Revert "of/irq: of_irq_find_parent: check for parent equal to child"
This reverts commit dc9372808412edbc653a675a526c2ee6c0c14a91.
As requested by Ben Herrenschmidt:
"This breaks some powerpc platforms at least. The practice of having
a node provide an explicit "interrupt-parent" property pointing to
itself is an old trick that we've used in the past to allow a
device-node to have interrupts routed to different controllers.
In that case, the node also contains an interrupt-map, so the node is
its own parent, the interrupt resolution hits the map, which then can
route each individual interrupt to a different parent."
Grant says:
"Ah, nuts, yes that is broken then. Yes, please revert the commit and
Rob & I will come up with a better solution.
Rob, I think it can be done by explicitly checking for np ==
desc->interrupt_parent in of_irq_init() instead of relying on
of_irq_find_parent() returning NULL."
Requested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: Tanmay Inamdar <tinamdar@apm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 6d3dd39..791270b 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -60,27 +60,27 @@
*/
struct device_node *of_irq_find_parent(struct device_node *child)
{
- struct device_node *p, *c = child;
+ struct device_node *p;
const __be32 *parp;
- if (!of_node_get(c))
+ if (!of_node_get(child))
return NULL;
do {
- parp = of_get_property(c, "interrupt-parent", NULL);
+ parp = of_get_property(child, "interrupt-parent", NULL);
if (parp == NULL)
- p = of_get_parent(c);
+ p = of_get_parent(child);
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(c);
- c = p;
+ of_node_put(child);
+ child = p;
} while (p && of_get_property(p, "#interrupt-cells", NULL) == NULL);
- return (p == child) ? NULL : p;
+ return p;
}
/**
