x86: ioapic: Add io_apic_setup_irq_pin()

There are about four places in the ioapic code which do exactly the
same setup sequence. Also the OF based ioapic setup needs that
function to avoid putting the OF specific code into ioapic.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/io_apic.h

@@ -151,6 +151,8 @@ void setup_IO_APIC_irq_extra(u32 gsi);
 extern void ioapic_and_gsi_init(void);
 extern void ioapic_insert_resources(void);
 
+int io_apic_setup_irq_pin(unsigned int irq, int node, struct io_apic_irq_attr *attr);
+
 extern struct IO_APIC_route_entry **alloc_ioapic_entries(void);
 extern void free_ioapic_entries(struct IO_APIC_route_entry **ioapic_entries);
 extern int save_IO_APIC_setup(struct IO_APIC_route_entry **ioapic_entries);

arch/x86/kernel/apic/io_apic.c

@@ -3607,6 +3607,21 @@ int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev)
 }
 #endif /* CONFIG_HT_IRQ */
 
+int
+io_apic_setup_irq_pin(unsigned int irq, int node, struct io_apic_irq_attr *attr)
+{
+	struct irq_cfg *cfg = alloc_irq_and_cfg_at(irq, node);
+	int ret;
+
+	if (!cfg)
+		return -EINVAL;
+	ret = __add_pin_to_irq_node(cfg, node, attr->ioapic, attr->ioapic_pin);
+	if (!ret)
+		setup_ioapic_irq(attr->ioapic, attr->ioapic_pin, irq, cfg,
+				 attr->trigger, attr->polarity);
+	return ret;
+}
+
 int __init io_apic_get_redir_entries (int ioapic)
 {
 	union IO_APIC_reg_01	reg_01;