From: Changhwan Youn <chaos.y...@samsung.com>
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.j...@samsung.com>
Signed-off-by: Changhwan Youn <chaos.y...@samsung.com>
Signed-off-by: Kukjin Kim <kgene....@samsung.com>
---
Changes since v1:
- Modified to ffs as per Troy Kisky's pointing out
In this case, the ffs is more suitable according to original code.
arch/arm/mach-s5pv310/irq-combiner.c | 6 +-----
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 0f70521..c3f88c3 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))
--
1.6.2.5
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