MIPS: lantiq: enable oprofile support on lantiq targets

This patch sets the performance counters irq on Lantiq SoCs.
Signed-off-by: NJohn Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3720/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/lantiq/irq.c

@@ -40,6 +40,9 @@
 
 #define MAX_EIU			6
 
+/* the performance counter */
+#define LTQ_PERF_IRQ		(INT_NUM_IM4_IRL0 + 31)
+
 /* irqs generated by device attached to the EBU need to be acked in
  * a special manner
  */
@@ -316,6 +319,9 @@ void __init arch_init_irq(void)
 	set_c0_status(IE_SW0 | IE_SW1 | IE_IRQ0 | IE_IRQ1 |
 		IE_IRQ2 | IE_IRQ3 | IE_IRQ4 | IE_IRQ5);
 #endif
+
+	/* tell oprofile which irq to use */
+	cp0_perfcount_irq = LTQ_PERF_IRQ;
 }
 
 unsigned int __cpuinit get_c0_compare_int(void)