MIPS: Loongson-3: Adjust irq dispatch to speedup processing

This patch adjust the logic in mach_irq_dispatch(), allow multiple IPs
handled in the same dispatching. This can speedup interrupt processing.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Steven J . Hill <sjhill@realitydiluted.com>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12891/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/loongson64/loongson-3/irq.c

@@ -24,19 +24,21 @@ static void ht_irqdispatch(void)
 	}
 }
 
+#define UNUSED_IPS (CAUSEF_IP5 | CAUSEF_IP4 | CAUSEF_IP1 | CAUSEF_IP0)
+
 void mach_irq_dispatch(unsigned int pending)
 {
 	if (pending & CAUSEF_IP7)
 		do_IRQ(LOONGSON_TIMER_IRQ);
 #if defined(CONFIG_SMP)
-	else if (pending & CAUSEF_IP6)
+	if (pending & CAUSEF_IP6)
 		loongson3_ipi_interrupt(NULL);
 #endif
-	else if (pending & CAUSEF_IP3)
+	if (pending & CAUSEF_IP3)
 		ht_irqdispatch();
-	else if (pending & CAUSEF_IP2)
+	if (pending & CAUSEF_IP2)
 		do_IRQ(LOONGSON_UART_IRQ);
-	else {
+	if (pending & UNUSED_IPS) {
 		pr_err("%s : spurious interrupt\n", __func__);
 		spurious_interrupt();
 	}