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Subject[PATCH 1/3] of/irq: of_irq_find_parent: check for parent equal to child
Date
From: Rob Herring <rob.herring@calxeda.com>

An interrupt controller may often implicitly inherit itself from a parent
node when in fact the controller is the interrupt root controller. Guard
against the case of child == parent and return NULL in this case.

This can also be fixed by adding an explicit "interrupt-parent;" to a root
interrupt controller node.

Based on code from Grant Likely.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
---
drivers/of/irq.c | 14 +++++++-------
1 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 9f689f1..6a5b5e7 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -58,27 +58,27 @@ EXPORT_SYMBOL_GPL(irq_of_parse_and_map);
*/
struct device_node *of_irq_find_parent(struct device_node *child)
{
- struct device_node *p;
+ struct device_node *p, *c = child;
const __be32 *parp;

- if (!of_node_get(child))
+ if (!of_node_get(c))
return NULL;

do {
- parp = of_get_property(child, "interrupt-parent", NULL);
+ parp = of_get_property(c, "interrupt-parent", NULL);
if (parp == NULL)
- p = of_get_parent(child);
+ p = of_get_parent(c);
else {
if (of_irq_workarounds & OF_IMAP_NO_PHANDLE)
p = of_node_get(of_irq_dflt_pic);
else
p = of_find_node_by_phandle(be32_to_cpup(parp));
}
- of_node_put(child);
- child = p;
+ of_node_put(c);
+ c = p;
} while (p && of_get_property(p, "#interrupt-cells", NULL) == NULL);

- return p;
+ return (p == child) ? NULL : p;
}

/**
--
1.7.5.4


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