Index: target/linux/atheros/files/include/asm-mips/mach-atheros/ar531x.h
===================================================================
--- target/linux/atheros/files/include/asm-mips/mach-atheros/ar531x.h	(revision 10877)
+++ target/linux/atheros/files/include/asm-mips/mach-atheros/ar531x.h	(working copy)
@@ -12,29 +12,6 @@
 #endif
 
 /*
- * C access to CLZ instruction
- * (count leading zeroes).
- */
-static inline int clz(unsigned long val)
-{
-	int ret;
-
-	__asm__ volatile (
-		".set\tnoreorder\n\t"
-		".set\tnoat\n\t"
-		".set\tmips32\n\t"
-		"clz\t%0,%1\n\t"
-		".set\tmips0\n\t"
-		".set\tat\n\t"
-		".set\treorder"
-		: "=r" (ret)
-		: "r" (val)
-	);
-
-	return ret;
-}
-
-/*
  * Atheros CPUs before the AR2315 are using MIPS 4Kc core, later designs are
  * using MIPS 4KEc R2 core. This makes it easy to determine the board at runtime.
  */
Index: target/linux/atheros/files/arch/mips/atheros/ar5315/irq.c
===================================================================
--- target/linux/atheros/files/arch/mips/atheros/ar5315/irq.c	(revision 10877)
+++ target/linux/atheros/files/arch/mips/atheros/ar5315/irq.c	(working copy)
@@ -20,6 +20,7 @@
 #include <linux/kernel.h>
 #include <linux/reboot.h>
 #include <linux/interrupt.h>
+#include <linux/bitops.h>
 #include <asm/bootinfo.h>
 #include <asm/irq_cpu.h>
 #include <asm/io.h>
@@ -39,7 +40,7 @@
 	if (!pend)
 		return;
 
-	do_IRQ(AR531X_GPIO_IRQ_BASE + 31 - clz(pend));
+	do_IRQ(AR531X_GPIO_IRQ_BASE + fls(pend) - 1);
 }