[PATCH 20/33] serial: 8250: extract serial8250_set_afe()

Jiri Slaby (SUSE)
2025-06-11T10:04:01Z

serial8250_do_set_termios() consists of many registers and up flags
settings. Extract all these into separate functions. This time, setting
of MCR for UART_CAP_AFE ports.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
drivers/tty/serial/8250/8250_port.c | 32 +++++++++++++++--------------
1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 52385314c426..b15371838366 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2704,6 +2704,22 @@ static void serial8250_set_trigger_for_slow_speed(struct uart_port *port, struct
up->fcr |= UART_FCR_TRIGGER_1;
}

+/*
+ * MCR-based auto flow control. When AFE is enabled, RTS will be deasserted when the receive FIFO
+ * contains more characters than the trigger, or the MCR RTS bit is cleared.
+ */
+static void serial8250_set_afe(struct uart_port *port, struct ktermios *termios)
+{
+ struct uart_8250_port *up = up_to_u8250p(port);
+
+ if (!(up->capabilities & UART_CAP_AFE))
+ return;
+
+ up->mcr &= ~UART_MCR_AFE;
+ if (termios->c_cflag & CRTSCTS)
+ up->mcr |= UART_MCR_AFE;
+}
+
void
serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
const struct ktermios *old)
@@ -2729,21 +2745,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,

up->lcr = cval; /* Save computed LCR */
serial8250_set_trigger_for_slow_speed(port, termios, baud);
-
- /*
- * MCR-based auto flow control. When AFE is enabled, RTS will be
- * deasserted when the receive FIFO contains more characters than
- * the trigger, or the MCR RTS bit is cleared.
- */
- if (up->capabilities & UART_CAP_AFE) {
- up->mcr &= ~UART_MCR_AFE;
- if (termios->c_cflag & CRTSCTS)
- up->mcr |= UART_MCR_AFE;
- }
-
- /*
- * Update the per-port timeout.
- */
+ serial8250_set_afe(port, termios);
uart_update_timeout(port, termios->c_cflag, baud);

/*
--
2.49.0