[PATCH RESEND] irqchip: omap-intc: improve IRQ handler

2015-07-20 Thread Felipe Balbi 
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
---
 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 a569c6dbd1d1..0706db624213 100644
--- a/drivers/irqchip/irq-omap-intc.c
+++ b/drivers/irqchip/irq-omap-intc.c
@@ -331,37 +331,12 @@ 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 omap3_init_irq(void)
-- 
2.4.4

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Re: [PATCH RESEND] irqchip: omap-intc: improve IRQ handler

2015-07-20 Thread Thomas Gleixner 
On Mon, 20 Jul 2015, Felipe Balbi wrote:
 + irqnr = intc_readl(INTC_SIR);
 + irqnr = ACTIVEIRQ_MASK;
 + WARN(!irqnr, Spurious IRQ ?\n);

Shouldn't that be WARN_ONCE?

Thanks,

tglx
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Re: [PATCH RESEND] irqchip: omap-intc: improve IRQ handler

2015-07-20 Thread Felipe Balbi 
On Mon, Jul 20, 2015 at 10:44:08PM +0200, Thomas Gleixner wrote:
 On Mon, 20 Jul 2015, Felipe Balbi wrote:
  +   irqnr = intc_readl(INTC_SIR);
  +   irqnr = ACTIVEIRQ_MASK;
  +   WARN(!irqnr, Spurious IRQ ?\n);
 
 Shouldn't that be WARN_ONCE?

Sure, why not ?

8

From a71590d725e54b888db278de6c278d2a106fc76d Mon Sep 17 00:00:00 2001
From: Felipe Balbi ba...@ti.com
Date: Fri, 2 Jan 2015 16:18:54 -0600
Subject: [PATCH RESEND v2] irqchip: omap-intc: improve IRQ handler

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 from V1:

 - replace WARN() with WARN_ONCE()

 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 a569c6dbd1d1..e15f10746310 100644
--- a/drivers/irqchip/irq-omap-intc.c
+++ b/drivers/irqchip/irq-omap-intc.c
@@ -331,37 +331,12 @@ 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_ONCE(!irqnr, Spurious IRQ ?\n);
+   handle_domain_irq(domain, irqnr, regs);
 }
 
 void __init omap3_init_irq(void)
-- 
2.4.4


-- 
balbi


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