ARM: EXYNOS4: Add chained enrty/exit function to uart interrupt handler

This patch adds chained IRQ enter/exit functions to uart
interrupt handler in order to function correctly on primary
controllers with different methods of flow control.
Signed-off-by: Changhwan Youn <chaos.youn@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/plat-samsung/irq-uart.c

@@ -19,6 +19,8 @@
 #include <linux/irq.h>
 #include <linux/io.h>
 
+#include <asm/mach/irq.h>
+
 #include <mach/map.h>
 #include <plat/irq-uart.h>
 #include <plat/regs-serial.h>
@@ -30,9 +32,12 @@
 static void s3c_irq_demux_uart(unsigned int irq, struct irq_desc *desc)
 {
 	struct s3c_uart_irq *uirq = desc->irq_data.handler_data;
+	struct irq_chip *chip = irq_get_chip(irq);
 	u32 pend = __raw_readl(uirq->regs + S3C64XX_UINTP);
 	int base = uirq->base_irq;
 
+	chained_irq_enter(chip, desc);
+
 	if (pend & (1 << 0))
 		generic_handle_irq(base);
 	if (pend & (1 << 1))
@@ -41,6 +46,8 @@ static void s3c_irq_demux_uart(unsigned int irq, struct irq_desc *desc)
 		generic_handle_irq(base + 2);
 	if (pend & (1 << 3))
 		generic_handle_irq(base + 3);
+
+	chained_irq_exit(chip, desc);
 }
 
 static void __init s3c_init_uart_irq(struct s3c_uart_irq *uirq)