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

This reverts commit dc93728084.

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>
This commit is contained in:
Linus Torvalds 2011-11-22 15:09:20 -08:00
parent 2db1125d51
commit b4bbb02934
1 changed files with 7 additions and 7 deletions
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14
drivers/of/irq.c
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@ -60,27 +60,27 @@ EXPORT_SYMBOL_GPL(irq_of_parse_and_map);
*/ */
struct device_node *of_irq_find_parent(struct device_node *child) struct device_node *of_irq_find_parent(struct device_node *child)
{ {
struct device_node *p, *c = child; struct device_node *p;
const __be32 *parp; const __be32 *parp;
if (!of_node_get(c)) if (!of_node_get(child))
return NULL; return NULL;
do { do {
parp = of_get_property(c, "interrupt-parent", NULL); parp = of_get_property(child, "interrupt-parent", NULL);
if (parp == NULL) if (parp == NULL)
p = of_get_parent(c); p = of_get_parent(child);
else { else {
if (of_irq_workarounds & OF_IMAP_NO_PHANDLE) if (of_irq_workarounds & OF_IMAP_NO_PHANDLE)
p = of_node_get(of_irq_dflt_pic); p = of_node_get(of_irq_dflt_pic);
else else
p = of_find_node_by_phandle(be32_to_cpup(parp)); p = of_find_node_by_phandle(be32_to_cpup(parp));
} }
of_node_put(c); of_node_put(child);
c = p; child = p;
} while (p && of_get_property(p, "#interrupt-cells", NULL) == NULL); } while (p && of_get_property(p, "#interrupt-cells", NULL) == NULL);
return (p == child) ? NULL : p; return p;
} }
/** /**