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Subject[RFC PATCH 3/4] dt/irq: add of_irq_domain_add_simple() helper
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of_irq_domain_add_simple() is an easy way to generate an irq translation
domain for simple irq controllers. It assumes a flat 1:1 mapping from
hardware irq number to an offset of the first linux irq number assigned
to the controller

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
drivers/of/irq.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_irq.h | 2 ++
2 files changed, 46 insertions(+), 0 deletions(-)

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 6da0964..641590c 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -24,6 +24,7 @@
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/string.h>
+#include <linux/slab.h>

/* For archs that don't support NO_IRQ (such as x86), provide a dummy value */
#ifndef NO_IRQ
@@ -147,6 +148,49 @@ unsigned int irq_create_of_mapping(struct device_node *controller,
}
EXPORT_SYMBOL_GPL(irq_create_of_mapping);

+/*
+ * A simple irq domain implementation that 1:1 translates hwirqs to an offset
+ * from the irq_start value
+ */
+struct of_irq_domain_simple {
+ struct of_irq_domain domain;
+ int irq_start;
+ int irq_size;
+};
+
+static unsigned int of_irq_domain_simple_map(struct of_irq_domain *domain,
+ struct device_node *controller,
+ const u32 *intspec, u32 intsize)
+{
+ struct of_irq_domain_simple *ds;
+
+ ds = container_of(domain, struct of_irq_domain_simple, domain);
+ if (intspec[0] >= ds->irq_size)
+ return NO_IRQ;
+ return ds->irq_start + intspec[0];
+}
+
+/**
+ * of_irq_domain_create_simple() - Set up a 'simple' translation range
+ */
+void of_irq_domain_add_simple(struct device_node *controller,
+ int irq_start, int irq_size)
+{
+ struct of_irq_domain_simple *sd;
+
+ sd = kzalloc(sizeof(*sd), GFP_KERNEL);
+ if (!sd) {
+ WARN_ON(1);
+ return;
+ }
+
+ sd->irq_start = irq_start;
+ sd->irq_size = irq_size;
+ sd->domain.controller = of_node_get(controller);
+ sd->domain.map = of_irq_domain_simple_map;
+ of_irq_domain_add(&sd->domain);
+}
+
/**
* irq_of_parse_and_map - Parse and map an interrupt into linux virq space
* @device: Device node of the device whose interrupt is to be mapped
diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
index 511dbc3..8e49a0e 100644
--- a/include/linux/of_irq.h
+++ b/include/linux/of_irq.h
@@ -63,6 +63,8 @@ struct of_irq_domain {
extern void of_irq_domain_add(struct of_irq_domain *domain);
extern void of_irq_set_default_domain(struct of_irq_domain *host);
extern struct of_irq_domain *of_irq_domain_find(struct device_node *controller);
+extern void of_irq_domain_add_simple(struct device_node *controller,
+ int irq_start, int irq_size);

/*
* Workarounds only applied to 32bit powermac machines


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