serial: exar: Fix stuck MSIs

[zynq/linux.git] / drivers / tty / serial / 8250 / 8250_port.c

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index e7765f010fe814a7e11ca010a7dbd31fd875413f..68fd045a7025047726860547ecd661b95d61ac80 100644 (file)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -47,6 +47,7 @@
 /*
  * These are definitions for the Exar XR17V35X and XR17(C|D)15X
  */
+#define UART_EXAR_INT0         0x80
 #define UART_EXAR_SLEEP                0x8b    /* Sleep mode */
 #define UART_EXAR_DVID         0x8d    /* Device identification */
 
@@ -1869,17 +1870,13 @@ static int serial8250_default_handle_irq(struct uart_port *port)
 static int exar_handle_irq(struct uart_port *port)
 {
        unsigned int iir = serial_port_in(port, UART_IIR);
-       int ret;
+       int ret = 0;
 
-       ret = serial8250_handle_irq(port, iir);
+       if (((port->type == PORT_XR17V35X) || (port->type == PORT_XR17D15X)) &&
+           serial_port_in(port, UART_EXAR_INT0) != 0)
+               ret = 1;
 
-       if ((port->type == PORT_XR17V35X) ||
-          (port->type == PORT_XR17D15X)) {
-               serial_port_in(port, 0x80);
-               serial_port_in(port, 0x81);
-               serial_port_in(port, 0x82);
-               serial_port_in(port, 0x83);
-       }
+       ret |= serial8250_handle_irq(port, iir);
 
        return ret;
 }
@@ -2177,6 +2174,8 @@ int serial8250_do_startup(struct uart_port *port)
        serial_port_in(port, UART_RX);
        serial_port_in(port, UART_IIR);
        serial_port_in(port, UART_MSR);
+       if ((port->type == PORT_XR17V35X) || (port->type == PORT_XR17D15X))
+               serial_port_in(port, UART_EXAR_INT0);
 
        /*
         * At this point, there's no way the LSR could still be 0xff;
@@ -2335,6 +2334,8 @@ dont_test_tx_en:
        serial_port_in(port, UART_RX);
        serial_port_in(port, UART_IIR);
        serial_port_in(port, UART_MSR);
+       if ((port->type == PORT_XR17V35X) || (port->type == PORT_XR17D15X))
+               serial_port_in(port, UART_EXAR_INT0);
        up->lsr_saved_flags = 0;
        up->msr_saved_flags = 0;