genirq: irqchip: Add mask to block out invalid irqs

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.likely@linaro.org>
Link: http://lkml.kernel.org/r/1369793454-19197-2-git-send-email-grant.likely@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/include/linux/irq.h b/include/linux/irq.h
index af7052c6a45c67850a476455923808faf318b0b8..298a9b9ce67551b7cab771b6f11c428d9941f525 100644 (file)
--- 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 8743d62fded7922320e0e862fd989377278b8b6a..95575d8d5392e08f285ef411c2d96e9dd7edd4da 100644 (file)
--- 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;