[PATCH] [POWERPC] mpic: deal with bogus NIRQ in Feature Reporting Register

[Kumar Gala <galak@kernel.crashing.org>]

Some chips (like the SoCs from Freescale) report the wrong value in NIRQ
and this causes issues if its doesn't match or exceed the value of
irq_count.

Add a flag that board code can set to just use irq_count instead of
FRR[NIRQ].  Eventually we'll add a device tree property with the number
of sources.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
---
 arch/powerpc/sysdev/mpic.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
index 8619f2a..4530b38 100644
--- a/arch/powerpc/sysdev/mpic.c
+++ b/arch/powerpc/sysdev/mpic.c
@@ -1144,9 +1144,9 @@ struct mpic * __init mpic_alloc(struct device_node *node,
 	mpic->num_cpus = ((greg_feature & MPIC_GREG_FEATURE_LAST_CPU_MASK)
 			  >> MPIC_GREG_FEATURE_LAST_CPU_SHIFT) + 1;
 	if (isu_size == 0)
-		mpic->num_sources =
+		mpic->num_sources = max(mpic->irq_count,
 			((greg_feature & MPIC_GREG_FEATURE_LAST_SRC_MASK)
-			 >> MPIC_GREG_FEATURE_LAST_SRC_SHIFT) + 1;
+			 >> MPIC_GREG_FEATURE_LAST_SRC_SHIFT) + 1);

 	/* Map the per-CPU registers */
 	for (i = 0; i < mpic->num_cpus; i++) {
-- 
1.5.4.5