[patch 18/50] genirq: add IRQ_NOREQUEST support

[Ingo Molnar <mingo@elte.hu>]

From: Thomas Gleixner <tglx@linutronix.de>

enable platforms to disable request_irq() for certain interrupts.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 include/linux/irq.h |    1 +
 kernel/irq/manage.c |    4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

Index: linux-genirq.q/include/linux/irq.h
===================================================================
--- linux-genirq.q.orig/include/linux/irq.h
+++ linux-genirq.q/include/linux/irq.h
@@ -41,6 +41,7 @@
 #endif
 
 #define IRQ_NOPROBE	512	/* IRQ is not valid for probing */
+#define IRQ_NOREQUEST	1024	/* IRQ cannot be requested */
 /**
  * struct hw_interrupt_type - hardware interrupt type descriptor
  *
Index: linux-genirq.q/kernel/irq/manage.c
===================================================================
--- linux-genirq.q.orig/kernel/irq/manage.c
+++ linux-genirq.q/kernel/irq/manage.c
@@ -141,7 +141,7 @@ int can_request_irq(unsigned int irq, un
 {
 	struct irqaction *action;
 
-	if (irq >= NR_IRQS)
+	if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST)
 		return 0;
 
 	action = irq_desc[irq].action;
@@ -356,6 +356,8 @@ int request_irq(unsigned int irq,
 		return -EINVAL;
 	if (irq >= NR_IRQS)
 		return -EINVAL;
+	if (irq_desc[irq].status & IRQ_NOREQUEST)
+		return -EINVAL;
 	if (!handler)
 		return -EINVAL;