powerpc/mpc62xx_pic: Fix get_irq handling of NO_IRQ
authorMilton Miller <miltonm@bga.com>
Tue, 10 May 2011 19:30:18 +0000 (19:30 +0000)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>
Thu, 19 May 2011 05:31:49 +0000 (15:31 +1000)
commit67347eba156d64150be73c9f5797342a66b123d9
tree6778f8fe44efc633e9169a722628d8e86d9eeb17
parentc42385cd4533b5ba9b9dd0034285cfcfd7982708
powerpc/mpc62xx_pic: Fix get_irq handling of NO_IRQ

If none of irq category bits were set mpc52xx_get_irq() would pass
NO_IRQ_IGNORE (-1) to irq_linear_revmap, which does an unsigned compare
and declares the interrupt above the linear map range.  It then punts
to irq_find_mapping, which performs a linear search of all irqs,
which will likely miss and only then return NO_IRQ.

If no status bit is set, then we should return NO_IRQ directly.
The interrupt should not be suppressed from spurious counting, in fact
that is the definition of supurious.

Signed-off-by: Milton Miller <miltonm@bga.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
arch/powerpc/platforms/52xx/mpc52xx_pic.c