diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index cbef41f..0e97fd0 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -253,30 +253,20 @@ static void gic_set_irq_properties(unsigned int irq, bool_t level,
     spin_unlock(&gic.lock);
 }
 
-/* Program the GIC to route an interrupt */
-static int gic_route_irq(unsigned int irq, bool_t level,
-                         const cpumask_t *cpu_mask, unsigned int priority)
+/* Program the GIC to route an interrupt to the host (i.e. Xen)
+ * - needs to be called with desc.lock held
+ */
+void gic_route_irq_to_xen(struct irq_desc *desc, bool_t level,
+                          const cpumask_t *cpu_mask, unsigned int priority)
 {
-    struct irq_desc *desc = irq_to_desc(irq);
-    unsigned long flags;
-
     ASSERT(priority <= 0xff);     /* Only 8 bits of priority */
-    ASSERT(irq < gic.lines);      /* Can't route interrupts that don't exist */
-
-    if ( desc->action != NULL )
-        return -EBUSY;
-
-    spin_lock_irqsave(&desc->lock, flags);
-
-    /* Disable interrupt */
-    desc->handler->shutdown(desc);
+    ASSERT(desc->irq < gic.lines);/* Can't route interrupts that don't exist */
+    ASSERT(desc->status & IRQ_DISABLED);
+    ASSERT(spin_is_locked(&desc->lock));
 
     desc->handler = &gic_host_irq_type;
 
-    gic_set_irq_properties(irq, level, cpu_mask, priority);
-
-    spin_unlock_irqrestore(&desc->lock, flags);
-    return 0;
+    gic_set_irq_properties(desc->irq, level, cpu_mask, priority);
 }
 
 /* Program the GIC to route an interrupt to a guest
@@ -300,17 +290,6 @@ void gic_route_irq_to_guest(struct domain *d, struct irq_desc *desc,
     p->desc = desc;
 }
 
-/* Program the GIC to route an interrupt with a dt_irq */
-void gic_route_dt_irq(const struct dt_irq *irq, const cpumask_t *cpu_mask,
-                      unsigned int priority)
-{
-    bool_t level;
-
-    level = dt_irq_is_level_triggered(irq);
-
-    gic_route_irq(irq->irq, level, cpu_mask, priority);
-}
-
 static void __init gic_dist_init(void)
 {
     uint32_t type;
@@ -564,30 +543,6 @@ void gic_disable_cpu(void)
     spin_unlock(&gic.lock);
 }
 
-void gic_route_ppis(void)
-{
-    /* GIC maintenance */
-    gic_route_dt_irq(&gic.maintenance, cpumask_of(smp_processor_id()),
-                     GIC_PRI_IRQ);
-    /* Route timer interrupt */
-    route_timer_interrupt();
-}
-
-void gic_route_spis(void)
-{
-    int seridx;
-    const struct dt_irq *irq;
-
-    for ( seridx = 0; seridx <= SERHND_IDX; seridx++ )
-    {
-        if ( (irq = serial_dt_irq(seridx)) == NULL )
-            continue;
-
-        gic_route_dt_irq(irq, cpumask_of(smp_processor_id()),
-                         GIC_PRI_IRQ);
-    }
-}
-
 static inline void gic_set_lr(int lr, struct pending_irq *p,
         unsigned int state)
 {
diff --git a/xen/arch/arm/irq.c b/xen/arch/arm/irq.c
index 2d7a9e5..aac39b0 100644
--- a/xen/arch/arm/irq.c
+++ b/xen/arch/arm/irq.c
@@ -247,15 +247,37 @@ int setup_dt_irq(const struct dt_irq *irq, struct irqaction *new)
     int rc;
     unsigned long flags;
     struct irq_desc *desc;
+    bool_t disabled;
 
     desc = irq_to_desc(irq->irq);
 
     spin_lock_irqsave(&desc->lock, flags);
+
+    disabled = (desc->action == NULL);
+
     rc = __setup_irq(desc, new);
+    if ( rc )
+        goto err;
 
-    if ( !rc )
+    /* First time the IRQ is setup */
+    if ( disabled )
+    {
+        bool_t level;
+
+        level = dt_irq_is_level_triggered(irq);
+        /* It's fine to use smp_processor_id() because:
+         * For PPI: irq_desc is banked
+         * For SPI: we don't care for now which CPU will receive the
+         * interrupt
+         * TODO: Handle case where SPI is setup on different CPU than
+         * the targeted CPU and the priority.
+         */
+        gic_route_irq_to_xen(desc, level, cpumask_of(smp_processor_id()),
+                             GIC_PRI_IRQ);
         desc->handler->startup(desc);
+    }
 
+err:
     spin_unlock_irqrestore(&desc->lock, flags);
 
     return rc;
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 0892a54..7b02282 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -718,8 +718,6 @@ void __init start_xen(unsigned long boot_phys_offset,
 
     init_IRQ();
 
-    gic_route_ppis();
-    gic_route_spis();
     xsm_dt_init();
 
     init_maintenance_interrupt();
diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index 7f28b68..cf149da 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -287,8 +287,6 @@ void __cpuinit start_secondary(unsigned long boot_phys_offset,
 
     init_secondary_IRQ();
 
-    gic_route_ppis();
-
     init_maintenance_interrupt();
     init_timer_interrupt();
 
diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index 2db6148..1d4317d 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -218,17 +218,6 @@ static void vtimer_interrupt(int irq, void *dev_id, struct cpu_user_regs *regs)
     vgic_vcpu_inject_irq(current, current->arch.virt_timer.irq);
 }
 
-/* Route timer's IRQ on this CPU */
-void __cpuinit route_timer_interrupt(void)
-{
-    gic_route_dt_irq(&timer_irq[TIMER_PHYS_NONSECURE_PPI],
-                     cpumask_of(smp_processor_id()), GIC_PRI_IRQ);
-    gic_route_dt_irq(&timer_irq[TIMER_HYP_PPI],
-                     cpumask_of(smp_processor_id()), GIC_PRI_IRQ);
-    gic_route_dt_irq(&timer_irq[TIMER_VIRT_PPI],
-                     cpumask_of(smp_processor_id()), GIC_PRI_IRQ);
-}
-
 /* Set up the timer interrupt on this CPU */
 void __cpuinit init_timer_interrupt(void)
 {
diff --git a/xen/include/asm-arm/gic.h b/xen/include/asm-arm/gic.h
index 18a55c5..83000ca 100644
--- a/xen/include/asm-arm/gic.h
+++ b/xen/include/asm-arm/gic.h
@@ -170,15 +170,13 @@ extern void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int irq);
 extern void vgic_clear_pending_irqs(struct vcpu *v);
 extern struct pending_irq *irq_to_pending(struct vcpu *v, unsigned int irq);
 
-/* Program the GIC to route an interrupt with a dt_irq */
-extern void gic_route_dt_irq(const struct dt_irq *irq,
-                             const cpumask_t *cpu_mask,
-                             unsigned int priority);
+/* Program the GIC to route an interrupt */
+extern void gic_route_irq_to_xen(struct irq_desc *desc, bool_t level,
+                                 const cpumask_t *cpu_mask,
+                                 unsigned int priority);
 extern void gic_route_irq_to_guest(struct domain *, struct irq_desc *desc,
                                    bool_t level, const cpumask_t *cpu_mask,
                                    unsigned int priority);
-extern void gic_route_ppis(void);
-extern void gic_route_spis(void);
 
 extern void gic_inject(void);
 extern void gic_clear_pending_irqs(struct vcpu *v);
diff --git a/xen/include/asm-arm/time.h b/xen/include/asm-arm/time.h
index 9bbab0b..d544b5b 100644
--- a/xen/include/asm-arm/time.h
+++ b/xen/include/asm-arm/time.h
@@ -25,9 +25,6 @@ enum timer_ppi
 /* Get one of the timer IRQ number */
 unsigned int timer_get_irq(enum timer_ppi ppi);
 
-/* Route timer's IRQ on this CPU */
-extern void __cpuinit route_timer_interrupt(void);
-
 /* Set up the timer interrupt on this CPU */
 extern void __cpuinit init_timer_interrupt(void);
 
