ARM: 6806/1: irq: introduce entry and exit functions for chained handlers

Some chained IRQ handlers are written to cope with primary chips of
potentially different flow types. Whether this a sensible thing to do
is a point of contention.

This patch introduces entry/exit functions for chained handlers which
infer the flow type of the primary chip as fasteoi or level-type by
checking whether or not the ->irq_eoi function pointer is present and
calling back to the primary chip as necessary. Other methods of flow
control are not considered.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 31 insertions, 0 deletions

diff --git a/arch/arm/include/asm/mach/irq.h b/arch/arm/include/asm/mach/irq.h
index 22ac140edd9e..febe495d0c6e 100644
--- a/arch/arm/include/asm/mach/irq.h
+++ b/arch/arm/include/asm/mach/irq.h
@@ -34,4 +34,35 @@ do {							\
         raw_spin_unlock(&desc->lock);                   \
 } while(0)
 
+#ifndef __ASSEMBLY__
+/*
+ * Entry/exit functions for chained handlers where the primary IRQ chip
+ * may implement either fasteoi or level-trigger flow control.
+ */
+static inline void chained_irq_enter(struct irq_chip *chip,
+                                     struct irq_desc *desc)
+{
+        /* FastEOI controllers require no action on entry. */
+        if (chip->irq_eoi)
+                return;
+
+        if (chip->irq_mask_ack) {
+                chip->irq_mask_ack(&desc->irq_data);
+        } else {
+                chip->irq_mask(&desc->irq_data);
+                if (chip->irq_ack)
+                        chip->irq_ack(&desc->irq_data);
+        }
+}
+
+static inline void chained_irq_exit(struct irq_chip *chip,
+                                    struct irq_desc *desc)
+{
+        if (chip->irq_eoi)
+                chip->irq_eoi(&desc->irq_data);
+        else
+                chip->irq_unmask(&desc->irq_data);
+}
+#endif
+
 #endif