.org/r/1394733834-26839-5-git-send-email-hdegoede@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 drivers/irqchip/irq-sun4i.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index 60a28c6..2029cc5 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -76,16 +76,29 @@ static void sun4i_irq_unmask(struct irq_data *irqd)
 
 static struct irq_chip sun4i_irq_chip = {
 	.name		= "sun4i_irq",
-	.irq_ack	= sun4i_irq_ack,
 	.irq_mask	= sun4i_irq_mask,
 	.irq_unmask	= sun4i_irq_unmask,
 };
 
+/* IRQ 0 / the ENMI needs a late eoi call */
+static struct irq_chip sun4i_irq_chip_enmi = {
+	.name		= "sun4i_irq",
+	.irq_eoi	= sun4i_irq_ack,
+	.irq_mask	= sun4i_irq_mask,
+	.irq_unmask	= sun4i_irq_unmask,
+	.flags		= IRQCHIP_EOI_THREADED | IRQCHIP_EOI_IF_HANDLED,
+};
+
 static int sun4i_irq_map(struct irq_domain *d, unsigned int virq,
 			 irq_hw_number_t hw)
 {
-	irq_set_chip_and_handler(virq, &sun4i_irq_chip,
-				 handle_level_irq);
+	if (hw == 0)
+		irq_set_chip_and_handler(virq, &sun4i_irq_chip_enmi,
+					 handle_fasteoi_irq);
+	else
+		irq_set_chip_and_handler(virq, &sun4i_irq_chip,
+					 handle_level_irq);
+
 	set_irq_flags(virq, IRQF_VALID | IRQF_PROBE);
 
 	return 0;