x86/ioapic: Use irq_find_matching_fwspec() to find remapping irqdomain

All possible parent domains have a select method now. Make use of it.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201024213535.443185-29-dwmw2@infradead.org

arch/x86/kernel/apic/io_apic.c

@@ -2320,36 +2320,37 @@ static inline void __init check_timer(void)
 
 static int mp_irqdomain_create(int ioapic)
 {
-	struct irq_alloc_info info;
 	struct irq_domain *parent;
 	int hwirqs = mp_ioapic_pin_count(ioapic);
 	struct ioapic *ip = &ioapics[ioapic];
 	struct ioapic_domain_cfg *cfg = &ip->irqdomain_cfg;
 	struct mp_ioapic_gsi *gsi_cfg = mp_ioapic_gsi_routing(ioapic);
 	struct fwnode_handle *fn;
-	char *name = "IO-APIC";
+	struct irq_fwspec fwspec;
 
 	if (cfg->type == IOAPIC_DOMAIN_INVALID)
 		return 0;
 
-	init_irq_alloc_info(&info, NULL);
-	info.type = X86_IRQ_ALLOC_TYPE_IOAPIC_GET_PARENT;
-	info.devid = mpc_ioapic_id(ioapic);
-	parent = irq_remapping_get_irq_domain(&info);
-	if (!parent)
-		parent = x86_vector_domain;
-	else
-		name = "IO-APIC-IR";
-
 	/* Handle device tree enumerated APICs proper */
 	if (cfg->dev) {
 		fn = of_node_to_fwnode(cfg->dev);
 	} else {
-		fn = irq_domain_alloc_named_id_fwnode(name, ioapic);
+		fn = irq_domain_alloc_named_id_fwnode("IO-APIC", ioapic);
 		if (!fn)
 			return -ENOMEM;
 	}
 
+	fwspec.fwnode = fn;
+	fwspec.param_count = 1;
+	fwspec.param[0] = ioapic;
+
+	parent = irq_find_matching_fwspec(&fwspec, DOMAIN_BUS_ANY);
+	if (!parent) {
+		if (!cfg->dev)
+			irq_domain_free_fwnode(fn);
+		return -ENODEV;
+	}
+
 	ip->irqdomain = irq_domain_create_linear(fn, hwirqs, cfg->ops,
 						 (void *)(long)ioapic);