[Blackfin] serial driver: Clean up UART DMA code.

Start next TX DMA in tx dma handler instead of rx timer handler.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

1 files changed, 10 insertions, 15 deletions

diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index e059475c91ae..3a2aa7e277fa 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -84,7 +84,7 @@ static void bfin_serial_mctrl_check(struct bfin_serial_port *uart);
 static void bfin_serial_stop_tx(struct uart_port *port)
 {
         struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
-#ifndef CONFIG_BF54x
+#if !defined(CONFIG_BF54x) && !defined(CONFIG_SERIAL_BFIN_DMA)
         unsigned short ier;
 #endif
 
@@ -307,7 +307,6 @@ static void bfin_serial_tx_chars(struct bfin_serial_port *uart)
                 UART_PUT_CHAR(uart, uart->port.x_char);
                 uart->port.icount.tx++;
                 uart->port.x_char = 0;
-                return;
         }
         /*
          * Check the modem control lines before
@@ -376,28 +375,26 @@ static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart)
 
         if (!uart->tx_done)
                 return;
-
         uart->tx_done = 0;
 
+        if (uart_circ_empty(xmit) || uart_tx_stopped(&uart->port)) {
+                bfin_serial_stop_tx(&uart->port);
+                uart->tx_done = 1;
+                return;
+        }
+
         if (uart->port.x_char) {
                 UART_PUT_CHAR(uart, uart->port.x_char);
                 uart->port.icount.tx++;
                 uart->port.x_char = 0;
-                uart->tx_done = 1;
-                return;
         }
+
         /*
          * Check the modem control lines before
          * transmitting anything.
          */
         bfin_serial_mctrl_check(uart);
 
-        if (uart_circ_empty(xmit) || uart_tx_stopped(&uart->port)) {
-                bfin_serial_stop_tx(&uart->port);
-                uart->tx_done = 1;
-                return;
-        }
-
         spin_lock_irqsave(&uart->port.lock, flags);
         uart->tx_count = CIRC_CNT(xmit->head, xmit->tail, UART_XMIT_SIZE);
         if (uart->tx_count > (UART_XMIT_SIZE - xmit->tail))
@@ -471,8 +468,6 @@ void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart)
         int x_pos, pos;
         int flags = 0;
 
-        bfin_serial_dma_tx_chars(uart);
-
         spin_lock_irqsave(&uart->port.lock, flags);
         x_pos = DMA_RX_XCOUNT - get_dma_curr_xcount(uart->rx_dma_channel);
         if (x_pos == DMA_RX_XCOUNT)
@@ -513,9 +508,9 @@ static irqreturn_t bfin_serial_dma_tx_int(int irq, void *dev_id)
                 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                         uart_write_wakeup(&uart->port);
 
-                if (uart_circ_empty(xmit))
-                        bfin_serial_stop_tx(&uart->port);
                 uart->tx_done = 1;
+
+                bfin_serial_dma_tx_chars(uart);
         }
 
         spin_unlock(&uart->port.lock);