2 files changed, 64 insertions, 1 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index a31a7d8acdb2..82dbb0e8f40b 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -404,8 +404,15 @@ set_irq_chained_handler(unsigned int irq,
         __set_irq_handler(irq, handle, 1);
 }
 
-/* Set/get chip/data for an IRQ: */
+/* Handle dynamic irq creation and destruction */
+extern int create_irq(void);
+extern void destroy_irq(unsigned int irq);
+
+/* Dynamic irq helper functions */
+extern void dynamic_irq_init(unsigned int irq);
+extern void dynamic_irq_cleanup(unsigned int irq);
 
+/* Set/get chip/data for an IRQ: */
 extern int set_irq_chip(unsigned int irq, struct irq_chip *chip);
 extern int set_irq_data(unsigned int irq, void *data);
 extern int set_irq_chip_data(unsigned int irq, void *data);
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 736cb0bd498f..0dc24386dd99 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -18,6 +18,62 @@
 #include "internals.h"
 
 /**
+ *      dynamic_irq_init - initialize a dynamically allocated irq
+ *      @irq:   irq number to initialize
+ */
+void dynamic_irq_init(unsigned int irq)
+{
+        struct irq_desc *desc;
+        unsigned long flags;
+
+        if (irq >= NR_IRQS) {
+                printk(KERN_ERR "Trying to initialize invalid IRQ%d\n", irq);
+                WARN_ON(1);
+                return;
+        }
+
+        /* Ensure we don't have left over values from a previous use of this irq */
+        desc = irq_desc + irq;
+        spin_lock_irqsave(&desc->lock, flags);
+        desc->status = IRQ_DISABLED;
+        desc->chip = &no_irq_chip;
+        desc->handle_irq = handle_bad_irq;
+        desc->depth = 1;
+        desc->handler_data = NULL;
+        desc->chip_data = NULL;
+        desc->action = NULL;
+        desc->irq_count = 0;
+        desc->irqs_unhandled = 0;
+#ifdef CONFIG_SMP
+        desc->affinity = CPU_MASK_ALL;
+#endif
+        spin_unlock_irqrestore(&desc->lock, flags);
+}
+
+/**
+ *      dynamic_irq_cleanup - cleanup a dynamically allocated irq
+ *      @irq:   irq number to initialize
+ */
+void dynamic_irq_cleanup(unsigned int irq)
+{
+        struct irq_desc *desc;
+        unsigned long flags;
+
+        if (irq >= NR_IRQS) {
+                printk(KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
+                WARN_ON(1);
+                return;
+        }
+
+        desc = irq_desc + irq;
+        spin_lock_irqsave(&desc->lock, flags);
+        desc->handle_irq = handle_bad_irq;
+        desc->chip = &no_irq_chip;
+        spin_unlock_irqrestore(&desc->lock, flags);
+}
+
+
+/**
  *      set_irq_chip - set the irq chip for an irq
  *      @irq:   irq number
  *      @chip:  pointer to irq chip description structure