[PATCH v1 6/7] serial: imx: stop using USR2 in FIFO reading loop

[Sergey Organov]

The chip provides all the needed bits in the URXD0 register that we read
anyway for data, so get rid of reading USR2 and use only URXD0 bits
instead.

Signed-off-by: Sergey Organov <sorganov at gmail.com>
---
 drivers/tty/serial/imx.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index af4349fe6970..488d8119562e 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -892,27 +892,21 @@ static irqreturn_t __imx_uart_rxint(int irq, void *dev_id)
 	struct tty_port *port = &sport->port.state->port;
 	u32 usr2;
 
-	usr2 = imx_uart_readl(sport, USR2);
-
 	/* If we received something, check for 0xff flood */
+	usr2 = imx_uart_readl(sport, USR2);
 	if (usr2 & USR2_RDR)
 		imx_uart_check_flood(sport, usr2);
 
-	for ( ; usr2 & USR2_RDR; usr2 = imx_uart_readl(sport, USR2)) {
+	while ((rx = imx_uart_readl(sport, URXD0)) & URXD_CHARRDY) {
 		flg = TTY_NORMAL;
 		sport->port.icount.rx++;
 
-		rx = imx_uart_readl(sport, URXD0);
-
-		if (usr2 & USR2_BRCD) {
-			imx_uart_writel(sport, USR2_BRCD, USR2);
-			if (uart_handle_break(&sport->port))
-				continue;
-		}
-
 		if (unlikely(rx & URXD_ERR)) {
-			if (rx & URXD_BRK)
+			if (rx & URXD_BRK) {
 				sport->port.icount.brk++;
+				if (uart_handle_break(&sport->port))
+					continue;
+			}
 			else if (rx & URXD_PRERR)
 				sport->port.icount.parity++;
 			else if (rx & URXD_FRMERR)
-- 
2.30.1