irq_domain: Move irq_virq_count into NOMAP revmap

This patch replaces the old global setting of irq_virq_count that is only
used by the NOMAP mapping and instead uses a revmap_data property so that
the maximum NOMAP allocation can be set per NOMAP irq_domain.

There is exactly one user of irq_virq_count in-tree right now: PS3.
Also, irq_virq_count is only useful for the NOMAP mapping.  So,
instead of having a single global irq_virq_count values, this change
drops it entirely and added a max_irq argument to irq_domain_add_nomap().
That makes it a property of an individual nomap irq domain instead of
a global system settting.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Milton Miller <miltonm@bga.com>

kernel/irq/irqdomain.c

@@ -23,7 +23,6 @@ static LIST_HEAD(irq_domain_list);
 static DEFINE_MUTEX(irq_domain_mutex);
 
 static DEFINE_MUTEX(revmap_trees_mutex);
-static unsigned int irq_virq_count = NR_IRQS;
 static struct irq_domain *irq_default_domain;
 
 /**
@@ -184,13 +183,16 @@ struct irq_domain *irq_domain_add_linear(struct device_node *of_node,
 }
 
 struct irq_domain *irq_domain_add_nomap(struct device_node *of_node,
+					 unsigned int max_irq,
 					 const struct irq_domain_ops *ops,
 					 void *host_data)
 {
 	struct irq_domain *domain = irq_domain_alloc(of_node,
 					IRQ_DOMAIN_MAP_NOMAP, ops, host_data);
-	if (domain)
+	if (domain) {
+		domain->revmap_data.nomap.max_irq = max_irq ? max_irq : ~0;
 		irq_domain_add(domain);
+	}
 	return domain;
 }
 
@@ -262,22 +264,6 @@ void irq_set_default_host(struct irq_domain *domain)
 	irq_default_domain = domain;
 }
 
-/**
- * irq_set_virq_count() - Set the maximum number of linux irqs
- * @count: number of linux irqs, capped with NR_IRQS
- *
- * This is mainly for use by platforms like iSeries who want to program
- * the virtual irq number in the controller to avoid the reverse mapping
- */
-void irq_set_virq_count(unsigned int count)
-{
-	pr_debug("irq: Trying to set virq count to %d\n", count);
-
-	BUG_ON(count < NUM_ISA_INTERRUPTS);
-	if (count < NR_IRQS)
-		irq_virq_count = count;
-}
-
 static int irq_setup_virq(struct irq_domain *domain, unsigned int virq,
 			    irq_hw_number_t hwirq)
 {
@@ -320,13 +306,12 @@ unsigned int irq_create_direct_mapping(struct irq_domain *domain)
 		pr_debug("irq: create_direct virq allocation failed\n");
 		return 0;
 	}
-	if (virq >= irq_virq_count) {
+	if (virq >= domain->revmap_data.nomap.max_irq) {
 		pr_err("ERROR: no free irqs available below %i maximum\n",
-			irq_virq_count);
+			domain->revmap_data.nomap.max_irq);
 		irq_free_desc(virq);
 		return 0;
 	}
-
 	pr_debug("irq: create_direct obtained virq %d\n", virq);
 
 	if (irq_setup_virq(domain, virq, virq)) {
@@ -378,7 +363,7 @@ unsigned int irq_create_mapping(struct irq_domain *domain,
 		return irq_domain_legacy_revmap(domain, hwirq);
 
 	/* Allocate a virtual interrupt number */
-	hint = hwirq % irq_virq_count;
+	hint = hwirq % nr_irqs;
 	if (hint == 0)
 		hint++;
 	virq = irq_alloc_desc_from(hint, 0);
@@ -516,7 +501,7 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
 			      irq_hw_number_t hwirq)
 {
 	unsigned int i;
-	unsigned int hint = hwirq % irq_virq_count;
+	unsigned int hint = hwirq % nr_irqs;
 
 	/* Look for default domain if nececssary */
 	if (domain == NULL)
@@ -537,7 +522,7 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
 		if (data && (data->domain == domain) && (data->hwirq == hwirq))
 			return i;
 		i++;
-		if (i >= irq_virq_count)
+		if (i >= nr_irqs)
 			i = 1;
 	} while(i != hint);
 	return 0;