tty: xuartps: Consolidate TX handling

start_tx and the ISR used largely identical code to transmit data.
Consolidate that in one place.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 3ff6e3c2347c259417bd15b1215576d5140e601b..131a3117fbbbdab18b116047946e7d0be30b493a 100644 (file)
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -239,6 +239,41 @@ static void cdns_uart_handle_rx(struct uart_port *port, unsigned int isrstatus)
        tty_flip_buffer_push(&port->state->port);
 }
 
+static void cdns_uart_handle_tx(struct uart_port *port)
+{
+       unsigned int numbytes;
+
+       if (uart_circ_empty(&port->state->xmit)) {
+               writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IDR);
+               return;
+       }
+
+       numbytes = port->fifosize;
+       while (numbytes && !uart_circ_empty(&port->state->xmit) &&
+              !(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)) {
+               /*
+                * Get the data from the UART circular buffer
+                * and write it to the cdns_uart's TX_FIFO
+                * register.
+                */
+               writel(port->state->xmit.buf[port->state->xmit.tail],
+                       port->membase + CDNS_UART_FIFO);
+               port->icount.tx++;
+
+               /*
+                * Adjust the tail of the UART buffer and wrap
+                * the buffer if it reaches limit.
+                */
+               port->state->xmit.tail =
+                       (port->state->xmit.tail + 1) & (UART_XMIT_SIZE - 1);
+
+               numbytes--;
+       }
+
+       if (uart_circ_chars_pending(&port->state->xmit) < WAKEUP_CHARS)
+               uart_write_wakeup(port);
+}
+
 /**
  * cdns_uart_isr - Interrupt handler
  * @irq: Irq number
@@ -250,7 +285,7 @@ static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
 {
        struct uart_port *port = (struct uart_port *)dev_id;
        unsigned long flags;
-       unsigned int isrstatus, numbytes;
+       unsigned int isrstatus;
 
        spin_lock_irqsave(&port->lock, flags);
 
@@ -262,40 +297,8 @@ static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
        if (isrstatus & CDNS_UART_RX_IRQS)
                cdns_uart_handle_rx(port, isrstatus);
 
-       /* Dispatch an appropriate handler */
-       if ((isrstatus & CDNS_UART_IXR_TXEMPTY) == CDNS_UART_IXR_TXEMPTY) {
-               if (uart_circ_empty(&port->state->xmit)) {
-                       writel(CDNS_UART_IXR_TXEMPTY,
-                                       port->membase + CDNS_UART_IDR);
-               } else {
-                       numbytes = port->fifosize;
-                       /* Break if no more data available in the UART buffer */
-                       while (numbytes--) {
-                               if (uart_circ_empty(&port->state->xmit))
-                                       break;
-                               /* Get the data from the UART circular buffer
-                                * and write it to the cdns_uart's TX_FIFO
-                                * register.
-                                */
-                               writel(port->state->xmit.buf[
-                                               port->state->xmit.tail],
-                                       port->membase + CDNS_UART_FIFO);
-
-                               port->icount.tx++;
-
-                               /* Adjust the tail of the UART buffer and wrap
-                                * the buffer if it reaches limit.
-                                */
-                               port->state->xmit.tail =
-                                       (port->state->xmit.tail + 1) &
-                                               (UART_XMIT_SIZE - 1);
-                       }
-
-                       if (uart_circ_chars_pending(
-                                       &port->state->xmit) < WAKEUP_CHARS)
-                               uart_write_wakeup(port);
-               }
-       }
+       if ((isrstatus & CDNS_UART_IXR_TXEMPTY) == CDNS_UART_IXR_TXEMPTY)
+               cdns_uart_handle_tx(port);
 
        writel(isrstatus, port->membase + CDNS_UART_ISR);
 
@@ -502,7 +505,7 @@ static int cdns_uart_clk_notifier_cb(struct notifier_block *nb,
  */
 static void cdns_uart_start_tx(struct uart_port *port)
 {
-       unsigned int status, numbytes = port->fifosize;
+       unsigned int status;
 
        if (uart_tx_stopped(port))
                return;
@@ -519,31 +522,11 @@ static void cdns_uart_start_tx(struct uart_port *port)
        if (uart_circ_empty(&port->state->xmit))
                return;
 
-       while (numbytes-- && ((readl(port->membase + CDNS_UART_SR) &
-                               CDNS_UART_SR_TXFULL)) != CDNS_UART_SR_TXFULL) {
-               /* Break if no more data available in the UART buffer */
-               if (uart_circ_empty(&port->state->xmit))
-                       break;
-
-               /* Get the data from the UART circular buffer and
-                * write it to the cdns_uart's TX_FIFO register.
-                */
-               writel(port->state->xmit.buf[port->state->xmit.tail],
-                               port->membase + CDNS_UART_FIFO);
-               port->icount.tx++;
+       cdns_uart_handle_tx(port);
 
-               /* Adjust the tail of the UART buffer and wrap
-                * the buffer if it reaches limit.
-                */
-               port->state->xmit.tail = (port->state->xmit.tail + 1) &
-                                       (UART_XMIT_SIZE - 1);
-       }
        writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_ISR);
        /* Enable the TX Empty interrupt */
        writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IER);
-
-       if (uart_circ_chars_pending(&port->state->xmit) < WAKEUP_CHARS)
-               uart_write_wakeup(port);
 }
 
 /**