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>

1 files changed, 38 insertions, 13 deletions

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index dd3971fe899f..d5a08cb5213d 100644
--- 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)