1 files changed, 21 insertions, 15 deletions

diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index faee021c27b0..856686d6dcdb 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -294,15 +294,6 @@ static int s3c24xx_serial_start_tx_dma(struct s3c24xx_uart_port *ourport,
 	if (ourport->tx_mode != S3C24XX_TX_DMA)
 		enable_tx_dma(ourport);
 
-	while (xmit->tail & (dma_get_cache_alignment() - 1)) {
-		if (rd_regl(port, S3C2410_UFSTAT) & ourport->info->tx_fifofull)
-			return 0;
-		wr_regb(port, S3C2410_UTXH, xmit->buf[xmit->tail]);
-		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
-		port->icount.tx++;
-		count--;
-	}
-
 	dma->tx_size = count & ~(dma_get_cache_alignment() - 1);
 	dma->tx_transfer_addr = dma->tx_addr + xmit->tail;
 
@@ -342,7 +333,8 @@ static void s3c24xx_serial_start_next_tx(struct s3c24xx_uart_port *ourport)
 	}
 
 	if (!ourport->dma || !ourport->dma->tx_chan ||
-	    count < ourport->min_dma_size)
+	    count < ourport->min_dma_size ||
+	    xmit->tail & (dma_get_cache_alignment() - 1))
 		s3c24xx_serial_start_tx_pio(ourport);
 	else
 		s3c24xx_serial_start_tx_dma(ourport, count);
@@ -736,7 +728,7 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id)
 	struct uart_port *port = &ourport->port;
 	struct circ_buf *xmit = &port->state->xmit;
 	unsigned long flags;
-	int count;
+	int count, dma_count = 0;
 
 	spin_lock_irqsave(&port->lock, flags);
 
@@ -744,8 +736,12 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id)
 
 	if (ourport->dma && ourport->dma->tx_chan &&
 	    count >= ourport->min_dma_size) {
-		s3c24xx_serial_start_tx_dma(ourport, count);
-		goto out;
+		int align = dma_get_cache_alignment() -
+			(xmit->tail & (dma_get_cache_alignment() - 1));
+		if (count-align >= ourport->min_dma_size) {
+			dma_count = count-align;
+			count = align;
+		}
 	}
 
 	if (port->x_char) {
@@ -766,14 +762,24 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id)
 
 	/* try and drain the buffer... */
 
-	count = port->fifosize;
-	while (!uart_circ_empty(xmit) && count-- > 0) {
+	if (count > port->fifosize) {
+		count = port->fifosize;
+		dma_count = 0;
+	}
+
+	while (!uart_circ_empty(xmit) && count > 0) {
 		if (rd_regl(port, S3C2410_UFSTAT) & ourport->info->tx_fifofull)
 			break;
 
 		wr_regb(port, S3C2410_UTXH, xmit->buf[xmit->tail]);
 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 		port->icount.tx++;
+		count--;
+	}
+
+	if (!count && dma_count) {
+		s3c24xx_serial_start_tx_dma(ourport, dma_count);
+		goto out;
 	}
 
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) {