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Commit dc937280 authored by Rob Herring's avatar Rob Herring
Browse files

of/irq: of_irq_find_parent: check for parent equal to child 



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: default avatarRob Herring <rob.herring@calxeda.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
parent f910b831

drivers/of/irq.c

+7 −7
Original line number Diff line number Diff line
@@ -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;

}



/**