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authorChanghwan Youn <chaos.youn@samsung.com>2010-09-29 20:31:42 +0900
committerKukjin Kim <kgene.kim@samsung.com>2010-10-21 07:52:18 +0900
commit0c0f909689c8387265a3682d4205c063071ec36a (patch)
tree3d341bd807e1bd050a393ee3ead44ff87bcda036
parent8d75c9128a07bd1f81952a518ed818d1a3e90c96 (diff)
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>
-rw-r--r--arch/arm/mach-s5pv310/irq-combiner.c6
1 files changed, 1 insertions, 5 deletions
diff --git a/arch/arm/mach-s5pv310/irq-combiner.c b/arch/arm/mach-s5pv310/irq-combiner.c
index 0f7052164f23..c3f88c3faf6c 100644
--- a/arch/arm/mach-s5pv310/irq-combiner.c
+++ b/arch/arm/mach-s5pv310/irq-combiner.c
@@ -66,11 +66,7 @@ static void combiner_handle_cascade_irq(unsigned int irq, struct irq_desc *desc)
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))