[PATCH 08/10] serial: arc_uart: simplify flags handling in arc_serial_rx_chars()

From: Jiri Slaby (SUSE)
Date: Wed Jul 12 2023 - 04:23:48 EST


* move the declaration of flg (with the initializer) to the loop, so
there is no need to reset it to TTY_NORMAL by an 'else' branch.
* use TTY_NORMAL as initializer above, not a magic zero constant
* remove the outer 'if' from this construct:
if (S & (A | B)) {
if (S & A)
X;
if (S & B)
Y;
}
* drop unlikely() as I doubt it has any benefits here. If it does,
provide numbers.

All four make the code easier to read.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@xxxxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxx>
---
drivers/tty/serial/arc_uart.c | 29 +++++++++++++----------------
1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c
index 4b2512eef577..835903488acb 100644
--- a/drivers/tty/serial/arc_uart.c
+++ b/drivers/tty/serial/arc_uart.c
@@ -195,8 +195,6 @@ static void arc_serial_start_tx(struct uart_port *port)

static void arc_serial_rx_chars(struct uart_port *port, unsigned int status)
{
- unsigned int ch, flg = 0;
-
/*
* UART has 4 deep RX-FIFO. Driver's recongnition of this fact
* is very subtle. Here's how ...
@@ -207,24 +205,23 @@ static void arc_serial_rx_chars(struct uart_port *port, unsigned int status)
* controller, which is indeed the Rx-FIFO.
*/
do {
+ unsigned int ch, flg = TTY_NORMAL;
+
/*
* This could be an Rx Intr for err (no data),
* so check err and clear that Intr first
*/
- if (unlikely(status & (RXOERR | RXFERR))) {
- if (status & RXOERR) {
- port->icount.overrun++;
- flg = TTY_OVERRUN;
- UART_CLR_STATUS(port, RXOERR);
- }
-
- if (status & RXFERR) {
- port->icount.frame++;
- flg = TTY_FRAME;
- UART_CLR_STATUS(port, RXFERR);
- }
- } else
- flg = TTY_NORMAL;
+ if (status & RXOERR) {
+ port->icount.overrun++;
+ flg = TTY_OVERRUN;
+ UART_CLR_STATUS(port, RXOERR);
+ }
+
+ if (status & RXFERR) {
+ port->icount.frame++;
+ flg = TTY_FRAME;
+ UART_CLR_STATUS(port, RXFERR);
+ }

if (status & RXEMPTY)
continue;
--
2.41.0