[PATCH v8 2/7] genirq: Add handle_fasteoi_{level,edge}_irq flow handlers.

[David Daney]

Follow-on patch for gpio-thunderx uses a irqdomain hierarchy which
requires slightly different flow handlers, add them to chip.c which
contains most of the other flow handlers.  Make these conditionally
compiled based on CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS.

Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
---
 include/linux/irq.h |   2 +
 kernel/irq/Kconfig  |   4 ++
 kernel/irq/chip.c   | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 112 insertions(+)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index d2d54379..d4728bf 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -568,6 +568,8 @@ static inline int irq_set_parent(int irq, int parent_irq)
 extern int irq_chip_pm_get(struct irq_data *data);
 extern int irq_chip_pm_put(struct irq_data *data);
 #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+extern void handle_fasteoi_ack_irq(struct irq_desc *desc);
+extern void handle_fasteoi_mask_irq(struct irq_desc *desc);
 extern void irq_chip_enable_parent(struct irq_data *data);
 extern void irq_chip_disable_parent(struct irq_data *data);
 extern void irq_chip_ack_parent(struct irq_data *data);
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 27c4e77..aada687 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -68,6 +68,10 @@ config IRQ_DOMAIN_HIERARCHY
 	bool
 	select IRQ_DOMAIN
 
+# Support for hierarchical fasteoi+edge and fasteoi+level handlers
+config IRQ_FASTEOI_HIERARCHY_HANDLERS
+	bool
+
 # Generic IRQ IPI support
 config GENERIC_IRQ_IPI
 	bool
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 6514f07..2395898 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -1092,6 +1092,112 @@ void irq_cpu_offline(void)
 }
 
 #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+
+#ifdef CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS
+/**
+ *	handle_fasteoi_ack_irq - irq handler for edge hierarchy
+ *	stacked on transparent controllers
+ *
+ *	@desc:	the interrupt description structure for this irq
+ *
+ *	Like handle_fasteoi_irq(), but for use with hierarchy where
+ *	the irq_chip also needs to have its ->irq_ack() function
+ *	called.
+ */
+void handle_fasteoi_ack_irq(struct irq_desc *desc)
+{
+	struct irq_chip *chip = desc->irq_data.chip;
+
+	raw_spin_lock(&desc->lock);
+
+	if (!irq_may_run(desc))
+		goto out;
+
+	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+	/*
+	 * If its disabled or no action available
+	 * then mask it and get out of here:
+	 */
+	if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
+		desc->istate |= IRQS_PENDING;
+		mask_irq(desc);
+		goto out;
+	}
+
+	kstat_incr_irqs_this_cpu(desc);
+	if (desc->istate & IRQS_ONESHOT)
+		mask_irq(desc);
+
+	/* Start handling the irq */
+	desc->irq_data.chip->irq_ack(&desc->irq_data);
+
+	preflow_handler(desc);
+	handle_irq_event(desc);
+
+	cond_unmask_eoi_irq(desc, chip);
+
+	raw_spin_unlock(&desc->lock);
+	return;
+out:
+	if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED))
+		chip->irq_eoi(&desc->irq_data);
+	raw_spin_unlock(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_fasteoi_ack_irq);
+
+/**
+ *	handle_fasteoi_mask_irq - irq handler for level hierarchy
+ *	stacked on transparent controllers
+ *
+ *	@desc:	the interrupt description structure for this irq
+ *
+ *	Like handle_fasteoi_irq(), but for use with hierarchy where
+ *	the irq_chip also needs to have its ->irq_mask_ack() function
+ *	called.
+ */
+void handle_fasteoi_mask_irq(struct irq_desc *desc)
+{
+	struct irq_chip *chip = desc->irq_data.chip;
+
+	raw_spin_lock(&desc->lock);
+	mask_ack_irq(desc);
+
+	if (!irq_may_run(desc))
+		goto out;
+
+	desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
+
+	/*
+	 * If its disabled or no action available
+	 * then mask it and get out of here:
+	 */
+	if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
+		desc->istate |= IRQS_PENDING;
+		mask_irq(desc);
+		goto out;
+	}
+
+	kstat_incr_irqs_this_cpu(desc);
+	if (desc->istate & IRQS_ONESHOT)
+		mask_irq(desc);
+
+	preflow_handler(desc);
+	handle_irq_event(desc);
+
+	cond_unmask_eoi_irq(desc, chip);
+
+	raw_spin_unlock(&desc->lock);
+	return;
+out:
+	if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED))
+		chip->irq_eoi(&desc->irq_data);
+	raw_spin_unlock(&desc->lock);
+}
+EXPORT_SYMBOL_GPL(handle_fasteoi_mask_irq);
+
+#endif /* CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS */
+
 /**
  * irq_chip_enable_parent - Enable the parent interrupt (defaults to unmask if
  * NULL)
-- 
1.8.3.1