1 files changed, 27 insertions, 28 deletions

diff --git a/kernel/drivers/irqchip/irq-omap-intc.c b/kernel/drivers/irqchip/irq-omap-intc.c
index a569c6dbd..f6cb1b8bb 100644
--- a/kernel/drivers/irqchip/irq-omap-intc.c
+++ b/kernel/drivers/irqchip/irq-omap-intc.c
@@ -17,13 +17,12 @@
 #include <linux/io.h>
 
 #include <asm/exception.h>
+#include <linux/irqchip.h>
 #include <linux/irqdomain.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 
-#include "irqchip.h"
-
 /* Define these here for now until we drop all board-files */
 #define OMAP24XX_IC_BASE	0x480fe000
 #define OMAP34XX_IC_BASE	0x48200000
@@ -48,6 +47,7 @@
 #define INTC_ILR0		0x0100
 
 #define ACTIVEIRQ_MASK		0x7f	/* omap2/3 active interrupt bits */
+#define SPURIOUSIRQ_MASK	(0x1ffffff << 7)
 #define INTCPS_NR_ILR_REGS	128
 #define INTCPS_NR_MIR_REGS	4
 
@@ -331,37 +331,36 @@ 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;
+	extern unsigned long irq_err_count;
+	u32 irqnr;
 
-		irqnr = intc_readl(INTC_SIR);
-		irqnr &= ACTIVEIRQ_MASK;
-
-		if (irqnr) {
-			handle_domain_irq(domain, irqnr, regs);
-			handled_irq = 1;
-		}
-	} while (irqnr);
+	irqnr = intc_readl(INTC_SIR);
 
 	/*
-	 * 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.
+	 * A spurious IRQ can result if interrupt that triggered the
+	 * sorting is no longer active during the sorting (10 INTC
+	 * functional clock cycles after interrupt assertion). Or a
+	 * change in interrupt mask affected the result during sorting
+	 * time. There is no special handling required except ignoring
+	 * the SIR register value just read and retrying.
+	 * See section 6.2.5 of AM335x TRM Literature Number: SPRUH73K
+	 *
+	 * Many a times, a spurious interrupt situation has been fixed
+	 * by adding a flush for the posted write acking the IRQ in
+	 * the device driver. Typically, this is going be the device
+	 * driver whose interrupt was handled just before the spurious
+	 * IRQ occurred. Pay attention to those device drivers if you
+	 * run into hitting the spurious IRQ condition below.
 	 */
-	if (!handled_irq)
+	if (unlikely((irqnr & SPURIOUSIRQ_MASK) == SPURIOUSIRQ_MASK)) {
+		pr_err_once("%s: spurious irq!\n", __func__);
+		irq_err_count++;
 		omap_ack_irq(NULL);
+		return;
+	}
+
+	irqnr &= ACTIVEIRQ_MASK;
+	handle_domain_irq(domain, irqnr, regs);
 }
 
 void __init omap3_init_irq(void)