ARM i.MX serial: fix tx buffer overflows

[Sascha Hauer <s.hauer@pengutronix.de>]

This patch fixes occasional tx buffer overflows in the i.MX serial
driver which came from the fact that space in the buffer was checked
after sending the first byte. Also, fifosize is 32 bytes, not 8.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de

---
 drivers/serial/imx.c |   11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

Index: linux-2.6.20-rc3/drivers/serial/imx.c
===================================================================
--- linux-2.6.20-rc3.orig/drivers/serial/imx.c
+++ linux-2.6.20-rc3/drivers/serial/imx.c
@@ -154,7 +154,7 @@ static inline void imx_transmit_buffer(s
 {
 	struct circ_buf *xmit = &sport->port.info->xmit;
 
-	do {
+	while (!(UTS((u32)sport->port.membase) & UTS_TXFULL)) {
 		/* send xmit->buf[xmit->tail]
 		 * out the port here */
 		URTX0((u32)sport->port.membase) = xmit->buf[xmit->tail];
@@ -163,7 +163,7 @@ static inline void imx_transmit_buffer(s
 		sport->port.icount.tx++;
 		if (uart_circ_empty(xmit))
 			break;
-	} while (!(UTS((u32)sport->port.membase) & UTS_TXFULL));
+	}
 
 	if (uart_circ_empty(xmit))
 		imx_stop_tx(&sport->port);
@@ -178,8 +178,7 @@ static void imx_start_tx(struct uart_por
 
 	UCR1((u32)sport->port.membase) |= UCR1_TXMPTYEN;
 
-	if(UTS((u32)sport->port.membase) & UTS_TXEMPTY)
-		imx_transmit_buffer(sport);
+	imx_transmit_buffer(sport);
 }
 
 static irqreturn_t imx_rtsint(int irq, void *dev_id)
@@ -678,7 +677,7 @@ static struct imx_port imx_ports[] = {
 		.mapbase	= IMX_UART1_BASE, /* FIXME */
 		.irq		= UART1_MINT_RX,
 		.uartclk	= 16000000,
-		.fifosize	= 8,
+		.fifosize	= 32,
 		.flags		= UPF_BOOT_AUTOCONF,
 		.ops		= &imx_pops,
 		.line		= 0,
@@ -694,7 +693,7 @@ static struct imx_port imx_ports[] = {
 		.mapbase	= IMX_UART2_BASE, /* FIXME */
 		.irq		= UART2_MINT_RX,
 		.uartclk	= 16000000,
-		.fifosize	= 8,
+		.fifosize	= 32,
 		.flags		= UPF_BOOT_AUTOCONF,
 		.ops		= &imx_pops,
 		.line		= 1,