[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>

3 files changed, 7 insertions, 2 deletions

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 9a39756bfd31..b2fcf330cf2e 100644
--- a/include/linux/irq.h
+++ b/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
  *
diff --git a/kernel/irq/autoprobe.c b/kernel/irq/autoprobe.c
index 5c988bba401f..ed98c7d46cf2 100644
--- a/kernel/irq/autoprobe.c
+++ b/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;
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index cffde4843897..90a944a7fadc 100644
--- a/kernel/irq/manage.c
+++ b/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 */
         }