[RFC 1/2] irq_domain: Create common xlate functions that device drivers can use

[Grant Likely]

Rather than having each interrupt controller driver creating its own barely
unique .xlate function for irq_domain, create a library of translators which
any driver can use directly.

Signed-off-by: Grant Likely <grant.likely at secretlab.ca>
Cc: Rob Herring <rob.herring at calxeda.com>
Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
---

This builds on top of my irq_domain series and will be included with it when
I post v3.  Rob, does this serve your needs for generic irq controller DT
support?

g.

 include/linux/irqdomain.h |   15 ++++++++++
 kernel/irq/irqdomain.c    |   69 +++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 76 insertions(+), 8 deletions(-)

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index e7379a3..5e497a0 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -110,6 +110,9 @@ struct irq_domain {
 	void *host_data;
 	irq_hw_number_t inval_irq;
 
+	/* Data for common irq xlate functions */
+	unsigned int xlate_type;
+
 	/* Optional device node pointer */
 	struct device_node *of_node;
 };
@@ -163,6 +166,18 @@ extern unsigned int irq_linear_revmap(struct irq_domain *host,
 				      irq_hw_number_t hwirq);
 
 extern struct irq_domain_ops irq_domain_simple_ops;
+
+/* stock xlate functions */
+int irq_domain_xlate_onecell(struct irq_domain *d, struct device_node *ctrlr,
+			const u32 *intspec, unsigned int intsize,
+			irq_hw_number_t *out_hwirq, unsigned int *out_type);
+int irq_domain_xlate_twocell(struct irq_domain *d, struct device_node *ctrlr,
+			const u32 *intspec, unsigned int intsize,
+			irq_hw_number_t *out_hwirq, unsigned int *out_type);
+int irq_domain_xlate_onetwocell(struct irq_domain *d, struct device_node *ctrlr,
+			const u32 *intspec, unsigned int intsize,
+			irq_hw_number_t *out_hwirq, unsigned int *out_type);
+
 #if defined(CONFIG_OF_IRQ)
 extern void irq_domain_generate_simple(const struct of_device_id *match,
 					u64 phys_base, unsigned int irq_start);
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index def8e7b..df80205 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -53,6 +53,7 @@ static struct irq_domain *irq_domain_alloc(struct device_node *of_node,
 	domain->ops = ops;
 	domain->host_data = host_data;
 	domain->of_node = of_node_get(of_node);
+	domain->xlate_type = IRQ_TYPE_NONE;
 
 	if (domain->ops->match == NULL)
 		domain->ops->match = default_irq_domain_match;
@@ -690,25 +691,77 @@ int irq_domain_simple_map(struct irq_domain *d, unsigned int irq,
 	return 0;
 }
 
-int irq_domain_simple_xlate(struct irq_domain *d,
-			    struct device_node *controller,
-			    const u32 *intspec, unsigned int intsize,
-			    unsigned long *out_hwirq, unsigned int *out_type)
+/**
+ * irq_domain_xlate_onecell() - Generic xlate for direct one cell bindings
+ *
+ * Device Tree IRQ specifier translation function which works with one cell
+ * bindings where the cell value maps directly to the hwirq number.
+ */
+int irq_domain_xlate_onecell(struct irq_domain *d, struct device_node *ctrlr,
+			     const u32 *intspec, unsigned int intsize,
+			     unsigned long *out_hwirq, unsigned int *out_type)
+{
+	if (WARN(intsize < 1, "Bad intspec for %s: intsize=%i < 1\n",
+		 ctrlr->full_name, intsize))
+		return -EINVAL;
+	*out_hwirq = intspec[0];
+	*out_type = d->xlate_type;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_domain_xlate_onecell);
+
+/**
+ * irq_domain_xlate_twocell() - Generic xlate for direct two cell bindings
+ *
+ * Device Tree IRQ specifier translation function which works with two cell
+ * bindings where the cell values map directly to the hwirq number
+ * and linux irq flags.
+ */
+int irq_domain_xlate_twocell(struct irq_domain *d, struct device_node *ctrlr,
+			const u32 *intspec, unsigned int intsize,
+			irq_hw_number_t *out_hwirq, unsigned int *out_type)
 {
-	if (d->of_node != controller)
+	if (WARN(intsize < 2, "Bad intspec for %s: intsize=%i < 2\n",
+		 ctrlr->full_name, intsize))
+		return -EINVAL;
+	if (intsize < 2)
 		return -EINVAL;
-	if (intsize < 1)
+	*out_hwirq = intspec[0];
+	*out_type = intspec[1] & IRQ_TYPE_SENSE_MASK;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(irq_domain_xlate_twocell);
+
+/**
+ * irq_domain_xlate_onetwocell() - Generic xlate for one or two cell bindings
+ *
+ * Device Tree IRQ specifier translation function which works with either one
+ * or two cell bindings where the cell values map directly to the hwirq number
+ * and linux irq flags.
+ *
+ * Note: don't use this function unless your interrupt controller explicitly
+ * supports both one and two cell bindings.  For the majority of controllers
+ * the _onecell() or _twocell() variants above should be used.
+ */
+int irq_domain_xlate_onetwocell(struct irq_domain *d,
+				struct device_node *ctrlr,
+				const u32 *intspec, unsigned int intsize,
+				unsigned long *out_hwirq, unsigned int *out_type)
+{
+	if (WARN(intsize < 1, "Bad intspec for %s: intsize=%i < 1\n",
+		 ctrlr->full_name, intsize))
 		return -EINVAL;
 	*out_hwirq = intspec[0];
-	*out_type = IRQ_TYPE_NONE;
+	*out_type = d->xlate_type;
 	if (intsize > 1)
 		*out_type = intspec[1] & IRQ_TYPE_SENSE_MASK;
 	return 0;
 }
+EXPORT_SYMBOL_GPL(irq_domain_xlate_onetwocell);
 
 struct irq_domain_ops irq_domain_simple_ops = {
 	.map = irq_domain_simple_map,
-	.xlate = irq_domain_simple_xlate,
+	.xlate = irq_domain_xlate_onetwocell,
 };
 EXPORT_SYMBOL_GPL(irq_domain_simple_ops);
 
-- 
1.7.5.4