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>

2 files changed, 21 insertions, 7 deletions

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 3ad553e8eae2..99834e581b9e 100644
--- a/include/linux/irqdomain.h
+++ b/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 */
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index b57a3776de44..200ce832c585 100644
--- a/kernel/irq/irqdomain.c
+++ b/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;
         }
 }