as it turns out the current IRQ number will
*always* be available from SIR register which
renders the reads of PENDING registers as plain
unnecessary overhead.

In order to catch any situation where SIR reads
as zero, we're adding a WARN() to turn it into
a very verbose error and users actually report
it.

With this patch average running time of
omap_intc_handle_irq() reduced from about 28.5us
to 19.8us as measured by the kernel function
profiler.

Tested with BeagleBoneBlack Rev A5C.

Tested-by: Tony Lindgren <t...@atomide.com>
Signed-off-by: Felipe Balbi <ba...@ti.com>
---

Changes since v1:
        - s/Spuriour/Spurious

 drivers/irqchip/irq-omap-intc.c | 35 +++++------------------------------
 1 file changed, 5 insertions(+), 30 deletions(-)

diff --git a/drivers/irqchip/irq-omap-intc.c b/drivers/irqchip/irq-omap-intc.c
index 28718d3..3c97025 100644
--- a/drivers/irqchip/irq-omap-intc.c
+++ b/drivers/irqchip/irq-omap-intc.c
@@ -315,37 +315,12 @@ static int __init omap_init_irq(u32 base, struct 
device_node *node)
 static asmlinkage void __exception_irq_entry
 omap_intc_handle_irq(struct pt_regs *regs)
 {
-       u32 irqnr = 0;
-       int handled_irq = 0;
-       int i;
-
-       do {
-               for (i = 0; i < omap_nr_pending; i++) {
-                       irqnr = intc_readl(INTC_PENDING_IRQ0 + (0x20 * i));
-                       if (irqnr)
-                               goto out;
-               }
-
-out:
-               if (!irqnr)
-                       break;
-
-               irqnr = intc_readl(INTC_SIR);
-               irqnr &= ACTIVEIRQ_MASK;
+       u32 irqnr;
 
-               if (irqnr) {
-                       handle_domain_irq(domain, irqnr, regs);
-                       handled_irq = 1;
-               }
-       } while (irqnr);
-
-       /*
-        * If an irq is masked or deasserted while active, we will
-        * keep ending up here with no irq handled. So remove it from
-        * the INTC with an ack.
-        */
-       if (!handled_irq)
-               omap_ack_irq(NULL);
+       irqnr = intc_readl(INTC_SIR);
+       irqnr &= ACTIVEIRQ_MASK;
+       WARN(!irqnr, "Spurious IRQ ?\n");
+       handle_domain_irq(domain, irqnr, regs);
 }
 
 void __init omap2_init_irq(void)
-- 
2.2.0

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