[PATCH V3 01/17] irqchip/gic: Don't unnecessarily write the IRQ configuration

Jon Hunter
2016-05-04T16:25:56Z

If the interrupt configuration matches the current configuration, then
don't bother writing the configuration again.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
---
drivers/irqchip/irq-gic-common.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-gic-common.c b/drivers/irqchip/irq-gic-common.c
index f174ce0ca361..ffff5a45f1e3 100644
--- a/drivers/irqchip/irq-gic-common.c
+++ b/drivers/irqchip/irq-gic-common.c
@@ -50,13 +50,17 @@ int gic_configure_irq(unsigned int irq, unsigned int type,
else if (type & IRQ_TYPE_EDGE_BOTH)
val |= confmask;

+ /* If the current configuration is the same, then we are done */
+ if (val == oldval)
+ return 0;
+
/*
* Write back the new configuration, and possibly re-enable
- * the interrupt. If we tried to write a new configuration and failed,
+ * the interrupt. If we fail to write a new configuration,
* return an error.
*/
writel_relaxed(val, base + GIC_DIST_CONFIG + confoff);
- if (readl_relaxed(base + GIC_DIST_CONFIG + confoff) != val && val != oldval)
+ if (readl_relaxed(base + GIC_DIST_CONFIG + confoff) != val)
ret = -EINVAL;

if (sync_access)
--
2.1.4