of/irq: of_irq_find_parent: check for parent equal to child (dc937280) · Commits · 戴 / test

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

+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;
		}

		/**

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