2 files changed, 41 insertions, 3 deletions

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 4a0952d9458b..54105bdfe20d 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -462,9 +462,18 @@ __set_irq_handler(unsigned int irq,
         if (!handle)
                 handle = handle_bad_irq;
 
-        if (is_chained && desc->chip == &no_irq_chip)
-                printk(KERN_WARNING "Trying to install "
-                       "chained interrupt type for IRQ%d\n", irq);
+        if (desc->chip == &no_irq_chip) {
+                printk(KERN_WARNING "Trying to install %sinterrupt handler "
+                       "for IRQ%d\n", is_chained ? "chained " : " ", irq);
+                /*
+                 * Some ARM implementations install a handler for really dumb
+                 * interrupt hardware without setting an irq_chip. This worked
+                 * with the ARM no_irq_chip but the check in setup_irq would
+                 * prevent us to setup the interrupt at all. Switch it to
+                 * dummy_irq_chip for easy transition.
+                 */
+                desc->chip = &dummy_irq_chip;
+        }
 
         spin_lock_irqsave(&desc->lock, flags);
 
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 6070e0464690..6d8b30114961 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -16,6 +16,10 @@
 #include <linux/interrupt.h>
 #include <linux/kernel_stat.h>
 
+#if defined(CONFIG_NO_IDLE_HZ) && defined(CONFIG_ARM)
+#include <asm/dyntick.h>
+#endif
+
 #include "internals.h"
 
 /**
@@ -92,6 +96,22 @@ struct irq_chip no_irq_chip = {
 };
 
 /*
+ * Generic dummy implementation which can be used for
+ * real dumb interrupt sources
+ */
+struct irq_chip dummy_irq_chip = {
+        .name           = "dummy",
+        .startup        = noop_ret,
+        .shutdown       = noop,
+        .enable         = noop,
+        .disable        = noop,
+        .ack            = noop,
+        .mask           = noop,
+        .unmask         = noop,
+        .end            = noop,
+};
+
+/*
  * Special, empty irq handler:
  */
 irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs)
@@ -113,6 +133,15 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
         irqreturn_t ret, retval = IRQ_NONE;
         unsigned int status = 0;
 
+#if defined(CONFIG_NO_IDLE_HZ) && defined(CONFIG_ARM)
+        if (!(action->flags & SA_TIMER) && system_timer->dyn_tick != NULL) {
+                write_seqlock(&xtime_lock);
+                if (system_timer->dyn_tick->state & DYN_TICK_ENABLED)
+                        system_timer->dyn_tick->handler(irq, 0, regs);
+                write_sequnlock(&xtime_lock);
+        }
+#endif
+
         if (!(action->flags & IRQF_DISABLED))
                 local_irq_enable();