+int nr_irqs = NR_IRQS;
+EXPORT_SYMBOL_GPL(nr_irqs);
+
+#ifdef CONFIG_SPARSE_IRQ
+
+static struct irq_desc irq_desc_init = {
+ .irq = -1,
+ .status = IRQ_DISABLED,
+ .chip = &no_irq_chip,
+ .handle_irq = handle_bad_irq,
+ .depth = 1,
+ .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
+};
+
+void __ref init_kstat_irqs(struct irq_desc *desc, int node, int nr)
+{
+ void *ptr;
+
+ if (slab_is_available())
+ ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs),
+ GFP_ATOMIC, node);
+ else
+ ptr = alloc_bootmem_node(NODE_DATA(node),
+ nr * sizeof(*desc->kstat_irqs));
+
+ /*
+ * don't overwite if can not get new one
+ * init_copy_kstat_irqs() could still use old one
+ */
+ if (ptr) {
+ printk(KERN_DEBUG " alloc kstat_irqs on node %d\n", node);
+ desc->kstat_irqs = ptr;
+ }
+}
+
+static void init_one_irq_desc(int irq, struct irq_desc *desc, int node)
+{
+ memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
+
+ spin_lock_init(&desc->lock);
+ desc->irq = irq;
+#ifdef CONFIG_SMP
+ desc->node = node;
+#endif
+ lockdep_set_class(&desc->lock, &irq_desc_lock_class);
+ init_kstat_irqs(desc, node, nr_cpu_ids);
+ if (!desc->kstat_irqs) {
+ printk(KERN_ERR "can not alloc kstat_irqs\n");
+ BUG_ON(1);
+ }
+ if (!alloc_desc_masks(desc, node, false)) {
+ printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
+ BUG_ON(1);
+ }
+ init_desc_masks(desc);
+ arch_init_chip_data(desc, node);
+}
+
+/*
+ * Protect the sparse_irqs:
+ */
+DEFINE_SPINLOCK(sparse_irq_lock);
+
+struct irq_desc **irq_desc_ptrs __read_mostly;
+
+static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
+ [0 ... NR_IRQS_LEGACY-1] = {
+ .irq = -1,
+ .status = IRQ_DISABLED,
+ .chip = &no_irq_chip,
+ .handle_irq = handle_bad_irq,
+ .depth = 1,
+ .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
+ }
+};
+
+static unsigned int *kstat_irqs_legacy;
+
+int __init early_irq_init(void)
+{
+ struct irq_desc *desc;
+ int legacy_count;
+ int node;
+ int i;
+
+ init_irq_default_affinity();
+
+ /* initialize nr_irqs based on nr_cpu_ids */
+ arch_probe_nr_irqs();
+ printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
+
+ desc = irq_desc_legacy;
+ legacy_count = ARRAY_SIZE(irq_desc_legacy);
+ node = first_online_node;
+
+ /* allocate irq_desc_ptrs array based on nr_irqs */
+ irq_desc_ptrs = kcalloc(nr_irqs, sizeof(void *), GFP_NOWAIT);
+
+ /* allocate based on nr_cpu_ids */
+ kstat_irqs_legacy = kzalloc_node(NR_IRQS_LEGACY * nr_cpu_ids *
+ sizeof(int), GFP_NOWAIT, node);
+
+ for (i = 0; i < legacy_count; i++) {
+ desc[i].irq = i;
+#ifdef CONFIG_SMP
+ desc[i].node = node;
+#endif
+ desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
+ lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
+ alloc_desc_masks(&desc[i], node, true);
+ init_desc_masks(&desc[i]);
+ irq_desc_ptrs[i] = desc + i;
+ }
+
+ for (i = legacy_count; i < nr_irqs; i++)
+ irq_desc_ptrs[i] = NULL;
+
+ return arch_early_irq_init();
+}
+
+struct irq_desc *irq_to_desc(unsigned int irq)
+{
+ if (irq_desc_ptrs && irq < nr_irqs)
+ return irq_desc_ptrs[irq];
+
+ return NULL;
+}
+
+struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
+{
+ struct irq_desc *desc;
+ unsigned long flags;
+
+ if (irq >= nr_irqs) {
+ WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
+ irq, nr_irqs);
+ return NULL;
+ }
+
+ desc = irq_desc_ptrs[irq];
+ if (desc)
+ return desc;
+
+ spin_lock_irqsave(&sparse_irq_lock, flags);
+
+ /* We have to check it to avoid races with another CPU */
+ desc = irq_desc_ptrs[irq];
+ if (desc)
+ goto out_unlock;
+
+ if (slab_is_available())
+ desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
+ else
+ desc = alloc_bootmem_node(NODE_DATA(node), sizeof(*desc));
+
+ printk(KERN_DEBUG " alloc irq_desc for %d on node %d\n", irq, node);
+ if (!desc) {
+ printk(KERN_ERR "can not alloc irq_desc\n");
+ BUG_ON(1);
+ }
+ init_one_irq_desc(irq, desc, node);
+
+ irq_desc_ptrs[irq] = desc;
+
+out_unlock:
+ spin_unlock_irqrestore(&sparse_irq_lock, flags);
+
+ return desc;
+}
+
+#else /* !CONFIG_SPARSE_IRQ */
+
+struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {