Some controllers have irqs that aren't wired up and must never be used.
For the generic chip attached to an irq_domain this provides a mask that
can be used to block out particular irqs so that they never get mapped.
Signed-off-by: Grant Likely <grant.lik...@linaro.org>
Cc: Thomas Gleixner <t...@linutronix.de>
---
include/linux/irq.h | 2 ++
kernel/irq/generic-chip.c | 3 +++
2 files changed, 5 insertions(+)
diff --git a/include/linux/irq.h b/include/linux/irq.h
index af7052c..298a9b9 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -679,6 +679,7 @@ struct irq_chip_type {
* @num_ct: Number of available irq_chip_type instances (usually 1)
* @private: Private data for non generic chip callbacks
* @installed: bitfield to denote installed interrupts
+ * @unused: bitfield to denote unused interrupts
* @domain: irq domain pointer
* @list: List head for keeping track of instances
* @chip_types: Array of interrupt irq_chip_types
@@ -702,6 +703,7 @@ struct irq_chip_generic {
unsigned int num_ct;
void *private;
unsigned long installed;
+ unsigned long unused;
struct irq_domain *domain;
struct list_head list;
struct irq_chip_type chip_types[0];
diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c
index 8e4d6bd..7b44aa2 100644
--- a/kernel/irq/generic-chip.c
+++ b/kernel/irq/generic-chip.c
@@ -359,6 +359,9 @@ static int irq_map_generic_chip(struct irq_domain *d,
unsigned int virq,
idx = hw_irq % dgc->irqs_per_chip;
+ if (test_bit(idx, &gc->unused))
+ return -ENOTSUPP;
+
if (test_bit(idx, &gc->installed))
return -EBUSY;
--
1.8.1.2
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