genirq/irqdomain: Reroute device MSI create_mapping

Reroute interrupt allocation in irq_create_fwspec_mapping() if the domain
is a MSI device domain. This is required to convert the support for wire
to MSI bridges to per device MSI domains.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240127161753.114685-13-apatel@ventanamicro.com

kernel/irq/irqdomain.c

@@ -29,6 +29,7 @@ static int irq_domain_alloc_irqs_locked(struct irq_domain *domain, int irq_base,
 					unsigned int nr_irqs, int node, void *arg,
 					bool realloc, const struct irq_affinity_desc *affinity);
 static void irq_domain_check_hierarchy(struct irq_domain *domain);
+static void irq_domain_free_one_irq(struct irq_domain *domain, unsigned int virq);
 
 struct irqchip_fwid {
 	struct fwnode_handle	fwnode;
@@ -858,6 +859,11 @@ unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec)
 	}
 
 	if (irq_domain_is_hierarchy(domain)) {
+		if (irq_domain_is_msi_device(domain)) {
+			mutex_unlock(&domain->root->mutex);
+			virq = msi_device_domain_alloc_wired(domain, hwirq, type);
+			mutex_lock(&domain->root->mutex);
+		} else
 			virq = irq_domain_alloc_irqs_locked(domain, -1, 1, NUMA_NO_NODE,
 							    fwspec, false, NULL);
 		if (virq <= 0) {
@@ -914,7 +920,7 @@ void irq_dispose_mapping(unsigned int virq)
 		return;
 
 	if (irq_domain_is_hierarchy(domain)) {
-		irq_domain_free_irqs(virq, 1);
+		irq_domain_free_one_irq(domain, virq);
 	} else {
 		irq_domain_disassociate(domain, virq);
 		irq_free_desc(virq);
@@ -1755,6 +1761,14 @@ void irq_domain_free_irqs(unsigned int virq, unsigned int nr_irqs)
 	irq_free_descs(virq, nr_irqs);
 }
 
+static void irq_domain_free_one_irq(struct irq_domain *domain, unsigned int virq)
+{
+	if (irq_domain_is_msi_device(domain))
+		msi_device_domain_free_wired(domain, virq);
+	else
+		irq_domain_free_irqs(virq, 1);
+}
+
 /**
  * irq_domain_alloc_irqs_parent - Allocate interrupts from parent domain
  * @domain:	Domain below which interrupts must be allocated
@@ -1907,9 +1921,9 @@ static int irq_domain_alloc_irqs_locked(struct irq_domain *domain, int irq_base,
 	return -EINVAL;
 }
 
-static void irq_domain_check_hierarchy(struct irq_domain *domain)
-{
-}
+static void irq_domain_check_hierarchy(struct irq_domain *domain) { }
+static void irq_domain_free_one_irq(struct irq_domain *domain, unsigned int virq) { }
+
 #endif	/* CONFIG_IRQ_DOMAIN_HIERARCHY */
 
 #ifdef CONFIG_GENERIC_IRQ_DEBUGFS