ARM: S5PV310: Optimize interrupt source searching code
It is reported by Junseok Jung that using clz instruction is
better instead of using for-loop to find the interrupt source.
This patch modifies interrupt source searching code using __ffs().
The __ffs() is implemented using clz instruction.
Suggested-by: Junseok Jung <jundols.jung@samsung.com>
Signed-off-by: Changhwan Youn <chaos.youn@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
diff --git a/arch/arm/mach-s5pv310/irq-combiner.c b/arch/arm/mach-s5pv310/irq-combiner.c
index 0f70521..c3f88c3 100644
--- a/arch/arm/mach-s5pv310/irq-combiner.c
+++ b/arch/arm/mach-s5pv310/irq-combiner.c
@@ -66,11 +66,7 @@
if (status == 0)
goto out;
- for (combiner_irq = 0; combiner_irq < 32; combiner_irq++) {
- if (status & 0x1)
- break;
- status >>= 1;
- }
+ combiner_irq = __ffs(status);
cascade_irq = combiner_irq + (chip_data->irq_offset & ~31);
if (unlikely(cascade_irq >= NR_IRQS))
