serial: omap: simplify IRQ handling

quite a few changes here, though they are
pretty obvious. In summary we're making sure
to detect which interrupt type we need to
handle before calling the underlying interrupt
handling procedure.

Tested-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index dd3971f..d5a08cb 100644 (file)
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -351,33 +351,58 @@ static inline irqreturn_t serial_omap_irq(int irq, void *dev_id)
 {
        struct uart_omap_port *up = dev_id;
        unsigned int iir, lsr;
+       unsigned int type;
        unsigned long flags;
+       irqreturn_t ret = IRQ_NONE;
 
+       spin_lock_irqsave(&up->port.lock, flags);
        pm_runtime_get_sync(up->dev);
        iir = serial_in(up, UART_IIR);
-       if (iir & UART_IIR_NO_INT) {
-               pm_runtime_mark_last_busy(up->dev);
-               pm_runtime_put_autosuspend(up->dev);
-               return IRQ_NONE;
-       }
+again:
+       if (iir & UART_IIR_NO_INT)
+               goto out;
 
-       spin_lock_irqsave(&up->port.lock, flags);
+       ret = IRQ_HANDLED;
        lsr = serial_in(up, UART_LSR);
-       if (iir & UART_IIR_RLSI) {
+
+       /* extract IRQ type from IIR register */
+       type = iir & 0x3e;
+
+       switch (type) {
+       case UART_IIR_MSI:
+               check_modem_status(up);
+               break;
+       case UART_IIR_THRI:
+               if (lsr & UART_LSR_THRE)
+                       transmit_chars(up);
+               break;
+       case UART_IIR_RDI:
                if (lsr & UART_LSR_DR)
                        receive_chars(up, &lsr);
+               break;
+       case UART_IIR_RLSI:
+               if (lsr & UART_LSR_BRK_ERROR_BITS)
+                       receive_chars(up, &lsr);
+               break;
+       case UART_IIR_RX_TIMEOUT:
+               receive_chars(up, &lsr);
+               break;
+       case UART_IIR_CTS_RTS_DSR:
+               iir = serial_in(up, UART_IIR);
+               goto again;
+       case UART_IIR_XOFF:
+               /* FALLTHROUGH */
+       default:
+               break;
        }
 
-       check_modem_status(up);
-       if ((lsr & UART_LSR_THRE) && (iir & UART_IIR_THRI))
-               transmit_chars(up);
-
+out:
        spin_unlock_irqrestore(&up->port.lock, flags);
        pm_runtime_mark_last_busy(up->dev);
        pm_runtime_put_autosuspend(up->dev);
-
        up->port_activity = jiffies;
-       return IRQ_HANDLED;
+
+       return ret;
 }
 
 static unsigned int serial_omap_tx_empty(struct uart_port *port)