irq: support domains with non-zero hwirq base

Interrupt controllers can have non-zero starting value for h/w irq numbers.
Adding support in irq_domain allows the domain hwirq numbering to match
the interrupt controllers' numbering.

As this makes looping over irqs for a domain more complicated, add loop
iterators to iterate over all hwirqs and irqs for a domain.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Tested-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/irqdomain.h

@@ -47,6 +47,7 @@ struct irq_domain_ops {
  *            of the irq_domain is responsible for allocating the array of
  *            irq_desc structures.
  * @nr_irq: Number of irqs managed by the irq domain
+ * @hwirq_base: Starting number for hwirqs managed by the irq domain
  * @ops: pointer to irq_domain methods
  * @priv: private data pointer for use by owner.  Not touched by irq_domain
  *        core code.
@@ -57,6 +58,7 @@ struct irq_domain {
 	struct list_head list;
 	unsigned int irq_base;
 	unsigned int nr_irq;
+	unsigned int hwirq_base;
 	const struct irq_domain_ops *ops;
 	void *priv;
 	struct device_node *of_node;
@@ -72,9 +74,21 @@ struct irq_domain {
 static inline unsigned int irq_domain_to_irq(struct irq_domain *d,
 					     unsigned long hwirq)
 {
-	return d->ops->to_irq ? d->ops->to_irq(d, hwirq) : d->irq_base + hwirq;
+	if (d->ops->to_irq)
+		return d->ops->to_irq(d, hwirq);
+	if (WARN_ON(hwirq < d->hwirq_base))
+		return 0;
+	return d->irq_base + hwirq - d->hwirq_base;
 }
 
+#define irq_domain_for_each_hwirq(d, hw) \
+	for (hw = d->hwirq_base; hw < d->hwirq_base + d->nr_irq; hw++)
+
+#define irq_domain_for_each_irq(d, hw, irq) \
+	for (hw = d->hwirq_base, irq = irq_domain_to_irq(d, hw); \
+	     hw < d->hwirq_base + d->nr_irq; \
+	     hw++, irq = irq_domain_to_irq(d, hw))
+
 extern void irq_domain_add(struct irq_domain *domain);
 extern void irq_domain_del(struct irq_domain *domain);
 #endif /* CONFIG_IRQ_DOMAIN */

kernel/irq/irqdomain.c

@@ -20,15 +20,15 @@ static DEFINE_MUTEX(irq_domain_mutex);
 void irq_domain_add(struct irq_domain *domain)
 {
 	struct irq_data *d;
-	int hwirq;
+	int hwirq, irq;
 
 	/*
 	 * This assumes that the irq_domain owner has already allocated
 	 * the irq_descs.  This block will be removed when support for dynamic
 	 * allocation of irq_descs is added to irq_domain.
 	 */
-	for (hwirq = 0; hwirq < domain->nr_irq; hwirq++) {
-		d = irq_get_irq_data(irq_domain_to_irq(domain, hwirq));
+	irq_domain_for_each_irq(domain, hwirq, irq) {
+		d = irq_get_irq_data(irq);
 		if (!d) {
 			WARN(1, "error: assigning domain to non existant irq_desc");
 			return;
@@ -54,15 +54,15 @@ void irq_domain_add(struct irq_domain *domain)
 void irq_domain_del(struct irq_domain *domain)
 {
 	struct irq_data *d;
-	int hwirq;
+	int hwirq, irq;
 
 	mutex_lock(&irq_domain_mutex);
 	list_del(&domain->list);
 	mutex_unlock(&irq_domain_mutex);
 
 	/* Clear the irq_domain assignments */
-	for (hwirq = 0; hwirq < domain->nr_irq; hwirq++) {
-		d = irq_get_irq_data(irq_domain_to_irq(domain, hwirq));
+	irq_domain_for_each_irq(domain, hwirq, irq) {
+		d = irq_get_irq_data(irq);
 		d->domain = NULL;
 	}
 }