[PATCH] genirq: add IRQ_NOPROBE support

Introduce IRQ_NOPROBE: enables platforms to control chip-probing.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/irq.h

@@ -40,6 +40,7 @@
 # define CHECK_IRQ_PER_CPU(var) 0
 #endif
 
+#define IRQ_NOPROBE	512	/* IRQ is not valid for probing */
 /**
  * struct hw_interrupt_type - hardware interrupt type descriptor
  *

kernel/irq/autoprobe.c

@@ -40,7 +40,7 @@ unsigned long probe_irq_on(void)
 		desc = irq_desc + i;
 
 		spin_lock_irq(&desc->lock);
-		if (!desc->action)
+		if (!desc->action && !(desc->status & IRQ_NOPROBE))
 			desc->chip->startup(i);
 		spin_unlock_irq(&desc->lock);
 	}
@@ -57,7 +57,7 @@ unsigned long probe_irq_on(void)
 		desc = irq_desc + i;
 
 		spin_lock_irq(&desc->lock);
-		if (!desc->action) {
+		if (!desc->action && !(desc->status & IRQ_NOPROBE)) {
 			desc->status |= IRQ_AUTODETECT | IRQ_WAITING;
 			if (desc->chip->startup(i))
 				desc->status |= IRQ_PENDING;

kernel/irq/manage.c

@@ -118,6 +118,10 @@ void enable_irq(unsigned int irq)
 		WARN_ON(1);
 		break;
 	case 1: {
+		unsigned int status = desc->status & ~IRQ_DISABLED;
+
+		/* Prevent probing on this irq: */
+		desc->status = status | IRQ_NOPROBE;
 		check_irq_resend(desc, irq);
 		/* fall-through */
 	}