[patch 17/50] genirq: add IRQ_NOPROBE support

[patch 17/50] genirq: add IRQ_NOPROBE support

[Ingo Molnar]

From: Thomas Gleixner <tglx@linutronix.de>

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>
---
 include/linux/irq.h    |    1 +
 kernel/irq/autoprobe.c |    4 ++--
 kernel/irq/manage.c    |    4 ++++
 3 files changed, 7 insertions(+), 2 deletions(-)

Index: linux-genirq.q/include/linux/irq.h
===================================================================
--- linux-genirq.q.orig/include/linux/irq.h
+++ linux-genirq.q/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
  *
Index: linux-genirq.q/kernel/irq/autoprobe.c
===================================================================
--- linux-genirq.q.orig/kernel/irq/autoprobe.c
+++ linux-genirq.q/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->handler->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->handler->startup(i))
 				desc->status |= IRQ_PENDING;
Index: linux-genirq.q/kernel/irq/manage.c
===================================================================
--- linux-genirq.q.orig/kernel/irq/manage.c
+++ linux-genirq.q/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 */
 	}